EFFECTS OF SEVERAL COMMERCIALLY AVAILABLE SOLIDIFYING ...
Transcript of EFFECTS OF SEVERAL COMMERCIALLY AVAILABLE SOLIDIFYING ...
Table 3. Continued.
mg B/6 inch
pot/3 trt
Schefflera arboricola
PPM B Plant
in foliage grade2
mg B/4 inch
pot/3 trt
Araucaria heterophylla
PPMB
in foliage
No. necrotic
tips
0
15
30
45
60
35
240
383
397
555
4.3
4.3
3.7
3.3
2.0
0
5
10
15
20
16
107
146
284
564
0.0
0.0
0.0
0.0
10.0
Alpinia zerumbet' Variegata'
mg B/6 inch PPM B No. necrotic
pot/3 trt in foliage leaves
Philodendron scandens oxycardium
mgB/8inch PPMB
pot/4 trt in foliage
Severity of
0
15
30
45
60
37
122
179
385
564
0.0
1.0
0.8
2.5
6.8
0
40
80
120
160
64
175
256
309
487
1.0
1.3
1.8
2.3
4.3
Neoregelia carolinae Tricolor*
mg B/6 inch PPMB
pot/4 trt in foliage
Severity of mg B/8 inch
pot/5 trt
Ficus benjamina
PPMB
in foliage
Severity of
0
20
40
60
80
43
434
645
784
899
1.5
2.5
3.6
3.8
4.5
0
50
100
150
200
67
267
309
410
425
1.0
1.0
1.2
1.4
1.7
zPlants were graded on a scale of 1 = poor quality, unsalable, 3 ySeverity of necrosis was based on a scale of 1 = no necrosis, 3 =
= fair quality, salable and 5 = excellent quality plant material.
■■ some necrosis, but still salable and 5 = severe necrosis, unsalable plant material.
(Poole and Conover, 1982). To avoid B toxicity problems
foliage producers should know the concentration of B in their irrigation water, growing medium, fertilizers and
amendments. If one irreplaceable component of a produc
tion program contains high levels of B, other components
should contain little or no B.
Literature Cited
ben Jaacov, J., R. T. Poole, and C. A. Conover. 1984. Tipburn of C.
comosum 'Vittatum.' HortScience 19(3):445-447. Conover, C. A. and R. T. Poole. 1973. Factors influencing micronutrient
use in tropical foliage production. Univ. Fla. Agr. Res. Center - Apopka
MimeoRpt. RH-73-1.
Kohl, H. C. and J. J. Oertli. 1961. Distribution of boron in leaves. Plant
Physiol. 26(4):420-424.
Marlatt, R. B. 1978. Boron deficiency and toxicity symptoms in Ficus
elastica 'Decora' and Chrysalidocarpus lutescens. HortScience 13(4):442-
443.
Poole, R. T. and C. A. Conover. 1976. Chemical composition of good
quality tropical foliage plants. Proc. Fla. State Hort. Soc. 89:307-308. Poole, R. T. and C. A. Conover. 1982. Micronutrients in tropical foliage
production. Proc. Intern. Soc. Tropical Hort. 30:269-274.
Poole, R. T. and C. A. Conover. 1985a. A test of micronutrient sources.
Agr. Res. and Educ. Center - Apopka Res. Rpt. RH-85-4.
Poole, R. T. and C. A. Conover. 1985b. Boron and fluoride toxicity of foliage plants. Agr. Res. and Educ. Center - Apopka Res. Rpt. RH-85-
19.
Proc. Fla. State Hort. Soc. 104:303-308. 1991.
EFFECTS OF SEVERAL COMMERCIALLY AVAILABLE SOLIDIFYING AGENTS ON IN VITRO
GROWTH OF ALOCASIA BELLOTA 'ALICIA1
John L Griffis, Jr., Heike Wedekind,
and Sherman Johnson
Citrus Institute
Florida Southern College
111 Lake Hollingsworth Drive
Lakeland, FL 33801
Abstract. Cultures of Aloeasia be I lota 'Alicia' growing on hor
mone-free medium were divided and single shoots were
weighed and transferred to modified basic MS medium sup
plemented with 30 g/l sucrose, various organic compounds,
100 mg/l inositol, 0.5 mg/l IAA and 0.0, 1.0, or 10.0 mg/l 2iP.
