Effect of salicylic acid Effect of application of salicylic acid and potassium silicate on some morphological, physiological and biochemical traits in wheat (Triticum aestivum L.) grown under salt stress

Water and soil salinity on environmental agents limit plant growth and its productivity in Iran. In order to reduce the adverse effects of salinity on plants, different compounds are used. In this study, the effects of salicylic acid and potassium silicate were investigated on wheat plants under salt stress. A factorial experiment in a randomized complete block was conducted by applying 100 mM NaCl and 14 mg of salicylic acid and 15 mg of potassium silicate. The plants were cultured hydroponically in a growth chamber at Hoagland solution. The results showed that in plants treated with NaCl, the fresh and dry weights,  chlorophyll a, b and total chlorophyll, carotenoids and total protein concentrations were declined significantly compared with control plants. While soluble sugars, malondialdehyde and hydrogen peroxide concentrations increased significantly. Also, the activity of superoxide dismutase, catalase and peroxidase were increased. According to the results, application of salicylic acid and potassium silicate in salt stressed plants decreased the activity of antioxidant enzymes, membrane lipid peroxidation and H2O2 content. While, assayed growth parameters, photosynthetic pigments, soluble sugars and protein contents of salt stressed plants increased significantly by application of these compounds. Comparative analysis of application of these compounds in amelioration of salt stress in wheat plants, showed not significant effect on SOD activity, whereas application of salicylic acid decresed CAT activity of root and shoot. Also, activity of POD in shoot in comparative with potassium silicat application was decreased.