Exogenous Zinc Induced NaCl Tolerance in Okra (Abelmoschus Esculentus) by Ameliorating Osmotic Stress and Oxidative Metabolism

Abstract

ABSTRACT Zinc appeared to be an important modulator with specific functions in plant physiology and increase resistance against different abiotic stresses. Many advances regarding role of zinc under abiotic stress in plants have been made since its revelation, therefore, present study was intended to understand the ameliorating role of zinc on morpho-physiological and biochemical responses of the okra varieties (Anmol and Haseena) when exposed to salt stress. A solution culture experiment was conducted to understand the protective role of zinc in relation to growth, physiological, ionic and antioxidant attributes in two okra varieties under saline condition. The growth medium was salinized with three salinity (Control, 80 mM L−1 and 160 mM L−1 NaCl) and one zinc level (30 µM L−1) applied exogenously in combine and sole form. Salt stress significantly reduces plant dry matter accumulation, chlorophyll contents, relative water contents (RWC), membrane stability index (MSI), K+/Na+ ratio and activities of antioxidant enzymes (POD, SOD, APX, CAT) and these effects are more prominent at high salt level (160 mM). Addition of zinc-alleviated salt toxicity is more conspicuous in okra variety Anmol as compared to variety Haseena as demonstrated by increasing RWC, MSI, K/Na ratio and activities of antioxidant enzymes. Our results suggested that zinc induced salt tolerance in Okra which can serve as a potential source to get sustainable production from salt-affected lands.