The Toxic Mechanism Study Of Heavy Metal Pollution On Aquatic Plant Under Different Growth Conditions

The paper imitated different gradient concentrations of Cd²⁺, Cr⁶⁺ and Pb²⁺ to pollute water environment, dealt with the toxic effects of them on Sagittaria sagittifolia L., Potamogeton crispus L. and Saluinia natans systemically by means of physiological, biochemical and ultrastructural aspects. The response mechanism of aquatic plants growing under different conditions to heavy metals was discussed. The detoxication of exogenous lanthanum and calcium against toxic effect of Cd²⁺ on S. natans, and the microtubular cytoskeleton in root tip cells of S. sagittifolia L. were explored primary. Results showed that all the Cd²⁺, Cr⁶⁺and Pb²⁺ in water solutions had poisoning effects on photosynthetic systems, protective enzyme systems, substance metabolism systems and cell ultrastructure of the plants. However, the toxic effects of different ions on the same plant material or a metal ion on different plant organs were either similar or different. The leaves lost their green color, leaf margin twisted following spoil spots and root like leaf broke when Cd²⁺ polluted S. natans. With the rise of Cd²⁺ concentration, the chlorophyll content of S. natans and S. sagittifolia L. both increased firstly and followed by a decrease. For S. natans plants,...