The Effects of Zinc Application on Growth, Nutrient Uptake and Antioxidant Enzyme Activity in Tomato (Lycopersicum esculentum) under Salinity stress

In this study, effects of salinity and Zinc sulphate application on growth parameters, nutrient uptake and antioxidant enzyme activity of Tomato (Lycopersicum esculentum) in a factorial experiment in completely randomized design with three replications were evaluated. Factors consisted of four salinity levels (0, 45, 90 and 120 mM NaCl) and three Zinc sulphate levels (0, 5, and 10 μM). Results showed that salinity decreased fresh and dry weight of plants, Zn and K contents whereas increased the Na content and antioxidant activity by increasing NaCl level. Also, results showed that ZnSO4 had positive effect on growth parameters, Zn and K concentration and antioxidant activity but reduced Na and P concentration. Zinc treatment especially at 10 μM concentration in tomato under salt conditions increased growth indexes, potassium concentration, percent of Inhibition of 1,1-diphenyl-2-picrylhydrazyl radical, catalase and superoxide dismutase activity and decreased sodium and phosphorus concentrations. The highest fresh and dry weight of plants and potassium uptake were measured in plants without salt stress with application of 10 μM ZnSO4 and the lowest on these indicator in plants under 120 mM NaCl without ZnSO4 application. Thus, it was concluded that Zinc could be improve performance and yield in tomato plants under salt stress conditions.