Toxic Effects of Hg~(2+),Cd~(2+)and Cu~(2+) on Photosynthetic Systems and Protective Enzyme Systems of Potamogeton crispus
GU Wei SHI Guo-Xin ZHANG Chao-Ying WANG Wen XU Qin-Song XU Nan ZENG Xiao-Min ZHANG Xiao-Lan ZHOU Hong-Wei(College of Life Science, Nanjing Normal University, Nanjing 210097)
The toxic effects of Hg 2+,Cd 2+and Cu 2+ on photosynthetic systems and protective enzyme systems of Potamogeton crispus Linn. were studied. The results showed that the three ions decreased auto-fluoresent intensity, chlorophyll content and photosynthesis rate(Figs.1,2) . The three ions had different effects on its protective enzyme systems(Figs.3,4). In shorter time and at lower concentrations, they could induce rises of the activities of superoxide dismutase (SOD),peroxidase (POD) and catalase (CAT) .With the increasing time and concentrations, the activities declined .The activities of SOD lasted the longest,and decreased slowest. The three ions decreased the soluble protein content (Fig.5).The toxic effects of Hg 2+and Cu 2+ on Potamogeton crispus Linn. were heavier than that of Cd 2+ .The lethal concentration of Hg 2+and Cu 2+ to Potamogeton crispus Linn. ranged from 0.5 to 1 mg/L and that of Cd 2+ ranged from 1 to 2.5 mg/L.