Proc. Fla. State Hort. Soc. 104: 1991.
Media were solidified with one of seven different solidifying
agents including agar agar, Agaran™, Acaragel™, Caragar™,
carageenan and gellan gum (all from Research Organics) and
Gel rite™ (Kelco/Scott). Increases in fresh weights and num
bers of shoots and roots produced were measured every four
weeks for 120 days. Development of minimal callus was
noted with a few treatments, but vitrification was not noted
on any of the media combinations. The greatest increases in
both fresh weights and in shoot production occurred on media
supplemented with 0.5 mg/l IAA, 1.0 mg/l 2iP, and solidified
with either gellan gum or Gelrite™. Plants grown on media
solidified with agar, regardless of growth regulator concentra-
303
tion, showed the smallest fresh weight gains and produced
the fewest average numbers of new shoots.
Until about a decade ago, the only solidifying agents in
widespread usage in commercial plant tissue culture
laboratories were several different grades and brands of
agar (Pierik, 1987). Despite numerous claims from agar
manufacturers, few significant chemical differences have
ever been discovered between the various brands or types
of agar (Pierik, 1987), although different brands and dif
ferent concentrations of agar have been reported to have
significant effects on the growth and development of vari
ous plants in culture (Bornman and Vogelmann, 1984; De-
Bergh, 1983). It has also been reported that certain plants
may become vitrified when cultured on media solidified
with varying concentrations of agar (Bornman and Vogel
mann, 1984; DeBergh, 1983, Kevers et aL, 19894 Paques
and Boxus, 1987; Pasqueletto^a/., 1988a, & 1988b; Pierik,
1987; Turner and Singha, 1990; Zimmerman et aL, 1991;
Ziv, 1991). Increasing the agar concentration in the various
media often eliminated vitrification, but it also tended to
slow the rate of multiplication (DeBergh, 1983).
In 1983, Gelrite™, a gellan gum product, was intro
duced as an altertative gelling agent for tissue culture.
Both commercial plant tissue culture laboratories and
plant research laboratories around the world began to ex
periment with this new solidifying agent (Bornman and
Vogelmann, 1984; Ichi et aL, 1986; Kane et aL, 1990; Pas-
qualetto et aL, 1988a & 1988b; Pierik, 1987; Turner and
Singha, 1990; Zimmerman etaL, 1991). Several researchers
reported vitrification problems with Gelrite™ equal to or
even greater than those associated with agar (Bornman
and Vogelmann, 1984; Pasqualetto et aL, 1988a & 1988b;
Turner and Singha, 1990; Zimmerman et aL, 1991).
Numerous plants, including nandina, daylily, and gerbera
daisy (Griffis, unpublished data), Norway spruce
(Bornman and Vogelmann, 1984), apple (Pasqualetto et
aL, 1988a & 1988b), crabapple (Turner and Singha, 1990),
pear (Turner and Singha, 1990), geum (Turner and
Singha, 1990), and petunia (Zimmerman et aL, 1991) pro
duced vitreous tissues when cultured on various media sol
idified with Gelrite™. Increasing the Gelrite™ concentra
tion in the various media did not always eliminate vitrifica
tion (Bornman and Vogelmann, 1984). However, combi
nation of other agents with Gelrite™ sometimes corrected
the vitrification problem. A combination of Gelrite™ with
agar, both added to the medium at one-half of the man
ufacturer's recommended rate, eliminated the vitrification
of nandina shoots in culture (Griffis, unpublished data).
Similar results were obtained with petunia (Zimmerman et
aL, 1991). Others have also reported combining Gelrite™
and agar in culture media and obtaining satisfactory results
(Kane et aL, 1990). A commercial mixture of gellan gum
and agar, called Agaran™, is now available from Research
Organics of Cleveland, Ohio.
