Indian 1. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

GROWTH REGULATOR MEDIATED CHANGES IN LEAF AREA ANDMETABOLIC ACTIVITY IN MUNGBEAN UNDER SALT STRESS CONDITION

*NANDINI CHAKRABARTI AND SUBHENDU MUKHERJI

Plant Physiology Laboratory, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Calcutta-700 019

Received on 30 April., 2001, Revised on 17 May, 2002

SUMMARY

Efficacy of treatment as foliar spray of indole-3-acetic acid, gibberellic acid and kinetin (6-furfurylaminopurine) at 0.1 to 10 11M in ameliorating the harmful effect of NaCI salinity (E.C value 4 ds/m) onmetabolic activity was investigated in Vigna radiata (L.) Wilczek. Application of NaCI resulted in decrease intotal leaf area in mungbean. Stomatal openings on leaf surface were less prominent and trichomes wereshorter in length under salinity stress in comparison with the control. Sodium and chloride contentsincreased in leaf, root and nodules under salinity whereas, potassium and calcium contents decreased underNaCl stress in various plant parts studied. Proline content increased under salt stress by 76, 217 and 119%in leaf, root and nodule respectively over the control set. Salt stress increased acid phosphatase enzymeactivity both in leaf and root of mung bean by about 61 and 48% respectively over the control set. All thethree growth regulators used in the present study were able to overcome to variable extents the adverseeffects of stress imposed by NaCI solution.

Key words : Acid phosphatase, phytohormone, proline, salt stress, Vigna radiata

INTRODUCTION

Salinity of soil is a serious agroeconomical problemwhich leads to metabolic alterations and graded reductionin plant growth in terms of all the growth parameters. Soilsalinity is a major limitation to all crops. Partially openedstomata ofthe salinized plants with reduced CO2 diffusionhas been reported in onion, bean and cotton plants (Galeet al. 1967). In potato, the levels of proline and sodiumincrease in different plant parts under salinity to maintainthe osmoregulation (Abdullah et al. 1990). Presence ofexcess NaCl in soil results in increasing Na+ and Cl-contents and decrease in K+and Ca2+ contents in differentplant parts of avocado, grapevines, maize, Vicia faba,horsegram, sudan grass, safflower, sweet pepper andwheat (Bernstein et al. 1969, Bernstein 1975, Patil et at.

1989, Sudhakar et al. 1990, Datta 1996, Patil et al. 1996,El-Bahr 1995, Maliwal 1997). Recent studies indicatethat adaptation to salinity is closely associated withproline accumulation. Ecological studies also support theidea that proline accumulation is important in plantsadaptation to dry or saline environments. Salt stressresults in a significant increase in the accumulation ofproline in Hordeum vulgare, Citrus, faba bean, tomatoand mulberry (Chaudhuri et at. 1997, Gomez-Cadenas etat. 1998, Trinchant et at. 1998, Aziz et at. 1998, Kumar etat. 2000). Phosphorus metabolism is also adversely affectedin plants growing under saline stress. Acid phosphatasecatalyzes a variety of biochemical reactions includingcarbohydrate metabolism and plays avital role in regulatingthe plant cell activities through inorganic phosphorus level(Turner and Wellburn 1985). Acid phosphatase enzyme

* Corresponding author present address: City College, Department of Botany, 102/1, Raja Rammohan Sarani, Calcutta-700 009,West Bengal. E-mail: chakrabartinandini@hotmail.com

256 Indian J. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

EFFECT OF GROWTH REGULATORS ON SALT STRESSED MUNGBEAN

activity under NaCl stress has been studied in rice andBrassica (Dubey and Sharma 1989, Mittal and Dubey1992, Gangopadhyay et al. 1995, Gangopadhyay et al.1997).

In our experiment, attention has been given tophytDmID1aneB:like JA..A I GA3 and kinetin as possibleinducers of resistance to unfavourable environmentalconditions. The main object was to determine the effect ofsalt stress on leaf area of a single plant, leaf surfacearchitecture, Na, K, Cl, Ca and proline contents and acidphosphatase activity in mung bean and to determine theefficiency of three classical phytohormones in restoringthe metabolic alterations resulting from salt stress.

