Evaluation of salicylic acid (SA) application on growth, osmotic solutes and antioxidant enzyme activities on broad bean seedlings grown under diluted seawater

摘要

Exogenously applied salicylic acid has been shown to be an essential signal molecule involved in both local defense reactions and induction of systemic resistance response of plants after salt stress. Our study was aimed at evaluating the foliar spray with different levels (0.0, 0.5 and 1.0 mM) of salicylic acid (SA) on broad bean (Vicia faba?L) seedlings grown under diluted seawater on growth and some related physiological responses. Seawater irrigation negatively affected growth parameters, free amino acids and K+, while the contents of soluble sugars and protein, proline, Cl?, Na+, ion leakage, lipid peroxidation and antioxidant enzyme activities were significantly increased. Foliar spray with SA improved all growth parameters and increases the activities of antioxidant enzymes. On the other hand, plants treated with SA had lower Cl??and Na+, while K+had a reverse pattern. Based on our findings, the effectiveness of SA in inducing seawater stress tolerance depends upon the concentration of SA applied. The inducer effect of SA was greater with 1 than 0.5 mM treatment. This effect includes the stimulation of antioxidant enzyme activities and regulation of osmotic adjustment through accumulation of osmotic solutes and regulation of absorption and distribution of inorganic ions.