Improvement of Salt Tolerance and Nutrient Absorption in Pepper (Capsicum annum) Through Application of Salicylic Acid and Humic Acid

Document Type : Research Article


1 Department of Horticultural Science, Islamic Azad University, Yasuj Branch, Yasuj, Iran and Sustainable Agriculture and Food Security Research Group, Yasuj Branch, Islamic Azad University, Yasuj, Iran

2 Yasooj Branch, Islamic Azad University


Introduction: Bell pepper (Capsicum annuum) belongs to solanaceae family, which is cultivated and consumed in the world due to its high economic value. Bell peppers also have valuable nutritional and medicinal compounds, including natural colors, antioxidants and vitamins A, B and E. Salinity stress is one of the most important environmental factors limiting growth, which has very adverse effects on plant growth and yield. Salinity stress reduced the yield of agricultural products due to the effect on the competitive absorption and transfer of nutrients in the plant. Nowadays, the increased tolerance of plants to environmental stresses from different pathways involve breeding programs and the use of plant growth regulators and organic substances. In comparison to breeding methods that are often long-term and cost-intensive, it is easy and inexpensive to use plant growth regulators such as Salicylic Acid (SA) and humic acid (HA). 
Material and Methods: To investigate the effect of Salicylic Acid (SA) and Humic Acid (HA) on the improvement of tolerance to salinity and absorption of mineral elements under salinity stress in greenhouse culture, a factorial experiment based on Randomized Complete Block Design (RCBD) was conducted in Yasooj. The first factor was SA in three levels (0, 1, and 2 mM), the second factors HA in two levels (0 and 5 g l-1), and the third factors salinity in three levels (0, 50, and 100 mM). The bell pepper seedlings cv. California were obtained from a commercial producer and planted in 4-liter plastic pots containing perlite and cocopeat (1:1) in 2015. Plants were grown in a hydroponic greenhouse with day/night temperature (24.3 and 15.4 oC) and 60 to 80% RH in the village of Nahrgah in Yasouj. After the plants were established (having about 4–5 leaves), sodium chloride salt was used in the concentrations of 0, 50, and 100 mmol in the nutrient solution for salinity stress. To prevent a sudden shock, the first one week all the pots were irrigated with a 10 mM-food solution and in the second week with a 25 mM salt solution. After that, the plants irrigated 50 and finally 100 mg of sodium chloride. Traits such as plant height, number of leaves, number of flowers, number of fruits, and average fruit weight, and yield, fresh and dry weight of leaf were measured. The content of K, Ca, Fe and Na elements in the leaves and roots of treated and untreated plants were measured by an atomic absorption device equipped with a graphite furnace system. Data analysis (ANOVA) was performed using MSTAT-C statistical software. The means were compared with the Tukey test (P≤ 0.05) and the graphs were plotted with Excel.
Results and Discussion: Results showed that the salinity has negative effects on growth factors. The application of HA and SA reduced the negative effects of salinity and increased growth parameters. The application of HA and Salicylic acid increased the number of pepper fruits under salt stress conditions. The highest number of fruits was obtained in the plants treated with 5 g l-1 HA and 2 mM salicylic acid compared to the other treatments. The results of this experiment showed that the application of HA and Salicylic acid had a significant effect on the content of mineral elements in the leaves and roots of sweet peppers under salt stress. The highest amount of Fe was observed in the leaves of pepper plants treated with 100 mM and the lowest in untreated plants. The highest amount of leaf calcium was obtained in peppers treated with SA 2 mM and HA 5 g l-1 in comparison to other treatments. Application of SA 1 and 2 mM increased the concentration of calcium of the leaves and roots of the pepper plant. The highest root potassium were obtained in plants treated with 5 g l-1 HA and 1mM SA at salinity level of 100 mM in comparison to the other treatments.
Conclusion: Salinity is an environmental factor limiting the production of crops in plants. According to the results of present study, it can be concluded that salinity reduced the growth parameters of the bell pepper plant. The use of SA and HA increased bell pepper tolerance to salinity and improved the vegetative and reproductive characteristics and absorption of mineral elements. Therefore, the application of HA 5 g l-1 and 2 mM SA is suggested to reduce the negative effects of salinity stress on bell pepper.


