Vol 1(2), September 2011 - Webs 2...Journal of Ornamental and Horticultural Plants, 1(2): 55-61,...

Investigation of Some Vegetative and Reproductive Characteristics of Five AppleCultivars in ‘Guttingen V’ System............................................................................55Ahmad Dadashpour, Sasan Sadegh Hasani, Seyed Fazel Mirahmadi,

The Influence of Water-Deficit Stress on Growth, Water Relations and SoluteAccumulation in Wild Jujube (Ziziphus lotus)............................................................63M. Maraghni, M. Gorai and M. Neffati

Increasing Shelf Life and Maintaining Quality of Mango by Postharvest Treatmentsand Packaging Technique..................................................................................................73M.M. Molla, M.N.Islam, M.A.Muqit, K.A.Ara, M.A.H.Talukder

Character Association in Improved Mulberry Genotypes Exhibiting DelayedLeaf Senescence.............................................................................................85 Doss, S. G., Chakraborti, S. P., e-Vijayan, K., Ghosh, P. D.

Influence of Different Colored Plastic Mulch on the Growth of Lettuce(Lactuca sativa)................................................................................................97Edmar N. Franquera

Effect of Salicylic Acid on Somatic Embryogenesis and Chlorogenic Acid Levelsof Carrot (Daucus carota cv. Nantes) Explants.......................................................105S. S. Hosseini, K. Mashayekhi, M. Alizadeh, P. Ebrahimi

The Effects of Different Floral Preservative Solutions on Vase life of LisianthusCut Flowers....................................................................................................115M. Kiamohammadi, D. Hashemaabadi

Study on Some Chemical Compounds on the Vase Life of Two Cultivars ofCut Roses.........................................................................................................123S. Mohammadi Ostad Kalayeh, Y. Mostofi, M. Basirat

Vol 1(2), September 2011

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Investigation of Some Vegetative and Reproductive Characteristics of Five Apple Cultivars in‘Guttingen V’ System...............................................................................................................................55

The Influence of Water-Deficit Stress on Growth, Water Relations and Solute Accumulation in WildJujube (Ziziphus lotus)...................................................................................................................................63

Increasing Shelf Life and Maintaining Quality of Mango by Postharvest Treatments and PackagingTechnique...............................................................................................................................................................73

Character Association in Improved Mulberry Genotypes Exhibiting Delayed LeafSenescence..................................................................................................................................85

Influence of Different Colored Plastic Mulch on the Growth of Lettuce (Lactuca sativa) ............................97

Effect of Salicylic Acid on Somatic Embryogenesis and Chlorogenic Acid Levels of Carrot(Daucus carota cv. Nantes) Explants....................................................................................................105

The Effects of Different Floral Preservative Solutions on Vase life of Lisianthus CutFlowers......................................................................................................................115

Study on Some Chemical Compounds on the Vase Life of Two Cultivars of Cut Roses...........................123

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Journal of Ornamental and Horticultural Plants, 1(2): 55-61, September, 2011 55

Investigation of Some Vegetative and Reproductive

Characteristics of Five Apple Cultivars in ‘Guttingen V’ System

Orchard intensification is motivated by the desire to produce fruitearly in the life of the orchard to rapidly recover establishment costs. Inten-sification is possible using dwarfing rootstocks that control tree size, induceearly cropping and produce large quantities of fruit compared to the amountof wood produced. Therefore, this study attempts to compare some yieldand fruit properties of five apple cultivars grown in Karaj, Iran. Theconcerned apple cultivars were ‘Golab-kohans’, ‘Fuji’, ‘Starking’, ‘Delbarestival’ and ‘Gala’ that were grafted on M.9 rootstock which were trained in‘Gutingen V’ system. All trees were planted in winter 2005. The trees wereirrigated since the second year after planting as drip irrigation. Resultsshowed that ‘Golab-kohans’ had the highest vegetative traits include TCSA(11.30 cm2), shoot growth (185.30 cm) and tree height (325.32 cm). Also‘Delbar estival’ had the highest amount of yield / tree (6.2 kg), yieldefficiency (1 kg/cm2) and fruit weight (147.52 g). ‘Starking’ owned thehighest fruit firmness (15.27 kg/cm2), dry matter (32.86 %) and ash (0.82%). In addition, ‘Gala’ had the most TSS (16.12), pH (4.02), fruit length(5.79 cm) and fruit diameter (6.68 cm). ‘Fuji’ had the greatest L/D (0.89),TA (0.74 %) and fruit sunburn (56.23 %).

Keywords: Commercial apple cultivar, Intensive orchard system, Vegetative and reproductive characteristics,

Abstract

Ahmad Dadashpour*,Department of Horticulture, University College of Agriculture & Natural Resources, University of Tehran,Karaj, IranSasan Sadegh Hasani,Department of Horticulture, University College of Agriculture & Natural Resources, University of Tehran,Karaj,Iran.Seyed Fazel Mirahmadi,Department of Horticulture, University College of Agriculture & Natural Resources, University of Tehran,Karaj,Iran.

*Corresponding author’s email: [email protected]

Journal of Ornamental and Horticultural Plants, 1(2): 55-61, September, 201156

INTRODUCTION

In the last 60 years, numerous planting systems for modern orchards have been developed.They all have the goals of high early yields, high sustained yields and superior fruit quality. Themove to high planting densities has been driven primarily by the need for early production to payback the primary investment cost and improve profitability. With most modern high densityplanting systems, a small but significant yield is expected during the second growing season ofthe orchard. The second reason for the change in orchard production systems has been the need toreduce tree size to facilitate management. Large trees are costly and hard to prune, spray andharvest. In addition, fruit color is often poor in the center of the canopy of large trees (Ferree andWarrington, 2003).

Small trees of uniform size are the aim for the future so that safer, more efficient sprayingpractices can be adopted. Trees must be trained and pruned to achieve a manageable uniform size,a balance between growth and regular yields, and to allow good penetration of light and it’sdistribution to the tree centre (Malavolta and Croos, 2009). During planting a grower must makefour key decisions about: a) the rootstock, b) the variety, c) the tree spacing and d) the trainingsystem. Research on apple trees using dwarf rootstocks in intensive planting systems has beencarried out in different countries (Barritt et al., 1995). The switch to smaller trees and higher treeplanting densities has allowed significant improvements in fruit quality (Robinson, 2007). Modernorchards planting systems are based on higher tree densities with 1000-6000 tree/ha and some upto 10000 tree/ha (Robinson, 2003). Over the last 25 years, the V systems have been becomeincreasingly popular and account for a significant portion of new fruit plantings in developedcountries. The first benefit of V systems is high yield/ha (Hutton et al., 1987; Ende et al., 1987;Robinson and Lakso, 1989; Robinson, 1992; Sosna and Czaplicka, 2008), high levels of light in-terception (Robinson and Lakso, 1991; Widmer, 2005) and improved fruit quality (Ende et al.,1987). Fruit quality is a combination of appearance, flavor, texture and nutritional value. It isaffected by pre-harvest factors such as climatic conditions and cultural methods (Licznar, 2006).Orchard trials with V-shaped canopies have shown to be highly productive and highly efficient atconverting light energy into fruit (Ferree and Warrington, 2003). Previous study (Strikic et al.,2007) showed that there are significant differences in growth and productivity between local andforeign cultivars in fruits trained to a high density system.

The aim of this study was to evaluation of some vegetative and reproductive traits of fiveapple cultivars grafted on M.9 in a ‘Gutingen V’ system that are more cultivated in Karaj climate.

MATERIALS AND METHODS

Plant Material and Experimental Design

The present study was conducted during 2006, 2007 and 2008 at the experimental field ofthe Horticultural Research Station of the University of Tehran, Karaj, Iran. The results of trialsobtaned in a 3-year-old apple trees ‘Gutingen V’ system include 5 cultivars: ‘Golab-kohans’,‘Fuji’, ‘Starking’, ‘Delbar estival’ and ‘Gala’ grafted on dwarfing M.9 rootstock. The averageannual maximum temperature of the region is 13.7 °C with an annual rainfall of 254 mm. Soil ofthe research station was clay-loam. The soil between the rows was mowed, and the strips in therow were fallowed with herbicides. Twenty representative trees in each replication were selectedfor sampling and data collection. The four replicates were arranged in a randomized completelyblock design (RCBD). The field and laboratory's data were analyzed using SAS software and theDuncan mean separation test.

Horticultural Traits

TCSA (20 cm above the graft union) was measured with a hand caliper at the end of thegrowing season in November and then converted to TCSA in cm2. Moreover, shoot growth was


measured by average current season growth of 5 branches in each tree (cm). In addition, yield oftree was recorded at harvest time. Yield efficiency was measured as yield per tree divided toTCSA in November, as well.

Fruit Properties

Individual fruit length, diameter and length to diameter ratio (L/D) were measured on 5-fruit random samples from each tree. In fact, fruit length and fruit diameter were measured usinga vernier caliper; fruit fresh weight was determined using a Mettler PC 8000 scale; fruit firmnesswas measured using a penetrometer (Instron Universal Machine, Model 1011). Total solublesolids (TSS) were measured with a Bausch and Lomb Abbe 3L refractometer; juice pH wasmeasured using an Accument pH meter 925 (Fisher Scientific pittsburgh, PA); dry matter contentwas determined from fresh and dry weight differences after drying at 70°C for 48 h. 1 g of drymatter was ashed in a Gaallankamp furnace at 550°C for 6 h. Titrable acids (TA) were determinedusing an Aminex HPX-87H column, run at 65°C and 4 mM sulphuric acid.

RESULTS AND DISCUSSIONS

Tree Height, TCSA and Shoot Growth

In the investigated cultivars, maximum tree height (325.32 cm), shoot growth (185.30 cm)and TCSA (11.30 cm2) were obtained in ‘Golab-kohans’ that means this cultivar was generallymore vigorous than other trees which may be result of a higher degree of shading than othercultivars (Table 1). Short-term shade causes an enhanced retention of assimilates in vegetativesinks, reduction in carbohydrate availability to the fruitlets, limited fruit growth rates andeventually fruit shedding (Byers et al., 1991; Kondo and Takahashi, 1987). In addition, Golab-kohans probably because of its early fruit harvest (the earliest harvested cultivar) had longerperiod for vegetative growing, resulted in more vegetative characteristics. Also this researchimplies that trees with the highest vegetative growth generally produce the lowest yield per tree,confirming previous study (Strikic et al., 2007). Tree growth and development can be markedlyinfluenced by both cultivar and rootstock (Hirst and ferree, 1995). Differences in TCSA indicatethat rootstock controls the tree size (Dolp and Proebsting, 1989). In fact in this study the rootstock(M.9) has controlled the tree size of ‘Delbar estival’ more than other cultivars resulted to thelowest TCSA (6.15 cm2) and the greatest yield (6.20 kg) in 2008. Other study also found thatscion and rootstock interaction influences the size and attributed rootstock (Hirst and ferree,1995). Small TCSA produced by ‘Delbar estival’ may be a genetic trait transferred from therootstock to the scion.

Yield Characteristics

The first production was obtained one year after planting, but this was relatively poor (datanot shown). By the secondary year after planting, the greatest yield per tree (1.48 kg tree-1) andyield efficiency (0.47 kg cm-2) were related to ‘Delbar estival’. So, the yield ranging was 3.71-6.20 kg tree-1 in 2008 (Table 2). This research showed that trees began to bearing in the secondyear, with yield increasing in the subsequent year. In fact, the ‘V system/M.9’ combinationpermitted early fruiting, confirming previous studies (Platon, 2007; Hampson et al., 2002). Inaddition, the most TCSA and the lowest yield resulted in the lowest yield efficiency in ‘Golab-kohans’ (Fig.1a). Although it is assumed that trees on dwarf rootstocks have limited vegetativegrowth resulting to higher yield (Robinson, 2007) but may be differences between cultivars inthis study (with a same rootstock) has been resulted from different morphological traits, accordingBarritt et al., (1995).

Researches show that yield linearly is related to light interception (Robinson and Lakso,1989; Robinson, 2007) but the best time for calculating the light interception is in the 4th or more


year (Hampson et al., 2002). Elfving and Schechter (1993) reported that annual yields per tree for‘Starkspur Supreme Delicious’ trees on nine dwarfing rootstocks were related linearly to thenumber of fruits per tree at harvest, independent of rootstock. They concluded that there is alinear relationship between yield and fruit count per tree and suggested that the sink strength of anapple crop is almost proportional to the number of fruit per tree.

According to the results, ‘Delbar estival’ trees represent a generally more efficient portion,at least in the early stages of orchard life, for apple cultivation using V-shape systems in Iran’sclimate conditions.

Fruit Weight, Fruit Length, Fruit Diameter and L/D

The maximum fruit weight (147.52 g) was recorded in ‘Delbar estival’. The greatest fruitlength (5.79 cm) and fruit diameter (6.68 cm) were shown in ‘Gala’. The highest L/D (0.89) wasrecorded in ‘Fuji’, a good cultivar due to its visual appearance (Table 4). Although fruit number isassumed to be the most relevant component of yield (Derkacz and Norton, 2000), in this casegreater yields in ‘Delbar estival’ trees are not due to a greater number of fruits (data not shown),but it is due to bigger fruits. ‘Fuji’’ had the highest L/D (0.89), i.e., this cultivar has moremarketable value than other cultivars although this characteristic is affected by both genetic andenvironmental factors. L/D (≥1) is a criteria for marketing in apple but fruits of this study had L/D<1, probably was due to warm nights in Karaj, resulting to insufficient cell elongation at night.Studies have shown that fruit size is smaller on the most dwarfing rootstock and large with thesemi-vigorous and vigorous rootstocks such as M.27, M.26, and P.18 (Barritt et al., 1995). Thephysiological mechanisms by which dwarfing rootstocks affect fruit characteristics can be due tothe reduction in transport of nutrients and hormones, especially gibberellins across the scion/rootstockunion. In this research the fruits of ‘Delbar estival’ were affected by the dwarf rootstock (M.9)less than other cultivars, because they resulted in the largest fruits.

TSS, Dry Matter, Firmness and Fruit Sunburn

The highest TSS content in ‘Gala’ (18) (Table 4) may be explained by differences in leafarea, as suggested by Hudina and Stamper (2002) or by a presumed higher degree of shading forother cultivars (Garriz et al., 1996; Garriz et al., 1998). High exposure of fruit and leaves to lightmay increase TSS in the fruit compared to fruit that has poor exposure to light (Tustin et al.,1988). ‘Starking’ had the highest dry matter (32.86 %), thus it can be said this cultivar has thehighest organic and mineral materials (Table 4). Total dry matter is related to total lightinterception (Palmer and Jackson 1974; Monteith, 1977). The highest fruit sunburn percentage(56.23 %) was shown in ‘Fuji’ due to latest harvesting (Table 4). ‘Golab-kohans’ and ‘Delbarestival’ had the lowest fruit sunburn (0%) resulting from an early fruit harvest. The highest (15.27kg cm-2) and the lowest (8.89 kg cm-2) firmness were obtained in ‘Starking’ and ‘Delbar estival’,respectively (Table 3,4). Firm fruit in ‘Starking’ may be due to small fruit size, confirming aprevious study (Drake et al., 1988). In addition, difference in firmness may have resulted fromgenetic traits in each cultivar (King et al., 2000).

TA, Ash and pH

The TA content differed among cultivars. In ‘Fuji’ the average of TA was 0.74, in ‘Golab-kohans’ 0.43, in ‘Delbar estival’ 0.37, in ‘Gala’ 0.35 and in ‘Starking’ 0.22 (Table 4). In fact,‘Fuji’ fruits are the sourest. The greatest ash (0.82 %) was obtained in ‘Starking’ (Table 4),implying that this cultivar has good nutrition resulting in a higher nutritional value. In this study‘Gala’ had the highest pH (4.02); the lowest pH was in ‘Starking’ (3.28) (Table 4) which mayhave resulted from morphological differences, confirming a previous study (Platon, 2007). Ingeneral, juice pH ranged from 3.39 to 3.99 for the rootstock/cultivar combination. These results


show that acidity generally varies with the cultivar, confirming previous study (Platon, 2007),that may have resulted from lower shading in ‘Starking’. These results show that acidity generallyvaries with cultivar, confirming previous studies (Platon, 2007). According to the results, thesecultivars represent a generally more efficient portion, at least in the early stages of orchard life,for apple cultivation using V-shape systems in Karaj’s climatic conditions.

ACKNOWLEDGMENT

We would like to gratefully thank all the members of the Department of Horticulture,College of Agriculture and Natural Resource, University of Tehran for providing the facilities tocarry out this work and their suggestions.

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Elfving, D. C. and Schechter, I. 1993. Fruit count, fruit weight, and yield relationship in ‘Delicious’ apple tree on nine rootstocks. J. Hort. Sci. 28: 793-795.

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Kondo, S. and Takahashi, Y. 1987. Effects of high temperature in the nighttime and shading in the


daytime on the earlydrop of apple fruit ‘Starking Delicious’. J. Jpn. Soc. Hort. Sci. 56: 142-150. Licznar, M. 2006. Training system and fruit qualaity in the apple cultivar ‘Jonagold’. J. Fruit

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Cultivar

Trunk-cross sectional area

TCSA

(cm2)

Shoot growth

(cm)

Tree height

(cm)

Delbar estivalStarkingGalaGolab-kohansFuji

2006

1.43 b1.89 a1.83 a2.14 a1.83 a

2007

3.14 d4.12 dc4.78 bc7.30 a5.32 b

2008

6.15 d7.10 dc7.56 bc11.30 a8.43 b

2006

21.03 b22.60 b20.53 b24.03 a20.53 b

2007

52.83 d69.45 c74.48 bc100.58 a89.77 b

2008

120.34 d141.71 c165.31 bc185.30 a171.10 b

2006

133.56 b97.680 bc111.34 bc94.560 c133.73 c

2007

220.38 dc208.56 d242.19 b271.63 a259.25 ab

2008

300.24 c285.12 d312.25 b325.32 a320.45 ab

Table 1. Vegetative traits in 5 apple cultivars trained as Guttingen V system in 2006-2008.

Table 2. Yield in 5 apple cultivars trained as Guttingen V system in 2006-2008.

Table 3. Fruit properties in 5 apple cultivars trained as Guttingen V system in 2007.

Table 4. Fruit properties in 5 apple cultivars trained to Guttingen V system in 2008.

