Salicylic acid affects wheat cultivars antioxidant system under saline and non-saline condition

Salicylic acid (SA), a naturally occurring plant hormone, is an important signal molecule known to have diverse effects on biotic and abiotic stress tolerance. In this study the effects of exogenous application of different levels of SA (0, 250, and 750 µM) in hydroponic culture on hydrogen peroxide (H 2 O 2 ) and MDA generation, the content of soluble proteins and activities of antioxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in shoots of two wheat ( Triticum aestivum L.) cultivars (Azar2 and Chamran) under different concentrations of NaCl (0, 75, and 150 mM) were investigated. Concentration of 150 mM NaCl induced deleterious effects in both wheat cultivars. Application of 250 µM SA was effective in alleviation of salt stress. Activities of SOD, POD, and CAT enzymes were augmented by SA treatments. The highest SOD and POD activities were recorded at 250 µM SA + 150 mM NaCl, while CAT activity was increased at 250 µM SA + 75 mM NaCl. With the increase in antioxidative enzyme activities, SA decreased H 2 O 2 and MDA content of the seedlings grown under salt stress.