EFFECTS OF DIFFERENT CONCENTRATIONS OF NaCl AND ZnSO4 ON THE ANTIOXIDANT SYSTEM AND SOME ANABOLIC ENZYMES IN THE COTTON PLANT

Abstract

Summary: The article investigates the effects of NaCl and ZnSO₄ at concentrations of 25, 50, 100, and 200 mM on the activity of antioxidant enzymes, catalase (CAT) and ascorbate peroxidase (APX), as well as carbon metabolism enzyme carbonic anhydrase (CA), and H⁺-ATPase in the root system of upland cotton (Gossypium hirsutum L.). The activity of CA and H⁺-ATPase enzymes was found to increase adequately in the presence of Zn²⁺ ions. During the ontogenetic phases of first true leaf formation (FTLF), budding (BP), and flowering (FP), a gradual increase in salt concentration up to 200 mM leads to an increase in CAT and APX activity, followed by a gradual decrease, which can be associated with the amount of H₂O₂ formed under stress conditions.Under salt stress, slight changes in lipid content do not depend on the nature of the salt. The increasing requirement of young plants for nicotinamide coenzymes results in the gradual activation of the studied enzymes and, consequently, in enhanced ATP synthesis. In contrast, under stress conditions, ATP content gradually decreases.

Keywords: Gossypium hirsutum L., NaCl, ZnSO₄, CA, CAT, APX, H⁺-ATPase, tolerance