Other solidifying agents have also been suggested for
use in plant tissue cultures from time to time. Among those
suggested was carageenan (Ichi et aL, 1986), which is also
available from Research Organics as are a proprietary mix
ture of carageenan and agar, called Caragar™, and a blend
of carageenan and acacia gum, called Acaragel™. This last
blend always separated into distinct layers in the culture
vessels. Research Organics also markets their own brand
of agar, gellan gum, and agarose as "tissue culture medium
solidifiers."
This experiment was undertaken to evaluate and com
pare the effects of these various commercially available sol
idifying agents on a specific plant cultivar maintained for
several months in culture. The plant selected for this pro
ject was Alocasia bellota 'Alicia', an aroid of some minor
commercial value. However, other aroids, such as dieffen-
bachia, spathiphyllum, and syngonium, make up the vast
majority of plants propagated in commercial plant tissue
culture laboratories (Pierik, 1987) and data obtained from
this experiment with alocasia may be equally applicable to
other aroids. Solidifying agents selected for comparison
included Gelrite™ from Kelco/Scott and agar, carageenan,
Caragar™, Acaragel™, Agaran™, and gellan gum from Re
search Organics. Agarose was not trialed because it was at
least six times more expensive than any of the other sol
idifying agents and therefore, would not be cost-effective
for use by commercial laboratories even if it proved
superior to the others. Alocasia bellota 'Alicia' was main
tained in culture in a manner similar to that reported for
other aroids (Gomez et aL, 1989), except that side shoots
were not removed from the cultures during the course of
the four month experiment.
Materials and Methods
Multiplying cultures of Alocasia bellota 'Alicia' which had
been specially cultured on medium without plant hor
mones for thirty days were donated for this study by Dr.
Alvan Donnan and Plant Tech, Inc. of Apopka, Florida.
In the laminar flow environment, several single shoots
were removed from each culture. Each excised shoot was
carefully weighed and then cultured on one of twenty-one
different media. The various culture media were prepared
using modified MS basic salts (Sigma) supplemented with
30 g/1 sucrose, 2.0 mg/1 glycine, 0.5 mg/1 nicotinic acid, 0.5
mg/1 pyrodoxine HC1, 10.0 mg/1 thiamine HC1, 100 mg/1
myo-inositol, and 0.5 mg/1 indoleacetic acid (I A A). Cytoki-
nin levels were varied: media contained either 0.0, 1.0, or
10.0 mg/1 N6-(A2Isopentenyl) adenine (2iP). Media were solidified with one of seven different commercially avail
able solidifying agents including Agar Agar, Agaran™,
Acaragel™, Caragar™, Carageenan, and Gellan Gum (all
from Research Organics) or Gelrite™ (Kelco/Scott). Sol
idifying agents were used at the maximum rate suggested
by the supplier. These rates are sumamrized in Table 1
along with the coast of a kg of each solidifying agent
(purchased in 1990) and the coast of each solidifying agent/
liter of media. Single plantlets were cultured initially in 25
mm x 150 mm test tubes containing 10 ml of medium.
There were ten replicates of each treatment, 210 cultures
in all. After 30, 60, and 90 days in culture, plantlets were
removed from the various media, weighed and transferred
to fresh media. The number of additional shoots and roots
produced by each plantlet were also determined at each
transfer date. All transfers after the initial ones were made
to baby food jars (BFJ) each containing 25 ml of media.
After 120 days in culture, final measurements were taken
and cultures were terminated. During the course of the
experiment, cultures were maintained at 24 ± 1°C under
a 16-hour photoperiod per day provided by cool-white
fluorescent tubes at 60 (xmol-s-1 nrr2 as measured at the cul-
304 Proc. Fla. State Hort. Soc. 104: 1991.
Table 1. Solidifying Agent Cost Comparison.
Solidifying agent
Acaragel™ (ROZ
AgarAgar(RO)
Agaran™ (RO)
Caragar™ (RO)
Carageenan (RO)
Gellan Gum (RO)
Gelrite™ (Kelco/Scotty)
Gelrite™ (Kelco/Scott)
Cost/kg
$54.00
$41.00
$54.00
$54.00
$20.00
$83.00
$90.00
$90.00
Recommended
Rate
10g/l
8g/l
5g/l
6g/l
10g/l
3g/l 3g/l 2g/l
liters of
media/kg
100
125
200
166
100
333
333
500
actual cost
/liter
$0.54/1
$0.33/1
$0.27/1
$0,325/1
$0.20/1
$0.25/1
$0.27/1
$0.18/1
Note: Culture vessels (baby food jars) hold approximately 25 ml of media,
so 1 liter of media will fill 40 vessels. From the above figures, it can be
determined that the cost of solidifying agent varies from about 0.5tf to
1.5tf per vessel.
