Effect of salt stress, application of salicylic acid and proline on endogenous growth hormones of sweet pepper (Capsicum annum L.) during vegetative stage.

Effect of salt stress, application of salicylic acid and proline on

endogenous growth hormones of sweet pepper (Capsicum annum L.)

during vegetative stage.

Basheer A. AL-Alwani Coll.of sci. Univ. of babylon

Ali H. Jasim Coll.of agric. Univ. of al-qasim

Wassan M. Abu ALTimmen Coll.of sci. Univ. of babylon

Abstract Factorial experiment with three factors was conducted to study the effect of salt stress on plant hormones concentration during vegetative growth of sweet pepper (Cpsicum annuum L.) planting individually in pots (5kg) and its interactions with exogenous application of salicylic acid and proline. Sodium chloride (NaCl) was added to water irrigation in two concentrations (1.3 and 5 dsm/m). Three concentrations of salicylic acid (SA): 0 , 5*10-5, 10-4 M, and four concentrations of proline : 0, 1, 5, 10 mM were sprayed exogenously on seedlings. The results showed that salt stress was negatively affect on free IAA,GA, CK and ABA concentrations. While increase in almost bound hormone concentrations. Spraying plants with SA caused a decrease in free IAA,CK concentrations, while free ABA concentration was increased significantly. In contrast, SA caused a reversible effect on bound hormones. Whereas, proline caused a significant decrease in free IAA and ABA concentrations and an increase in bound hormones concentrations.

Introduction

World population is increasing at an alarming rate and is expected to reach about six billion by the end of year 2050. On the other hand food productivity is decreasing due to the effect of various abiotic stresses; therefore minimizing these losses is a major area to concern for all nations to cope with the increasing food requirements. Cold, salinity and drought are among the major stresses, which adversely affect plants growth and productivity; hence it is important to develop stress tolerant crops (Mahajan and Tuteja , 2005). The stress imposed by 25 or 50 mm NaCl reduced substantially leaf area, dry mass, leaf chlorophyll content, stomatal conductance and net photosynthetic rate 50 days after emergence of mustard plants (Shah,2007). Taffouo et al.,2008 showed that low concentrations of NaCl had a negative effect on agronomic parameters and limited the growth of plants, as well as the Na+ and K+ contents in the shoots of C. lanatus and C. moshata. Salt stress also resulted in growth reduction, increase of Na+/K+ ratio, increase of Pro level and up-regulation of Pro synthesis genes

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Jornal of Babylon Univ. Special Issue - Proceding of 5th International Conference of Environmental Scince University of Babylon / Environmental Research Center 3-5 December 2013th 5 International Conference for Environmental Researcuys-Environmental Researc

(pyrroline-5-carboxylatesynthetase, P5CS; pyrroline-5-carboxylate reductase, P5CR) as well as accumulation of hydrogen peroxide (H2O2), increased activity of antioxidative enzymes (superoxide dismutase, SOD; peroxidase, POX; ascorbate peroxidase, APX; catalase, CAT) and transcript up- regulation of genes encoding antioxidant enzymes (Nounjan et al,2012). Sweet pepper (capsicum annuum L.) is one of sensitive plants, (zapata et al.,2008). So, it affect negatively when grown in saline conditions. Bethke and Drew ,1992 found that saline treatments decreased the quality of pepper fruits and growth rate. Also, Chartzoulakis and Klapaki,2000 demonstrated that pepper plants treated to 100 or 150 moles per cubic meter NaCI had up to 85% inhibition in photosynthetic ability. Salicylic acid (SA) is an endogenous growth regulators of phenolic nature, which participates in the regulation of physiological processes in plant (Ebrahimian and Bybordi,2012). It significantly increased the fresh and dry weights of wheat plants roots and shoots under salt stress. Similarly, it promoted the activities of antioxidative enzymes (Arfan, 2009). Salicylic acid pre-treatment alleviated the adverse effects of salinity stress on germination percentage, length of shoot, fresh and dry weight, photosynthetic pigments and K+ concentration (Delavari et al, 2010). Plants treated with SA showed no recovery from excessive accumulation of Na+ in their shoot/root, under salt stress (Mahmood et al 2010 ). Proline (Pro) function as compatible solutes and are up regulated in plants under abiotic stress. They play an osmoprotective role in physiological responses, enabling the plants to better tolerate the adverse effects of abiotic stress. Exogenous application of proline considered as an important agent to maintain osmotic potential of the plant cell (Ali, et al, 2007) and it considered as an antioxidant agent through its role in increasing the ability of plant to tolerate salt stress (Okuma et al, 2004). Plant hormones are comprised of a group of structurally unrelated small molecules that regulate a wide variety of plant processes. The hormones also act to integrate diverse environmental cues with endogenous growth programs. So, far ten phytohormones have been identified including auxin, abscisic acid (ABA), cytokinin (CK), gibberellin (GA), ethylene, brassinosteroids (BR), jasmonate (JA), salicylic acid (SA), nitric oxide, and strigolactones (Davies, 1995; Browse, 2005; Vert et al., 2005; Grun et al., 2006; Loake and Grant, 2007; Gomez-Roldan et al., 2008; Umehara et al., 2008). Plants also utilize several peptide hormones to regulate various growth responses (Jun et al., 2008).With the application of biochemical, genetic, and genomic approaches, many aspects of hormone biology have been elucidated, especially in the model flowering plant Arabidopsis thaliana. Most hormones are involved in multiple processes and impact each other through elaborate crosstalk strategies in elucidating these hormone-signalling pathways (Santner and Estelle,2010). The objective of the present study was to observe the effect of the individually and simultaneous

