摘要：Physiological responses and bioaccumulation in Nymphaea tetragona Georgi under cadmium (Cd) stress were studied. Most of the Cd accumulated in roots followed by lamina, petiole and rhizome under 0, 25, 50, 100, 150 and 200 mg L-1 Cd exposure. Moreover Cd induced lipid peroxidation. Toxic effects of Cd on Nymphaea tetragona were reflected by the reductions in photosynthetic pigments and protein, however, leaves of Cd treated Nymphaea tetragona showed increased malondialdehyde (MDA), proline and glutathione (GSH) content. Hyperactivity of the superoxide dismutase (SOD) and peroxidase (POD) indicated that antioxidant enzymes played an important role in protecting the plant from Cd toxicity. Results also indicated that phytochelatins (PCs) production increased after exposure to Cd which suggested a pivotal role for PCs in the sequestration of metal. Sub-cellular localization of Cd in root cells was evaluated using transmission electron microscopy (TEM) and numerous Cd deposits were found on the outer surface of the root tip cells from Nymphaea tetragona. We can conclude that Nymphaea tetragona can protect itself from phytotoxicity of Cd by altering various metabolic processes and it has the ability to accumulate large amount of Cd from the polluted water.
