The effect of zinc nutrition on alleviating oxidative damages induced by salinity stress on two olive cultivars

As a destructive effect of salinity, raising free radicals in root cells and thus leakage of ions is seen. In order to study the zinc effect on some of antioxidant enzymes (Catalase [CAT], Ascorbat Peroxidase [APX]) and decreasing salinity-induced by NaCl, oxidative damages in two cultivars of olive (Olea europea L.)(Frontoio and Conservollea), this pot experiment conducted, in factorial arrange and completely randomized design in three replication. One-year seedling of two olive cultivars treated with nutrition solutions involved different levels of sodium chloride (0, 40, 80, 120 mM) and zinc (0, 1, 5µ molar) of zinc sulfate (ZnSO4. 7H2O ). The results showed that with increasing of salinity levels decreased root and leaf dry weight and plant height, but increased ion leakage of potassium and zinc in root and activity of CAT and APX enzymes in leaf, as well, using Zn, decreased ion leakage of potassium and zinc; whereas root and leaf dry weight, plant height, CAT and APX activity increased. Based on the results, the greater the concentration of sulfhydryl groups in roots in Frontoio variety compared to Conservolea was in acceptance with less leakage of potassium and zinc ions on the Frontoio compared to Conservolea. Therefore the Frontoio variety was more resistant to salinity in comparison with Conservolea.