Z(RO); Research Organics of Cleveland, Ohio.
y( Kelco/Scott); Kelco is a division of Merck and Co., Rahway, NJ.
ture level. Data were analyzed using the ANOVA proce
dure.
Results and Discussion
Roots
There were significant differences among the 21 treat
ments in average numbers of roots produced after one,
two, three, and four 30-day culture periods, hereafter re-
fered to as 30, 60, 90, and 120 days in culture (Table 2).
As might be expected, the cultures maintained on MS
medium supplemented with 0.5 mg/1 IAA, but no cytoki-
Table 2. Comparative production of roots in vitro by Alocasia bellota 'Alicia'.
Solidifying agent/
cytokinin level
Acaragel™/0 mg/1 2iP
Acaragel™/1 mg/1 2iP
Acaragel™/10 mg/1 2iP
Agar Agar/ 0 mg/1 2iP
Agar Agar/1 mg/1 2iP
Agar Agar/10 mg/1 2iP
Agaran™/0 mg/1 2iP
Agaran™/1 mg/1 2iP
Agaran™ 10/mg/12iP
Caragar™/ 0 mg/1 2iP
Caragar™/1 mg/1 2iP
Caragar™/10 mg/1 2iP
Carageenan/ 0 mg/1 2iP
Carageenan/1 mg/1 2iP
Carageenan/10 mg/1 2iP
Gellan Gum/ 0 mg/1 2iP
Gellan Gum/1 mg/1 2iP
Gellan Gum/10 mg/1 2iP
Gelrite™/0 mg/12iP Gelrke™/1 mg/1 2iP
Gelrite™/10 mg/1 2iP
ANOVA: Pr>Fat.O5
30 Days
1.80z
0.60
0
0.90
0.20
0
0.90
0.60
0
1.20
0.40
0
1.70
0.60
0
2.20
1.50
0
0.90
1.80
0.10
0.000
60 Days
1.90
0.70
1.33
2.33
0.50
0
2.20
0.30
0.30
1.22
0.43
0.60
2.50
0.50
0
2.11
2.11
2.78
7.89
1.33
1.33
0.011
90 Days
2.78
0.50
1.22
1.00
0.22
0.22
2.25
0.80
1.70
1.88
0.43
0.67
4.11
2.75
0.25
2.50
10.17
5.11
14.88
9.25
4.63
0.000
120 Days
2.43
2.88
1.56
2.14
2.00
1.00
2.50
2.67
3.25
1.86
1.17
1.25
4.89
8.00
0.50
3.13
17.67
6.71
2.43
18.57
7.25
0.000
zValues in each column represent the average increase in number of
roots produced per treatment. All values are cumulative from day zero
up to the evaluation date listed at the top to each column. The initial
explants had no roots and there were initially ten replicates of each treat
ment. A decrease in the average number of roots produced by any treat
ment over time may have occurred because one or more cultures of that
treatment were lost to contamination during the experiment.
Proc. Fla. State HorL Soc. 104: 1991.
nin, regardless of solidifying agent, demonstrated the
greatest initial increases in average numbers of roots pro
duced. Cultures maintained on medium supplemented
with 0.5 mg/1 IAA and 10 mg//l 2iP, regardless of solidify
ing agent, produced the lowest average numbers of roots
at each evaluation. Cultures maintained on medium sup
plemented with 0.5 mg/1 IAA and 1 mg/1 2iP and solidified
with either gellan gum or Gelrite™ had produced the
greatest average numbers of roots at the end of 120 days.
Moreover, these last two particular combinations of growth
regulators and solidifying agents also produced the great
est averge number of shoots in 120 days and many of the
new shoots also had begun to produce roots at the time the
experiment was terminated.
