THE EFFECTS OF LEAD-ZINC STRESS ON ADSORPTION AND PHYSIOLOGICAL RESPONSE OF HYDRILLA VERTICILLATE

To investigate the adsorption and physiological response of Hydrilla verticillate under lead-zinc stress, H. verticillata were stressed by lead (Pb²⁺: 0, 0.01, 0.05, 0.10 and 0.20 mg/L) and zinc (Zn²⁺: 0, 0.05, 1.00, 2.00 and 4.00 mg/L) with single and composite process for 28 days to measure the adsorption of Pb²⁺, Zn²⁺, chlorophyll a, chlorophyll b, malondialdehyde (MDA), total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and peroxidase (POD) activity. The result showed that the Zn²⁺ absorption was Zn²⁺ concentration-dependent, and the high concentration of Zn²⁺ (≥1.00 mg/L) promoted the Pb²⁺ absorption by H. verticillata; The low concentration of Zn²⁺ and Pb²⁺ promoted the synthesis of chlorophyll, while high concentration (≥1.00 mg/L) inhibited the synthesis of chlorophyll. Pb²⁺ and Zn²⁺ significantly mediated antioxidant indexes of H. verticillata to damage the organism. The results of this study will provide a theoretical basis for application of H. Verticillata in heavy metal remediation.