Changes in antioxidant enzymes activity and plant performance by salinity stress and zinc application in soybean (Glycine max L.)

An experiment was conducted to investigate the effects of zinc application and salinity stress (0, 33, 66 and 99 mM NaCl) on some morphological and physiological parameters of soybean (Glycine max L., var. Williams). Results showed that zinc application improved shoot length, root fresh and dry weight and shoot fresh and dry weight under all salinity treatments. The catalase (CAT), ascorbate peroxidase (APX), polyphenoloxidase (PPO) and peroxidase activity (POD) and also proline content increased as a result of salinity stress. Lipid peroxidation and hydrogen peroxide concentration under the highest salinity were significantly greater than those under other treatments. However, lipid peroxidation and hydrogen peroxide concentration under salinity treatments significantly reduced as a result of zinc application. Zinc may act as a scavenger of ROS for mitigating the injury on biomembranes under salt stress. Adequate zinc also prevents uptake and accumulation of Na in shoot, by increasing membrane integrity of root