Fresh Weight
There were also significant differences among the 21
treatments in percentage fresh weight gain after 30, 60,
90, and 120 days in culture (Table 3). Not surprisingly, the
cultures maintained on MS medium supplemented with
0.5 mg/1 IAA, but no cytokinin, regardless of solidifying
agent, produced the smallest increases in average percent
fresh weight gain at each evaluation. Numerous cultures
actually demonstrated decreases in fresh weight after three
or four transfers onto media without cytokinin. On the
other hand, cultures maintained on medium supple
mented with 0.5 mg/1 IAA and 10 mg/1 2iP, regardless of
solidifying agent, produced substantial increases in aver
age percent fresh weight gain at each evaluation. Notably,
however, cultures maintained on medium supplemented
with 0.5 mg/1 IAA and only 1 mg/1 2iP and solidified with
either gellan gum or Gelrite™ produced the greatest aver
age increases in percent fresh weight gain at every evalua tion.
Shoots
There were also significant differences among the 21
treatments in average numbers of shoots produced after
30, 60, 90, and 120 days in culture. The ANOVA pro
duced a Pr>F (.05) of 0.000 at all four evaluations. The
cultures maintained on MS medium supplemented with 0.5 mg/1 IAA, but no cytokinin, regardless of solidifying
agent, produced the fewest average number of shoots at
each evaluation. Numerous explants failed to produce a
single new shoot after 120 days in culture when cytokinin
was left out of the culture medium (Fig. 1). When 2iP was
included in the culture medium at either 1 mg/1 or 10 mg/1,
substantial average numbers of new shoots were produced
in culture, regardless of the solidifying agent. Average shoot production was almost identical at either 2iP level
after 60 days and 90 days. Only after 120 days in culture was there a large difference in the average number of
shoots produced per culture between the two cytokinin treatments.
Cultures maintained on MS medium solidified with
agar, regardless of cytokinin level, produced the smallest
increase in average numbers of new shoots at each evalua tion (Fig. 2). Cultures maintained on medium solidified with either gellan gum or Gelrite™, regardless of cytokinin
level, produced the greatest increase in average numbers of new shoots at each evaluation.
305
Table 3. Comparative percent fresh weight gain in vitro of Alocasia bellota 'Alicia'.
Solidifying agent/
cytokinin level 30 Days 60 Days 90 Days 120 Days
Acaragel™/0mg/12iP
Acaragel™/1 mg/1 2iP
Acaragel™/10mg/12iP
Agar Agar/ 0 mg/1 2iP
Agar Agar/ 1 mg/1 2iP
Agar Agar/10 mg/1 2iP
Agaran™/0mg/l2iP
Agaran™/1 mg/1 2iP
Agaran™ 10/mg/12iP
Caragar™/0mg/12iP
Caragar™/1 mg/1 2iP
Caragar™/10mg/12iP
Carageenan/ 0 mg/1 2iP
Carageenan/1 mg/12iP
Carageenan/10 mg/1 2iP
Gellan Gum/ 0 mg/1 2iP
Gellan Gum/1 mg/1 2iP
Gellan Gum/10 mg/12iP
Gelrite™/0mg/12iP
Gelrite™/1 mg/1 2iP
Gelrite™/10mg/12iP
194.89%z
102.82%
148.05%
72.55%
60.86%
89.75%
123.27%
89.29%
134.35%
162.82%
131.62%
161.67%
147.96%
178.36%
129.04%
149.96%
316.72%
289.72%
181.92%
404.84%
249.41%
343.11%
375.78%
683.05%
24.55%
167.67%
455.40%
383.74%
342.15%
1323.34%
420.15%
453.00%
756.56%
523.49%
852.50%
867.19%
414.50%
1997.92%
1348.96%
492.03%
2673.68%
1244.94%
598.72%
536.20%
1896.55%
-97.00%
334.32%
1115.50%
718.94%
688.16%
1837.51%
210.22%
553.77%
2170.53%
855.38%
963.62%
1707.67%
554.36%
5383.77%
3859.47%
1423.30%
8190.36%
4701.81%
117.15%
1575.04%
5238.19%
-223.16%
758.44%
3095.45%
1153.33%
1582.01%
5411.30%
-126.76%
1094.42%
6636.13%
1018.08%
3396.14%
5297.02%
718.18%
12940.17%
11396.36%
1792.88%
16010.13%
9010.94%
ANOVA: Pr>F at .05 0.000 0.011 0.000 0.000
zValues in each column represent the average increase fresh weight gain per treatment during the culture period. The variation in the initial fresh
weights of the explants has been taken into account. There were initially ten replicates of each treatment.
