The Effect of Different Concentrations of Salicylic Acid on Qualitative and Quantitative Characteristics of Barley under Salt Stress Conditions

The current study was conducted to evaluate the effect of different salicylic acid levels on salinity tolerance of barley as a factorial experiment based on a completely randomized design in the controlled conditions in College of Agriculture, Shiraz University, in 2013. In this study, the effects of four salicylic acid concentrations (0.0, 0.5, 1.0 and 1.5 mM) were examined on growth, yield, yield components, ions content, and activity of antioxidant enzymes of barley (cv. Reyhane) under five salt stress conditions (tapwater as control, 5, 10, 15 and 20 dS m-1). The results showed that salt stress caused a significant reduction in plant height (%41.1), leaf area (%23.4), grain number per ear (%19.5), dry weight (%26.8), grain yield (%34.6), and shoot potassium concentration (%28.2). Furthermore, salinity significantly increased shoot sodium concentration (%239.4), activity of catalase (%46.0), superoxide dismutase (%256.6), and peroxidase (%760.3). Salicylic acid, depending on the concentration, had a positive effect on growth and other measured traits, with the highest effect found in 1.0 and 1.5 mM salicylic acid in most cases. The interactions also showed that salicylic acid application and increase of its concentration compensated for some negative impact of salt stress on growth, yield, ions content and activities of antioxidant enzymes. By contrast, 0.5 mM salicylic acid had no significant effect. Overall, the result of this study indicated that exogenous application of salicylic acid increases salinity tolerance of barley, with a change in sodium/potassium absorption, as well as, an increase in the activity of antioxidant enzymes.