Exogenous Salicylic Acid Alleviates Zinc-induced Oxidative Damage in Tomato Plants

Abstract

In the present study, the effects of Zinc (Zn) and salicylic acid (SA) interaction on tomato plants were examined. 25-day-old tomato plants were subjected to different concentrations of ZnSO4 . 7H2O (0, 250, 500 μM) and SA (0, 100 μM) for 10 days. Zn was accumulated in roots and shoots of Zn-stressed plants. Treatment with Zn reduced dry weight of roots and shoots and decreased chlorophyll content in leaves. In Zn-treated plants, Malondialdehyde (MDA), H2O2 and proline contents significantly increased in leaves. Moreover, changes in the
activities of the antioxidant enzymes, catalase, guaiacol peroxidase, ascorbate peroxidase and superoxide dismutase in leaves indicated that
Zn caused an oxidative stress in tomato plants. In Zn-stressed plants, application of SA reduced root-to-shoot translocation of Zn and enhanced growth and chlorophyll content. Adding of SA in the nutrient solution, increased the antioxidant enzymes activities and decreased the level of lipid peroxidation, H2O2 and proline accumulation in leaves of Zn-treated plants. As a result, SA by sequestration of Zn in roots
and increase in the activities of antioxidant enzymes, considerably decreased Zn induced oxidative damage on tomato plants.