MATERIALS AND METHODS

The experiment was conducted in sandy-loam soil inthe experimental garden using mungbean [Vigna radiata(L.) Wilczek] cultivar B-1 05 collected from Oil and PulseResearch Institute, Berhampore, West Bengal. Ten plantswere kept in each pot and the five sets maintained were (1)Control (2) NaCl stressed (3) Salt stressed treated withIAA (0.1 to 10 /lm), (4) Salt stressed treated with GA3 (0.1to 10 /lM) and (5) Salt stressed treated with kinetin (0.1to 10 /lm).

IAA, GA3 and kinetin were sprayed at the rate of 50mlperpoteachatconcentrationsO.1, 1.0 and 10 /lMmixedwith Tween-20 from day 13 (emergence offirst trifoliateleaf) upto day 35, once a week. Control set was sprayedwith equal amount of water mixed with Tween-20. Allthese sets were treated with NaCl solution to maintainelectrical conductivity values of the soil as 4,8 and 12 dSmi. The soil used has initial electrical conductivity 0.3 dSm1 and pH 7.6. The set receiving no NaCl was designatedas control. This condition was maintained until grain fillingwas complete. The garden temperature where theexperiment was conducted was (34 ± 2)OC.

After grain filling, average leaf area of a plant wasmeasured from 20 randomly selected plants from each setusing a leaf area planimeter. Leaf surface architecturewas studied using scanning electron microscope asdescribed by Boyde and Wood (1969) and Bradbeer et al.(1970). Mature mung bean plants were uprooted carefully,washed thoroughly with deionized water, separated intoleaves, roots and nodules and oven dried for estimating

Indian J. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

sodium, potassium, chloride and calcium contents usingatomic absorption spectrophotometer (AAS). Thepenultimate leaves and roots were collected to measureproline content (Bates et al. 1973) and acid phosphataseactivity (Malik and Singh 1980).

RESULTS AND DISCUSSION

Among the three salinity levels, only 4 dSml was themost effective sublethal concentration. It producedmetabolic injuries to a moderate level which could berestored to different degrees by the three hormones eachused at three different concentrations. So the results ofthese four treatments viz., salt stressed, lAA treated, GA3

treated and kinetin treated have been presented here.

Compared with the control set, total leaf area of plantwas reduced by about 40% under salt stress. GA3 at aconcentration of 10 /lM was able to minimize the per centreduction from 40 to 10%. IAA and kinetin each at aconcentration of 1.0 /lM caused increase in leaf area ofabout 33% and 31 % respectively over the control(Table 1).

Table 1. Total leaf area of control and treated 56 days oldmung bean plants.

Set Leaf area (Cml)

Control 23.11±2.31

NaCI stressed 13.72±2.45

IAA (10 flM) + NaCI 28.51±3.23

IAA (1.0 flM) + NaCI 30.72±2.83

IAA (0.1 flM) + NaCI 25.18±2.88

GA3 (10 flM) + NaCl 20.85±1.44

GA3 (1.0 flM) + NaCI 16.32±1.61

GA3 (0.1 flM) + NaCI 14.88±1.73

Kinetin (10 flM) + NaCI 28.31±2.94

Kinetin (1.0 flM) + NaCI 30.26±2.59

Kinetin (0.1 flM) + NaCI 27.17±3.06

Reduced leaf area under salinity stress was due toinhibition of cell division and cell enlargement and loss ofcapacity to maintain an adequate tissue ion concentration(Zidan et al. 1990). Leaf area was mostly increased by

257

NANDINI CHAKRABARTI AND SUBHENDU MUKHERJI

Plate 2. Scanning electron microscopic photographs of mungbean leaf surface showing stomata (®) and trichomes (t) ofsalt stressed plats treated with A. IAA (10 IJM), B. IAA (1.0

IJM), C. IAA (O.lIJM).

A

Plate 1. Scanning electron microscopic photographs of mungbeanleaf surface showing stomata (®) and trichomes (t). A. Control

(X 400), B. NaCI stressed (X 400).

