ALTERATION OF AMYLASE AND PHOSPHATASE IN Macrotyloma uniflorum UNDER INFLUENCE OF CADMIUM, MERCURY AND ZINC STRESSES

Abstract

Physical weathering of parent rocks, mining, and other anthropogenic activities lead to impermissible levels of heavy metals in plant tissues. Effect of Cd²⁺, Hg²⁺, and Zn²⁺ on metabolic enzymes, Amylase (EC; 3.2.1.1), and AP (EC; 3.1.3.2), were studied to assess horse gram response to these heavy metal stress. Enzyme activity and TC were evaluated. Amylase decreased in response to increasing Cd²⁺ concentration, with great impact at 48-72h. It rose under 5 ppm Hg²⁺, while dropped under 10 ppm beyond 24h reaching ~25% of control, and recovered with time to reach 80-90% under 20 ppm. Under Zn²⁺ stress, amylase rose in concentration- and time-dependent manner. AP declined under metal stress in concentration, time-dependent manner, except at 100 ppm Zn²⁺. TC fluctuated in metal-specific manner with positive influence by Zn²⁺ (300-600 ppm) and Cd²⁺ (100-200 ppm) at 24 h. TC diminished under Cd²⁺ stress beyond 24 h, and over entire duration under Hg²⁺ stress. It can deduce that Hg²⁺ and Cd²⁺ exhibited toxic effects on horse gram while Zn²⁺ had positive effects. Amylase responded negatively to Hg²⁺, positively to Zn²⁺, and showed mixed response to Cd²⁺. AP levels decreased under metal stresses, except Zn²⁺.