Tables

CultivarYield per tree

(kg)

Yield Efficiency

(kg/cm2)


2006

-----

2007

1.48 a0.92 b0.47 bc0.28 c0.52 bc

2008

6.2 a5.2 b

4.56 bc3.71 c4.80 bc

2006

-----

2007

0.47 a0.22 b0.098 c0.03 c0.097 c

2008

1.00 a0.73 ab0.65 ab0.32 c0.56 b

Trait

Cultivar

Fruit

Firmness

(kg cm-2)

Fruit

Weight

(g)

Fruit Diameter

(cm)

Fruit

Length

(cm)

L/D TSS TA

(%)pH Dry Matter

(%)

Ash

(%)

Fruit

sunburn

(%)


10.47 b15.82 a14.59 a10.48 b15.13 a

131.29 a85.71 c

102.01 b70.72 d106.12 b

6.72 a5.72 c6.13 b5.58 c6.17 b

5.91 a4.62 c5.16 b4.76 c5.10 b

0.87 a0.79 c0.84 b0.84 b0.82 b

13.43 c12.23 c16.12 a10.75 d15.24 b

0.64 ab0.72 a0.57 b0.44 c0.69 ab

3.34 d3.60 c3.68 b4.85 a3.55 c

16.07 d18.08 c20.28 b14.75 e21.70 a

0.34 b0.40 b0.65 a0.42 b0.64 a

0.00 c33.83 b43.92 ab

0.00 c56.91 a

Trait

Cultivar

Fruit

Firmness

(kg cm-2)

Fruit

Weight

(g)

Fruit Diameter

(cm)

Fruit

Length

(cm)

L/D TSS TA

(%)pH Dry Matter

(%)

Ash

(%)

Fruit

sunburn

(%)


10.24 c15.27 a13.35 b8.89 d13.75 b

147.52 a110.43 b137.58 ab108.22 b 123.75 ab

6.47 a4.36 b6.68 a6.05 a6.14 a

5.56 a3.50 b5.79 a5.23 a5.35 a

0.85 a0.77 b0.86 a0.857 a0.89 a

16.72 b13.92 c

18 a11.09 d14.16 c

0.37 ab0.22 b0.35 ab0.35 ab0.74 a

3.66 c3.28 d4.02 a3.65 c3.80 b

10.51 b32.86 a17.27 ab32.63 a20.80 ab

0.63 ab0.82 a0.67 ab0.45 b0.48 b

0.00 c31.58 b39.21 b0.00 c56.23 a

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The Influence of Water-Deficit Stress on Growth,

Water Relations and Solute Accumulation in Wild

Jujube (Ziziphus lotus)

Wild jujube, Ziziphus lotus, is a multipurpose xerophytic shrub of theRhamnaceae family widely distributed in arid and semi-arid regions ofTunisia, where it occupies most soil types. The fruit is the edible part of theplant by local population. The reintroduction of this shrub requires thecontrol of its multiplication in response to water shortage. This study aimsto evaluate growth and water relations of wild jujube seedlings under waterdeficit stress. After multiplication and growth under well-watered conditions,water deficit stress was imposed to seedlings by controlled deficit irrigationto 40 and 70% of field capacity (FC) for 15, 30 and 45 days. Soil of controlplants was maintained at 100% FC throughout the experiments. Best growthwas recorded for control plants, while water deficit successively reduceddry matter production and leaf number per plant. In addition, relative watercontent of leaves and branch water potential decreased significantly undersevere drought stress. Plants subjected to 40% FC, accumulated respectively,1.5 and 15-fold more soluble sugars and proline in leaves than controls.There was a strong negative relationship identified between leaf prolineconcentration and branch water potential with R2 = 0.85, reflecting the im-portance of this amino acid ability for osmotic adjustment in Z. lotus.

Keywords: Drought, Growth, Osmotic adjustment, Proline, Soluble sugars, Water potential, Ziziphus lotus.

Abstract

M. Maraghni1, M. Gorai1 and M. Neffati.Laboratoire d’Ecologie PastoraleInstitut des Régions AridesMédenine 4119Tunisia1 Authors contributed equally to this work

*Corresponding author e-mail: [email protected]


INTRODUCTION

Drought stress is considered to be the main environmental factor limiting plant growth andyield of many agronomic and horticultural crops, especially in semi-arid areas (Boyer, 1982). InMediterranean-type ecosystems, seasonal water shortage is the main factor constraining survivaland growth of plants (Di Castri et al., 1981). Accordingly, agronomic or horticultural plantsadapted to survive under these conditions are resistant to recurrent summer drought and thereforeoffer an excellent model to study their life strategies (Von Willert et al., 1990; Munné-Bosch et al.,2009). Soil depth and texture are considered the most important edaphic properties that influencethe moisture regime in arid environments with episodic rainfall (Grigg et al., 2008). To date, agreat deal of effort has been focused on physiological process underlying plant responses todrought stress (Van Hees, 1997).

Mediterranean shrubs are excellent models to study plant responses to drought since theyare generally very resistant and well adapted to decreased soil water availability during thesummer. Several native species are potentially interesting under aspects of dune stabilization andextension of plant cover, including some Ziziphus species. The ability of some species of thegenus Ziziphus to withstand drought has been attributed to a combination of avoidance andtolerance mechanisms, including osmotic adjustment and sensitive stomatal closure (Arndt et al.,2001; Pareek, 2001).

The genus Ziziphus (Rhamnaceae) includes evergreen or deciduous trees or shrubs whichare usually armed with unequal stipular spines. In Tunisia, Ziziphus is represented by 3 species: Z.spina-christi (L.) Willd, Z. vulgaris Lam. and Z. lotus (L.) Lam. (Maraghni et al., 2010). Thelatter species, known as "Sedra", is indigenous to Tunisia. The edible fruit called a nabk is asubglobose dark yellow drupe (c. 1–1.5 cm in diameter) at maturity (Maraghni et al., 2010). It ishas a wide ecological and geographical distribution and grows under a variety of environmentalconditions (Maraghni et al., 2010” Gorai et al., 2010).

Ziziphus lotus differs from the other two species by its deciduous shrubby habit withintricately branched stems and smaller flowers and fruits (Jafri, 1977). It is a shrub that reaches 2–5 m and is found in depressions with deep sandy soil. Mounds composed of wind-borne sedimentthat accumulated around Z. lotus thorn scrub have long been reported from the Tunisian stepperegions (Tengberg and Chen, 1998). Ziziphus lotus is dormant from October through March andflowers in May and June and produce fruits in August (Gorai et al., 2010). It is browsed bylivestock and its leaves are valuable animal forage and fodder under open grazing conditions.

As dried powder leaves and fruit were typically used as emollient in the treatment of boils(Le Floc’h, 1983). Recently, the anti-inflammatory, analgesic and anti-spasmodic activities of thisplant were demonstrated in rodents (Borgi et al., 2008; Borgi and Chouchane, 2009). These char-acteristics make Z. lotus a valuable multipurpose shrub for semi-arid to arid ecological areas. Toour knowledge, no study has, as yet, been carried out on the effects of water deficit stress on thisarid fruit plant. Therefore, the present investigation was undertaken to characterize the potentialof cultivating Z. lotus under conditions of low water availability.


Plant Material and Growth Conditions

Mature fruits were collected in September 2007 from plants in natural Z. lotus populationsgrowing at Samaâlyate (33°17'N, 10°55'E; Ben Gardane, Southeast Tunisia) where annual meanprecipitation is around 186 mm and annual mean temperature is 19.4°C with a minimumtemperature 3.9°C in January and a maximum temperature 35.9°C in August. Fruits were cleanedand stored for six months in the seed bank of the Laboratoire d'Ecologie Pastorale at the Institutdes Régions Arides, Médenine (20°C, 30% RH).

After removing pulps from fruits, endocarps were cracked using a manual peeler. The pots


filled with a mixture of sand and soil (1:2, by volume), three seeds were planted per pot (20 cm indiameter) and watered to field capacity (FC) to facilitate germination. The maximum germinationwas observed after 15 days. At this stage, the seedlings were thinned to one per pot. Plants weregrown in a growth chamber under the following conditions: 25±1°C temperature, 40% day and75% night relative humidity and 16 h light/8 h dark regime with 250 μmol m–2 s–1 photosyntheticflux density (PFD).

Individual plants of uniform stage of development and size were selected. The experimentwas arranged in a completely randomized design (CRD) with three levels of water deficit stress(100, 70 and 40% FC) × four replicates. After 3 months of ample irrigation (100% FC), the waterdeficit stress was applied and plants were harvested after 15, 30 and 45 days. Regular weightingsof pots and plants (every 2 days) enabled to restore the moisture of soil with nutrient solution(Hewitt, 1966) at 40, 70 and 100% FC. Fresh mass (FM) and dry mass (DW) of shoots and rootsof each plant were determined after counting all leaves. Leaves were dried using a LDC-1lyophilizer (Martin Christ Gefriertrocknungsanlagen GmbH, Osterode am Harz, Germany) todetermine proline and soluble sugar concentrations and dry mass of roots was obtained after ovendrying (60°C, 48 h).

Water Relations

Leaf relative water content (RWC) was estimated by recording the turgid mass (TM) of freshleaf samples by keeping them in distilled water overnight under low light conditions, followed byoven dry for 48 h at 60°C for dry mass measurement. Leaf RWC was calculated as RWC (%) =(FM–DM)/(TM–DM) × 100. The branch water potential (Ψw) was measured using a pressurechamber (PMS Instrument Co., Corvallis, Oregon, USA) according to Scholander et al., (1965).

Determination of Organic Solutes

Free proline was assayed spectrophotometrically by the ninhydrin method (Bates et al.,1973). The plant material was homogenized in 3% aqueous sulfosalicylic acid and the homogenatewas centrifuged at 14,000 rpm. The supernatant was used for the estimation of the prolineconcentration. The reaction mixture consisted of 2 ml of acid ninhydrin and 2 ml of glacial aceticacid, which was boiled at 100°C for 1 h. After termination of reaction in ice bath, the reactionmixture was extracted with 4 ml of toluene, and absorbance was read at 520 nm using L-prolineas standard. The leaf proline concentration was expressed on dry weight basis.

Soluble sugars were quantified following the phenolsulfuric acid method (Robyt andWhite, 1987). 100 mg dry weight of shoots was extracted in 80% (v/v) methanol heated to 70°Cin a water bath. The extract was then centrifuged at 5,000 × g for 10 min. The supernatant wasused for the estimation of soluble sugars concentrations. The reaction mixture consisted of 1 ml5% phenol and 5 ml 98% sulphuric acid. Once the extract had cooled, its absorbance wasdetermined at 490 nm using D-glucose as standard.

Statistical Analysis

Statistical analyses, including test for homogeneity of variance, were performed usingSPSS for Windows, version 11.5. The experimental data were analyzed with a one-way ANOVAto determine if significant differences were present among means. A Tukey test was used todetermine the significant (P < 0.05) differences among treatments.

RESULTS

Growth Analysis

Water deficit significantly reduced whole plant biomass accumulation after 30 days oftreatment. At the end of experimental period, the dry matter production of plants was 48 and 35%


of the controls when treated with 70 and 40% FC, respectively (Fig. 1A). The plants receiving awater regime of 100% FC have the highest number of leaves. In 45-day water-stressed plants, thisparameter decreased significantly by 56 and 82% as compared to controls, respectively, at 70 and40% FC (Fig.1B). Water-deficit stress increased dry matter allocation to the roots (data notshown). On the other hand, the root to shoot DW ratio increased significantly under severe stresstreatment from 45 days (Fig. 2). This ratio allows evaluating the effect of water-deficit stress onthe dry mass allocation of the plants. A reduction of the aerial biomass production to allow limitedits water losses by the phenomenon of transpiration and to guarantee the turgescence of its cells.

Water Relations

The changes in the leaf RWC along with increase in water-deficit stress are presented inFig 3A. At the end of treatment, the depressive effect of water deficit was more pronounced whenwatering regime intensified. Water deficit at 40% FC decreased the leaf RWC by 20% ascompared to controls after 45 days of treatment (Fig. 3A). The Ψw was significantly lower inplants subjected to water-deficit stress than in controls (Fig. 3B). Water deficit at 40% FCdecreased Ψw reaching the most negative values. With the same watering regime, the Ψw reached–2.1 MPa at the end of treatment.

Organic Solute Accumulation

At the end of experimental period, proline concentration was significantly increased inresponse to drought stress (Fig. 4A). The lowest concentration was recorded in control plants (3.06µmol g–1 DM) and plants subjected to 70 and 40% FC accumulated, respectively, 5 and 15-foldmore proline than the control.

Leaf-soluble sugar concentrations were significantly increased at 70 and 40% FC and rep-resented, respectively ca. 132 and 151% of the controls (Fig. 4B). Linear regression analysis wasused to determine the relationships between leaf proline concentration and branch water potentialof plants subjected for 45 days to different drought stress. There was a strong negative relationshipbetween these parameters, with a coefficient of determination R2 = 0.85 (Fig. 5).

DISCUSSION

The drought stress is a very important limiting factor during early seedling growth and es-tablishment (Jaleel et al., 2009). It affects both elongation and expansion growth (Shao et al.,2008). Results from this study indicate that water-deficit stress reduced the growth of Z. lotus byrestricting leaf formation. Furthermore, the effect of drought stress indicating that shoot growth ismore sensitive to water availability than root growth (Ashraf and Foolad, 2007). Our data areconsistent with findings reported on Z. mauritiana (Clifford et al., 1998) and Z. rotundifolia(Arndt et al., 2001). Both Ziziphus species have developed various mechanisms to cope withrestricted water supply. Osmotic adjustment may occur concomitant with an increased rootgrowth, followed by leaf loss and ultimately drought-enforced dormancy (Arndt et al., 2001;Clifford et al., 1998). In particular, Z. rotundifolia has a high degree of plasticity in response towater deficits. It appears that the extensive root systems and readiness to shed leaves under severedrought constitute the main mechanism of success of Ziziphus species in extremely hot and aridenvironments (Sankhla, 1998; Jones, 1999). According to Gorai et al., (2010), wild jujube is atypical phreatophyte by maintaining its vegetative growth throughout summer months andbehaves as arido-active species (Evenari et al., 1982). Gorai et al., (2010) reported that this deep-rooted shrub is able to obtain water from lower soil horizons, and possibly from a free water table.This conforms to the report that rooting depth of Z. lotus in Morroco can reach about 60 m (LeHouérou, 1972).

Measurement of plant water potential has gained widespread acceptance as a useful


approach to quantify plant and soil water status (Pallardy et al., 1991). Water losses result in thedecline of turgor and, this both results in a decrease in leaf water potential (Boyer, 1982).Maintaining leaf RWC under lowering leaf Ψw in drought stress condition is short termadaptation exhibited by Z. mauritiana to improve the ability of plant to extract moisture from aprogressively drying soil profile (Clifford et al., 2002),. In the present study the decline in Ψw canbe related to drought tolerance and the water storage in the plant. Similar results were found intwo species of the same genus, Z. mauritiana (Clifford et al., 1998) and Z. rotundifolia (Arndt etal., 2001). During the hot and dry summer, the midday water potential of wild jujube reachedvalues almost near –4 MPa and the diurnal amplitude (ΔΨ) was more pronounced during the dryseason than that of wetting months, revealing a high biological activity of this species (Goraiet al., 2010).

Different abiotic stress factors may induce osmotic stress, oxidative stress and protein de-naturation in plants, which lead to similar cellular adaptive responses such as accumulation ofcompatible solutes, induction of stress proteins, and acceleration of reactive oxygen speciesscavenging systems (Zhu, 2002). The accumulation of compatible solutes such as sugars, prolineor glycine betaine in plants benefit stressed cells by protecting and stabilizing macromoleculesand structures from damage induced by stress conditions (Papageorgiou and Murata, 1995;Bohnert and Jensen, 1996;). Such solute accumulation in response to drought stress is quite welldocumented and is an important part of osmotic adjustment (Martínez et al., 2004; Ennajeh et al.,2006). In our study plants subjected to severe water-deficit stress during 45 days, accumulatehigher concentrations of proline (15-fold) and soluble sugars (1.5-fold) than controls. Proline ac-cumulation under moisture stress was previously reported in Ziziphus species; besides, this aminoacid plays an important role as a compatible solute in Z. mauritiana (Clifford et al., 1998; Arndtet al., 2000) and Z. rotundifolia (Arndt et al., 2001). Previous studies on Ziziphus species haveshown that the intensity of drought stress is an important factor in the expression of droughttolerance or avoidance with osmotic adjustment (Clifford et al., 1998; Arndt et al., 2001).Mucilages and glucans in the leaves of Z. mauritiana and Z. rotundifolia are reported to functionas hydraulic capacitors and remobilizers of solutes for osmotic adjustment (Clifford et al., 2002),thus enabling more effective water uptake and assimilate redistribution into roots and stems.

According to the analysis of morphological and physiological traits, and biomass allocationpattern under drought stress conditions, it is concluded that wild jujube plants were able totolerate conditions of low water availability. Further, osmotic adjustment in leaves is an importantmechanism enabling plants to cope with extreme drought.

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Figures

Fig. 1. Water-deficit stress effect on (A) whole plant dry mass (DW, g plant–1) and (B) leaf number of Ziziphus lotuswhen 3-month old plants were subjected for 15, 30 and 45 days to three water regimes (100, 70, and 40%

FC). Data represent mean ± 95% confidence limits, n = 4. Different letters indicate significant differences be-

tween treatments (P < 0.05).

Fig. 2. Changes in the root/shoot dry mass ratio of Ziziphus lotus when 3-month old plants were subjected for 15,

30 and 45 days to three water regimes. Data represent mean ± 95% confidence limits, n = 4. Different letters indi-

cate significant differences between treatments (P < 0.05).


Fig. 3. Changes in (A) leaf relative water content (RWC, %) and (B) branch water potential (Ψw, MPa) of Ziziphuslotus when 3-month old plants were subjected for 15, 30 and 45 days to three water regimes. Data represent

mean ± 95% confidence limits, n = 4. Different letters indicate significant differences between treatments (P < 0.05).

Fig. 4. Mean concentrations (µmol g–1 DW) of (A) proline and (B) soluble sugars in leaves of Ziziphus lotus when

3-month old plants were subjected for 15, 30 and 45 days to three water regimes. Data represent mean ± 95%

confidence limits, n = 4. Different letters indicate significant differences between treatments (P < 0.05).


Fig. 5. Relationship between leaf proline concentration and branch water potential of Ziziphus lotus when 3-month

old plants were subjected for 45 days to three water regimes. Data represent mean ± 95% confidence limits,

n = 4. The line describing the dependency was obtained using linear regression, R2 = 0.85.


Increasing Shelf Life and Maintaining Quality of Mango

by Postharvest Treatments and Packaging Technique

This experiment was carried out to increase the shelf life andmaintaining the quality of mango (Mangifera indica) fruits. There were twofactors. Factor A: postharvest treatments with six levels (1. untreated (control),2. washing with chlorine, 3. dipping (5 minutes) in calcium chloride (CaCl2),4. dipping (5 minutes) in bavistin and rinse in clean water, 5. hot watertreatment and 6. tap water wash) and factor B: packaging technique with fivelevels (1. without packaging (control), 2. perforated poly bag (0.5%), 3.non- perforated poly bag, 4. plastic crate and 5. corrugated fibre boardcarton). The fruits treated with chlorine wash, tap water wash, hot watertreatment, dipping in calcium chloride and bavistin were significantdifference on chemical parameter (total sugar content, vitamin-C, totaltitrable acidity and total soluble solid) of mango. Treated fruits performedless disease incidence compared to without treated fruits. Non-treatedfruits were attacked by the sunken black spots on the surface of the fruitsas well as anthracnose (Colletotrichum gloeosporioides). In case of packagingtechnique, fruits packed in different packaging materials (like corrugatedfibre board carton, plastic crate, perforate and non-perforated polyethylenebag) had the maximum shelf life, lower physiological loss in weight and lessdisease incidence than without package. Among the different packagingmaterials, fruits packed in corrugated fibre board carton had the maximumshelf life (13.02 days), lower physiological loss in weight (4.11%) and lessdisease incidence (1.12%) without excessive deterioration compared toothers. The shelf life of mango could be extended up to 5 days by hot watertreatment and packed in. corrugated fibre board carton compared to others.The color and quality of mango was very better in treated fruits compared tonon-treated fruits.

Keywords: Chemical factor and Packaging, Hot water, Mango, Postharvest.