application of SA and proline as a foliar spray on the endogenous hormones of pepper plants under saline and non-saline conditions.

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Material and Methods Planting method: This experiment was conducted under saran canopy at the Department of Biology, collage of science Babylon University. Sweet pepper (Capsicum annuum L.) seedlings of 45 days old were obtained from gbela, Babylon. The original seeds were irrigated with water of (1.3 dsm/m). The seedlings were planted in plastic pots containing 5 kg of soil (six pots for each treatment). Each one supplied with 0.5 gm of NPK and granular fungicide. Seedlings were irrigated with tap water (1.3 dsm/m) for ten days twice a day before salinity treatment, followed by irrigation with salted water (5 dsm/m) every day until seedlings were reaching 70 days old. Plants were sprayed twice with different concentrations of S.A (0 , 5*10-5,10-4 M) and proline (0 , 1 , 5 , 10 mM). The first treatment added when the plants was 60 days old and the second treatment after a week of the first one. The interaction between S.A and proline was applied by spraying seedlings with proline in the concentrations mentioned above after two days of S.A application.

Plant hormones determination Plant hormones were determined according to (Ergun et al.,2002). Either one gram fresh or dry weight of leaves sample was taken and combined with 60 ml of methanol: chloroform: 2N ammonium hydroxide (12:5:3 v/v/v). Each combined extract (60 ml) was kept in a bottle at -20oC in deep freeze for further analysis. Combined extract was treated with 25 ml of distilled water. The chloroform phase was discarded. The water-methanol phase was evaporated. The water phase was adjusted to the extract pH value of 2.5 or 7 with 1 N HCl or 1 N NaOH respectively and 15 ml ethyl acetate was added at each of three steps. This procedure provided the isolation of free-form IAA, GA3, ABA and zeatin from the extraction solvent. After an incubation period of 1 hour at 70 oC, the same procedure was used for the isolation of bound form IAA, GA3, ABA and zeatin from the extraction solvent. Spectrophotometric assay was done using 222 nm and 280 nm wave lengths for IAA, 254 nm for GA3, 263 nm for ABA, and 269 nm for zeatin and for all standard synthetic IAA, GA3, ABA and zeatin and isolated samples.

Statistical analysis : This factorial experiment included three factors (24 treatments) . Each pot was treated as one replicate and all the treatments were repeated three times. The data were analyzed statistically with SPSS-17 statistical software. Means were statistically compared by L.S.D test at p<5% level.

Results

Tabe (1) demonstrated that salt stress caused a significant decrease about 12.1% in free IAA concentration. Also, the concentrations 10-4 M , 5*10-5 M of SA and the concentrations 1,5 mM of proline caused a significant decrease in hormone concentration. Stressed plants treated with both concentrations of SA and 1, 10 mM proline showed a significant decrease in hormone concentration. The bilateral interaction treatments between SA and proline showed that (1 mM pro.+ 10-4 , 5*10-5 M of SA ) and (5 mM pro.+ 5*10-5 M of SA) caused a significant decrease in free IAA concentration.

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The triple interaction between salt,SA and proline showed that free IAA concentration was decreased significantly in stressed plants compared to unstressed plants. Also, the same result was observed during 1,5 mM proline treatments in unstressed plants. While free IAA concentration increased in stressed plants. SA treatment maintain free IAA concentration in normal range compared to control plants. All interaction treatments decreased IAA concentration.