When the combined effects of cytokinin level and so
lidifying agent were examined more thoroughly, several
trends were discovered. Cultures maintained on MS
medium supplemented with 1 mg/1 2iP and solidified with
either gellan gum or Gelrite™ produced the greatest in
creases in average numbers of shoots at each evaluation
when compared with other solidifying agents trialed (Fig.
3). However, cultures maintained on medium supple
mented with 10 mg/1 2iP produced very nearly the same
increases in average numbers of shoots at each evaluation
no matter which solidifying agent was used (Fig. 4). Even
at the higher 2iP level, agar remained the poorest per
former of all solidifying agents trialed when evaluted for
increase in average numbers of shoots produced at each
evaluation.
A comparison of cultures maintained on MS medium
supplemented witn various levels of 2iP and solidified with
either gellan gum, Gelrite™, or agar produced some in
teresting comparisons (Fig. 5). There was little difference
Gelrlte ||j||||)j^ | |
Gellan Gum IHBiMHHlHsIS'
Carageenan wsSBmEggP^'
Caragar teaftjmfflf*[^
1 j ) 1 Agaran |H|
Agar Wfflf
Acaragel &&£&&
■n
1
(ff{
H j
0 120 days
■ 90 days
H 60 days
■ 30 days
10 12 14
Average Increase in Numbers of Shoots per Culture
Fig. 2. Effects of Solidifying Agent on Average Numbers of Shoots
Produced In Vitro by Alocasia bellota 'Alicia'.
IOmg/1 21P
I mg/1 21P
0mg/l 21P
120 days
90 days
60 days
30 days
Gelrite 1 mg/1 2iP
Gellan Gum 1 mg/1 2iP
Carageenan 1 mg/1 2iP
Caragar 1mg/l 2iP
Agaran 1 mg/1 2iP
Agar 1 mg/1 21P
Acaragel 1 mg/1 2iP
120 days
90 days
60 days
30 days
0 4 8 12 16
Average Increase in Numbers of Shoots per Culture
0 3 6 9 12 15 18 21
Average Increase in Numbers of Shoots per Culture
Figure 3. Combined Effects of Both Solidifying Agent and Cytokinin
Fig. 1. Effect of 2iP Levels on Average Numbers of Shoots Produced Level (2iP 1 mg/1) on Average Numbers of Shoots Produced In Vitro by In Vitro by Alocasia bellota 'Alicia'. Alocasia bellota 'Alicia'.
306 Proc. Fla. State Hort. Soc. 104: 1991.
120 days
90 days
60 days
30 days
Gelrite IOmg/1 21P
GellanGum IOmg/1 2iP
Carageenan 10mg/l 2iP
Caragar IOmg/1 2iP
Agaran IOmg/1 2iP
Agar IOmg/1 2iP
Acaragel, 10mg/l 2iP
0 3 6 9 12 15 18 21
Average Increase in Numbers of Shoots per Culture
Fig. 4. Combined Effect of Both Solidifying Agent and Cytokinin
Level (2iP 10 mg/1) on Average Numbers of Shoots Produced In Vitro by
Alocasia bellota 'Alicia'.