1- Agarawal S,. Sairam R.K., Srivasta G.C., and Meena R.C. 2005. Changes in antioxidant enzymes activity and oxidative stress by abscisic acid and salicylic acid in wheat genotypes. Biologia Plantarum 49(4): 541-550.
2- Ali Ahmadi H., Jahantighi H., and Rostami H. 2004. Study on yield of sweet, green and salad pepper cultivars in sistan. Seed and Plant 20(2): 259-262. (In Persian with English abstract)
3- Ameri A., and Tehranifar A. 2012. Effect of Humic acid on nutrient uptake and physiological characteristic Fragaria ananassa var: Camarosa. Journal of Biodiversity and Environmental Sciences 6(16): 77-79.
4- Amir J., Eshghi S., Tafazoli E., Abbaspour N. 2015. Growth and photosynthesis of two cultivars of grapevine (Vitis vinifera L.) in response to salicylic acid application under salinity. Journal of Crop Production and Processing 5(17): 15-29. (In Persian with English abstract)
5- Amirinejad A.A., Sayyari M., Ghanbari F., and Kordi S. 2017. Salicylic acid improves salinity-alkalinity tolerance in pepper (Capsicum annuum L.). Advance in Horticultural Science 31(3): 157-163.
6- Amirjani M.R. 2010. Effect of NaCl on some physiological parameters of rice. European Journal of Biological Science 3(1): 06-16.
7- Aşık B.B., Turan M.A., Çelik H., and Katkat A.V. 2009. Effects of humic substances on plant growth and mineral nutrients uptake wheat (Triticum durum Salihli) under conditions of salinity. Asian Journal Crop Science 1:87–95.
8- Barzegar Hafshejani Z., Mobli M., Khoshgoftarmanesh A., and Abedi-Koupai J. 2015. The effects of adding pumice and bentonite to sawdust substrate on growth and productivity of greenhouse-grown bell pepper. Journal of Science and Technology of Greenhouse Culture 6 (1): 77-85. (In Persian with English abstract)
9- Bayat H., Alirezaie M., and Neamati H. 2012. Impact of exogenous salicylic acid on growth and ornamental characteristics of calendula (Calendula officinalis L.) under salinity stress. Journal of Stress Physiology and Biochemistry 8(1): 258-267.
10- Çimrin K.M., Türkmen Ö., Turan M., and Tuncer B. 2010. Phosphorus and humic acid application alleviate salinity stress of pepper seedling. African Journal of Biotechnology 9(36): 5845-5851.
11- Daneshmand F., Arvin M.J. and Keramat B. 2014. Salicylic acid induced changes in safflower (Carthamus tinctorius L.) under salinity stress. Journal of Plant Research 27(2): 204-215.
12- Dastyaran M., and Hosseini Farahi M. 2015. Effects of humic acid and puterscine on vegetative properties and vase life of rose in soilless culture system. Journal of Science and Technology of Greenhouse Culture 5 (4):241-250. (In Persian with English abstract)
13- Delfine S., Tognetti R., Desiderio E., and Alvino A. 2005. Effect of foliar application of N and humic acids on growth and yield of durum wheat. Agronomy for Sustainable Development 25: 183-191.
14- El-Tayeb M.A. 2005. Response of barley grain to the interactive effect of salinity and salicylic acid. Journal of Plant Growth Regulators 45: 215-225.
15- Eshghi S., Moharami S., and Jamali B. 2017. Effect of salicylic acid on growth, yield and fruit quality of strawberry cv. ‘Paros’ under salinity conditions 7(4): 163-174. (In Persian with English abstract)
16- Gunes A., Inal A., Alpaslan M., Cicek N., Guneri E., Eraslan F., and Guzelorda T. 2005. Effects of exogenously applied salicylic acid on the induction of multiple stress tolerance and mineral nutrition in maize (Zea mays L.). Archives of Agronomy and Soil Science 51: 687-695.