Table (1):The effect of salt , S.A , proline and their interaction on free IAA concentration (M) of leaves / vegetative stage.

Salt concentration dSm/m S.A concentration M

0

0

1.3 10 -4

Proline concentration mM

1

.920

.795

.908

1.054

.700

.690

.845

5

.891

1.043

.866

1.218

.946

.623

.931

10

1.314

1.130

1.120 .938

.639

.845

.998

Mean of Salt*SA

1.122

.920

1.062

1.025

.906

.798

1.365

.710 -5

5*10

0 5

10

1.355

.889

1.341 -4

-5 5*10

Mean of proline

L.S.D0.05

Salt * Proline

L.S.D0.05

0

S.A * Proline 10

1.032

1.115 salt * SA * proline =0.4 proline=0.164

1.3

5

1.143

salt * SA =0.2

.874

.815

.933

.929 salt =0.12

1.055

1.188

.807

Mean of salt

1.035

.910 Mean of S.A

1.074

1.087 salt * proline = 0.23

1.127 .987 1.126

-4 1.026

-5 .748

.799

.994 .885 .913

.930 SA=0.14

5*10

L.S.D0.05 1.194 .744.983

SA * proline = 0.283

Table (2) showed no significant effect in bound IAA concentration between unstressed and stressed plants neither treated with SA and proline nor untreated plants. While, bound IAA concentration increased significantly during SA 5*10-5 M treatment of unstressed plants. But it decreased in stressed plants. Whereas, proline had no effect on hormone concentration both in stressed and unstressed plants. The combination (10mM pro.+ 5*10-5 M SA) showed a significant increase in bound IAA concentration compared with control plants. The same results were observed at the combinations (5,10mM pro.+ 5*10-5 M SA) and (1,5 mM pro.+ 10-4 M SA) of stressful and unstressed plants.

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Table (3) clarify a non significant decrease in free GA concentration in stressful plants. Also, neither SA nor proline treatments lonely or in combination had significant effect on the plants.

Table (2):The effect of salt , S.A , proline and their interaction on bound IAA concentration (M) of leaves /

vegetative stage.

Salt concentration dSm/m

Proline concentration mM S.A concentration M

0

0 1.3 10-4

5*10-5

0

5 10-4

5*10-5

Mean of proline

L.S.D0.05

Salt * Proline 5

L.S.D0.05

0

S.A * Proline 10-4

5*10-5

L.S.D0.05

.636

salt * proline =0.14

.575

.567

.679

.645 .640 .623 .636

Mean of S.A

.735

.565

.751

.586

.610

.659

salt =0.07

.602

.584

.550

.433

.724

.655

SA=0.08

proline=0.095

1.3

.5085

.5147

.7105

.6417

.6190

.6467

.607

1

.5943

.3886

.5555

.6101

.7804

.5454

.607

5

.2867

.6397

.7747

.5785

.8078

.5350

.604

10

.6581

.7269

.8475

.8122

.4026

.6548

.684

Mean of salt

.600

Mean of Salt*SA

.512

.567

.722

.661

.652

.595

salt * SA * proline =0.23

.578 .513

salt * SA =0.12

.567 .744

SA * proline =0.17

Table (3):The effect of salt , S.A , proline and their interaction on free GA concentration (M) of leaves / vegetative stage.