IAA and kinetin. The ameliorative role of growth regulatorson leaf size enlargement might be attributed to acceleratedcell division and cell enlargement (Darra and Saxena1971).The bioregulatants-induced high uptake of essentialnutrients (like K+ and Ca2+) and antagonistically lowuptake of Na+ ions might also be responsible for theenhanced leaf growth (Banuelos and Bangerth 1986).

Stomatal openings on leaf surface were less prominentand trichomes were shorter in length under salt stress incomparison with the control set as studied by scanningelectron microscopy (Plate-I). All the three phytohormonesviz. IAA, GAj and kinetin each used at three differentconcentrations were found to overcome the stress effectson leaf surface showing much prominent stomatal openingsin addition to restoring longertrichomes (Plates 2, 3 and 4).

258 Indian J. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

EFFECT OF GROWTH REGULATORS ON SALT STRESSED MUNGBEAN

Plate 3. Scanning electron microscopic photographs of mungbean leaf surface showing stomata (® ) and trichomes (t) ofsalt stressed plants treated with A. GA3 (10 fJM), B. GA3 (1.0

fJM) and C. GA3 (0.1 fJM).

Plate 4. Scanning electron microscopic photographs of mung beanleaf surface showing stomata (® ) and trichomes (t) of salt stressedplants treated with A. Kinetin (10 fJM), B. Kinetin (1.0

fJM) and C. Kinetin (0.1 fJM).

Indian J. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002) 259

NANDINI CHAKRABARTI AND SUBHENDU MUKHERJI

In our experiment shorttrichomes and reduced stomatalopenings on leaf surface under salt stress resulted inreduced gaseous exchange between the internal tissuesand outer atmosphere as evidenced by reduced CO2

uptake and release by leaves in comparison with thecontrol set (Chakrabarti and Mukherji 1994).

Sodium content in leaf increased by 144% under NaCIstress as compared with the control set. IAA at aconcentration of 1.0 11m, GA3 at 0.1 11Mand kinetin at allconcentrations were effective in reducing the sodiumuptake. In root, sodium content increased 71% understress as compared with control. IAA at a concentration of1.0 11M,GA3 at 1.0 and 10 11Mand kinetin atO.1 11Mweremost effective and completely reversed the stress effect.In case of nodule, sodium content increased about 47%under stress and IAA at 0.1 to 10 11M,GA3 at 1.0 11Mandkinetin at 10 11Mwere able to completely overcome thestress effect (Table 2). Potassium content in mung beanleaf decreased about 7% under NaCI stress as comparedwith the control set. IAA at 0.1 to 10 11M,GA3 at 0.1 11Mand kinetin at 0.1 to 10 11Mcompletely reversed the stresseffect. In root, potassium content decreased about 9%under stress and IAA and GA3 at concentrations 0.1 and1.0 11Mreduced the per cent reduction from 9 to 2.5%.Kinetin at 0.1 to 10 11Mcompletely reversed the stresseffect. In nodule, potassium content decreased about 30%under stress as compared with the control set. IAA andGA3 at a concentration of 0.1 11M 'and kinetin atconcentrations of 1.0 to 10 11Mwere effective in reducingthe per cent reduction from 30 to 16,21 and 22 respectively(Table 2). Chloride content in mung bean leaf increased by149% under NaCI stress over the control set. IAA at 1.011M,GA3 and kinetin at 10 11Mwere the most effective inreducing the per cent increase from 149 to 78, 47 and 47respectively. In root, chloride content increased by 28%under stress, whereas IAA at 1.0 to 10 11M,GA3 at 0.1 to1.0 11Mand kinetin at 0.1 11Mreduced the per cent increasefrom 28 to 15. In nodule, chloride content increased by33% under stress as compared with the control set. IAAatO.lIlM, GA3 at 1.0 11Mand kinetin at 10 11Mreduced theper cent increase from 33 to 8, 12 and 8respectively (Table2). Calcium content decreased about 7% in mung beanleafunder stress as compared with the control set. IAA at1.0 and 10 11Mcompletely reversed the stress effect. GA3

atO.l and 1.0 11Mand kinetin at 0.1 to 10 11Mwere able to

260

reduce the per cent reduction from 7 to 5 and 2respectively.In case of root, calcium content decreased by 11% underNaCI stress and IAA at a concentration of 10 11M,GA3 at0.1 and 1.0 11M,kinetin at 1.0 and 10 11Mcompletelyreversed the stress effect. In nodule, calcium contentdecreased about 14% under NaCI stress as comparedwith the control set. All the three phytohormones usedeach at 0.1 and 1.0 11Mcompletely reversed the stresseffect (Table 2).

