Physiological mechanisms of a wetland plant (Echinodorus osiris Rataj) to cadmium detoxification.

Physiological responses of Echinodorus osiris Rataj plant under cadmium (Cd) stress (5 and 15 mg L-1) were studied by researching the change of non-enzymatic antioxidants and the exudation of root organic acids. There was a significant increase of ascorbic acid, glutathione, and non-protein thiols in the plant, and the increment was much obvious in roots than that in leaves with increased Cd stress. The accumulation of Cd was associated with mitochondrial structural damages in roots, while the organelle structure, such as chloroplast, in leaves remains intact. In exudates collected from the plants in the treatment with 15 mg L-1 Cd, oxalate, citric, and succinic acids responded intensively than other organic acids.