17- Habibi Sharafabad M., Hosseini Farahi M., Didgah S.K. 2017. Effect of salicylic acid and humic acid on quantitative and qualitative properties of tomato (Lycopersicon esculentum cv. Goldi). Journal of Science and Technology of Greenhouse Culture 8(2): 49-65. (In Persian with English abstract)
18- Hayat Q., Hayat S., Irfan M., and Ahmad A. 2009. Effect of exogenous salicylic acid under changing environment: A review. Journal of Experimental Botany 68:14-25.
19- Hosseini Farahi M., Ameri Fahliani R., Yosefi F. 2015. Effects of humic acid and fertilizer containing calcium and boron (Calboron) on vegetative and reproductive properties of strawberry in soil-less culture system. Journal of Plant Ecophysiology 7(21): 235-250. (In Persian with English abstract)
20- Hosseini S., Hosseini Farahi M., Aboutalebi A., Jowkar M.M. 2017. Effect of different media substrate and humic acid on growth and nutrient absorption of soilless cultured cut rose flowers. Journal of Science and Technology of Greenhouse Culture 8(2): 89-103. (In Persian with English abstract)
21- Hosseinifarahi M., Dastyaran M., and Yousefi F. 2017. Effect of polyameins (PAS) and humic acid (HA) on growth, yield and concentration of mineral elements in shoot and root of strawberry. Iranian Journal of Horticultural Science and Technology 18(2): 209-220. (In Persian with English abstract)
22- Jamali B., Eshghi S., and Tafazoli E. 2013. Vegetative growth, yield, fruit quality and fruit and leaf composition of strwberry cv. ‘Pajaro’ as influenced by salicylic acid and nickel sprays. Journal of Plant Nutrition 36: 1043-1055.
23- Jamali S., Sharifan H., and Sajadi F. 2018. Investigation the use of irrigation by caspian seawater on sweet pepper (Capsicum annum) under greenhouse conditions. Journal of Water and Soil Conservation 25(1): 243-256. (In Persian with English abstract)
24- Kamali M., Kharazi S.M., Selahvarzi Y., and Tehranifar A. 2012. Effect of salicylic acid on growth and some morfophysiologic of (Gomphrena globosa L.) in salt stress condition. Journal of Horticultural Science 26(1): 104-112. (In Persian with English abstract)
25- Khoshbakht D., Ramin A.A., Baghbanha M.R. 2012. Possible reduction of the ٍ ffect of salinity on bean (Phaseolus vulgaris) with application of salicylic acid. Journal of Crop Production and Processing 2(5):189-200. (In Persian with English abstract)
26- Kiarostami KH., Abdolmaleki N., and Haydari M. 2012. Study the effect of salicylic acid on reduce salt stress in canola (Brassica napus L.). Journal of Plant Biology 4(12): 69-82.
27- Mohamed W.H. 2012. Effects of humic acid and calcium forms on dry weight and nutrient uptake of maize plant under saline condition. Australian Journal of Basic and Applied Sciences 6: 597–604.
28- Nemeth M., Janda T., Hovarth E., Paldi E., and Szali G. 2002. Exogenous salicylic acid increases polyamine content but may decrease drought tolerance in maize. Plant Science 162: 569-574.
29- Qados A.M.A. 2015. Effects of salicylic acid on growth, yield and chemical contents of pepper (Capsicum Annuum L.) plants grown under salt stress conditions. The International Journal of Agriculture and Crop Sciences 8(2): 107-113.
30- Raghami M., Estaji A., Bagheri V., and Aryakia E. 2016. Effect of salinity stress and salicylic acid on some morphophysiological characteristics of eggplant (Solanum melongena var. Taki) in soilless culture. Journal of Science and Technology of Greenhouse Culture. 7(3):77-87. (In Persian with English abstract)
31- Rajaravindran M., and Natarajan S. 2012. Effects of salinity stress on growth and antioxidant enzymes of the halophyte Sesuvium portulacastrum. International Journal of Research in Biological Sciences 2(1): 18-25.