1.3 10

5*10

S.A concentration M

0 -4 -5

Proline concentration mM Mean of Salt*SA

0 28.0209 19.6583

35.6918 23.8708

27.1680 26.5647

26.829

1 24.2453 24.7445

28.2289 27.3656

19.5439 22.2014

24.388

5 22.1858 29.5291

26.1643 30.8604

30.6420 16.2259

25.935

10 34.4385 31.8070

29.8619

26.4919 18.5350 26.6791

27.969 Mean of salt

27.881

24.679

Mean of S.A

27.185

25.203

26.452

SA=4.25

27.223 26.435 29.987 27.147

23.972 29.987

0 5 10-4

5*10 Mean of proline

L.S.D0.05

Salt * Proline

L.S.D0.05

0

S.A * Proline 10-4

5*10-5

L.S.D0.05

-5


1.3 5

27.790

25.868

salt * SA =6.01 proline=4.9 25.960

25.909

32.036

23.902

salt =3.47

30.465

25.171

28.271

SA * proline =8.5

25.740

23.037

salt * proline =6.94

25.946

23.413

31.128

25.805

22.144

25.215

26.523

30.086

21.195

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Table (4) demonstrated a significant decrease in bound GA concentration in stressful plants. Alternatively, SA and proline had no significant effect on hormone concentration. Meanwhile, 5*10- 5 M SA caused a significant increase in bound GA concentration in unstressed plants, while it caused a decrease in GA concentration in stressful plants. But, proline at 5 mM caused an increase in hormone concentration compared with 0 mM. The combination between SA and proline showed that ( 1 mM pro.+ 0, 10-4 M SA) caused an increase in GA concentration. The triple combination between salt ,SA and proline showed that 5*10-5 M SA caused an increase in GA concentration in unstressed plants. Whereas no significant effect appeared neither in stressful plants nor in the combination treatments.

Table (4):The effect of salt , S.A , proline and their interaction on bound GA concentration (M) of leaves / vegetative stage.


1.3

S.A concentration M 0

10 -4


0

11.3347

11.9250

1

13.2668

12.1772

11.1709

10.5221

12.0550

8.6122 11.301

5

9.0257

10.5676

12.6921

12.0290

11.5610

10.5468 11.070

10

11.4361

12.1070

12.7857 12.1226

5.7935

10.9681 10.869

Mean of Salt*SA

11.266

11.694

12.840

10.922

9.160

10.215

5*10

0 5 10

-5 14.7125

9.0153

7.2315 -5

-4

5*10

Mean of proline

L.S.D0.05

Salt * Proline

L.S.D0.05

0 S.A * Proline 10

10.7341 10.826

salt * SA * proline = 2.41 proline=0.99

1.3

5

12.657 12.205

salt * SA =1.21

10.762 12.110

9.628

Mean of salt

11.933

10.099 Mean of S.A

11.094

10.427

11.528

8.99410.39611.379 salt * proline =1.39salt =0.7

10.175

9.578 -5

11.894

12.116

10.527

11.064

11.779

8.950 -4

5*10

L.S.D0.05 12.7239.892 SA * proline =1.71

11.61911.877 SA=0.85

The results in table (5) showed that salt stress caused a significant decrease in free CK concentration about 30.5%. Also, we demonstrated that 10-4 M SA caused a significant decrease in free CK concentration compared with control plants. But, 5*10-5 M SA maintain hormone concentration in the leaves. Whereas, proline caused hormone concentration decrease.

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The combination between salt and SA had no effect on free CK concentration in unstressed and stressful plants which their hormone concentration still lower than control plants. The same results observed in proline treated plants. The combination between SA and proline showed that (5,10 mM pro.+ 10-4 M SA) caused a significant decrease in free CK concentration, whereas10-4 M SA alone increased it. The triple interaction between salt ,SA and proline showed that both concentrations of SA and the interaction (10 mM pro.+ 5*10-5 M SA) caused an increase in free CK concentration in unstressed plants, but salt stress cancelled the positive effect of SA.

Table (5):The effect of salt , S.A , proline and their interaction on free CK concentration (M) of leaves / vegetative stage.


1.3

S.A concentration M

0

10 -4


0

8.7112

11.6121

1

10.2875

9.9349

10.1838

6.5140

6.0508

6.8445 8.303

5

8.9020

5.6802

7.3755

5.3760

3.5467

7.5331 6.402

10

9.6376

6.2942

11.5319 7.4764

3.6545

6.6910 7.548

Mean of Salt*SA

9.3845

8.3803

10.1627

6.7546

5.6308

7.0343

5*10

0 5 10

-5 11.5596

7.6520

9.2712 -5

-4

5*10

Mean of proline

L.S.D0.05

Salt * Proline

L.S.D0.05

0 S.A * Proline 10

7.0685 9.312

salt * SA * proline = 2.54 proline=1.04

1.3

5

10.628

7.997 salt * proline =1.47

8.182

10.442 -5

salt * SA =1.27 Mean of salt

9.309

6.473 Mean of S.A

8.070

7.006

8.598

10.135 7.319 9.155

5.941 6.4705.485 salt =0.73

8.401

7.993

7.139

4.613

7.454

8.557

4.974

9.111 SA=0.9

-4

5*10

L.S.D0.05 9.3148.514 SA * proline =1.8

Table (6) showed that bound CK increased during salt stress treatment about 24.2%. The same results observed at 10-4 M SA treatment. Whereas, proline had no significant effect on bound CK concentration. The interaction between salt and SA showed that untreated plants and treated plants with 10-4 M SA caused an increase in hormone concentration. The same results were observed in plants treated with 1,5 mM proline in stressful plants when compared with unstressed plants. The table also showed disappearance of significant differences in bound CK concentration in unstressed plants except of (0, 10 mM pro.+ 5*10-5 M SA) which increase hormone concentration.

