Hg2+、Cd2+和Cu2+对菹草光合系统及保护酶系统的毒害作用

研究了Hg2 、Cd2 、Cu2 对高等水生沉水植物菹草光合系统及保护酶系统的毒害作用。结果表明 :3种离子均使菹草叶片叶绿体自发荧光强度、叶绿素含量、光合速率降低。Hg2 、Cd2 、Cu2 对菹草保护酶系统存在不同的影响 ,短时间低浓度条件下 ,诱导超氧化物歧化酶 (SOD )、过氧化氢酶 (CAT)、过氧化物酶(POD)活性上升 ,随着污染时间的延长、污染浓度的增加 ,酶活性下降 ,其中SOD活性上升持续时间最长 ,下降最慢。 3种离子均使菹草可溶性蛋白含量减少。Hg2 、Cu2 毒性较强 ,Cd2 毒性较弱。Hg2 、Cu2 对菹草的致死浓度为 0 .5～ 1mg/L ,Cd2 为 1～ 2 .5mg/L

Toxic Effects of Hg2+,Cd2+and Cu2+ on Photosynthetic Systems and Protective Enzyme Systems of Potamogeton crispus

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.