Abstract

M.M. Molla*Scientific Officer, Postharvest Technology Section, Horticulture Research Centre (HRC),Bangladesh Agricultural Research Institute (BARI), Gazipur, BangladesM.N.Islam2 Senior Scientific Officer, Postharvest Technology section, HRC, BARI, Gazipur, BangladeshM.A.MuqitSenior Scientific Officer, Postharvest Technology section, HRC, BARI, Gazipur, BangladeshK.A.AraSenior Scientific Officer, Landscape, Ornamental and Floriculture Division, HRC, BARI, Gazipur,BangladeshM.A.H.TalukderSenior Scientific Officer, Pomology Division, HRC, BARI, Gazipur, Bangladesh



INTRODUCTION

Mango (Mangifera indica) is one of the popular and delicious fruits in Bangladesh. It isgrown almost all over the country but its production is mostly concentrated in the northern andeastern region (BBS, 2006). The leading mangoes producing districts are Chapai Nawabgonj,Rajshahi and Satkhira areas. At present, the area of this fruit under cultivation is 1681 hectares ofland with production of 40195 metric tons (BBS, 2006). A considerable amount of mango fruitslosses every year due to lack of proper harvesting technique, sorting, storing, transportation,selling and consumption due to its perishability nature. The perishability of this fruit is attributedto immense physiological changes after harvest (Momen et al., 1993). Molla et al., (2010)reported that the post harvest losses of mango in Bangladesh are 51.88% (including agro-foodsector) while it is only 5-25% in developed countries (Kader, 1992). Postharvest diseases as wellas anthracnose are appeared due to the effect of fruit maturity, handling and storage condition.Washing produce before preparation or consumption is recommended but does not guarantee thatfresh produce is pathogen free. Washing produce in cold chlorinated water will reduce microbialpopulations by 2 or 3 logs (100 to 1000-fold), but sterility is not achieved because microorganismsadhere to surfaces of produce and may present in microscopic nooks and crannies on the surfaceof produce (Zhuang et al., 1995). Wash with water is an important part of assuring producequality during postharvest handling. The wash water can easily spread disease from one unit ofproduce to another if there is not use clean and sanitized with chlorine bleach (hypochlorite) 100to 200ppm is the recommended level of chlorine in wash water that will provide adequateprotection when the pH is 6.5 (Kitinoja, 2001). Many chemical treatments have been banned orrestricted as postharvest fungicide treatments of fruits in some countries, and the demand ofpesticide free produce has increased (Adaskaveg et al., 2002). So, it has been necessary todevelop alternative treatments in order to avoid toxic and dangerous chemicals compounds infoods for human consumption. Heat treatments may be effective as a non-chemical mean ofimproving postharvest quality of a range of horticultural products. They are usually applied asa hot water dips, vapor heat or hot air treatments (Lurie, 1998). Hot water treatments affectripening and protect against physiological disorders (Klein and Lurie, 1992).In many countries ofthe world, fruits and vegetables are washed in chlorine or potassium permanganate or hot benomilas well as bavistin before storage (Giraldo et al., 1977). Chlorine water is achieved by adding 200ppm sodium hypochlorite in clean water (Amiruzzaman, 2000). Good package design contributes agreat deal to the quality image of the product both in domestic and export markets. It is reported thatdifferent postharvest treatments have significant effect on the quality and storage life of mango. Useof packaging technique, washing with chlorine, dipping in fungicides, calcium chloride and hotwater treatment are usually employed for increasing the shelf life and reducing the post-harvestlosses of fruits. Information regarding packaging and postharvest treatments of mango is meager inBangladesh. Hence, the study was undertaken to extend the shelf life, maintain the quality andminimize postharvest diseases of mango as well as reducing postharvest losses of mango.


Nutrient Management of Orchard

Since, the farm yard manure directly responsible to increase the fruit yields either byaccelerating the respiratory process by increasing cell permeability by hormone growth action orby combination of all these processes. Therefore, 900g nitrogen, 250g phosphorus and 250g


potassium were applied per tree per year with irrigation at 55-60 per cent of field capacity.

Soil Texture of Orchard: Sandy-loam soil: Climatic conditionMaximum and minimum temperature were recorded as 31.6-32.5oC and 25.7-26.1oC with

relative humidity 80-85%. The rainfall was recorded as 311.2- 345.1mm and the number of rainyday was found 14 and 16 days during conducting the experiment in Tangail.

Preparation Before Storage

After harvest from orchard, the mango was carried out in the laboratory of PostharvestTechnology Section of Horticulture Research Centre, Bangladesh Agricultural Research Institute,Gazipur. After carrying in laboratory, the fruits were cooled immediately in ice water to removefield heat. Then the fruits were sorted out to eliminate bruised, punctured and damaged ones.

Design of Experiment

The experiment was laid out in Complete Randomized Design (CRD) with factorial. Thereare two factors; factor A: postharvest treatment with six levels (1. untreated, 2 washing withchlorine, 3.dipping in bavistin for five minutes, 4. dipping in calcium chloride for five minutes, 5.treated with hot water at 55oC for five minutes and 6. washing with tap water), factor B: packagingtechnique with five levels (1. without packaging, 2..perforated poly bag, 3. non-perforated poly bag,4. plastic crate, 5. corrugated fibre board carton). These factorial treatments were replicated fourtimes (three replications were used for physical parameter and one replication was used forchemical parameter)

Data Recorded

Data on physical parameter like physiological loss in weight (%), disease incidence (%) ,shelf life (days) and chemical parameter like vitamin-C (mg/100g), total titrable acidity (%), totalsoluble solid (oB), reducing sugar (%) and total sugar (%) content were recorded.

Physical Parameter

Physiological Loss in Weight (%)

It was determined by periodical weighing of fruits at storage and expressed as percentageof original weight. Damaged fruits were not included with it (Amayogi and Alloli, 2007).

Where, PLW= Physiological loss in weight of mangoIW= Initial weight of mangoFW= Final weight of mango

Percent Disease Incidence (Anthracnose)

Disease incidence was calculated as the percentage of diseased fruit (1/10th) per totalnumber of fruits (25 fruits in separate treatments). The fruits were observed visually for rottingand microbial infection. Percent disease incidence was identified and calculated using the formula

% PLW =


of Mamatha and Rai (2000).

Where, DI= Disease incidenceDo= Number of diseased fruit

D= Total number of fruits Disease severity was calculated as defined as the percentage of fruit area diseased (1/10th).

Estimates of disease severity per fruit were expressed as the mean disease severity of per fruit.Disease severity was calculated using the following formula of Johnston (2000).

Where, DS= Percent disease severity Ao= Area of fruit infected by disease

A= Total area of fruitShelf Life (Day)

The shelf life of fruits was determined from the days of harvesting to marketable stage byevaluating the non marketability parameter such as damaging, shriveling, bruising, diseaseinfected etc. (Nazrul et al., 2010). During storage, the room temperature and relative humiditywas 28-32oC and 85-905% respectively. Each package contains 25 fruits per replication.

Chemical Analysis

Among four replications three replications were used for physical parameter likephysiological loss in weight (%), disease incidence (%), shelf life (days) and one replication wereused for chemical analysis like vitamin-C (mg/100g), total titrable acidity (%), total soluble solid(oB), reducing sugar (%) and total sugar (%).

Vitamin-C (mg/ 100g)

Vitamin-C (mg/100g) by 2, 6- Diclorophenol-Indophenol Visual Titration Method describedby Rangana (1991).

Total Titratable Acidity

The acidity was determined by diluting the known volume of clear juice, filtered throughwhatmen paper, with distilled water and titrating the same against standard 0.1N sodium hydroxidesolution, using phenolphthalein indicator. The appearance of light pink colour was marked as theend point. The result was expressed in terms of citric acid as per cent total titratable acidity of thefruit juice according to the method of Ranganna (1991).

Total Soluble Solids

The total soluble solids of the pulp for each treatment was recorded with the help of handRefractometer of 0-80o Brix range and expressed as per cent total soluble solids of the fruit(Ranganna, 1991).

Total and Reducing Sugar Content (%)

Total sugar (%) and reducing sugar (%) content was determined by Lane and EynonMethod. These methods were conducted described by Rangana (1991).


Statistical Analysis

The experiment was laid out in Complete Randomized Design ( factorial) with three repli-cations. A two-way analysis of variances (ANOVA) was done by using statistical method(MSTAT-C). The difference was quantified by Duncan’s Multiple Range Test (DMRT)

RESULTS AND DISCUSSION

Postharvest Quality Of Mango

Most of the mango fruits lost their quality due to postharvest diseases when the fresh fruitswere stored at ambient condition and without treated (control). The symptoms of postharvestdiseases were appeared sunken black spots on the surface of the fruits and it was identifiedanthracnose (Colletotrichum gloeosporioides) (Hadi and Meity, 2007). This fungal disease mightbe occurred from flowering to fruit set and after harvest. After harvest, disease is mostly severedduring ripening process of the fruits. The combined effect (Table 1) shows that fruits treated withdifferent treatments (like chlorine wash, tap water wash, hot water, dipping in calcium chlorideand bavistin) and packed in different packaging materials (like corrugated fibre board carton,plastic crate, perforated polyethylene and non- perforated polyethylene bag) minimized maximumpostharvest diseases through maintaining the quality compared to without treated (control) andnon-packed at different storage periods (Table 1). These might be due to its thermal treatment andpackaging technique which has a lethal effect of surface pathogens for minimizing damages offruits. These results are partially supported by the Wenzhong et al., (2004).

Combined Effect of Postharvest Treatments and Packaging Technique for Maintaining

Quality of Mango

The fruits were treated with chlorine water (NaoCl), tap water, bavistin, calcium chlorideand packed in plastic crate, corrugated fibre board carton, perforated and non-perforatedpolyethylene bag within 24 hours of harvest. The lowest physiological loss in weight wasrecorded in mango fruits treated with hot water treatment, bavistin, chlorine and calcium chloridefollowed by untreated fruits (control) (Table 1). Considering storage periods (after 12 days) andtreatments combination, the lowest physiological loss in weight and less disease incidence wasrecorded in hot water treatment and packed in corrugated fibre board carton compared to others.Therefore, the corrugated fibre board carton could contribute to minimize the postharvest lossesof mango during storage. The lowest physiological loss might be due to inactivate the protein andtissue of surface flesh of mango to retard the evaporation of water through the skin and alsoformed the protection tissue from pathogens. These results are supported by the Wenzhong et al.,(2004).The less disease incidence might be due to wash out of spores of the pathogens and lesscontamination as well as prevents the transfer of spores and debris from fruit to fruit in the samecontainer during storage. These results are fully supported by the (Barmore et al., (1983). In caseof shelf life, fruits treated with hot water treatment and packed in corrugated fibre board cartonhad the maximum shelf life (13.02 days ) compared to untreated and without packed (Table 1).Therefore, the fruits treated with hot water and packed in corrugated fibre board carton increasedthe shelf life 5 days compared to others (Table 1). These results are partially supported by Aminet al., (2007).On the other hand, fruits packed in plastic crate resists the produce from internal andexternal stresses during handling of mango due to its adequate strength to hold. These results arean agreement with Kitinoja (2001).


Effect of Postharvest Treatments on Chemical Parameter of Mango

There was significant difference between the treated and non-treated mango (Table 3). Thehighest total sugar content was observed in the treated mango compared to untreated mango(Table 3). This might be due to hydrolysis of starch and accumulation of sugars (Patil and Magar,1976 and Ngalana et al., 1999) and conversion of starch through the process of glucogenesis(Islam, 1998).There was an appreciable increase in the content of total sugar with the increase ofstorage periods. The vitamin-C of treated mango was more than non-treated fruits comparatively.But after 12 days of storage, the decreasing tendency of vitamin-C was observed with theincreasing of storage periods (Table 2&3). These might be due to its oxidation during the longconcentration steps in room temperature. The results were similar to El.Ashwash et al., (1980). Itwas interesting to note that the highest total titrable acidity was recorded in non-treated mangocompared to treated mango (Table 3). Waskar and Roy (1992) stated that the acid content in fruitsduring ripening depends upon the proton transfer process as the fruits ripen. Therefore, thelower acidity in treated fruits might be resulting from an excess transfer of proton duringripening. On the other hand, after 12 days of storage, the acidity was decreased with theincrease of storage periods (Table 2&3). The decreased acidity might be due to inverse relationwith the increased of storage periods. The results are an agreement with Singh and Roy (1984).The total soluble solid increased during ripening process of mango during storage (Table 2&3).These might be due to hydrolysis of polysaccharides and concentration of the pulp as a result ofdehydration.

Effect of Packaging Technique on Chemical Parameter of Mango

The effect of different packaging materials on pattern of changes in total sugar contentof mango fruits during storage is shown in Table 4. The total sugar content of the mango fruitsincreased with the advancement of storage periods. Vitamin-C of storage fruits were 0.333 inopen condition (without packed) but it was increased in perforated and non-perforatedpolyethylene bag and then it was decreased in other packaging materials. However, thedifference of vitamin-C for various packaging materials was non- significant. Total titrableacidity and total soluble solid slightly increased in different packaging materials compared towithout package. But, the differences were statistically negligible. Therefore, the effect ofpackaging materials on chemical parameters like total soluble solid, total titrable acidity, vita-min-C, total sugar and reducing sugar content was non-significant (Table 4). These results aresupported by Mohla et al., (2000).

Combined Effect of Postharvest Treatments and Packaging Technique on Chemical Parameter

of Mango

The fruits were treated with different postharvest treatments like hot water treatment, washwith chlorine (NaoCl), dipping in bavistin and calcium chloride and packed in plastic crate,corrugated fibre board carton, perforated and non-perforated polyethylene bag. But after 12 daysof storage, vitamin-C, total titrable acidity, total soluble solid, total sugar and reducing sugarcontent slightly increased compared to non-treated and non-packed fruits. But, statistically, nosignificant difference was observed among the different postharvest treatments and packagingtechniques on chemical parameter of mango (Table 5). These results are partially supported byDilawar et al., (2007).


CONCLUSION

The fruits treated with chlorine wash, tap water wash, hot water treatment, dipping incalcium chloride and bavistin were significant difference on chemical parameter (total sugarcontent, vitamin-C, total titrable acidity and total soluble solid) of mango. In case ofpackaging, no significant difference was observed on chemical parameter of mango. Treatedfruits performed less disease incidence compared to without treated fruits. Non-treated fruitswere attacked by the sunken black spots on the surface of the fruits as well as anthracnose(Colletotrichum gloeosporioides). In case of packaging technique, fruits packed in differentpackaging materials (like corrugated fibre board carton, plastice crate, perforated and non-perforated polyethylene bag) had the maximum shelf life, lower physiological loss in weightand disease incidence than without package. Among the different packaging technique, fruitspacked in corrugated fibre board carton had the maximum shelf life (13.02 days) withoutexcessive deterioration compared to others. The shelf life of mango could be extended up to5 days by hot water treatment and packed in. corrugated fibre board carton compared toothers. The colour and quality of mango was very attractive in treated fruits compared tountreated fruits. But further study, it is necessary to know the toxicity of bavistin of thetreated mango.

ACKNOWLEDGEMENT

The authors express their gratitude and valuable thanks to the “Ministry ofScience and Information and Communication Technology”, Bangladesh secretariat,Dhaka for approved and funding the project entitled” Postharvest diseases and qualitymanagement of major fruits and vegetables”. The author also grateful to Dr. MoznurRahman, Director (Research) and Dr. Md. Abdul Hoque, Director, Horticulture ResearchCentre, BARI, Gazipur for their valuable suggestions and technical support duringconducting the research.

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Tables

Treatments

combination

After 4 days After 8 days After 12 days

Shelf life

(days)

Physio-

logical loss

in weight

(%)

Disease

inci-dence

(%)

Shelf

life (days)

Physio-

logical loss

in weight

(%)

Disease

inci-dence

(%)

Shelf

Life

(days)

Physio-

logical loss

in weight

(%)

Disease

inci-dence

(%)

AoBoAoB1AoB2AoB3AoB4A1BoA1B1A1B2A1B3A1B4A2BoA2B1A2B2A2B3A2B4A3B0A3B1A3B2A3B3A3B4A4B0A4B1A4B2A4B3A4B4A5B0A5B1A5B2A5B3A5B4LSDCV (%)

4.004.004.004.004.004.004.004.004.004.004.004.004.004.004.004.004.004.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 ns-

11.05a9.58b9.02b8.10c9.09b6.79d4.05h4.31h4.15h4.17h6.07e

4.50gh4.42gh4.11h4.14h5.14fg4.14h4.17h4.10h4.16h5.37ef4.11h4.14h

4.82fgh4.14h5.48ef4.20h4.15h4.13h4.21h

**6.19

4.53.503.352.503.50

------------------- ---------

8.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.008.00 8.008.008.008.008.008.008.008.00ns-

14.14a10.14b10.13b8.41d9.55c7.11e4.13h4.43h4.27h4.37h6.15f4.47h5.48g4.14h4.14h5.15g4.18h4.36h4.22h4.35h6.42f4.26h4.37h4.19h4.28h7.12e4.29h4.35h4.23h4.36h

**3.18

8.506.506.356.566.51

------------------ ----------

8.11j8.28j8.38j8.80j8.28j

10.50fgh10.50fgh

9.83h12.09bc11.28de10.50fgh11.32de10.08gh12.20bc10.51fgh10.67efg12.00bc10.17fgh12.64ab10.51fgh11.29de11.59cd10.87ef12.30b13.02a8.15j8.25j8.31j9.86h9.07i

**2.78

16.21a13.21b11.14c9.58e

10.14d7.59f4.35j6.32h4.31j4.53j6.54h5.22i5.09i4.24j4.61j5.52i4.41j4.45j4.26j4.45j6.36h4.39j4.33j4.53j4.11j7.13g4.50j4.52j4.54j4.47j

**3.49

16.70a12.62b11.63d12.03c12.13c2.16e1.54f2.14e1.12f1.55f2.16e1.54f2.14e1.12f1.55f2.16e1.54f2.14e1.12f1.55f2.16e1.54f2.14e1.55f1.12f2.16e1.54f2.14e1.12f1.55f

**4.75

AoBo= without wash and kept in ambient condition, AoB1= without wash and kept in perforated polyethylene

bag, AoB2= with out wash and kept in non-perforated polyethylene bag, AoB3= without wash and kept in plastic

crate, AoB4 =without wash and kept in corrugated fibre board carton, A1Bo = wash with chlorine water and kept

in ambient condition, A1B1 = wash with chlorine and packed in perforated polyethylene bag, A1B2 = wash with

chlorine and packed in non- perforated polyethylene bag , A1B3 = wash with chlorine and packed in plastic

crate, A1B4 = wash with chlorine and packed in corrugated fibre board carton, A2Bo = dipping in calcium chloride

and kept in ambient condition, A2B1 = dipping in calcium chloride and packed in perforated polyethylene bag,

A2B2 = dipping in calcium chloride and packed in non-perforated polyethylene bag,, A2B3 = dipping in calcium

chloride and packed in plastic crate, A2B4 = dipping in calcium chloride and packed in corrugated fibre board

carton, A3Bo = dipping in bavistin and kept in ambient condition, A3B1 = dipping in bavistin and packed in per-

forated polyethylene bag, A3B2 = dipping in bavistin and packed in non-perforated polyethylene bag,, A3B3 =

dipping in bavistin and packed in plastic crate, A3B4 = dipping in bavistin and packed in corrugated fibre board

carton, A4Bo = treated with hot water and kept in ambient condition, A4B1= treated with hot water and packed in

perforated polyethylene bag, A4B2 = treated with hot water and packed in non-perforated polyethylene bag,