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The same results were found in stressful plants treated with the interaction (1,5 mM pro.+ 5*10 -5 M SA) and 10-4 M SA alone when compared with control plants. Table (6):The effect of salt , S.A , proline and their interaction on bound CK concentration (M) of leaves / vegetative stage.


1.3

S.A concentration M

0

10 -4


0

5.6332

6.7062

1

6.7311

6.4255

4.6155

9.7766

7.0713

9.2504 7.312

5

8.4830

4.8464

6.7449

10.7894

6.8528

8.8978 7.769

10

6.9219

5.6885

10.6719 8.6185

8.4623

6.5804 7.824

Mean of Salt*SA

6.9423

5.9167

7.9711

9.4870

8.5003

7.8836

5*10

0 5 10

-5 9.8519

8.7637

11.6149 -5

-4

5*10

Mean of proline

L.S.D 0.05

Salt * Proline

L.S.D 0.05

0 S.A * Proline 10

6.8058 8.229


1.3

5

7.397

salt * SA =1.58

5.924

8.699

6.691

proline=1.3

7.761

7.887

Mean of salt

6.943

8.624 Mean of S.A

6.943

8.624

6.943

9.061 salt * proline =1.82

7.198

9.161 -5

8.847 salt =0.91

9.636

5.850

8.254

6.748

7.770

7.075 -4

5*10

L.S.D0.05 8.3296.933 SA * proline =2.23

7.8218.626 SA=1.12

Table (7) showed that salt stress caused a significant decrease in free ABA concentration about 10.7%.When the plants were treated with SA, the significant effects were disappeared. Whereas, proline treatments(1,10) mM caused decrease hormone concentration. The combination between salt and SA or proline clarify a significant decrease in free ABA concentration when unstressed plants were treated with 10-4 M SA ,whereas, the concentrations 0, 5*10-5 M SA and 1,5 mM proline caused the same results in stressful plants when compared with control once. The combination between SA and proline had no significant effect on free ABA concentration except the interaction (5 mM pro.+ 5*10-5 M SA) which cause free ABA decrease. The triple interaction between salt, SA and proline showed no significant effect of almost treatments in stressful plants.

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Table (7):The effect of salt , S.A , proline and their interaction on free ABA

concentration (M) of leaves / vegetative stage.


1.3


10 -4


0

387.6787

248.9844

1

316.9242

326.1363

366.6955

282.6024

256.7892

280.7792 304.988

5

294.4055

277.7085

339.5068

251.4154

391.5171

213.7991 294.725

10

442.0561

351.9816

381.5373 342.5775

248.3447

348.2711 352.461

Mean of Salt*SA

360.2661

301.2027

386.4952

297.5962

339.3148

298.6118

5*10

0 5 10

-5 458.2414

313.7895

460.6084 -4

-5 5*10

Mean of proline

L.S.D0.05

Salt * Proline

L.S.D0.05

0 S.A * Proline 10

351.5977 370.150


1.3

5

364.968

salt * SA =46.9

336.585

proline=38.33

391.858

313.064

Mean of salt

349.321

311.841 Mean of S.A

328.931

320.259

342.553

303.874

285.577 salt =27.11

272.910

334.613

375.332273.390 salt * proline =54.2

350.734

354.796 -5

299.763

291.463

392.317

300.163

364.904 SA=33.2

-4

5*10

L.S.D0.05 404.920 323.737276.653

SA * proline =66.4

Table (8) clarify a significant decrease about 18.9% in bound ABA concentration during stress treatment. Also, we observed a decrease in hormone concentration in plants treated with 10-4 M SA and its increase in plants treated with 5*10-5 M SA. This is observed increase the concentration of the bound hormone when spraying with the concentrations(1 and 10) mM proline. While, 5 mM caused hormone decrease significantly. Bilateral interactions showed increase free ABA concentration significantly in stressful plants. The same result were observed in unstressed plants treated with 5*10-5 M SA. While, it decreased in stressful plants treated with (0,5.10) mM proline. Sequential spraying with SA and proline showed that bound ABA concentration decreased in plants treated with (0,5,10 mM pro.+ 10-4 M SA). The triple interaction clarify a significant increase in bound ABA concentration when exposing to salt stress without any treatment. But its concentration decreased when stressful plants sprayed with (0,1,5,10 mM proline +5*10-5 M SA),while there were no effect in plants treated with 10-4 M SA.