Hormone treatment helped in reduced accumulationof sodium and chloride content in different plant parts ascompared with the stressed plants without hormonetreatment, whereas, potassium and calcium contents werealmost like control plants in hormone treated plants.Calcium has been reported to play an important role in theselective transport of potassium by protecting membraneintegrity in the presence of excess sodium, thereby makingthe plants more salt tolerant (Clarkson and Hanson 1980).Less sodium accumulation was also reported in cassavawhen growth regulators were used to counter the stresseffects (Indira and Ramanujam 1985). Phytohormoneshelp in maintaining the cell membrane structure and ionicmovement through it. Kinetin affects membranepermeability to mono - and divalent ions.

Proline content under salt stress increased by 76, 217and 119% in leaf, root and nodule, respectively over thecontrol set. In leaf, IAA, GA3 and kinetin each at aconcentration of 1.0 11Mreduced the per cent increasefrom 76 to 56, 45 and 21, respectively (Fig. 1). In root,IAA at a concentration of 1.0 11Mand GA3 and kinetineach at a concentration of 0.1 11Mreduced the per centincrease of proline from 217 to 164, 71 and 140 (Fig. 1).In nodule, all the three phytohormones were most effectiveat a concentration of 1.0 11M.IAA completely reversedthe stress effect and GA3 and kinetin reduced the per centincrease of proline from 119 to 53 and 105 respectively(Fig. 1).

Role of proline in plant is related to survival ratherthan to maintenance of growth (Greenway and Munns1980). Hormone application before stress helped mungbean to overcome the stress effect to some extent bymaintaining the intracellular water potential and ionbalance which ultimately reduced the necessity ofaccumulating higher levels of proline.

Indian 1. Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

Tab

le2.

Sodi

um,

pota

ssiu

m,

chlo

ride

and

calc

ium

cont

ents

(mg

g-ld

ryw

t.)in

cont

rol

and

treat

edm

ungb

ean

plan

tpa

rtsat

56da

ysso

win

g.

±0.0

17±0

.150

±0.1

96±0

.155

±0.1

15±0

.098

±0.0

86±0

.178

±0.1

27±0

.015

±0.0

92

0.07

0

±0.0

15

0.06

0

±0.0

12

0.06

0

±0.0

15

0.07

0

±0.0

17

0.07

0

±0.0

10

0.06

0

±0.0

08

0.07

0

±0.0

10

0.07

0

±0.0

1O

0.06

0

±0.0

12

0.07

0

±0.0

17

0.07

0

±0.0

16

Nod

ule

Roo

t

Cal

cium

0.18

0

0.15

0

0.03

9

0.03

8

Nod

ule

Leaf

0.24

0

0.28

0

Roo

t

Chl

orid

e

0.32

0

0.37

0

0.06

1

0.12

0

Nod

ule

Leaf

0.28

0

0.21

6

Con

tent

inm

g/g

dry

mat

eria

l

Pota

ssiu

m

Roo

t

0.31

6

0.33

0

0.32

0

0.33

2

Nod

ule

Leaf

0.19

0

0.17

0

Roo

t

Sodi

um

0.21

0

0.20

8

Leaf

0.04

5

0.08

1

±0.0

10±0

.092

±0.1

03±0

.069

±0.0

86±0

.103

±0.0

09±0

.103

±0.0

69±0

.012

±0.0

86

0.11

00.

360

0.28

00.

296

0.28

60.

195

0.15

2DA

IO0.

320

0.03

60.

160

±0.0

57±0

.109

±0.0

92±0

.080

±0.0

98±0

.127

±0.1

21±0

.161

±0.0

86±0

.015

±0.1

03

0.07

00.

206

0.17

00.

321

0.30

70.

220

0.11

00.

370

0.29

00.

039

0.18

0

±0.0

16±0

.132

±0.1

21±0

.121

±0.1

50±0

.121

±0.1

27±0

.121

±0.1

03±0

.017

±0.1

09

0.06

90.