A4B3 = treated with hot water and packed in plastic crate, A4B4 = treated with hot water and packed in corrugated

fibre board carton, A5Bo = tap water wash and kept in ambient condition, A5B= tap water wash and packed in

perforated polyethylene bag, A5B2 = tap water wash and packed in non-perforated polyethylene bag, A5B3= tap

water wash and packed in plastic crate, A5B4= tap water wash and packed in corrugated fibre board carton, (-)

indicates no disease found

Table 1. Shelf life (days), physiological loss in weight (%) and disease incidence (%) of mango after 4,8 and 12 days storage


TreatmentTotal sugar (%) Reducing sugar

(%)

Vitamin-C

(mg/100g)

Total titrable

acidity TSS (oB)

Fresh mango (before treated) 11.47 `2.98 0.44 0.95 11.50

Treatment Total sugar (%) Reducing sugar (%) Vitamin-C (mg/100g) Total titrable acidity TSS (oB)

Ao

A1

A2

A3

A4

A5

LSDCV (%)

15.335d19.510bc20.028b20.982b22.015a18.608c

**12.66

2.5252.5232.5192.5202.5172.520

ns0.81

0.311d0.345a0.343a0.339b0.336b0.327c

**7.05

0.605a0.449b0.442c0.439d0.451b0.441c

**23.35

14.773d17.093b17.213a15.687c15.667c15.067c

**10.70


Bo

B1

B2

B3

B4

B5

LSDCV (%)

19.321

19.351

19.525

19.432

19.436

ns

12.66

2.521

2.518

2.518

2.525

2.521

ns

0.81

0.333

0.334

0.335

0.331

0.332

ns

7.05

0.470

0.473

0.474

0.473

0.474

ns

23.35

16.028

16.028

16.078

16.156

16.128

ns

23.35

Table 2. Chemical parameter of mango on the day of storage (0 day)

Table 3. Effect of postharvest treatments on chemical parameter of mango after 12 days of storage

Table 4. Effect of packaging technique on chemical parameter of mango after 12 days of storage

Ao = non-treated, A1 = washing with chlorine, A2 = dipping (5 minutes) in calcium chloride, A3 = dipping (5 minutes)

in bavistin and rinse in clean water, A4 = hot water treatment and A5 = wash with tap water

Bo= without packaging, B1= perforated poly bag, B2= non-perforated poly bag, B3=plastic crate and

B4= corrugated fibre board carton



AoBoAoB1AoB2AoB3AoB4A1BoA1B1A1B2A1B3A1B4A2BoA2B1A2B2A2B3A2B4A3B0A3B1A3B2A3B3A3B4A4B0A4B1A4B2A4B3A4B4A5B0A5B1A5B2A5B3A5B4LSDCV (%)

15.29315.30315.30015. 35315.42319.58019.20319.80319.28320.20020.23320.10019.80319.80320.86720.96720.76721.20321.10721.39721.69022.56022.38022.04718.77018.52718.62018.57018.553

ns12.66

2.5272.5232.5172.5172.5402.5272.5272.5232.5202.5172.4832.5272.5202.5472.5202.5172.5102.5272.5232.5232.5172.5272.5072.5202.5172.5402.5132.5132.5232.510

ns0.81

0.3070.3070.3170.3200.3500.3530.3470.3470.3300.3330.3430.3330.3500.3570.3530.3470.3370.3370.3230.3230.3330.3330.3270.3200.3400.3270.3430.3300.340

ns7.05

0.6070.6030.6100.6030.6000.4400.4470.4430.4530.4630.4370.4470.4430.4400.4430.4370.4300.4370.4470.4500.4530.4530.4530.4470.4500.4570.4570.4430.447

ns23.35

14.53315.00014.66714.83314.83317.33317.03317.03317.03317.03317.03317.03317.33317.33317.33315.66715.66715.66715.86715.86715.83315.66715.66715.66715.50015.86715.86716.20016.20016.200

ns23.35

Table 5. Combined effect of postharvest treatments and packaging technique on chemical parameterof mango after 12 days of storage

AoBo= without wash and kept in ambient condition, AoB1= without wash and kept in perforated poly-

ethylene bag, AoB2= with out wash and kept in non-perforated polyethylene bag, AoB3= without wash

and kept in plastic crate, AoB4 =without wash and kept in corrugated fibre board carton, A1Bo = wash

with chlorine water and kept in ambient condition, A1B1 = wash with chlorine and packed in perforated

polyethylene bag, A1B2= wash with chlorine and packed in non- perforated polyethylene bag, A1B3 =

wash with chlorine and packed in plastic crate, A1B4= wash with chlorine and packed in corrugated

fibre board carton, A2Bo= dipping in calcium chloride and kept in ambient condition, A2B1= dipping in

calcium chloride and packed in perforated polyethylene bag, A2B2 = dipping in calcium chloride and

packed in non-perforated polyethylene bag,, A2B3 = dipping in calcium chloride and packed in plastic

crate, A2B4 = dipping in calcium chloride and packed in corrugated fibre board carton, A3Bo = dipping

in bavistin and kept in ambient condition, A3B1= dipping in bavistin and packed in perforated polyeth-

ylene bag, A3B2= dipping in bavistin and packed in non-perforated polyethylene bag,, A3B3 = dipping

in bavistin and packed in plastic crate, A3B4 = dipping in bavistin and packed in corrugated fibre board

carton, A4Bo= treated with hot water and kept in ambient condition, A4B1= treated with hot water and

packed in perforated polyethylene bag, A4B2 = treated with hot water and packed in non-perforated

polyethylene bag, A4B3 = treated with hot water and packed in plastic crate, A4B4 = treated with hot

water and packed in corrugated fibre board carton, A5Bo = tap water wash and kept in ambient condi-

tion, A5B1 = tap water wash and packed in perforated polyethylene bag, A5B2= tap water wash and

packed in non-perforated polyethylene bag, A5B3= tap water wash and packed in plastic crate, A5B4=

tap water wash and packed in corrugated fibre board carton, (-) indicates no disease found


Character Association in Improved Mulberry Genotypes

Exhibiting Delayed Leaf Senescence

Mulberry (Morus spp.) is a perennial tree cultivated for its foliage to rearthe domesticated silkworm, Bombyx mori L. Mulberry has improved throughconventional breeding in general aims to improve the quantity and quality ofleaf yield, which have direct bearing on silk productivity. Leaf senescence is oneof the major constraints, which restricts the quantity of quality leaf availabilityfor silkworm rearing. High yielding mulberry varieties often show leaf fall inthe range of 20 – 33% in tropical sericultural belts. Hence, in order to increasethe leaf availability, it is essential to delay the senescence of leaves. Keeping thisin view, the present study was undertaken on 9 mulberry genotypes, which weredeveloped systematically for delayed senescence. The interrelationship amongfactors that contribute to growth, yield and low foliar senescence were investigated.Correlation between agronomic traits and leaf yield revealed the existence ofstrong positive associations among plant height, total shoot length (TSL), nodaldistance (ND), leaf fall (LF), number of leaves/ plant (NLP), fresh and dryweight of 100 leaves (FWL & DWL), leaf area (LA), leaf area index (LAI),above ground biomass (AGB) with leaf yield. However, leaf harvest index(LHI) had a strong negative correlation with leaf fall % and leaf yield. Significantimprovement in the important growth and yield attributing characters viz.,FWL, DWL, LA, AGB, LHI and LAI contributed to a higher yield in CT44.Path co-efficient analysis revealed the direct positive effect of the charactersviz., AGB (1.233), LHI (0.449), NLP (0.217), and LA (0.181), on leaf yield.From the studies it is concluded that low leaf fall coupled with high LHI can beconsidered for the selection of varieties with delayed leaf senescence in mulberry.

Keywords: Delayed senescent mulberry, High yielding mulberry, LAI, LHI, Leaf productivity, Leaf quality.

AbstractDoss, S. G.*, Central Sericultural Research and Training Institute, Berhampore – 742 101, West Bengal. India.Present address: Central Sericultural Research and Training Institute, Mysore – 570008, Karnataka.India. Chakraborti, S. P., Research Extension Center, Nabagram, Murshidabad, West Bengal. India.Roychowdhuri, S. and Das, N. K. Central Sericultural Research and Training Institute, Berhampore – 742 101, West Bengal. India.Vijayan, K. Central Sericultural Research and Training Institute, Berhampore – 742 101, West Bengal. India.Ghosh, P. D.Cytogenetics and Tissue culture Laboratory, Botany Department, Kalyani University, Kalyani, West Bengal, India. e-mail: [email protected]



INTRODUCTION

Sericulture, an agro-based industry encompassing the activities of mulberry cultivation,silkworm rearing, reeling and weaving, provides employment to more than 7,00,000 people inWest Bengal, India (Dutta and Nanavaty, 2005). The Gangetic plains have a tropical humidclimate with alluvial soil having high water holding capacity. As the region is warm and humid,mulberry grows luxuriantly in all the seasons except in late autumn and winter when thetemperature and soil moisture go down below tolerable level (<15oC). This low growth coupledwith high leaf senescence, generate a high leaf scarcity for silkworm rearing during this period. InWest Bengal, the current popular mulberry variety, S1635, shows high seasonal variation in leafproduction a sharp decrease in November (Autumn) and February (Winter), when the bivoltinesilkworm rearing is at its peak (Moorthy and Das, 2007). This sharp decline in the leaf yield ismainly due to the early leaf maturity induced leaf fall during the colder months (Vijayan et al.,1999). The average leaf fall % in S1635 under normal conditions was reported to be 31% under60 × 60 cm spaced plantations, and it goes upto 33% under close planting systems (60 × 10 cm)of irrigated conditions in West Bengal (Rahman et al., 1999). In order to develop a seasoninsensitive variety with uniform pattern of growth and leaf yield through out the year, attemptshave been made to identify mulberry accessions with less response to seasonal variations, fromthe germplasm and used them in breeding. As a consequence, a number of hybrids have beendeveloped and are being evaluated for their suitability for silkworm rearing and responses toseasonal variations. In order to select hybrids indirectly without the need of being subjected tovarious seasonal changes, it is essential to identify reliable selection parameters. This study wastaken up with such an objective of working out the interrelationship among various parameters ofgrowth, leaf yield and leaf senescence so that some of these parameters can be used for selectingthe hybrids at an early stages of its growth.


1. Plant Materials and Experimentation

The field experiments were conducted at the mulberry farm of Central SericulturalResearch and Training Institute, Berhampore, West Bengal by planting 8-month-old saplings of 9selected mulberry genotypes viz., CT6, CT9, CT11, CT15, CT44, CT94, CT159, CT185, andS210 along with a check (S-1635) raised from their hard wood stem cuttings. The new mulberrygenotypes were evolved from the cross involving 3 female and 5 male parents selected fromgermplasm (Table 1). Experimental plantation was laid out in a randomized block design with 3replications. The size of the individual sub-plots within the blocks was 17.64 m² and the numberof plants was 49 in a square plot under 60 cm x 60 cm spacing. Inter-block as well as inter-genotype distance was 150 cm. The experimental plants in the field were maintained as per rec-ommended package of practices for irrigated plains of West Bengal (Ray et al., 1973) andirrigated at an interval of 15 days during dry seasons. The crop was protected against the attack ofinsect pests and diseases by spraying 0.1 % Rogor (30% EC) and Bavistin (Carbendazim 50%EC), respectively, as and when required. Leaf harvests were made after one year of plantation inaccordance with the 5 silkworm commercial crop schedule, which are in vogue in Murshidabaddistrict of West Bengal (Moorthy and Das, 2007).

2. Growth Parameters

The data on different growth and yield attributing parameters viz., plant height, number ofbranches per plant, total shoot length, nodal distance, leaf fall (%), number of leaves per plant,fresh and dry weight of leaves (g), single leaf area (cm2), leaf yield, above-ground biomass, leafharvest index (%), leaf area index (LAI) and foliage yield were recorded for 3 consecutive years.


3. Statistical Analysis

Data were analyzed for analysis of variance (Sharma, 2000). Critical difference (CD) at5% level of significance was estimated to compare the different genotypes with check consultingFisher and Yate’s table. Character associations among different traits and leaf yield were calculatedthrough correlation and path analysis by following the method described by Panse and Sukhatme(1967).


Genotypes CT44 and CT11 showed superiority over other genotypes including the checkS1635 in annual leaf yield. These genotypes yielded 47940 kg ha-1 year-1 and 43990 kg ha-1 year-1,which were higher than the leaf yield of the check variety S1635 by 17.1 % and 7.5 %respectively (Table 3). This higher yield was observed consistently in all the 5 different commercialcrop seasons and the 3 years (Fig. 1 & 2). The data on different growth and other leaf yieldattributing characters revealed variations among them (Table 3 and Fig. 3). The leaf fall %, whichindicates the rate of senescence, was found to be significantly lower in CT44 than S1635 in all the5 crop seasons (Fig. 4), consistently, with mean values of 9.80 and 20.13% for the respectivegenotype (Table 3).

It is a known fact that leaf senescence is a complex and highly organized process resultingin several changes in gene expression and metabolic processes. These metabolic changes areconsidered to be important to maintain the continuous growth and development of the plant.During the senescence, nutrients are mobilized from the senescing leaves to younger parts of theplant to support their growth (Hörtensteiner and Feller, 2002). In fact, senescence in plants ishighly regulated and modulated expression of many different genes (Buchanan-Wollaston et al.,2003). A microarray analysis of Arabidopsis has revealed that during senescence, changes in theexpression of more than 800 genes take place (Buchanan-Wollaston et al., 2005). Comparison ofchanges in gene expression patterns further revealed involvement of salicylic acid (SA), jasmonicacid (JA) and ethylene pathways. Therefore, it is obvious that a complex polygenic trait like leafsenescence cannot be controlled or improved by manipulating one or a few genes or traits. Hence,concerted efforts are required by integrating the genetic, physiological and biochemical afpects toimprove the leaf retention by delaying the process of senescence. Information on characterassociation provides an opportunity to manipulate those traits that contribute greatly towardsdelayed leaf senescence or retention of leaves to increase the leaf yield of the plant.

Correlation coefficients among leaf yield and other yield attributing characters revealedthat leaf yield was significantly correlated positively with plant height, total shoot length, nodaldistance, leaf fall%, total number of leaves per plant and above ground biomass (Table 4). Similarresults were also reported by Sarkar et al., (1992), Rahman et al., (1995), Vijayan et al., (1997b),Tikader and Rao (2001). The character leaf fall %, which shows the leaf senescence rate, also hada significant positive correlation with other yield attributes viz., plant height, total shoot lengthand had a significant negative correlation with number of branches/plant and LHI. This may bedue to the plants having more number of branches had slow growth rate and low leaf fall %, whilethe plants with comparatively lesser number of branches had a high growth rate (PH) and also hada high leaf fall %. The higher LHI in delayed senescent genotypes (low leaf fall %) may also bedue to more allocation of dry matter in the foliage than in the stems. In the present investigation,number of branches per plant did not show significant correlation with the leaf yield. This differswith the findings of Sahu et al., (1995), Vijayan et al., (1997b) and Susheelamma et al., (1998)who reported the positive association of number of branches per plant with leaf yield in mulberry.However, number of branches had a significant positive correlation with number of leaves perplant (NLP) and negative correlations with plant height and leaf fall %. Nodal distance showedpositive correlations with fresh (FWL) and dry (DWL) weights of leaves, LA and AGB (Table 4).


These results are in conformation with the findings of Vijayan et al., (1997b), Sarkar et al., (1992;1987), Tikader and Rao (2001), Banerjee et al., (2007) and Tikader and Kamble (2008; 2009).Vijayan et al., (2010) also got similar results with saline stressed mulberry genotypes. The highleaf yield noticed in the variety CT-44 was due to the corresponding enhancement in leaf area,fresh and dry weights of 100 leaves, leaf harvest index and aboveground biomass (17% increaseover the leaf yield of S1635) and ND was also within the optimum range (4.5 –5.5 cm) for gettinghigher leaf yield in mulberry (Vijayan et al., 1997b). Similarly, higher leaf retention due todelayed leaf senescence has also contributed to the better leaf yield potential of CT-44.

Since leaf yield is a complex character selection for it based on the one or two charactersmay not be sufficient to provide reliability in the process. Hence, in order to identify thosecharacters that have major contributions to the leaf yield, the path coefficient analysis is used toelucidate the direct and indirect relationships. The results of the present study (Table 5) revealedthat direct contributions of agronomic traits on leaf yield ranged from 1.233 in AGB to –0.292 inLAI. The second highest direct effect on leaf yield was shown by LHI (0.449) followed by NLP(0.217), LA (0.181), number of branches per plant (NB) (0.120) and plant height (PH) (0.107).The direct effect of LA, NB, PH was very low. However, LA and PH are likely to be contributingtowards leaf yield indirectly through AGB. Besides, positive correlations and direct negativeeffects on leaf yield were also found in the characters viz., LAI (-0.292), TSL (-0.146), ND (-0.010) and DWL (-0.021) but their indirect effect was via AGB. The delayed senescence hadmoderate to low TSL, which in turn had direct negative effect (-0.146) on leaf yield. The onlycharacter that had a negative correlation with leaf yield was LHI (-0.343) but it showed a directpositive effect on leaf yield and a indirect negative effect through AGB. Leaf fall had low positivedirect effect (0.081) on leaf yield and showed indirect negative effect through LHI (-0.175) andTSL (-0.078). This supports the hypothesis that the plants having low or delayed leaf senescence(leaf fall) had a high LHI, which in turn contribute to the leaf yielding capacity in mulberry.

Since in mulberry leaf yield is the primary product, its improvement entails greatsignificance. Leaf yield is a polygenic trait contributed by a number of important associated traits.Although, much improvement was made in leaf yield using conventional breeding methods(Vijayan et al., 2011), developing a variety having stable leaf yield potential still eludes thescientists. Most of the high yielding varieties are prone to seasonal variations as during lowtemperature they yield very less as compared to their yield during summer and rainy seasons.Since the main purpose of mulberry cultivation is to feed the silkworm, availability of sufficientquantity of leaf during the season when the silkworms can be reared is important. The bestseasons for silkworm rearing are winter and spring. However, during these seasons the mulberryleaf yield is the minimum. Hence, it is essential to develop a variety, which has the capability tosustain good growth during these seasons. The delayed senescence observed in CT-44 along withhigher leaf yield contributed by plant height, number of branches and leaf weights make CT-44the best mulberry variety available for bivoltine sericulture areas of West Bengal.

Thus, from the study, it can be concluded that using a systematic and integrated approachand integrated approach using knowledge of genetic, physiological and biochemical aspects, it ispossible to develop mulberry varieties with stable leaf yield irrespective of the seasonal orclimatic changes.

Literature cited

Banerjee, R., Roychowdhuri, S., Sau, H., Das, B.K., Ghosh, P. and Saratchandra, B. 2007.Genetic diversity and interrelationship among mulberry genotypes. J. Gene. Genom. 34:691-697.

Buchanan-Wollaston, V., Page, T., Harrison, E., Breeze, E., Lim, O.K., Nam, H.G., Lin, J.F., Wu, S.H., Swidzinski, J., Ishizaki, K. and Leaver, J. 2005. Comparative transcriptome analysis reveals significant differences in gene expression and signalling pathways between developmental


and dark/starvation-induced senescence in Arabidopsis. Plant J., 42:567 - 585. Buchanan-Wollaston, V., Earl, S., Harrison, E., Mathas, E., Navabpour, S., Page, T. and Pink, D.

2003. The molecular analysis of plant senescence: a genomics approach. Plant Biotech. J. 1: 3–22.Dutta, R.K. and Nanavaty, M. 2005. Global silk industry – A complete source book. Universal

Publishers, USA.Hörtensteiner, S. and Feller, U. 2002. Nitrogen metabolism and remobilization during senescence.