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Table (8):The effect of salt , S.A , proline and their interaction on bound ABA concentration (M) of leaves /vegetative stage.



10 -4


0

237.5012

227.8092

1

276.8128

246.6174

375.3319

289.9914

274.8297

261.9710 287.592

5

181.9403

225.9220

365.2880

228.3850

261.3953

173.6877 239.436

10

249.1763

271.8869

515.3056 275.2135

168.5699

246.6174 287.795

Mean of Salt*SA

236.3577

243.0589

413.5400

286.2969

221.3479

216.5499

1.3 5*10

0 5 10

-5 398.2343

351.5977

180.5969 -4

-5 5*10

Mean of proline

L.S.D0.05

183.9235 263.277

salt * SA * proline =56.6 proline=23.12

1.3

5

287.848 299.587

salt * SA =28.3 Mean of salt

Salt * Proline

L.S.D0.05

257.717

221.156 salt =16.4

205.163

243.659

345.456

230.134

297.652

241.398 Mean of S.A

261.327

232.203

315.045

238.706275.597 salt * proline =32.7

294.549

204.203 -5

0 S.A * Proline 10 -4

283.402

260.724

262.195

220.228 5*10

L.S.D0.05 291.079318.651269.488380.962 SA * proline = 40.04SA=20.02

Discussion Plant hormones auxin (indole-3-acetic acid), gibberellins, cytokinins, and abscisic acid are central to regulation of plant growth and defence to abiotic stresses such as salinity. Quantification of the hormone concentration can reveal different plant strategies to cope with the stress, e.g., suppression of growth or mobilization of plant metabolism. As mentioned in our previous research the growth parameters were decreased significantly (Jasim et al,2012), This is may be related to the lack of cell division resulting from a lack of free auxin and free CK table (1 and5). This is compatible with (Yew et al., 2010) who found that CK is one of the hormones necessary to stimulate the elongation of the shoot. In addition, (Vernoux et al., 2010) mentioned that free auxin plays an important role in meristimatic cell division of the shoot to configure the parts of the plant, or due to the inability of GA concentration to cope with the adverse effect of salt stress even though it does not differ significantly from its concentration in the treatment of control plant (table 3). In addition our results regarding free and bound ABA decreases in the leaves were in agreement with the decrease wet weight of the leaves due to decrease hormone efficiency in controlling stomata closure. Spraying pepper plant with SA caused decrease free IAA and CK concentrations table(1 and 5) because SA might interfere with auxin responses resulting in stabilization of the Aux/IAA repressor proteins and inhibition of auxin responses (Wang et al., 2007). Or, due to its ability to inhibit CK signaling because SA negatively regulates cytokinin signaling creates a sort of balance helps the plant to withstand stress (Argueso et al.,2012;Choi et al.,2011).

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Exogenous proline supply showed a negative role in maintaining cell hormone system during vegetative stage of plant growth table (1,5,7) due to its poisoning effect causing mitochondria and chloroplast break down and accelerating programmed cell death (Bonner et al., 1996; Hellmann et al., 2000; Hare et al., 2002). This result was compatible with (Mattoli et al., 2009) who demonstrated that exogenous proline cause excessive increase of endogenous proline in shoot and root leading to cell damage. Or this decrease in hormones concentration as a result of an attempt of plant to cope against the stress conditions to reduce water loss. Many studies had noted to the role of bound IAA with increased susceptibility of the plant to stress tolerance (Muller, 2011). Junghans et al., 2006 isolated enzymes liberated for auxin (Axin - conjugate hydrolase) from tissues exposed to stress in the poplar plant, also he found that the IBA - glucose has a role in the response of the plant to saline stress (Tognetti et al., 2010), and found that bound CK had an importance in plant development because its ability to organize active CK concentration and its transmission and inhibition (Auer, 1997) and this is evidenced by the results of this study table (2,6). In addition, bound ABA had an active role in plant stress tolerance which is associated with an increased in endogenous proline content table (8). Dietz et al.,2000 demonstrated that bound ABA concentration decreased when exposed to saline stress due to increasing the effectiveness of certain enzymes liberated bound hormone and the formation of active form of the hormone and the most important of these enzymes is B - glucosidase which rises effectiveness during plant exposure to salt stress. It is believed that the external proline stimulates the effectiveness of this enzyme. The accumulation of endogenous proline needs to change the sensitivity of the cells to the ABA by affecting the metabolism or association of the hormone, and that many of the metabolic pathways of the hormone was considered within the mechanical mechanism of hormonal imbalance that prevents ABA accumulation to maintain a certain concentration of the hormone that fits the type of stress )Verslues and Bray,2006 ( .