207

0.16

00.

310

0.30

80.

230

0.10

90.

370

0.29

00.

039

0.17

0

±0.0

17±0

.115

±0.1

27±0

.173

±0.1

38±0

.098

±O.1

03±0

.173

±0.1

21±0

.015

±0.1

21

0.07

10.

203

0.16

80.

330

0.30

80.

234

O.1

120.

380

0.26

00.

038

0.16

0

±0.0

10±0

.178

±0.1

50±0

.150

±0.0

98±0

.178

±0.1

73±0

.127

±0.1

50±0

.010

±0.1

27

0.07

90.

207

0.17

00.

300

0.30

60.

210

0.09

00.

380

0.28

00.

036

0.16

0

±0.0

15±0

.127

±0.1

27±0

.127

±0.0

86±0

.173

±0.0

1O±0

.144

±0.1

73±0

.017

±0.1

73

0.07

30.

207

0.18

00.

310

0.30

80.

216

0.12

00.

370

0.27

00.

037

0.18

0

±0.0

12±0

.196

±0.1

09±0

.098

±0.0

98±0

.127

±0.1

27±0

.138

±0.1

09±0

.015

±0.1

27

0.07

20.

205

0.16

00.

320

0.30

80.

220

0.13

00.

370

0.28

00.

037

0.18

0

±0.0

15±0

.167

±0.0

98±0

.109

±0.1

21±0

.109

±0.1

38±0

.121

±0.0

98±0

.016

±0.1

50

0.08

I0.

203

0.18

00.

322

0.31

00.

217

0.09

00.

390

0.26

00.

038

O.I8

0

±0.0

10±0

.144

±0.1

32±0

.121

±0.1

38±0

.103

±0.0

40±0

.109

±0.0

92±0

.008

±0.1

44

0.11

00.

206

0.17

00.

310

0.30

00.

217

0.11

30.

380

0.28

00.

037

0.18

0

±0.0

57±0

.098

±0.1

78±0

.167

±0.1

55±0

.121

±0.0

86±0

.190

±0.1

21±0

.010

±0.1

09

NaC

Ist

ress

ed

Set

lAA

(10

~M)

+N

aCI

Con

trol

lAA

(l.0

~M)

+N

aCI

lAA

(0.1

~M)

+N

aCI

GA

3(l.

0~M

)+

NaC

I

Kin

etin

(I0

~M)

+N

aCl

GA

3(1

0~M

)+

NaC

I

GA

3(0

.I~M

)+

NaC

I

Kin

etin

(0.1

~M)

+N

aCI

Kin

etin

(l.0

~M)

+N

aCI

N 0\

NANDINI CHAKRABARTI AND SUBHENDU MUKHERJI

200 [

"'[l.,,~r I Roo<

"

i

It,1,1,-1,T,TT,l,f t,t,l, " , T,T.,T, T,T,L 1,I,T" " "

Phosphorus deficiency in soil and plants is known toinduce the activity of phosphatase to cope up the inorganicphosphorus requirement of the plants (Dubey and Sharma1989). Phytohormone treatment in the present experimentretained the acid phosphatase activity under stress almostat control level indicating the presence of adequate Picontent within a cell. Adequate phosphorus supply improvestolerance to NaCI (Karaki and Ghazi 1997). So thcre wasprobably no need for increased enzyme activity inhormonetreated stressed sets.

Treatments

Fig. 1. Proline content of control and treated mungbean leaves,roots and nodules. Vertical bars represent standard error of themean of 3 replicates (P=0.05). To= Control, TI = Salt stressed, T2= T,+ IAA (10 11M),TJ = T1+lAA (1.0 11M), T4 = T1+lAA (0.1 11M),T, = T,+ GAJ (10 11M), T6 = TI+ GAJ (1.0 11M), T7 = T1+ GAJ (0.111M), T 8 = T I+ Kinetin (10 11M), T 9 = T 1+ Kinetin (1.0 11M), T 10=TI+ Kinetin (0.1 11M).