J. Exp. Bot. 53:927-937. Moorthy, S.M. and Das, S.K. 2007. Silkworm seed and commercial crops in West Bengal. Indian

Silk, June, 2007:12-15.Panse, V.G. and Sukhatme, P.V. 1967. Statistical methods for agricultral workers. ICAR Publication,

New Delhi.Rahman, M.S., Doss, S.G. Vijayan, K. and Roy, B.N. 1999. Performance of the mulberry variety

S1635 under three system of planting in West Bengal. Indian J. Seric., 38(2):165-167.Rahman, M.S., Sarkar, A. and Chaturvedi, H.K. 1995. Influence of leaf physio-anatomical

characters on yield potentiality in mulberry. Bull. Seric. Res., 6:1-5.Ray, D., Mondal, L.N., Pain, A.K. and Mondal, S.K. 1973. Effect of NPK and farm yard manure

on the leaf yield and nutritive values of mulberry leaf. Indian J. Seric., 12:7-12.Sahu, P.K., Yadav, B.R.D. and Saratchandra, B. 1995. Evaluation of yield component in mulberry

germplasm varieties. Acta Botanica Indica, 23:191-195. Sarkar, A., Quader, M.A., Rab, M.A. and Ahmed, S.U. 1992. Studies on nutrition composition of

some indigenous and exotic mulberry varieties. Bull. Seric. Res., 3:8-13.Sarkar, A., Roy, B.N., Gupta, K.K. and Das, B.C. 1987. Character association in mulberry under

close planting. Indian J. Seric., 26:76-78. Sharma, J.D. 2000. Statistical and biometrical techniques in plant breeding. New-age International

Publishers, New Delhi. Susheelamma, B.N., Jolly, M.S., Giridhar, K.S., Dwivedi, N.K. and Suryanarayana, N. 1998.

Correlation and path analysis in mulberry under stress and non-stress conditions. Sericologia, 28:239-244.

Tikader, A. and Anantha Rao, A. 2001. Ex-citu performance of some mulberry (Morus spp.) germplasm. Bull. Indian Acad. Seric., 5:29-35.

Tikader, A. and Kamble, C.K. 2008. Studies on variability of indigenous mulberry germplasm ongrowth and leaf yield. Pertanika J. Trop. Agric. Sci. 31:163-170.

Tikader, A. and Kamble, C.K. 2009. Development of core collection for perennial mulberry(Morus spp.) germplasm. Pertanika J. Sci. Tech. 17:43-51.

Vijayan, K. Chakrabori, S.P., Chaterjee, K.K., Doss, S.G., Roy, B.N. and Saratchandra, B. 1999. S1635: A mulberry variety for Eastern and North-Eastern regions in India. Indian silk, November, 1999, pp. 22-24.

Vijayan, K. Srivastava, P.P. Raghunath M. K. and Saratchandra B. 2011. Enhancement of stress tolerance in mulberry. Scientia Horticulturae Doi: 10.1016/j.scienta.2011.04.018

Vijayan, K. Tikader, A., Das, K.K., Chakraborti, S.P. and Roy, B.N. 1997b. Correlation studies in mulberry (Morus spp.). Indian J. Gnet., 57:455-460.

Vijayan, K., Doss, S.G., Chakraborti, S.P., Ghosh, P.D. and Saratchandra, B. 2010. Character association in mulberry under different magnitude of salinity stress. Emir. J. Food Agric. 22:318-325.


Sl.

No. Genotype PedigreeParent character

Female Male

123456789

CT6 (C2043)CT9 (C2044)CT11 (C2045)CT15 (C2046)CT44 (C2047)CT94 (C2048)CT159 (C2049)CT185 (C2050)CT210 (C2051)

M indica HP x CHF-13-do--do--do-

M indica HP x CHF-12Berhampore local x ZingM indica HP x CHF-13M indica HP x CHF-23

KPG-II x Maliha

Large leaf area-do--do--do--do--do--do--do-

Cold tolerance

Low senescence-do--do--do--do-

Cold toleranceLow senescence

-do-Thick leaves

Tables

Table 1. Pedigree details of newly evolved delayed senescent mulberry genotypes.

Table 2. Leaf yield performance of 9 selected mulberry genotypes in 5 different crop seasons (Figures aver-age of 3 years each year comprising 5 commercial crop seasons).

Genotype’s name in parenthesis is as per the Serial of Elite germplasm register maintenance by our Institute.

** Significant at 1 % level (p<0.01) Genotype’s name in parenthesis is as per the Serial of Elite germplasm

register maintenance by our Institute.

Genotype Leaf yield (t ha-1 season-1)Total

(t ha-1 year-1)Yield gain over check

(%)

CT6 (C2043)CT9 (C2044)CT11 (C2045)CT15 (C2046)CT44 (C2047)CT94 (C2048)CT159 (C2049)CT185 (C2050)CT210 (C2051)S1635 (Check)MeanCD at 5%

CV%

Sept.

8.87.08.67.89.66.27.18.27.47.77.8

Nov.

7.17.47.77.09.15.56.27.18.07.77.3

Feb.

6.37.08.17.67.94.76.35.06.27.06.6

Apr.

8.08.08.68.59.57.17.48.68.28.28.2

July

9.48.410.79.311.58.48.99.48.810.19.5

GenotypeSeason

Season x Genotype

39.838.043.940.447.932.036.138.538.840.9

1.8**0.2**0.8**11.0

----

7.5--

17.1----------


Characters PH TSL ND LF NLP FLW DLW LA LAI AGB LHI LY

NB

PH

TSL

ND

LF

NLP

FLW

DLW

LA

LAI

AGB

LHI

-0.464** 0.251**

0.689**

-0.043

0.072

0.050

-0.336**

0.695**

0.532**

0.049

-0.336**

0.695**

0.532**

0.049

0.415**

0.371**

0.779**

-0.326**

0.085

0.031

-0.013

-0.039

0.287**

-0.038

-0.137

0.762**

-0.111

0.136

-0.003

0.513**

-0.012

-0.234**

0.801**

0.681**

0.305**

0.397**

0.677**

0.066

0.055

0.705**

0.444**

0.368**

0.503**

-0.020

0.736**

0.806**

0.262**

0.553**

0.485**

0.364**

0.194*

0.344**

0.662**

0.123

-0.658**

-0.598**

0.026

-0.389**

-0.439**

0.028

0.122

0.057

-0.341**

-0.652**

0.018

0.610**

0.699**

0.333**

0.544**

0.354**

0.455**

0.283**

0.438**

0.604**

0.922**

-0.343**

NB - No. of branches plant-1; PH - Plant height; TSL - Total shoot length; ND - Nodal distance; LF - Leaf fall (%); NLP -

Total no. of leaves plant-1; FWL - Fresh weight of 100 leaves; DWL - Dry weight of 100 leaves; LA - Leaf area; LAI - Leaf

Area Index; AGB - Aboveground biomass; LHI – Leaf Harvest Index; LY – Leaf Yield; * and ** - significant at 5 and 1%

level, respectively.

Table 4. Correlation among various growth and yield attributing characters that influence leaf yield in se-lected delayed senescent mulberry genotypes

Genotype

NB

(plant-1)

PH

(cm)

TSL

(cm)

ND

(cm)

Leaf fall

(%)

NLP FWL

(g)

DWL

(g)

LA

(cm²)

LAI AGB

(t ha-1

Year-1)

LHI

(%)

CT6 (C2043)

CT9 (C2044)

CT11 (C2045)

CT15 (C2046)

CT44 (C2047)

CT94 (C2048)

CT159(C2049)

CT185(C2050)

CT210(C2051)

S1635(Check)

CD at 5%

CV%

7.3

8.3

7.7

7.6

8.2

7.1

8.1

8.2

7.4

8.2

0.3**

10.4

96.5

88.8

98.4

100.8

92.5

97.0

100.2

94.1

102.9

95.4

4.1**

10.3

565.9

609.2

611.4

598.5

593.9

557.5

636.7

607.9

653.0

651.6

31.9**

12.6

4.6

4.5

4.7

4.5

5.1

4.3

4.4

4.5

4.4

4.6

0.1**

7.2

15.7

14.1

16.7

14.3

9.8

12.9

14.5

17.8

16.5

20.1

1.1**

17.1

100.0

111.0

101.7

109.8

97.3

107.3

118.5

105.0

118.2

109.0

5.7**

12.9

369.0

350.6

431.9

367.0

509.2

293.2

304.5

367.1

374.7

410.3

19.2**

12.2

79.1

75.2

86.3

77.0

103.7

63.5

62.8

76.3

75.4

82.4

4.8**

15.0

207.6

202.6

235.6

204.4

289.6

178.0

180.4

214.3

213.8

210.3

12.1**

13.7

5.7

6.1

6.6

6.2

7.7

5.2

5.8

6.2

6.9

6.3

0.4**

17.9

65.4

63.0

70.9

67.9

75.6

57.4

63.7

64.3

65.5

68.1

3.2**

11.7

61.6

61.1

61.8

59.8

64.3

57.2

57.8

61.2

59.9

60.3

1.2**

5.0

Table 3. Performance of 9 selected delayed senescent mulberry genotypes on different growth and yieldattributing characters.

PH- Plant height; NB- No. of branches; ND- Nodal distance; SWL- Fresh weight of 100 leaves; DWL - Dry weight of 100

leaves; SLA- Single leaf area; AGB- Aboveground biomass; LHI – Leaf harvest index; TLA- Total leaf area; LAI – Leaf

area index; LF-Leaf fall %; * and ** - significant at 5 and 1% level, respectively.


NB - No. of branches plant-1; PH - Plant height; TSL - Total shoot length; ND - Nodal distance; LF - Leaf fall (%); NLP -

Total no. of leaves plant-1; FWL - Fresh weight of 100 leaves; DWL - Dry weight of 100 leaves; LA - Leaf area; LAI - Leaf

Area Index; AGB - Aboveground biomass; LHI – Leaf Harvest Index; LY – Leaf Yield; * and ** - significant at 5 and 1%

level, respectively; Residual effect = 0.024; r = correlation value.

Table 5. Direct and indirect path co-efficient of different agronomic traits that influence leaf yield in theselected delayed senescent mulberry genotypes.

Characters NB PH TSL ND LF NLP FLW DLW LA LAI AGB LHI r with LY

NB

PH

TSL

ND

LF

NLP

FLW

DLW

LA

LAI

AGB

LHI

0.120

-0.056

0.030

-0.005

-0.040

0.050

0.004

0.004

-0.013

0.037

-0.002

0.015

-0.050

0.107

0.074

0.008

0.075

0.040

0.009

-0.001

0.015

0.043

0.079

-0.071

-0.037

-0.101

-0.146

-0.007

-0.078

-0.114

-0.010

0.006

0.000

-0.099

-0.118

0.087

0.000

-0.001

0.000

-0.010

0.000

0.003

-0.004

-0.003

-0.005

-0.001

-0.003

0.000

-0.027

0.056

0.043

0.004

0.081

0.007

-0.003

-0.003

-0.001

0.004

0.045

-0.032

0.090

0.080

0.169

-0.071

0.018

0.217

-0.031

-0.030

-0.051

0.153

0.105

-0.095

0.001

0.003

0.002

0.012

-0.001

-0.004

0.030

0.023

0.024

0.013

0.011

0.001

-0.001

0.000

0.001

-0.006

0.001

0.003

-0.016

-0.021

-0.015

-0.008

-0.004

-0.003

-0.020

0.025

-0.001

0.093

-0.002

-0.042

0.145

0.123

0.181

0.091

0.062

0.010

-0.089

-0.116

-0.198

-0.019

-0.016

-0.206

-0.130

-0.108

-0.147

-0.292

-0.193

0.100

-0.025

0.907

0.994

0.323

0.682

0.598

0.449

0.239

0.424

0.816

1.233

-0.804

0.055

-0.296

-0.269

0.012

-0.175

-0.197

0.013

0.055

0.026

-0.153

-0.293

0.449

0.018

0.610**

0.699**

0.333**

0.544**

0.354**

0.455**

0.283**

0.438**

0.604**

0.922**

-0.343**


Figures

Fig. 1. Leaf yield performance of CT44 in comparison with the Check S-1635 in 5 different

commercial silkworm crop seasons.

Fig. 2. Leaf yield performance of CT44 in comparison with the Check S-1635 in 3 different years of study.


A

C

E F

D

B

Fig. 3. Comparative performance of CT44 with the Check S-1635 for Fresh weight of 100 leaves

(A), Dry weight of 100 leaves (B), Single leaf area (C), Aboveground biomass (D), Leaf harvest

index (E) and Leaf area index (F) in 5 different crop seasons.


Fig. 4. Performance of CT44 for leaf fall (senescence rate) (%) in comparison to check S-1635 in 5

different crop seasons.

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Influence of Different Colored Plastic Mulch on the

Growth of Lettuce (Lactuca sativa)

Mulches bring several benefits to lettuce cultivation.A study on thelettuce ‘Red Rapids’ has been conducted to determine the influence of thedifferent colored plastic mulch on its growth. The experiment consisted offive color treatments as follows; treatment 1- metallic silver (control),treatment 2- red, treatment 3- orange, treatment 4- yellow and treatment 5-green. Results showed that the colored mulch treatments had significant in-fluenced on the different parameters including: root length at harvest,average leaf length, leaf diameter, plant height, plant weight, number ofleaves at harvest and percentage survival. Lettuce grown in red mulch hadsignificantly outperformed the other colored treatments.

Keywords: Colored plastic mulch, Lactuca sativa, Lettuce.

Abstract

Edmar N. Franquera Ph.D Horticulture University of the Philippines Los Banos, College, Laguna



INTRODUCTION

Lettuce (Lactuca sativa) comes from the family Asteraceae. Lettuce ‘Red Rapids’ hasideal leaves for salads. This variety can be grown in cold-frames, greenhouses or in the garden.This cultivar has crisp, tender and tasty leaves and approximately it’s growths period is 55 daysto maturity. An excellent variety for forcing, or outdoor planting, being quick of growth, and littleliable to rot.

Plastic mulches directly impact the microclimate around the plant by modifying theradiation budget (absorbitivity vs. reflectivity) of the surface and decreasing the soil water loss.The color of a mulch largely determines its energy-radiating behavior and its influence on the mi-croclimate around a vegetable plant. Color affects the surface temperature of the mulch and theunderlying soil temperature. The degree on contact between the mulch and soil, often quantifiedas a thermal contact resistance, can affect greatly the performance of a mulch. If an air space iscreated between the plastic mulch and the soil by a rough soil surface, soil warming can be lesseffective than would be expected from a particular mulch. Extensive research utilizing certainphotoselective mulch has been reported to increase yields of various horticultural crops (Lamont,2004). The purpose of assorted colors is to reflect FR:R ratios that result in phytochromeregulation that may enhance plant growth and yield. In a tomato production study, Orzolek et al.,(2000) found silver and red plastic mulches to have the greatest reflected FR:R ratios. This studyreported an increase in marketable fruit yields occurred with tomatoes growing on silver or redmulch compared to the use of traditional black plastic.

Originally, plastic mulches were primarily black, clear, and white. Clear produces the mostheat, but weeds grow like crazy. White keeps the soil cool. Black warms the soil and blocks weedgrowth. Additional colors have now been introduced such as red, blue, yellow, gray, orange,brown, green, and silver or silver- black. In recent years, it has been shown that selecting a plasticmulch of the right color is very important in vegetable production. The objective of this study wasto determine the influence of different colored plastic mulch on the growth of lettuce.


Crop Establishment

Seeds of the lettuce variety Red Rapids (Known You), were sown in a seedling tray. At 5days after germination the seedlings were pricked to ensure individual seedlings per hole in thetray. The seedlings were maintained at the plastic house for 2 weeks after pricking before theywere transplanted in the field.

Plot Preparation and Plastic Mulch Coloring and Treatments

Five treatments (10 m2 plot) laid with plastic mulch were used for this study. The plotswere subdivided following the treatments and replicated four times. The plastic mulch weresprayed with different colors using a spray paint with the following color treatments:

treatment 1-metallic silver (control) treatment 2-red treatment 3-orange treatment 4- yellow treatment 5- green Seedlings of 5 cm leaves were transplanted in the field spaced with 35 cm x 30 cm.

Replanting were done 1 day after transplanting to cope for the missing hills and dead plants.Watering was done as often as necessary to ensure the growth of the lettuce. Fertilizer applicationwas done one week after transplanting with 10 grams of urea (46-0-0) diluted in galloon of waterdrenched within the individual plant with a volume of 150 ml per plant. Spraying was not donesince occurence of insects were not prevalent.


Harvesting and Data Gathering

Lettuce were harvested four weeks after transplanting. Random sampling were done tomeasure the different parameters per plot.

Parameters Measured

1. Percentage survival: The total number of lettuce plants survived divided by the totalnumber of lettuce plants transplanted in a plot.

2. Weight of plant: The weight of the representative plants were weighted individually atharvest

3. Leaf diameter: The leaf diameter of the representative plants were taken at harvest withthe average of ten leaf samples per plant.

4. Number of leaves: This was taken at harvest time the total number of leaves per plantwere counted and recorded.

5. Leaf length: This was taken from the ten leaf of the representative which was measuredusing a ruler.

6. Root length: This was taken during the harvest and the root length were measured using aruler.

7. Plant height at harvest: This was taken at harvest time and was measured from the basalto the tip of the leaves.

The data gathered were statistically analysed using the SAS computer software program.


Percentage Survival Plants

The percentage of survival plants (Fig.1a,b) showed significant differences on the coloredmulch treatments. No significant differences were noted in red, orange, green and metallic silvermulch. However, the four colored mulch was significantly different with yellow colored mulch. Itwas observed that yellow colored mulch has the least percentage of survival. It has been statedthat yellow color is the most fatigue color which could be related with this observation. Asobserved and shown in figure 1b yellow color has least perecentage survival in the field ascompared with the other colored mulch treatments. Kaspabeauer an Wilkinson (1995) stated thateven a small differences in FR to R ratio over the various colored mulch surfaces could have asignificant effect on plant development and since as they found out that red surfaces had higherFR to R ratio that would signal the plants to develop characteristics that would favor survivalamong relatively competition from other plants.

Weight of the Plant

Fig. 2 presents the weight of the lettuce grown in different colored mulch. Resultsshowed that the weight of the lettuce plant at harvest collected from treatment 2-red was theheaviest on all the treatments. Red plastic mulch causes plants to put more of their energy intoupper growth improving yields which could affect the weight of the plant. Yellow colored plasticmulch has the lightest plant weight. This implies that the different color of mulch had asignificant influence on the weight of the lettuce plant. Research conducted by Decotaeu (2008)mentioned that the lighter color mulches reflected more light; but a lower ratio of FR/R.Increasing in light intensity can affect plant development and yield through greater photosyntheticrates, and the ratio of FR/R is important in phytochrome regulation of plant physiologicalprocesses and can affect internode lengths and stem elongation, chloroplast ultrastructure, pho-tosynthetic efficiency, and photosynthate partitioning among leaves, stems and roots. Redplastic mulch has been reported to increase tomato yields and quality by various scientists, whileothers have reported a reduced severity of early blight in tomatoes. It also has been shown to


increase yields of strawberry, honeydews, muskmelons and zucchini. In addition, it has beenshown to significantly increase soil temperatures.

