Physiological responses induced by copper bioaccumulation in Eichhornia crassipes (Mart.)
Eichhornia crassipes (Mart.) has strong ability to remove Cu2+ from copper-contaminated water. Physiological responses in E. crassipes exposed to known concentrations of Cu2+ were examined in this study, and demonstrated that E. crassipes could accumulate 314 mg kg−1 dry weight of Cu when exposed to 5 mg l−1 of Cu2+ for periods up to 14 d. However, there were marked changes in physiology of the plant commencing at Cu2+ concentrations of 1 mg l−1. Results of this study showed that E. crassipes could tolerate moderate concentrations (i.e. 0.5 mg l−1) of Cu2+, without significant changes in photosynthetic pigment concentrations, while high concentrations (i.e. 5 and 10 mg l−1) of Cu2+ resulted in substantial loss in pigment concentrations. Increases in malondiadehyde (MDA) content were also demonstrated in plant exposure to high Cu2+ concentrations. Soluble protein content increased to a level slightly higher than the control at <0.5 mg l−1 of Cu2+, but then decreased with exposure to >1 mg l−1 of Cu2+. Our results suggest that E. crassipes has a substantial capacity to accumulate copper when cultivated at moderate concentrations of Cu2+, without marked changes in its physiology. The findings indicate that E. crassipes is a promising possibility for phytoremediation of moderately Cu-contaminated water bodies.
KeywordsEichhornia crassipes Copper Physiological responses Bioaccumulation
This study was supported by the National Natural Science Foundation of China (20577013) and the Scientific and Technological Innovation Scheme of Water Conservancy Department in China (5CX2003-02).
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