Gellan Gum 10 mg/l 2iP
Gellan Gum I mg/l 2iP
Gellan Gum 0mg/l 2IP
Agaran 10mg/l 2iP
Agaran I mg/l 21P
Agaran 0mg/l 2IP
Agar IOmg/1 2IP
Agar lmg/l 2iP
Agar 0mg/l 2IP
120 days
90 days
60 days
30 days
0 3 6 9 12 15 18 21
Average Increase in Numbers of Shoots per Culture
Fig. 6. Combined Effect of Both Selected Solidifying Agents (Gellan
Gum, Agar, and Agaran™) and Various Cytokinin Levels on Average
Numbers of Shoots Produced In Vitro by Alocasia bellota 'Alicia'.
between gellan gum and Gelrite™ in average numbers of
shoots produced at any evaluation. Agar was clearly in
ferior to the other two gelling agents when any level of 2iP
trialed was added to the culture medium, but when cytoki
nin was excluded from the medium, none of the three
solidifying agents differed significantly in the average
numbers of shoots produced at each evaluation. The addi
tion of the higher 2iP level (10 mg/l) to the culture medium
produced a four-fold increase in the average numbers of
shoots produced on the medium solidified with agar after
120 days when compared to medium supplemented with
only 1 mg/l 2iP. However, the inclusion of 10 mg/l 2iP did
not produce any increase in average numbers of shoots
produced on medium solidified with either gellan gum or
Gelrite™ after 120 days when compared to medium sup
plemented with only 1 mg/l 2iP. In fact, there was no dif
ference at all in average numbers of shoots produced be
tween cultures maintained on MS medium supplemented
with either 1 mg/l 2iP or 10 mg/l 2iP and solidified with
gellan gum after 120 days in culture. There was an actual
decrease in average numbers of shoots produced at all
evaluations when the higher level of 2iP was added to
medium solidified with Gelrite™ when compared to
medium supplemented with the lower level of 2iP and sol
idified with Gelrite™ (Fig. 5).
A comparison of cultures maintained on MS medium
supplemented with various levels of 2iP and solidified with
either agar, gellan gum, or Agaran™ also produced some
interesting comparisons (Fig. 6). Agaran™ is a proprietary
Gelrite 10 mg/l
Gelrite lmg/l
Gelrite 0mg/1
Gellan Gum 10mg/l
GellanGum lmg/l
GellanGum 0mg/l
Agar 10mg/l
Agar lmg/l
Agar 0mg/l
120da>s
90 days
60 days
30 days
0 3 6 9 12 15 18 21
Average Increase in Numbers of Shoots per Culture
Fig. 5. Combined Effect of Both Selected Solidifying Agents (Gel
rite™ , GeWan Gum, and Agar) and Various Cytokinin Levels on Average
Numbers of Shoots Produced In Vitro by Alocasia bellota 'Alicia'.
Proc. Fla. State Hort. Soc. 104: 1991.
combination of agar and gellan gum and its performance
as a solidifying agent was intermediate between the other
two agents when evaluated for average numbers of shoots
produced at all evaluations. Among these nine variations,
cultures maintained on medium supplemented with 1 mg/l
2iP and solidified with gellan gum produced the greatest
increases in average numbers of shoot at all evaluations.
Production Comparisons
Examinations of the various experimental data sets pre
sented above have yielded several important production
comparisons that may be of some commercial interest.
Some of them are listed below.
1) Without cytokinin in the media, there was little dif
ference between the solidifying agents; none could pro
duce a satisfactory increase in average numbers of shoots
of Alocasia bellota 'Alicia' per culture even after four 30-day
culture periods.
2) With the addition of 1 mg/l 2iP to the media, only
gellan gum or Gelrite™ produced a commercially accept
able increase in average numbers of shoots (>3) of Alocasia
bellota 'Alicia' per culture in the initial 30-day culture
period.
3) With the addition of 1 mg/l 2iP to the media, all
other solidifying agents trialed required either two or three
30-day culture periods to produce a reasonable increase in
average numbers of shoots (>3) per culture except agar,
which required four 30-day culture periods to produce a
reasonable increase in average numbers of shoots (>3) per
culture.
4) With the addition of 10 mg/l 2iP to the media, there
was initially little difference between solidifying agents
trialed; none could produce an increase in average num
bers of shoots per culture during the initial 30-day culture
period as great as that achieved in certain Alocasia bellota
'Alicia' cultures grown on media supplemented with only 1 mg/l.
5) Two or three 30-day culture periods of growth on
media supplemented with 10 mg/l 2iP did not substantially
increase the average number of shoots produced per cul
ture compared to the number of shoots produced on
media supplemented with only 1 mg/l 2iP, except in the
case of Agaran™, where average number of shoots pro
duced was doubled on media supplemented with the
higher level of 2iP.