Leaf Diameter

Data pertaining to the effect of different colored plastic mulches on leaf diameter of lettucerevealead significant differences on the different colored mulch treatments. Lettuce grown in red,orange and silver colored plastic mulch had greater leaf diameter as compared to green andyellow mulch. These colors were statistically different from green and yellow colored plasticmulch. Smallest leaf diameter was observed under the yellow colored plastic mulch. Use ofcolored plastic mulches offers the possibilty of using basic principles of photomorphogenesis toenhance plant productivity. In this system, plants will grow in sunlight and in appropriate surfacecolor will reflect light of predetermined spectral balance up to the plant where it will be absorbedby photoreceptors and result in a desired plant response (Kaul and Kasperbaeuer, 1992). Someauthors concluded that the FR/R ratio in the upwardly reflected light over the various soil surfacecolors acted through the phytochrome system and played a major role in plant development.

Leaf Length

Fig. 4 indicates the result of lettuce leaf length. Significant differences were noted on thedifferent treatments. It was observed that lettuce obtained from red colored plastic mulch had thelongest length of leaves as compared with the other color treatments. Plant metabolism processesrely on the wavelengths inside red and blue light to regulate stages of photosynthesis, accordingto plant physiology. Red wavelengths stimulate carbon dioxide absorption, which is needed tomanufacture glucose materials which could be attributed for the longer leaves of lettuce grown inred colored mulch. This was followed by orange mulch. Green colored mulch had comparablemeans with the silver colred mulch. The shortest leaves were obtained from lettuce grown inyellow mulch.

Number of Leaves

In terms of the number of leaves at harvest, it was shown that significant differences onthe color treatments (Fig. 5). Lettuce grown in red mulch had most number of leaves ascompared with the other colored treatments. Followed by orange, green and silver. The leastnumber of leaves was observed in lettuce obtained from yellow colored plastic mulch. The colorthat has the highest influence on photosynthesis is blue, which is why many plant growers useblue lights to grow indoor plants. Red light is next best for photosynthesis and yellow lightcreates the lowest amount of light absorption. Thus, yellow plastic mulch resulted to the leastnumber of leaves produced.

Root Length

The data (Fig.6) shows the average length of roots in lettuce with the different coloredplastic mulch treatments. Significant differences were noted on the different treatments. Lettucegrown in red plastic mulch had the longest roots and was significantly different from the othertreatments. Followed by orange, green and silver, although they were not significantly different.Lettuce grown in yellow colored mulch had the shortest roots. The results was in accordance withthe study conducted by Kasperbauer (2010) that leaves of basil developing over red mulch, hadgreater area, succulent and heavier leaves than those grown in black. He also mentioned that col-ored-mulch technology relies greatly on "fooling" plants into behaving as if they face stiffercompetition for sunlight than they actually do. This is achieved when they receive high amountsof FR light. Plants reflect FR and sense reflected FR to gauge how close and dense othervegetation around them is.


Plant Height

The final height of the lettuce plants were determined at harvest. It was observed thatlettuce grown from red mulch were the tallest. Orange, green and silver colored mulch were notstatistically different which followed. The yellow colored mulch was the smallest. The color ofthe mulch also influenced the plant light environment. The lighter color mulches reflected moretotal light; but a lower ratio of far-red relative to red light. Increases in light intensity can affectplant development and yie1d through greater photosynthetic rates, and the ratio of FR/R isimportant in phytochrome regulation of plant physiological processes and can affect internodelengths and stem elongation, chloroplast ultrastructure, photosynthetic efficiency, and photosynthatepartitioning among leaves, stems and roots. According to Decoteau (2008) in red bell pepper,plants grown in red mulch were taller compared to the other colored mulch treatments. Kasperbaeur(2010) stated that the reflected FR from the red mulch tricked the plants to believe there was morecompetition thus development was stimulated and thus this could be a reason why the lettucegrown in red mulch were the tallest.

CONCLUSIONS

Lettuce ‘Red Rapids’ was grown under plastic mulch subjected to five different colorsmetallic silver, red, orange, yellow and green. Harvesting was done four weeks after transplanting.Results showed that on the percentage survival of the plants it was found to be significantlydifferent with yellow colored mulch as the lowest percentage of survival under field conditions.Other parameters tested namely; leaf length, leaf diameter, number of leaves, root length, plantweight, and plant height were also statistically tested and had shown to be statistically different.The results on all the parameters showed that red mulch had the best performance compared withthe other colored mulchs and lettuce grown in yellow colored mulch has the least performanceshowing the shortest and lightest plants.

RECOMMENDATIONS

Based on the results, there were significant differences on the different colored mulchsemployed as statistically analysed. It was observed that lettuce grown in red mulch performed thebest among the other colors used for mulch which was noted on all the parameters used on theroot lenght, leaf diameter, leaf length, plant height, number of leaves and plant height. Althoughin terms of percentage survival. Red colored mulch was not statistically different from orange andgreen but significantly different from yellow colored mulch. Dry weight of the samples shouldalso be determined in order to find out if there was differences in the assimilates. Black and clearplastic mulch could also be included in order to compare its differences with the other colors.Ttherefore, based on the results of this study, using of red mulch for better lettuce growth andsince it are recommended.

ACKNOWLEDGEMENTS

The assistance of the staff and field workers at the Vegetable Production Division,Department of Horticulture, ASC-CA, UPLB, College, Laguna is greatly appreciated.

Literature Cited

Decoteau, D.M. 2008. The emergence and early development of colored reflective plastic mulch technology in agriculture. Recent Advances in Agriculture: ISBN: 978-81-308-0222-0.

Hasing, J.E. 2002. Agroeconomic effect of soil solarization in fall planted lettuce. A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College.

Kasperbauer, M.J. 2010. More than meets the eye: New findings on how mulch color can affect


food plants. Auburn University, Auburn Alabama 36849. Auburn University.Kasperbauer, M.J.and Wilkinson, R.E. 1995. Mulch surface color affects accumulation of

epicuticular wax on developing leaves. Photochemistry and Photobiology, Vol. 62, No.5 pp.940-944.Kaul, K.J. and Kasperbauer M.J. 1992. Mulch color effects on reflected light, rhizosphere,

temperature and pepper yield. Ky. Acad. Sci (3-4) : 10.Lamont, J.W. 2004. Vegetable production using plasticulture The Pennsylvania State University

University Park, Pennsylvania 16802-4200 USA.Orzolek, M.D. 2004. The Effect of colored polyethylene mulch on the yield of squash, tomato and

cauliflower. The Pennsylvania State University, University Park, PA 16802.


Fig. 1a. Percentage of survival plants as affected by the different colored mulchs.

Fig. 1b. Percentage of survival plants in the field.

Fig. 2. Weight of plants as affected by coloredplastic mulch.

Fig. 3. Leaf diameter of plants as affected bydifferent colored plastic mulchs.

Figures


Fig. 4. Effect of colored mulchs on leaf length.

Fig. 5. Effects of different colored plastic mulchson the number of leaves.

Fig. 6. Roots length as affected by colored plasticmulchs.


Effect of Salicylic Acid on Somatic Embryogenesis andChlorogenic Acid Levels of Carrot (Daucus carota cv. Nantes)Explants

Many factors may influence the efficiency of somatic embryogenesis.This capability may be differ with regard to media compositions, genotype,tissue, organ ontology and the stage of differentiation. The effects of fivesalicylic acid concentrations (0, 25, 50, 75 and 100 µM) on different stagesof carrot somatic embryogenesis were studied using petiole and rootsecondary phloem explants as starting materials. The salicylic acid treatmentswere applied in two culture media; B5 and NL supplemented with 0.5 mgl-

1 2,4-Dichlorophenoxy acetic acid (2,4-D) and 1.0 mgl-1 Indole-3-aceticacid (IAA), respectively. The chlorogenic acid (CGA) levels produced bythe explants during embryogenesis were monitored using high performanceliquid chromatography (HPLC) technique. The results proved that petiolesare superior explants over root secondary phloems with regard to somaticembryogenesis. The B5 medium also exhibited induction of greater numberof embryos over NL medium. The results of the present study unequivocallysuggest that, irrespective of the type of explants and media culture, SA in-crements beyond than 75 µM negatively affect carrot somatic embryogenesis.A considerable elevation in CGA production during embryogenesis followingSA treatments was also found. Chlorogenic acid produced by cultures wascoincided with the SA treatments almost as the same manner that it affectssomatic embryogenesis process. Salicylic acid at the rate of 100 µMinduced highest level of CGA production and as result least number ofembryos was formed.

Keywords: Carrot, Chlorogenic acid, High performance liquid gas chromatography, Salicylic acid,Somatic embryogenesis.

Abstract

S. S. HosseiniDepartment of Horticulture, Pardis Faculty of Agriculture, Gorgan University of Agricultural Sciencesand Natural Resources (GUASNR),Golestan, Gorgan, I.R. Iran.K. MashayekhiDepartment of Horticulture, Pardis Faculty of Agriculture, Gorgan University of Agricultural Sciencesand Natural Resources (GUASNR),Golestan, Gorgan, I.R. Iran.M. Alizadeh*Department of Horticulture, Pardis Faculty of Agriculture, Gorgan University of Agricultural Sciencesand Natural Resources (GUASNR),Golestan, Gorgan, I.R. Iran.P. EbrahimiGonbad Institute of Higher Education, P.O.Box.163, Gonbad, Golestan, Iran.



INTRODUCTION

Somatic embryogenesis (a process in which a bipolar structure resembling a zygoticembryo develops from a non-zygotic cell) is a multi-step regeneration process starting withformation of pro-embryogenic masses, followed by somatic embryo formation, maturation andregeneration. It is an alternative to traditional vegetative propagation methods as it offers a rapidlarge-scale propagation system (Sobri et al., 2006). Acquiring embryogenesis potential has beenreported to be not analogous among different plants or even their various cells, but it is an innatecompetence that only in special circumstances, i.e. induction conditions, can be emerged (Bonetet al., 1998). This capability may be differ with regard to genotype, tissue, organ ontology and thestage of differentiation etc.(Hosseini, 2009). Many factors may influence the efficiency ofsomatic embryogenesis. The influence of exogenous growth regulators and the accumulation ofmetabolites during cell culture and somatic embryogenesis and possible role of such compoundsin plant improvement via somatic embryogenesis has been examined only in a few plants forinstance, date palm (El Bellaj and El Hadrami 1998), rice (Zhou et al., 2004) common bean(Luthria and Pastor-Corrales 2006) and cotton (Kouakou et al., 2007).

Salicylic acid (SA) or 2-hydroxybenzoic acid belongs to a diverse group of phenoliccompounds which encompasses an aromatic ring as well as one hydroxyl group. Salicylategenerally found in numerous plant species and owing to its implication in most of the biologicalevents has recently been grouped as a new plant growth regulator (Raskin, 1992a, b). Salicylicacid interferes in many biological events such as plant stomata closure, adventitious root initiationand thermogenesis during pollination. It can also be capable of furnishing resistance to pathogensand the biosynthesis of pathogenesis-related (PR) proteins and some kinds of phytoalexins. Inaddition, SA has a control over regulation of other plant growth substances as it inhibits ethyleneproduction (Quiroz-Figueroa, 2001; Hosseini et al., 2009).

There are numerous studies conducted on the effects of media compositions, mainly plantgrowth regulators on somatic embryogenesis. Salicylic acid as a new plant growth regulator(Raskin, 1992b) and its role in somatic embryogenesis has been targeted by many researches indifferent woody and herbaceous crops such as carrot (Roustan et al., 1990; Nissen, 1994), coffee(Quiroz-Figueroa et al., 2002), geranium (Hutchinson and Saxena, 1996), alfalfa (Meijer andBrown, 1988) and Astragalus (Jian-Ping et al., 2001). Roustan et al., (1989) reported that salicylicacid (50 µM) induces somatic embryogenesis in carrot hypocotyls whereas Hutchinson and Saxena(1996) accomplished embryogenesis in Geranium using lower concentrations of salicylic acid (20µM). Working with carrot petioles, it was found that higher levels of salicylic acid (more than 100µM) not only did not encourage somatic embryogenesis but also inhibited the same (Nissen, 1994).Corroboratory findings were already reported in alfalfa as well (Meijer and Brown, 1988).

Phenolic compounds constitute a wide range of plant substances which all possess anaromatic ring bearing one or more hydroxyl groups (Harborne, 1998). They are considered asdetrimental compounds during in vitro culture, since their exudation and oxidation negativelyaffect the explants due to browning and necrosis (Benson 2000, Martin and Madassery, 2005).However, there are some reports on positive effects of phenolic compounds on in vitro morphogenicprocesses such as root formation and elongation, shoot proliferation,organogenesis, androgenesisand even somatic embryogenesis (Reis et al., 2008).

A major class of phenolic compounds are hydroxycinnamic acids, which are found inalmost every plant. Phenolic compounds, their antioxidant properties and distribution in carrotswere investigated by Zhang et al., (2004). They reported that carrots contained mainlyhydroxycinnamic acids and derivatives. Among them chlorogenic acid (CGA) was a major hy-droxycinnamic acid, representing from 42.2% to 61.8% of total phenolic compounds detected indifferent carrot tissues.

Reis et al., (2008) observed that exogenous phenolic compounds added to the embryogenic


induction medium of Feijoa explants affect both the somatic embryogenesis induction and thefurther somatic embryo germination. Furthermore, their microscopic analysis showed a strong re-lationship between somatic embryo development and phenolic-rich cells. There are some otherworks representing that phenolic compounds are often positively associated with somatic embryoformation. Working with coffee, it was found that embryogenic calli developed only afterbrowning of the initial explant (Neuenschwander and Baumann 1992). The browning and/orexplants necrosis process, which is normally deleterious during in vitro culture, does not damagesomatic embryo formation in their experiment. In the other hand, a more detailed analysis of theliterature shows that differentiation of somatic embryos in some plants like cocoa is coincidentwith a decrease in phenolic content (Ndoumou et al., 1997).

The present study was also conducted to examine somatic embryogenesis of two differentcarrot explants (petiole and root secondary phloem) cultured in two culture media and to explorethe effects of elevated salicylic acid levels on CGA production and overall somatic embryogenesis.


The present investigation was carried out in the Plant Tissue Culture Laboratory, HorticultureDepartment, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.

Explant Selection, Preparation and Culture

Two types of explants (petiole / root secondary phloem) were exploited for cultureestablishment procured from carrot (Daucus carrota cv. Nantes). Initially, the seeds/roots werewashed thoroughly with normal tap water (30 min.) and surface sterilized with ethanol (70% v/vfor 40 sec.) followed by sodium hypochlorite solution (5% v/v plus two drops of tween-20 for 15min. ). Sterile petioles were obtained following in vitro seed germination on full strength, solid,hormone free B5 medium (Gamborg et al., 1968 ). The sterilized, clean roots were transverselycut up employing a hand mirotome. Disk-like, uniform explants were obtained by the help of aTrokar instrument. The media utilized for culture establishment were liquid B5 and NL (Neumann,1966) containing 2,4-D (0.5 mgl-1) and IAA (1.0 mgl-1), respectively.

Salicylic Acid Treatments, Growth Conditions and Sub-culture Intervals

Five salicylic acid concentrations (0, 25, 50, 75 and 100 µM) in four replications wereapplied. The treatments in B5 medium were applied both in induction and realization phases ofembryogenesis while in NL medium the same treatments were applied only in realization phase(in NL medium IAA was used as auxin source and there is no distinct phase for induction andrealization as B5 medium). The cultured secondary phloem explants in Erlenmeyer were placedon a horizontal shaker (120 rpm) and the petiole explants were cultured in distinctive "nipple"culture flasks and arranged on an auxophyton apparatus (to rotate containers around a horizontalaxis at the rate of 2 rpm). All the inoculated containers were incubated at 27 ±2°C withcontinuous light generated by cool white fluorescent tubes (2000 lux). Petiole and secondaryphloem explants growing on B5 medium were sub-cultured 3 and 5 weeks after inoculation re-spectively. Fresh, hormone-free B5 medium was used for this purpose. The petiole / phloemexplants were examined for embryo development 3 and 5 weeks after sub-culture, respectively.The explants cultured on NL media were also examined for embryo development 5 (petiole) and7 (phloem) weeks after inoculation. The embryos were observed under stereoscope connected toa monitoring system (20x and 40x magnification).

Estimation of Chlorogenic Acid

Plant Material Extraction

Following embryo observations by formerly above mentioned monitoring system the


samples were oven dried (50ºC) and finely powdered from which 1 g was taken and transferred toa glass vial. Extraction was done using a reflux method comprising a simple water circulatingsystem and a magnetic heater using Acetone (30 ml) as solvent. This was done for 1 hourfollowed by centrifugation (4000 rpm for 5 min.) The supernatant was isolated and debris wasdissolved in 30 ml acetone and extraction procedure was again repeated for 1 hour. The finalsolution was evaporated using a rotary evaporator adjusted to 50ºC. Prior to HPLC analysis eachsample was dissolved in methanol (1 ml) by the help of an ultrasonic water bath. All extracts werefiltered through 0.22 mm filters (Sigma, USA) and aliquots (25 ml) were analyzed by HPLC.

Chlorogenic acid standard was HPLC-grade purity procured from (Sigma, USA). HPLCwas performed with a Merck Hitachi (MH) system (Merck Hitachi, Japan) comprising a quaternarypump (MH, L-7100), a vacuum degasser (Merck L-7614), a UV detector (Merck L-7400), and a20-μL sample injector (injector 2041 series, USA). Compounds were separated on a 250 mm ×4.6 mm, C-18 column (Merck, Germany). Detection was carried out at 270 nm. The mobile phasecomprised a mixture of acetonitril (10 ml), acetic acid (1 ml) and deionized water (98 ml).Acetonitrile and water were of HPLC-grade purity. Acetic acid was of analytical grade. Acalibration curve also was constructed using the integrator values obtained from the quantificationof standard solutions.

Experimental Design And Data Analysis

The present experiment was conducted as complete randomized design in factorialarrangement (explant × treatment × medium) with four replications. The percentage data weretransformed using root square method (√ % + 0.5) prior to analysis. The results were analyzedusing SAS software and the mean values were compared by LSD test in p < 0.01 probability.


Somatic Embryogenesis

The procedures for carrot somatic embryogenesis using B5 and NL media were alreadystandardized in our laboratory (Hosseini, 2009) and based on that sub-experiments includingeffects of different salicylic acid treatments were performed. The analyzed data for somatic em-bryogenesis is shown in Table 1. A significant difference between two media culture was recordedwith regard to all stages of embryogenesis. The B5 medium showed higher potential forembryogenesis and more number of embryos were recorded as compared to NL medium. Apartfrom the media compositions, the synthetic auxin (2,4-D) supplemented to B5 medium can beconsidered as a source of variation and appearance of higher numbers of somatic embryos.Encouraging role of synthetic auxins, particularly 2,4-D in plant somatic embryogenesis is wellknown and many reports have revealed that adding 2,4-D to the medium will alter the somaticcells differentiation. The results of the present study for influence of natural / synthetic auxins onembryogenesis are analogous to records reported for banana (Strosse et al., 2006) and guava (Raiet al., 2007) embryogenesis.

Besides normal somatic embryos (Fig.1b), some embryoides, so called neomorph embryoswere also developed (Table 1). These are actually under-developed embryos with abnormal mor-phological stature (Fig. 1a). The higher number of neomorphs was recorded in explants preparedfrom secondary phloem. Also, more number of neomorphs was recorded in B5 as compared toNL medium. Generation of neomorphs was also found to be affected by SA treatments. Though itwas not significantly different with control, but apparently the highest level of neomorph embryoswas found in explants treated with SA 100 µM. John et al., (1995) reported that these types ofembryos are induced during embryogenesis but they are not released to the culture medium asother normal ones. Developing these embryos and their maturation are not only associated to en-dogenous auxins but also highly correlated with the presence of higher concentration of abscisic


acid in the medium.In addition to embryogenesis, root formation also occurred in some explants (Fig. 1c).