Salt stress increased the acid phosphatase activityboth in leaf and root of mung bean by about 61% and 48%,respectively over the control. In leaf, all the three hormonesused each at a concentration of 10 IlM helped to restorethe normal enzyme activity of the plant. In case of IAAand GAl treatment, per cent activity increase over controlwas only about 13 and 19, whereas kinetin completelyreversed the stress effect (Fig. 2). In root, IAA atconcentrations 1.0 and 10 IlM, GA3 at lOIlM and kinetinat all the three concentrations he lped to reduce the per centincrease from 48 to 39, 13 and 13 respectively (Fig. 2).

Root

Treatments

Fig. 2. Acid phosphatase enzyme activity of control and treatedmung bean leaves and roots. Vertical bars represent standard

error of the mean of 3 replicates (P = 0.05). (Legends aresimilar to Fig. 1).

262

From the results presented here, It IS pertinent tosuggest the possibility of adopting different strategies forgrowing this crop under saline conditions, and one maytake recourse to the treatment of the crop with growthregulators.

REFERENCESAbdullah,Zaibunnisaand Ahmed, R, (1990), Effect of pre-kinetin and

post kinetin treatments on salt tolerance of diffcrent potatocultivars growing on saline soils. J Agron, Crop Sci, 165:94-102,

Aziz, A" Martin-Tanguy, 1. and Larher, F, (1998). Stress inducedchanges in polyamine and tyramine levels can regulatc prolineaccumulation in tomato leaf discs treated with sodium chloridc,Physior Plan(, 104: 195-202.

Banuelos, G. and Bangerth, F (1986), Interrelationship between IAAand Ca transport in rcspect to Ca nutrition offruits, Acta Horf,179: 817-8]8.

Bates,LS" Waldren, R.P. and Teare, LD, (1973). Rapid detem1inationof free proline for water stress studies. Plant Soi/39: 205-208,

Bemstein, L, Ehlig, C.F, and Clark, R.A. (1969), Effcct of graperootstocks on chloridc accumulation in leaves, J Am, Soc.Hortic. Sci, 94: 584-590,

Bemstein, L (1975), Effects of salinity and sodicity on plant growth,Ann. Rev. Phytopathol. 13: 295-312,

Boyde, A, and Wood, C. (] 969). Preparation of animal tissucs forsurface scanning electron microscopy, J Microscopy 90: 221-249,

Bradbeer, 1.W., Clijsters, R, Gyldenholm, A,O, and Edge, H.J.W,(] 970), Plastid development in primary leaves of Phaseolusvulgaris. The effect of brief flashes of light on dark-grownplants. J. Exp. Bot. 21: 525-533.

Chakrabarti, N. and Mukherji, S. (1994). Effectofindole-3-acetic acid,gibberellic acid and kinetin pretreatment as foliar spray onchlorophyll content, chlorophyllase enzyme activity,

Indian J. Plant Physiol., Vol. 7, No.3, (N's,) pp, 256-263 (July-SepL, 2002)

EFFECT OF GROWTH REGULATORS ON SALT STRESSED MUNGBEAN

photosynthetic non-cyclic electron transport and CO2 uptake inC

3glycophyte Vigna radiata (L.) Wilczek under salt stress. Plant

Physiol. Biochem. 2]: 59-64.

Chaudhuri, P., Sengupta, R.K. and Ghosh, P. (I 997)./n vitro assessmentof salinity tolerance in Hordeum Vulgare L. Indian.!. PlantPhysiol. 2: 123-126.

Clarkson, D.T. and Hanson,). B. (I 980). The mineral nutrition ofhigherplants. Ann. Rev. Plant Physiol. 3]: 239-298.

Darra, B.L. and Saxena, S.N. (1971). Effect of gibberellic acid pre-soaking seed treatment at differentsalinityregimes on germination,growth and yield attributes of hybrid maize (Ganga-3). Indian.!. Agron. ]6: 46-49.

Datta, K.S. (1996). Effects of salinity on waterrelations and ion uptakein three tropical forage crops. Indian.!. PlantPhysiol. 1: 102-108.

Dubey, R.S. and Sharma, K.N. (1989). Acid and alkaline phosphatases,in rice seedlings growing under salinity stress. Indian.!. PlantPhysiol. 32: 217-223.