References

Ali, Q.; M. Ashraf And H.R. Athar ( 2007). Exogenously applied proline at different growth stages enhances growth of two maize cultivars grown under water deficit conditions. Pak. J. Bot., 39(4): 1133-1144. Arfan M. (2009). Exogenous application of salicylic acid through rooting medium modulates ion accumulation and antioxidant activity in spring wheat under salt stress.Int. J. Agric. Biol., 11 (4): 437–442. Argueso C.; F. Ferreira ; P. Epple ; C. Hutchison (2012) Two-Component Elements Mediate Interactions Between Cytokinin And Salicylic Acid In Plant Immunity. Plos Genet 8(1): E1002448. Doi:10.1371/Journal.Pgen.1002448. Auer C.A. (1997). Cytokinin conjugation: Recent Advances and patterns in plant evolution. Plant Growth Regulation, 23: 17–32. Bethke P.C. and M.C. Drew (1992). Stomatal and nonstomatal components to inhibition of photosynthesis in leaves of Capsicum Annuum during progressive exposure to NaCl salinity. Plant Physiology, 99: 219–226.

81


Bonner K.J.; W.B. Frommer ; D.R. Bush ; M. Kreman; D.D.F. Loo ; E.M. Wright (1996). Kinetics and specificity of a H+/amino acid transporter from Arabidopsis thaliana. J BioI Chem 271:2213-2220. Browse, J. (2005) Jasmonate: an oxylipin signal with many roles in plants. Vitam. Horm. 72, 431–456. Chartzoulakis K. and G. Klapaki (2000). Response of two greenhouse pepper hybrids to NaCl salinity during different growth stages. Scientia Horticulturae, 86: 247-260. Choi D.S. And B.K. Hwang (2011). Proteomics and functional analyses of pepper abscisic acid– responsive 1 (ABR1),Which is involved in cell death and defence signalling. The Plant Cell, 23: 823–842. Davies P.J. 1995. Plant hormones. Dordrecht: Kluwer Academic Publishers. Delavari P.M; A. Baghizadeh; S. Enteshari; K.M. Kalantari ; A. Yazdanpanah And E.A. Mousavi (2010). The effects of salicylic acid on some of biochemical and morphological characteristic of Ocimum Basilicucm under salinity stress. Australian Journal Of Basic And Applied Sciences, 4(10): 4832-4845. Dietz K.J.; A. Sauter ; K. Wichert; D. Messdaghi and W. Hartung (2000). Extracellular β‐glucosidase activity in barley involved in the hydrolysis of ABA glucose conjugate in leaves Journal of Experimental BotanyVolume 51, Issue 346 Pp. 937-944. Ebrahimian E. And A. Bybordi (2012). Effect of salinity, salicylic acid, selenium and ascorbic acid on lipid peroxidation, antioxidant enzyme activity and fatty acid content of sunflower. African Journal Of Agricultural Research , 7(25):3685-3694. Ergun N.; S.F. Topcuoúlu and A. Yildiz (2002). Auxin (Indole-3-acetic acid), Gibberellic acid (GA3), Abscisic Acid (ABA) and Cytokinin (Zeatin) Production by Some Species of Mosses and Lichens. 26 :13-18. Gomez-Roldan, V.; S. Fermas; P.B. ; T. Brewer ; et al (2008) Strigolactone inhibition of shoot branching. Nature, 455, 189–194. Grun, S.; G. Lindermayr ; S. Sell and J. Durner (2006) Nitric oxide and gene regulation in plants. J. Exp. Bot. 57, 507–516. Hare P.D.; W.A. Cress and J. Van Staden (2002) Disruptive effects of exogenous proline on chloroplast and mitochondrial ultrastructure in Arabidopsis leaves. S Afr J Bot 68:393–396. Hellmann H.; D. Funck ; D. Rentsch and W.B. Frommer (2000). Hypersensitivity of an Arabidopsis sugar signaling mutant toward exogenous proline application. Plant Physiol., 123:779–789. Jasim A.H.; A. Basheer and M. Wassan (2012) Effect of salt stress, application of salicylic acid and proline on seedling growth of sweet pepper (Capsicum annum L.). Euphrates journal of agriculture science,4(3):1-14. Jun, J.H.; E. Fiume and J.C. Fletcher (2008) The CLE family of plant polypeptide signaling molecules. Cell. Mol. Life Sci. 65, 743–755. Junghans U.; A. Polle ; P. Duchting ; E. Weiler ; B. Kuhlmann ; F. Gruber and T. Teichmann (2006). Adaptation to high salinity in poplar involves changes in xylem anatomy and auxin physiology. Plant Cell and Environment, 29:1519–1531. Loake, G. and M. Grant (2007) Salicylic acid in plant defense—the players and protagonists. Curr. Opin. Plant Biol. 10, 466–472.