Two B5 and NL media were significanltly different with regard to adventitious root formation(Table 1). Auxins can be considered as a source of root induction in explants as IAA, a naturaland photosensitive auxin was incorporated in NL medium, rooting is induced but IAA is graduallyvanished due to photoxidation and as a result roots are emerged more rapidly.

Influence of Salicylic Acid Treatments

The results clearly demonstrated the significant effects of salicylic acid supplementationon different stages of somatic embryogenesis (Table 2). Apart from highest level of SA (100 µM),the numbers of embryos were considerably increased following SA addition to both media.Different embryos observed in B5 medium supplemented with SA (50 µM) is shown in Figure 1.In fact, low concentrations of SA stimulated rather than inhibited embryo formation. However,the results of the present study unequivocally suggest that, irrespective of the type of explants andmedia culture, SA increments beyond than 75 µM negatively affect carrot somatic embryogenesis.Somatic embryogenesis was already induced from suspension cultures (derived from leaf callus)of Plumbago rosea L. an important medicinal plant (Komaraiah et al., 2004). Furthermore, theyobserved that acetylsalicylic acid (ASA) alone induced embryogenesis but indole-3-acetic acid(IAA) failed to elicit a similar response. While considering the salient points of the present study,it can be stated that SA at the rate of 50 and 75 µM are the most excellent levels for carrot somaticembryogenesis. In a preliminary study (data not shown) we observed that addition of 0.5 mM andmore SA can completely inhibit carrot somatic embryo formation in either B5 or NL media.

Chlorogenic Acid Production

Generally in carrot, somatic embryogenesis is occurred in two distinct phases i.e. inductionand emergence phases (Kamada and Harada 1979; Fridborg et al., 1978). It means, embryogeniccells, which have embryonic competence, are induced when explants are cultured on mediumcontaining 2,4-D (induction phase). Somatic embryos are formed following transfer of inducedcells to the medium devoid of 2,4-D (emergence phase). However, when embryogenic cells arecultured at high cell density, somatic embryogenesis is strongly inhibited, even with the use of2,4-D-free medium. The efficiency of somatic embryo formation can be improved by addingactivated charcoal, which absorbs some inhibitory factors. Various phenolic compounds are accu-mulated in culture medium when charcoal is not present. For this reason, phenolic compoundshave long been thought to inhibit somatic embryogenesis.

Previous studies revealed that carrots contained mainly hydroxycinnamic acids andderivatives that among them CGA was found to be a major hydroxycinnamic acid (Zhang et al.,2004). Therefore we estimated various CGA levels during carrot embryogenesis as affected bysalicylic acid treatments. Table 2 shows mean values of CGA levels produced by two carrotexplants in B5 and NL media supplemented with different salicylic acid concentrations. Therewas not any significant difference between two media with regard to CGA evolution; howevertwo carrot explants produced different levels of chlorogenic acids and phelom comprised morequantity of this phenolic compound as compared to petiole. Zhang et al., (2004) also found thatPhenolic content in different carrot tissues decreased from peel, phloem to xylem. So, it can bestated that CGA content is also tissue specifically produced. Furthermore, our salicylic acidtreatments considerably raised the CGA production (Table 2). The results of the HPLC analysisobviously authenticated a considerable elevation in CGA production during embryogenesisfollowing SA treatments (Table 3). It is clear that, following treatment with 25, 50 and 75 µM SA,the CGA was also produced but in lower concentrations than 100 µM. The results presented byReis et al., (2008) indicated that exogenous phenolic compounds added to the embryogenic


induction medium of Feijoa affect both the somatic embryogenesis induction and the furthersomatic embryo germination. They found that caffeic acid (140–560 µM) significantly increasedsomatic embryogenesis induction compared with the control. In the other hand, Ndoumou et al.,(1997) demonstrated the unhelpful effect of phenolic compounds on somatic embryogenesis of cocoa.

In conclusion, it can be stated that carrot petioles are superior explants over root secondaryphloems and somatic embryogenesis may be performed efficiently using the former explantscultured on B5 medium. Salicylic acid enhances somatic embryogenesis in a dose-dependentmanner up to 75 µM and beyond that inhibits the same. Chlorogenic acid produced by cultureswas coincided with the SA treatments almost as the same manner that it affects somaticembryogenesis process. Salicylic acid at the rate of 100 µM induced highest level of CGAproduction and as result least number of embryos was formed.

ACKNOWLEDGEMENT

The authors are thankful to Mrs Rastegar, Central Laboratory, GUASNR, Gorgan, Iran forher kind cooperation and assistance during HPLC analysis.

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Tables

Source of variation Somatic embryogenesis

Medium

Explant

SA

treatments

(µM)

B5NLLSD

PetiolePhloemLSD

0

25

50

75

100

LSD

Globular

7.94a

7.48a

0.55

8.33a

7.23b

0.47

6.72c

7.90b

9.49a

9.33a

5.46d

0.81

Heart-shaped

7.02a

5.97b

0.44

7.08a

6.25b

0.41

4.75c

6.94b

8.57a

8.75a

4.30d

0.66

Torpedo

6.49a

5.14b

0.51

6.32a

5.75b

0.48

4.39c

5.95b

7.84a

8.07a

3.92d

0.76

Cotyledonary

6.15a

4.90b

0.51

6.51a

4.95b

0.47

4.43c

6.04b

7.50a

4.43a

3.63d

0.75

Neomorph embryos

5.80a

4.39b

0.46

5.77a

4.88b

0.44

6.39a

5.29b

4.13c

4.25c

6.58a

0.69

Total embryos

14.08a

12.07b

0.60

14.40a

12.41b

0.56

10.55c

13.64b

16.93a

16.86a

9.05d

0.89

Number of roots

4.20b

5.49a

0.40

5.21a

4.04b

0.38

5.33b

6.21a

3.08c

3.02c

5.50b

0.61

Table 1. Mean values for number of carrot somatic embryos as affected by explant, medium and salicylic acid treatments.

Table 2. Mean values of chlorogenic acid produced by two carrot explants in B5 and NL media supplementedwith different salicylic acid concentrations.

Source of variation Chlorogenic acid (%) LSD

Medium

Explant

Salicylic acid treatments (µM)

B5NL

PetioleRoot secondary phloem

0255075100

6.475a

7.184a

2.227b

11.196a

3.142d

3.190d

5.206c

7.528b

14.492a

0.979

0.923

1.460


Figures

Fig 1. Under-developed or neomorph embryo (a) and normal embryos (b); Callus and roots

produced from petiole explants cultured on NL medium supplemented with 25 µM salicylic acid(c).

www.jornamental.com


The Effects of Different Floral Preservative Solutions

on Vase life of Lisianthus Cut Flowers

Two factorial experiments were conducted to study the interactiveeffects of four levels of sucrose (0, 20, 40 and 60 g l-1), two levels of citricacid (0 and 160 mg l-1) and two levels of one of the following compounds(aluminum sulphate, 0 and 160 mg l-1 and silver nitrate, 0 and 120 g l-1) onvase life and quality attributes of lisianthus cut flowers ‘Mariachi bluefonce.’ The experiments carried out a randomized complete block designwith three replications. After 34 days of storage at 20± 2 oC the amount ofwater absorption, relative water content and opened flower buds were deter-mined. According to the results application of 60 g l-1 sucrose in combinationwith citric acid led to the highest vase life (31 days). The highest relativewater content (82.37%) and also the highest percentage of opened flowerbuds were obtained in flowers treated with 60 g l-1 sucrose and 160 mg l-1

aluminum sulphate.

Keywords: Aluminum sulphate, Citric acid, Relative water content, Silver nitrate, Sucrose, Vase life.

Abstract

M. KiamohammadiDepartment of HorticultureIslamic Azad University, Abhar BranchZanjanIranD. HashemaabadiDepartment of Horticultural Science Islamic Azad University, Rasht BranchRashtIran



INTRODUCTION

Lisianthus (Eustoma grandiflorum) from Gentianaceae family is from wild flowers ofnorth and west America. It is native of Nebraska, Colorado and Texas. Another names oflisianthus are ‘Parirgentiane’, ‘Eustoma’ and ‘Texas Blue Bell’ which the scientific name obtainedfrom ‘Eustoma’ (Reid, 2009). Lisianthus in horticulture known both as indoor ornamental potplant and cut flower. At present, there are in different color and shape and it is grown as cut flowerin wide parts of the world. There are about 10 hactare of orchards under lisianthus in England.U.S.A, Netherland, Isreal, Kenia, Tanzania and Japan are major producers of this plant (Ohkawa& Sasaki, 1999). In recent decade, lisianthus as a cut flower increasingly known in all over theworld (Reid, 2009) and because of their similarity with rose and more vase life than rose, hadbeen located in 10 major cut flowers of the world.

Treatment of cut flowers with 2% sucrose, increases anthesis and develops color, remarkably(Ichimura & Korenaga, 1998).

The effect of Al2(SO4)3 (50, 100 and 150 mg l-1) had been tested on lisiantus vase life. Theresults indicate that applying 150 mg l-1 Al2(SO4)3 in 25°C increases vase life by 4.15 days, whilecontrol plants wilted after 3 days. Also, Al2(SO4)3 had positive effect on water uptake rate andraising fresh weight (Liao et al., 2001).

Also, it had been reported that AgNO3, STS and Al2(SO4)3 are the most importantbactericides that are used in preservative solutions (Figueroa et al., 2005).

Most of cut flowers including lisianthus have short vaselife which affect on production,selling and export. The most important goal of this research is to access a cheaper preservativesolution which can diminish the problem of storage and transport of lisianthus cut flowers by theleast environmental pollution and make possible supply and export into different part of theworld.


Lisianthus cut flowers, ‘Mariachi Blue fonce’, harvested in 40 cm length and had two openbuds in early morning and transferred to laboratory, quickly. Then flower had been located intopots contain 250 ml preservative solutions. In each pot, 3 cut flowers had been located. In vase liferoom light intensity was 15-20 µmol s-1 m-2 and photoperiod was 12 hours from fluorescent whitelight, relative humidity was about 60% and environmental temperature was 20± 2 °C.

In order to investigation of the effects of various preservative solutions on vaselife of cutliciantus, two different experiments performed as factorial experiment based on RCBD in 3replications. In the first experiment, the effects of sucrose (S1=0, S2=20, S3=40, S4=60 g l-1), citricacid (C1=0, C2=160 mg l-1) and Al2(SO4)3 (A1=0 & A2=160 mg l-1) and in the second experiment,the effects of sucrose (S1=0, S2=20, S3=40, S4=60 g l-1), citric acid (C1=0, C2=160 mg l-1) andAgNO3 (V1=0 and V2=120 mg l-1) had been investigated on licianthus cut flowers, continuously.In each experiment, we have 16 treatments, 48 plots and 144 cut flowers.

Changing of preservative solutions and 2 cm recutting of cut flowers carried out in every 10 days. Vase life was ended when the last

flower wilted. A wilted flower is a flower which their petal loses its turgidity.Relative water content (RWC) in leaves calculated due to Nerd and Nobel formula (1991): RWC = (fresh weight – dry weight)/ (saturation weight-dry weight) 14th Days, after starting the experiment, 1/3 of leaves was sampled. Then, in order to

measure saturation weight, samples maintained in a tubes containing distilled water in 4°C for 24hours. In order to obtain dry matter, samples maintained in an oven with 60°C for 3 days.

For evaluated the effect of chemical treatments on the percent of opened bud, the numberof flowers (open flowers, semi-open flowers and wilted flowers) and completely closed budsavailable in the first day and also the number of flower available in the end of vase life had been


calculated and the percent of opened bud calculated according the following formula:

Opened flowers = The number of flower in last day -The number of flowers in first day The number of flowers in first day Data were analysed with MSTATC software, means were compared with DNMRT and

figures were prepared with Excel software.


Vase life

Sucrose increased vase life of flower compared to control plants (table1). Mean comparisonthe of AgNO3 indicated that, with existing of 120 mg l-1 AgNO3 in the preservative solution, vaselife of cut flowers increased compared to control plants and reach to 27 days (table 1).

The results of present research agreed with Ichimura and Hiraya (1999) states that thetreatment with sucrose, cause to increase vase life in cut Lathyrus. Also the results of this researchwell supported the data from Anjum et al., (2001). He said that AgNO3 to inhibits bud openingand increasing vase life in tuberose cut flowers. Sucrose can provide the energy needed to cellprocesses including maintain the structure and function of mitochondria and the other cellularorganelles (Capdeville et al., 2003). Also, sucrose is the important material which obtainedthrough photosynthesis and transferred in to the plant, widely (Halevy and Mayak,1981; Kuiperet al., 1995; Huang and Chen, 2002 and Williamson et al., 2002).

Sucrose in preservative solution can replaces with the losses carbohydrates and preventsall activity related to senescence (Goszczynska and Rudnicki, 1988). Also, Van doorn (2001)reported that flowers in present of sugar, are resistant to ethylene. In postharvest treatments,sucrose can directly prevents from ACC oxidise and ACC synthase and delays the senescence(Nakai et al., 1997).

Ag+ blocks the special receptors on cell membrane and prevents from ethylene activitydelays the senescence (Capedeville et al., 2003).

Mean comparison from interaction between sucrose, citric acid and Al2(SO4)3 indicatedthat the vase life of 60 g l-1 sucrose +160 mg l-1 citric acid was 31 days and vase life of flowers in60 g l-1 sucrose + 160 mg l-1 Al2 (SO4)3 was 28 days (Fig. 1).

The mean comparison interaction effect of sucrose, citric acid and AgNO3 indicated thatvase life of cuts in 60 g l-1 sucrose +160 mg l-1 citric acid 31 days and vase life of cuts in 60 g l-1

sucrose +160 mg l-1 citric acid +120 mg l-1 AgNO3 was 31 days, while the vase life of flowers incontrol plants was 14 days. Adding AgNO3 to 60 g l-1 sucrose + 160 mg l-1 citric acid had noteffect on increasing the vase life of cut flowers until more than 3 days (Fig. 2). This results cansupported Reid (2009), who reported that, cut lisianthus is slightly sensitive to ethylene.

Relative Water Content

Various concentrations of sucrose in all experiments indicated that, sucrose in preservativesolution can increases relative water content (table 1).

Sucrose as a main material used in respiration (Liao et al., 2000) and can increase therespiration. Steam from respiration become a part of total water mass in cell which calledmetabolic water (Meyer et al., 2002). In addition, sucrose in this research had been preventedfrom the reduction of fresh weight. Although, sucrose reduced water uptake, but with existence ofsucrose in the preservative solutions, relative water content in petals had been increased.

Kiamohamad et al., (2009) reported that AgNO3 increased water uptake in lisianthus cutflowers and this can a reason to increase relative water content in the petals of lisianthus cutflowers. In this experiment, 60 g l-1 sucrose +160 mg l-1 Al2(SO4)3 was the most effectivetreatment to increase relative water content (82.37%) in the petals of cut flowers (Fig. 3). Our


results are agreed with the report of khan et al., (2006). They observed that with 40 g l-1 sucrose+ 200 mg l-1 Al2(SO4)3, relative water content increased in leaves and petals of cut tulips.

Also, 160 mg l-1 citric acid + 120 mg l-1 AgNO3 had significant effect on raising of relativewater content (81,44%) in the petals of cut lisianthus (Fig. 4). Over transpiration can causes towater deficiency (Vandoorn, 1997) and reducing relative water content in the plant Al3 + can stoptranspiration in the plants. In this research, Al2(SO4)3 increased water uptake in cut lisianthus.

Bud Opening

Sucrose, citric acid, AgNO3 and Al2(SO4)3 individually, increased bud opening (table1).The results of current experiment about being more effective of high sucrose concentrations areagreed with Doi and Reid (1995) on gladiolus and liathris. It seems that carbon is a key factor toanthesis (Yamane et al., 1991). It is possible that sucrose applied as a osmolite in anthesis of cutflowers (Liao et al., 2000).

The results from mean comparison of interaction effects of sucrose + citric acid +Al2(SO4)3 indicated that, the most bud opening percent observed in 60 g l-1 sucrose + 160 mg l-1

Al2(SO4)3 and the lowest bud opening percent observed in 160 mg l-1 citric acid without sucroseand Al2(SO4)3 (Fig. 5). Cell growth which have direct relation with anthesis, needed to wateruptake (Capedeville et al., 2003)

Embolism can reduce the water uptake + sugar from preservative solution and it canreduces anthesis (Srilaong and Buanong, 2006). Al2(SO4)3 is the most important bactericidewhich as same as citric acid have positive effect water uptake rate and consequence in anthesis(Liao et al., 2001).

Literature Cited

Anjum, M. A., Naveed, F., Shakeel, F. and Amin, S. 2001. Effect of some chemicals on keeping quality and vase life of tuberose ‘Polianthus Tuberosa L.’ cut flowers. J. Res. Sci., 12:1-7.

Capdeville, G. de., Maffia L. A., Finger F. L. and Batista U. G. 2003. Gray mold severity and vase life of rose buds after pulsing with citric acid , salicylic acid, calcium sulfate, sucrose and silver thiosulfate, Fitopatol., Bras, 28:380-385.

Chnabl, H. and Ziegler, H. 1975. Uber die Wirkung von Aluminiumionen auf die Stomatabewegung von Vicia faba-Epidermen, Z. Pflanzenphysiol, 74:394-403.

Doi, M. and Reid M. S. 1995. Sucrose improves the postharvest life of cut flowers of a hybrid limonium, HortScience, 30:1058-1060.

Figueroa, I., Colinas M. T., Mejia J. and Ramirez F. 2005. Postharvest physiological changes in roses of different vase life. Cien. Inv. Agr., 32:167-176.

Goszczynska, D.M. and Rudnicki, R.N. 1988. Storge of cut fliwers. Hort. Rev., 2: 35-62. Halevy. A. H. and Mayak, S. 1981. Senescence and postharvest physiology of cut flowers. part 2.

Hort.Rev., 3: 59-143. Huang, K. L. and Chen,W. S. 2002. BA and sucrose increase vase life of cut Eustoma flower.

HortScience, 37:547-49. Ichimura, K. and Hiraya, T. 1999. Effect of silver thiosulfate complex (STS) in combination with

sucrose on the vase life of cut sweet pea flowers. J. Japanese Soc. Hort. Sci., 68:23-27.Ichimura, K. and Korenaga, M. 1998. Improvement of vase life and petal color expression in

several cultivars of cut Eustoma flowers by sucrose with 8-hydroxyquinoline sulfate. Bulletin of the National Research Institute of Vegetables, ornamental plants and tea, Japan, 13:31-39.

Khan, F. U., Khan, F. A., Hayat, N. and Bhat,S. A. 2007. Influence of certain chemicals on vaselife of cut tulip. Indian J. of Plant Physiol., 12:127-132.

Kiamohammadi, M., Golchin, A. and Hashemabadi, D. 2009. Optimizing the post harvest lifre of Cut Lisianthus. M. Sc. Thesis. Faculity of Agriculture Abhar University, Iran.


Kuiper, D., S., Ribot,H. S., Van, R. and Marissen, N. 1995. The effect of sucrose on the flower bud ripening of 'Madelon' cut roses. Sci. Hort., 60:325-36.