32- Sajjadi F., Sharifan H., Hezarjaribi A., and Ghorbani-e-Nasrabad GH. 2016. The effect of salinity stress and over irrigation on yield and yield components of green pepper. Journal of Water and Irrigation Management 6(1): 89-100. (In Persian with English abstract)
33- Salarian M., Alizadeh A., Davari K., and Ansari H. 2018. Water and salinity stress on morphological characteristics, quality and quantity of sweet pepper in smart drip irrigation system. Iranian Journal of Irrigation and Drainage 11(6): 322-336. (In Persian with English abstract)
34- Saleh B. 2013. Water status and protein pattern changes towards salt stress in cotton. Journal of Stress Physiology and Biochemistry 9(1): 113-123.
35- Sanchez- Sanchez A., Sanchez-Andreu J., Juarez M., Jorda J., and Bermudez D. 2002. Humic substances and amino acids improve effectiveness of chelate FeEDDHA in lemon trees. Journal of Plant Nutrition 25: 2433-2442.
36- Savvas D., and Lenz F. 2000. Effects of NaCl or nutrient-induced salinity on growth, yield, and composition of eggplants grown in rockwool. Scientia Horticulture 84: 37-47.
37- Sevengor S., Yasar F., Kusvuran S., and Ellialtioglu S. 2011. The effect of salt stress on growth, chlorophyll content, lipid peroxidation and antioxidative enzymes of pumpkin seedling. African Journal of Agricultural Research 6(21): 4920- 4924.
38- Sharif M., Khattak R.A., and Sarir M.S. 2002. Effect of different levels of lignitic coal derived humic acid on growth of maize plants. Communications in Soil Science and Plant Analysis 33(19-20): 3567-3580.
39- Shayesteh N., Golchen A., and Shafe S. 2012. The Effects of irrigation water salinity, nitrogen and foliar application of calcium chloride on yield and growth indices of pepper. Journal of Agricultural Engineering, 34(2): 69-84.
40- Sönmez F., and Gülser F. 2016. Effects of humic acid and Ca (NO3)2 on nutrient contents in pepper (Capsicum annuum) seedling under salt stress. Acta Agriculturae Scandinavica Section B-Soil and Plant Science 66(7): 613-618.
41- Tester M., and Davenport R. 2003. Na tolerance and Na transport in higher plants. Annals of Botany 91: 503-527.
42- Topuz A., and Ozdem F. 2007. Assessment of carotenoids, capsaicinoids and ascorbicacid composition of some selected pepper cultivars (Capsicum annuum L.) grown in Turkey. Journal of Food Composition and Analysis 20: 596-602.
43- Trevisan S., Pizzeghello D., Ruperti B., Francioso O., Sassi A., Palme K., Quaggiotti S., and Nardi S. 2009. Humic substances induce lateral root formation and expression of the early auxin-responsive IAA19 gene and DR5 synthetic element in Arabidopsis. Biologia Plantarum 12: 604-614.
44- Türkmen Ö., Demir S., Şensoy S., and Dursun A. 2005. Effects of arbuscular mycorrhizal fungus and humic acid on the seedling development and nutrient content of pepper growth under saline soil conditions. Journal of Biological Sciences 5: 568–574.
45- Yildirim E., Turan M., and Guvenc I. 2008. Effect of foliar salicylic acid applications on growth, chlorophyll, and mineral content of cucumber grown under salt stress. Journal of Plant Nutrition 31: 593- 612.
46- Zarea Bavany MR., Peyvast GH., Ghasemnezhad M., and Forghani A. 2016. Evaluation of salt tolerance in commercial pepper cultivars at the seedling stage. Journal of Crops Improvement 17(4): 893-909. (In Persian with English abstract)
47- Ziaf K., Amjad M., Aslampervez M., Iqbal Q., Rajwana IA., and Ayyub M. 2009 Evaluation of different growth and physiological traits as indices of salt tolerance in pepper (Capsicum annuum L.). Pakistan Journal of Botany 41(4): 1797-1809.