The effect of sodium chloride and salicylic acid on antioxidant defense system in maize (Zea mays L.)

Salt stress causes ionic, osmotic and oxidative stresses in plants. Salicylic acid (SA) is a plant-produced phenolic compound that can function as growth regulator. In this study, the role of SA pretreatment in inducing tolerance to oxidative stress induced by salt in maize plants was investigated. In this research, effects of SA in three levels (control, soaked in water and soaked in solution of 0.1 mM salicylic acid) and also salt stress (0 and 80 mM NaCl) were studied. Salinity decreased growth parameters but increased lipid peroxidasion and electrolyt leakage. In addition, salt stress decreased the content of ascorbate pool and phenolic compounds and increased the activity of antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT) and peroxidase (GPOD). Meanwhile, SA pretreatment reduced lipid preoxidation and electrolyte leakage by increasing the nonenzymatic antioxidants such as ascorbate pool and phenolic compounds but the activity of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (GPOD) which were reflected in improving the plants growth. However, it was concluded that SA was able to induce protective reactions via increasing quantity and activity of these antioxidants under salt stress conditions.