Liao, L. J., Lin,Y. H., Huang, K. L. and Chen, W. S. 2001. Vase life of Eustoma grandiflorum as affected by aluminum sulfate. Bot. Bull. Acad. Sin., 42:35-38.

Liao, L. J., Lin,Y. H., Huang K. L., Chen ,W. S. and Cheng, Y. M. 2000. Postharvest life of cut rose flowers as affected by silver thiosulfate and sucrose. Bot. Bull. Acad. Sin., 41:299-303.

Meyer, B., Anderson, D. B., Bohning, R. H., Fratianne, D., lesani, H. and Mojtahedi, M. 2002. Introduction to plant physiology, Tehran univ. press, 726.

Nakai, T., Tonouchi, N., Tsuchida, T., Mori, H., Sakai, F. and Hayishi, T. 1997. Synthesis of asymmetrically labeled sucrose by a recombinant sucrose synthase, Bioscience Biotech, Biochem, 61:1955-1956.

Nerd, A. and Nobel, P. S. 1991. Effects of drought on water relation and nonstructural carbohydrate in cladodes of opuntia ficus-indica, Physiol. Plant. 81: 495-500.

Ohkawa, K. and Sasaki, E. 1999. Eustoma (Lisianthus) ITS past, present, and future, Acta Hort., 482: 423- 428.

Reid, M. S. 2009. The commercial storage of fruit, vegetables and florist and nursery stocks, USDA handbook 66: 36.

Srilaong, V. and Buanong, M. 2007. Effect of Chlorophenol and 8-Hydroxyquinoline Sulphate on Vase Life of Cut Rose ‘Rosa hybrida L. ’, Acta Hort., 755:455-450.

Van Doorn, W. G. 1997. Water relation of cut flower, Hort. Rev., 18: 1-85. Van Doorn, W. G. 2001. Role of soluble carbohydrates in flower senescence: a survey. Acta Hort.

543:179-183.Williamson, V. G., Faragher, J., Parsons , S. and Franz, P. 2002. Inhibiting the postharvest

wounding response in wild flowers, A report for the rural industries research and development corporation.

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Treatment First experiment

Vase life (R.W.C) Bud opening

(days) (%) (%)

Second experiment

Vase life (R.W.C) Bud opening

(days) (%) (%)

Sucrose

(g l-1)

Citric acid

(mg l-1)

Al2 (SO4)3

(mg l-1)

AgNO3

(mg l-1)

0 (S1)

20 (S2)

40 (S3)

60 (S4)

0 (C1)

160 (C2)

0 (A1)

160 (A2)

0 (V1)

120 (V1)

14 d*

22 c

25 b

28 a

23 a

22 b

22 a

22 a

-

-

48.96 c

59.89 ab

55.80 b

61.32 a

62.64 a

50.37 b

55.54 a

57.44 a

-

-

18.58 d

45.96 b

39.82 c

59.56 a

40.23 a

41.74 a

37.6 b

44.37 a

-

-

15 c

26 b

28 ab

29 a

23 b

25 a

-

-

23 b

27 a

58.56 b

67.48 a

62.85 ab

59.19 b

64.68 a

59.36 b

-

-

55.54 b

68.50 a

20.89 c

46.67 b

49.37 b

58.59 a

41.71 b

46.05 a

-

-

37.59 b

50.17 a

*Means followed by some letter within each column don’t differ significantly according to Duncan multiple range

test at P≤0.01

Table 1. Mean comparison of effect of different chemical compound on traits

Tables


Fig.1. Interaction between Sucrose(S), Citric acid(C) and Al2(SO4)3 (A) on vase

life of cut lisianthus

Fig.2. Interaction between Sucrose(S), Citric acid(C) and AgNO3 (A) on vase

life of cut lisianthus.

Fig.3. Interaction between Sucrose(S), Citric acid(C) and Al2(SO4)3 (A) on

RWC.

Figures


Fig.4. Interaction between Sucrose(S), Citric acid(C) and AgNO3 (A) on

RWC.

Fig.5. Interaction between Sucrose(S), Citric acid(C) and Al2(SO4)3 (A) on

bud opening.


Study on Some Chemical Compounds on the Vase Life

of Two Cultivars of Cut Roses

Rose (Rosa hybrida L.) is one of the mostly cultivated cut flowers inIran and around the world. The study was carried out to increase the vaselife and quality of cut rose ‘Grand Prix` and ‘Avallanche` by using variousfloral preservative solutions. Floral preservative solutions were AgNO3,8-HQS, nano silver and distilled water. Treatments were compared with tapwater as control. The experiment was arranged in a randomized completeblock design. The effects of applied treatments on longevity and quality ofcut rose flowers were evaluated by using the percentage of opening theflower, flower diameter, the vase life and relative fresh weight. Resultsshowed that the flowers treated with 8-HQS (250 mg l-1) + nano silver(2mg l-1) had the highest flower diameter and the percentage of opening theflower among treatments. Maximum vase life (14.33 d) of cut rose obtainedwith (nano silver 2mg l-1), and minimum (6.54 d) with AgNO3. The vase lifeof control was 5.79 d.

Keywords: Distilled water, Nano silver, Rose, Silver nitrate, 8-hydroxy quinoline sulphate.

Abstract

S. Mohammadi Ostad KalayehGraduated Student of Islamic Azad University.Scinece and Research Branch,TehranIranY. Mostofi,Associated Prof.University of Tehran.Karaj,IranM. BasiratScientific member of Soil and Water Research CenterTehranIran

*Corresponding author email: [email protected]


INTRODUCTION

Rose (Rosa sp.) is belong to Rosaceae family which identified as the highest demandflower in world (Khalighi & Shfiei, 1994). One problem in our country is postharvest waste ofhorticultural products, especially ornamental plants. Rose has short vase life. The most importantway to effects of ethylene on horticultural products, especially cut flowers, is to use of chemicalmaterials for blocking activity or synthesis of ethylene. This materials included that carbohydrates,bactericides, biocides, acidosis and ethylene inhibitors (Ebrahimzadeh and Seifi, 1999). Applicationof some compound such as sucrose or 8-hydroxy quinoline (8-HQ) is effective to increase vaselife of cut roses (Michalcznk et al., 1989).

Among the preservative solutions which are used to increase cut flowers longevity,8-HQ is more effective to control microbial agents and mostly uses in many of cut flowers(Kader, 2002; Reddy et al., 1995; Khalighi and Shafiei, 1994 and Hussein, 1994). Somepart of suitable effect of 8-HQ had been attributed to the water balance and closing ofstomata.

Also, 8-HQS and 8-HQC, cause to acidify of water and using them continuously, hadbeen increased vase life of cut roses remarkably, and when it used with sucrose, because offacilitating in transfer water through vessel elements, cause to increase sugar in petals and toincrease flower diameter (Ichimura and Sotu, 1999). It had been reported that using 8-HQS incut Lisianthus improves flower vase life (Ichimura and Korenaga, 1998). In a research, Reddy etal., (1995), used mixed compounds such as citric acid, 8-HQS and sucroce. 8-HQS and %4sucrose caused to increase flower longevity by 16 days and improve water retention and wateruptake by flowers.

Two common compounds containing silver which are used for cut flowers are AgNO3 andSTS (Azadi et al., 2001 and Fahmy et al., 2005). AgNO3 is relatively unmobile in plant and actsas an antimicrobial and ethylene blocker factor in plants (Bartoli et al., 1996). Effects of AgNO3

was studied on vase life and bud opening in cut orchids (Dendrobium pompadour), resultsshowed that AgNO3 is better than STS in controlling of microbial growth and increasing in budopening and vase life (Ketsa, 2000). Today, several chemical compounds were introduced forpreservation of plant against pathogens and increasing of vase life, but some of these compoundshave side effects for environment. Silver nano particles are good and safe antibacterial tool for or-namental and horticultural products.

Main aim of this study is research on effects of different chemical compounds such asAgNO3, 8- hydroqy quinoline sulphate (8-HQS), SNP and distilled water for increasing vaselifeof cut roses ‘Grand prix’ and Avalanche’.


Cut roses ‘Avalanche’ and ‘Grand prix’ harvested from a greenhouse around Takestan incommercial stage and after pre-cooling in temperature 5 °C for 4 hours, transferred to laboratory.All of the flowers harvested in optimum physiological stage. The flowers recutted under the waterand the height of all flower branches set on 55 cm.

The leaves and blades of lower part of branches eliminated and only 3 leaves over the stemprotected. Then the concerned treatments performed on them (Table 1). Environmental conditionsin vase life room was: temperature 19-21°C, photoperiod 9 hr, light intensity 15-20 µmol s-1m-2

using white fluorescent lamp and 60% relative humidity.

Experimental Design and Treatments

This experiment had been performed in RCBD on two cultivar of cut roses ‘Avalanche’and ‘Grand prix’ with 11 different chemical treatments in three replications, each plot was include4 cut flowers. Chemical treatment in this experiment is as follow (Table 1).


Measurement of Characteristics

Relative fresh weight, fresh weight to dry weight ratio, flower diameter, flower openingand vase life were measured. Vase life finished with some symptoms such as necrosis, wilting andabscission of petals, chlorosis and abscission of leaves, bent neck and outrolling of petals whichcause to reduce flower attraction and marketing.

Every 4 days, flower diameter measured by caliper and record in each flower, separately. Relative fresh weight measured every 2 days. For this purpose, flower branch was

weighted and its relative fresh weight calculated by using the following formula (Bartoli et al.,1996; Setyaddjit et al., 2004).

RFW=Wt/ Wt=0 × 100 Wt = F.W in 2, 4, 6th,…day.Wt=0 = F.W in zero day.For measuring of dry weight to fresh weight ratio, fresh weight was measured every 2 days

and after the end vase life, all of the cut flowers located in oven 60 °C for 72 hrs.

Data Analysis

Data were analysed with MSTATC software. Mean comparison carried out with DNMRT.

RESULTSA AND DISSCISSIONS

In Avalanche cultivar, 2 and 1 mg l-1 SNP (T4, T5) and distilled water (T10) have the highestvase life, 18.17, 17, 5 and 16, 58 days, respectively. These treatments had significant differencewith other treatments. Also the least vase life was showed in AgNO3 and control. In Grand prixcultivar, T6 and T8 had highest vase life and the least average in this cultivar is related to controltreatment (Table 2). Increasing vase life in T4 and T5 in Avalanch cultivar can attribute to theeffect of SNP in various levels and also it can refer to in water quality in T10 treatment (table 3).The existence of SNP inhibits growth of microorganisms. These results were agreed with Kimet al., (2005).

In AgNO3 treatment (T1), wilting and bent neck observed in early days. Water stresssymptoms (wilting) and bent neck are explainable in T1, AgNO3 banded to organic compoundsand cannot moves upward in vessels (Nowak and Rudnicki, 1990). Also, susceptibility of vesselsof herbaceous plants and toxicity of Ag+ as a heavy metal, are two important reasons for thiseffect (Alvarez et al., 1994). It seems that Ag+ damages to vessels and inhibits water transfer inxylem and flowers will wilt. The results of this research about the effect of AgNO3 is not agreedwith Khondakar and Mazumdar (1985), because they had been obtained the best results withsucrose 3% + 8-HQC 3% + AgNO3 %1, while the results of current research was similar toAlvarez et al., (1994), which in both two research, undesirable effect of AgNO3 on cut rose andtuberose had been observed. Alvarez et al., (1994) used 600 mg l-1 AgNO3, while Khondakar andMazumdar (1985) applied less than 1% and observed that this concentration had negative effect.It seems that 8-HQ eliminated the negative effect of AgNO3. Our results were agreed with theresults of Jowkar and Salehi (2006) but it was not agreed with Lal (1993).

If distillated water has high quality cut flowers have more vase life. Halvey (1976) showedthat distilled water is suitable for preservative solution. In the present research , distilled waterwas one of the best treatment to increasing vase life of cut Rose ‘Avalanche’.

According to ANOVA, simple effect of time, cultivar and treatment on flower diameterand the interaction between treatment and were significant (P≤ 0.01).

Treatments T6, T8 and T9 had the highest average of flower diameter, but them differencewith T3, T4, T5 and T7 was not significant. Lowest flower diameter was for control plants.

In rose ‘Grand Prix’ effect of interaction between chemical compounds and cultivars onflower diameter was significant and T8 had the highest average of flower diameter. T3, T4, T5, T6,


T7, T8 and T9 had not significant differences with each other. Also in cut roses ‘Avalanche’distilled water with the average of 105.7 mm had the highest flower diameter which had notsignificant differences with T6 treatment.

This results had agreed with the results of Hussein (1994), Fakhrae and Maidani (2004)and Kalatejari (2009).

Literature Cited

Alvarez, V. N., Colinas, M. T. and Villanueva, V. C. 1994. Postharvest uses of chemicals compounds to increase vase life of cut tuberose flowers. Hort. Sci. 1: 15-20.

Azadi, P., Edrisi, B., Banijamali, S. M., Bayat, H., Shafiei, M.R., Mirzakhani, A. and Hashemabadi, D. 2001. Carnation, (1st Special Bulletin of National Research Center of Ornamental Plants).Mahallat. Iran.

Bartoli, C., Guiamet, G. and Montaidi, S. 1996. Ethylene production and response to exogenous ethylene in senescing petals of Chrysanthemum morifolium. Plant Science, 124: 15-21.

Ebrahimzadeh, A. and Seifi, Y. 1999. Storage and transportation of cut flowers,green ornamentalplants. Akhtar publication.

Fahmy, A. E. L. Rahman, and S. Hassan. 2005. Postharvest studies on some important flower crops. www. Lib. Uni-Corvinus. Hu/PhD/Sadeck-hassan.

Fakhrayi, M. and Meidani, J. 2003. Effect of sucrose with 8-hydroxy quinoline citrate on the quality of cut Rose “First Red” on the vase life and postharvest in different situation. National Congress of cut flowers of Iran. Tehran.

Halvey, A. H. 1976. Treatments to improve water balance of cut flowers. Acta Hort. 64: 223-236.Hussein, H.A.A. 1994. Varietal responses of cut flowers to different antimicrobial agents of

bacterial contamination and keeping quality. Acta Hort. 368: 106-116.Ichimura, K. and Korenaga, M. 1998. Improvment of vase life and petal color expression in

several cultivars of cut Eustoma flowers using sucrose with 8-hydroxy quinoline sulfate. Bull. Natl. Res. Veg. Ornam. Plant and Tea, Japan. 13: 31-39.

Ichimura, K. and Sotu, K. 1999. Effects of the time of sucrose treatment of vase life, soluble carbohydrate concentrations and ethylene production in cut sweet pea flowers. Plant Growth Regul. 28: 117-123.

Jowkar, M., and Salehi, M.H. 2006. Effect of preservative compounds on the vase life of cut. Polianthus.Kader, A. A. 2002. Postharvest technology of horticulture crops. Third edition. University of

California. Publication 3311 .Kalateh jari, S. 2008. Increasing the qualificational characters andvase life with some chemical

treatments. PhD thesis. Islamic Azad University, Tehran. Iran. Ketsa, S. 2000. The effect of AgNO3 on the vase life and bud opening of cut flower of

Dendrobium “Pompadour”. Hort. Rev.,18: 1-85.Khalighi, A., and Shafiei, M. 2000. Study on effect of chemical,treatments and stage stage of

harvest on vase life and some qualifictional characters of cut Carnation. Iran agricautural Sciences. 31: 119-125.

Khondakar, S.R.K. and Mazumdar, B.C. 1985. Studies on prolonging the vase life of tuberose cut flowers. South Indian Hort. 33 (2): 145-147.

Kim. J. H., Lee, A. K. and Suh, J. K. 2005. Effect of certain pre-treatment substances on vase life and physiological character in Lilium spp. Acta Hort , 373: 22-30.

Lal, S. D. 1993. Effect of chemical substances on the vase life and quality of gladiolus ‘Silver Horn’. Progressive Horticulture. 22(1-4): 63-68.

Michalczuk, B.D. Goszczynska, M. Rudnicki, R.M. and Halevy, A. H. 1989. Calcium promotes longevity and bud opening in cut rose flowers. Israel Journal of Botany. 38: 209-215.

Nowak, J. and Rundicki, R. M. 1990. Postharvest handling and storage of cut flowers, florist


green, and pot plants. Timber Press INC. USA . P: 199.Reddy, B. S., Singh, K. and Singh, A. 1995. Effect of sucrose, citric acid and hydroxyquinoline

sulfate on postharvest physiology of tuberose ‘single’. Advances in Agricultural Research in India. 3: 161-167.

Setyadjit, J.D.C., Irving, D.E. and Simon, D.H. 2004. Effects of 6- benzyl aminopurine treatments on the longevity of harvested grevillea ‘Sylvia’ inflorescences. Plant Growth Regul. 43: 9-14.


Tables

Treatment Chemical compounds

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

AgNO3 (300 mgl-1)

8-HQS (250mg l-1)

8-HQS (500mg l-1)

SNP (1mg l-1)

SNP (2mg l-1)

8-HQS (250mg l-1) + SNP(1mg l-1)

8-HQS (500mg l-1) + SNP(1mg l-1)

8-HQS (250mg l-1) + SNP(2mg l-1)

8-HQS (500mg l-1) + SNP(2mg l-1)

Distilled Water

Control

Table 1. Chemical compounds

Treatment Flower opening (%) FW/DW Flower diameter (mm) RFW Vaselife (days)

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

48.75 f

84.17 ab

90.42 a

82.92 abc

84.17 ab

84.58 ab

86.25 ab

86.25 ab

83.75 ab

61.25 e

47.50 f

4.506 ghi

5.352 cde

4.499 hi

4.179 ij

4.447 hi

5.116 def

5.006 efg

5.098 def

4.805 fgh

4.009 ijk

3.544 k

81.38 e

94.05 d

97.31 bcd

95.91 bcd

95.22 cd

98.76 bcd

96.96 bcd

100.7 abc

100.3 abcd

81.21 e

64.85 f

69.92 i

100.6 a

90.01 f

84.40 g

91.41 f

97.87 abcd

98.24 abcd

99.31 abc

93.41 ef

68.23 ij

62.51 k

7.250 hij

11.17 bcde

8.833 fgh

9.917 efg

10.50 def

12.92 b

12.17 bcd

12.67 bc

10.92 cde

7.667 hi

5.500 j

Means followed by some letter within each column don’t differ significantly according to Duncan multiple

range test at P≤0.01

Table 2. Mean comparison of traits in ‘Grand prix’

Treatment Flower opening (%) FW/DW Flower diameter (mm) RFW Vaselife (days)

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

30.00 g

72.50 d

64.17 e

85.83 ab

85.83 ab

85.00 ab

78.75 bcd

83.33 ab

75.42 cd

82.92 abc

30.00 g

4.930 efgh

5.933 ab

5.906 ab

5.879 ab

5.977 ab

5.684 abc

5.780 abc

6.042 a

5.796 abc

5.524 bcd

3.822 jk

86.23 e

95.39 bcd

98.00 bcd

100.6 abc

98.19 bcd

101.8 ab

96.58 bcd

100.6 abc

101.1 abc

105.7 a

65.79 f

64.59 k

95.86 cde

79.37 h

97.89 abcd

97.84 abcd

97.24 abcd

96.57 bcde

99.97 ab

96.56 bcde

95.79 de

65.41 jk

5.833 j

11.00 cde

8.667 gh

16.58 a

18.17 a

11.42 bcde

10.75 de

11.83 bcd

10.00 efg

17.50 a

6.083 ij

Means followed by some letter within each column don’t differ significantly according to Duncan multiple

range test at P≤0.01

Table 3. Mean comparison of traits in ‘Avalanche’

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