307
6) Four 30-day culture periods on media supplemented
with 10 mg/1 2iP substantially increased the average num
bers of shoots produced per culture compared to the aver
age number of shoots produced on media supplemented
with 1 mg/1 2iP, except in the cases of Gelrite™ and gellan
gum, where shoot production was generally lower on
media supplemented with the higher level of 2iP.
Conclusions
1) Vitrification was a primary concern when this exper
iment was initiated. However, neither the addition of 1
mg/1 nor 10 mg/1 of 2iP to the culture medium caused
vitrification of any of the Alocasia bellota 'Alicia' plantlets
trialed, even after four 30-day culture periods. Solidifying
agents did not seem to have any effect on vitrification in
this experiment.
2) Callus was not a significant problem in any of the
Alocasia bellota 'Alicia' cultures, although small amounts of
callus were formed in several of the cultures after four
30-day culture periods on media supplemented with 10
mg/1 2iP. Solidifying agents did not seem to have any effect
on callus production in this experiment.
3) The most cost-effective combinations of cytokinin
and solidifying agent were 1 mg/1 2iP and either gellan
gum or Gelrite™ when cultures were evaluated for either
average shoot production or average fresh weight increase.
Cost of 2iP and either of these two solidifying agents would
be about 1# per culture vessel (BFJ). Both of these cytoki
nin and solidifying agent combinations yielded an average
of slightly more than nine shoots per culture after three
30-day culture periods and an average of more than 17
shoots per culture after four 30-day culture periods. All
other cytokinin and solidifying agent combinations trialed
in this experiment either cost more, produced fewer shoots
over time, or both.
Bibliography
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SUBSTRATE INFLUENCE ON COMPOST EFFICACY AS A NURSERY GROWING MEDIUM
George E. Fitzpatrick and Stephen D. Verkade
University of Florida
Fort Lauderdale Research and Education Center
3205 College Avenue
Fort Lauderdale, Florida 33314
Additional index words, waste management, municipal solid
waste, yard trash, sewage sludge.
Abstract. Composts made from municipal solid waste (MSW),
used disposable baby diapers (DIAP), horse stable waste (StW),
yard trash (YT), and a co-compost made from dewatered sew-
Florida Agricultural Experiment Stations Journal Series No. N-00581.
Portions of this research were supported by grants from Agripost, Inc.,
the Florida State Center for Hazardous and Solid Waste Management,
and the Horticultural Research Institute. We thank William R. Farrell of
the Broward County Pubic Works Department for providing the yard
trash compost and the sludge-yard trash co-compost; Ted Malloy, formerly
of the Pompano Harness Track, for providing the stable waste compost;
James McNelly, formerly of Recomp, Inc., for providing the disposable
diaper compost and John Nowell, formerly of Agripost, Inc., for providing
the municipal solid waste compost. We gratefully acknowledge the techni
cal assistance provided by Jane E. Slane and Richard R. Weidman.
308
age sludge and yard trash (1:3, by volume) (S-YT) were used
both as stand-alone growing media and as ingredients in
media blends for viburnum, Viburnum suspensum. Plants
were grown for 5 1/2 months in 25 cm. diameter containers
with a commercially available growing medium (4 sedge peat:
5 pine bark: 1 sand, by volume) as a control. When used as
a stand-alone medium, the S-YT produced plants that were
significantly taller and had significantly greater biomass than
plants grown in any of the other media, including the control
medium. The S-YT, when blended with pine bark and sand,
produced larger plants than did the blends using MSW and
YT, but the differences were smaller. Medium pH, total conduc
tivity, % pore space and % water holding capacity did not
seem to be as strongly related to efficacy as the relative level
of medium subsidence during production. The best performing
medium, S-YT, compacted the least during the production
period and the media that performed the poorest had the
greatest levels of compaction during the production period.
The issues of urban waste management on one hand
and the need of commercial horticultural production
facilities to have continued supplies of plant growing media
Proc. Fla. State Hdrt. Soc. 104: 1991.