82


Mahajan S. ; N. Tuteja (2005).Cold, salinity and drought stresses. Archives of Biochemistry and Biophysics ,444 :139–158. Mahmood T.; N. Iqbal; H. Raza ; M. Qasim And M. Yasin Ashraf (2010). Growth modulation and ion partitioning in salt stressed sorghum (Sorghum Bicolor L.) by exogenous supply of salicylic acid. Pak. J. Bot., 42(5): 3047-3054. Mattioli Ro.; Berto; P. Costantino And M. Trovato (2009). Proline accumulation in plants. Plant Signaling and Behavior., 4,11: 1016-1018. Muller D. And O. Leyser (2011). Auxin, cytokinin and the control of shoot branching. Annals Of Botany, 107: 1203–1212. Okuma E.; Y. Murakami ; Y. Shimoishi ; M. Tada And Y. Murata (2004). Effect of exogenous application of proline and betain on the growth of tobacco cultured cells under saline conditions. Soil.Sci.Plant Nutr., 50(8):1301-1305. Santner A. and M. Estelle (2010) .The ubiquitin-proteasome system regulates plant hormone Signalling. The Plant Journal 61, 1029–1040. Shah S. H. (2007).Effects of salt stress on mustard affected by gibberellic acid application. Gen.Appl.Plant Physiology,33(1-2):97-106. Taffouo D.V.; N.L. Djiotie ; M. Kenné ; N. Din ; J.R. Priso ; S. Dibong and A. Akoa (2008). Effects of salt stress on physiological and agronomic characteristics of three tropical cucurbit species. Journal of Applied Biosciences , 10: 434 – 441. Tognetti V.B., et al. (2010). Perturbation in indole-3-butyric acid homeostasis by the UDP- glucosyltransferase UTG74E2 modulates Arabidopsis architecture and water stress tolerance. Plant Cell. 22, 2660–2679. Umehara, M., Hanada, A., Yoshida, S. et al. (2008) Inhibition of shoot branching by new terpenoid plant hormones. Nature, 455, 195–200. Vernoux T.; F. Besnard And J. Traas (2010). Auxin at the shoot apical meristem. Cold Spring Harb Perspect Biol., 2:1-14. Verslues P.E. And E.A Bray (2006). Role of abscisic acid (ABA) and arabidopsis thaliana ABA- insensitive loci in low water potential-induced ABA and proline accumulation. Journal Of Experimental Botany, 57(1):201–212. Vert, G., Nemhauser, J.L., Geldner, N., Hong, F. and Chory, J. (2005) Molecular mechanisms of steroid hormone signaling in plants. Annu. Rev. Cell Dev.Biol. 21, 177–201. Wang D; K. Pajerowska-Mukhtar ; A.H. Culler and X. Dong (2007). Salicylic acid inhibits pathogen growth in plants through repression of the auxin signaling pathway. Current Biology, 17:1784–1790. Yew C.K.; B. Balakrishnan ; J. Sundasekaran and S. Subramaniam (2010).The effect of cytokinins on in vitro shoot length and multiplication of Hymenocallis littoralis . Journal of Medicinal Plants Research, 4(24):2641–2646. Zapata P.J.; M. Serrano ; M.T. Pretel and M.A. Botella (2008). Changes in free polyamine concentration induced by salt stress in seedlings of different species. Plant Growth Regul., 56:167–177.

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Effect of salt stress, application of salicylic acid and proline on endogenous growth hormones of sweet pepper (Capsicum annum L.) during vegetative stage.

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