EI-Bahr, M.K. (1995). Selection of salt tolerance in sweetpeppertissuecultures. Egyptian.!. Physiol. Sci. 19: 97-108.

Gale, J., Kohl, H.C. and Hagan, M.R. (1967). Changes in the waterbalance and photosynthesis of onion, bean and cotton plantsunder saline conditions. Physiol. Plant. 20: 408-420.

Gangopadhyay, G., Basu, S., Mukherjee, S.P., Poddar, R., Gupta, S.and Mukherjee, B.B. (1995). Water, salt and freezing stresses:Effect on relative water content, viability and banding patternsof some isoenzymes in Brassica juncea (L) Czern. callus. Indian.!. Plant Physiol. 38: 41-44.

Gangopadhyay, G., Basu, S. and Gupta, S. (1997). In vitro selection andphysiological characterization of NaCl and mannitol-adaptedcallus lines inBrassicajuncea. PlantCe!! Tissue Organ Cult. 50:161-169.

Gomez-Cadenas, A., Tadeo, F.R., Primo-Millo, E. and Talon, M.(1998). Involvementof abscisic acid and ethylene in the responsesof eimls seedlings to salt shock. Physiol. Plant. ]03: 475-484.

Greenway, H. and Munns, R. (1980). Mechanism of salt tolerance innonhalophytes. Ann. Rev. Plant Physiol. 31: 149-190.

Indira, P. and Ramanujam, T. (1985). Response ofCassava(undersaltstress) to ascorbic acid and growth regulators. Plant Physiol.Biochem.12:97-103.

Indian J Plant Physiol., Vol. 7, No.3, (N.S.) pp. 256-263 (July-Sept., 2002)

Karaki,A. and Ghazi, N. (1997). Barleyresponseto salt stress at variedlevels of phosphorus . .!. Plant Nutr. 20: 1635-1643.

Kumar, S.G., Madhusudhan, K.V., Sreenivasulu, N. and Sudhakar, e.(2000). Stress responses in two genotypes of mulberry (Morusalba L.) under NaCI salinity. Indian.!. Exp. BioI. 38: 192-195.

Malik, C.P. and Singh, M.B. (1980). Acid Phosphatase. In: e.P. Malikand M.B. Singh (eds.)PlantEnzymologyandHistoenzymology.pp. 66-67. Kalyani Publishers, New Delhi.

Maliwal, G. L. (1997). Response of wheat varieties to chloride andsulphate dominant salinity. Indian.!. Plant Physiol. 2: 225-228 .

Mittal, R and Dubey, R.S. (1992). Mitochondrial acid phosphatase andadenosine triphosphatase activities in germinating rice seedsfollowing NaCI salinity stress. Indian.!. Plant Physiol. 35: 174-181.

Patil, B.e., Rao, M.R.G., Parama, V.R.R. andVishwanath, D.P. (1989).Relative salt tolerance of safflower genotypes based on yield,sodium, potassium and calcium contents. Indian.!. Plant Physiol.32: 90-94.

Patil, B.e., Viswanath, D.P. and Patil, S.G. (1996). Effect of salinityon rate of photosynthesis and associated leaf characters in maize(Zea mays L.). Indian.!. Agric. Res. 30: 169-172.

Sudhakar, C., Reddy, P.S. and Veeranjaneyulu. (1990). Effect of saltstress on dry matter production and mineral content during earlyseedl ing growth of Horse gram (Macrotyloma uniflorum (Lam.)Verde.) and Greengram (Vigna radiata Wilczek). Plant Physiol.Biochem. 17: 88-91.

Trinchant, J.e. and Rigaud, J. (1998). Proline accumulation insidesymbiosomes of faba bean nodules under salt stress. Physiol.Plant. 104: 38-49.

Turner, L.B. and Wellburn, A.R. (1985). Changes in adenylate nucleotidelevels in the leaves of Capsicum annum during water stress . .!.Plant Physiol. 120: 111-] 22.

Zidan, I.,Azaizen, I. I. and Neuman, P.M. (1990). Does salinity reducegrowth in maize roots epidermal cells by inhibitingtheircapacityfor cell wall acidification? Plant Physiol. 93: 7-II.

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