有机农药百草枯对金鱼藻的生理生化参数的毒性作用

Toxic effect of organic pesticide Paraquat on physiological and biochemical indexes of Ceratophyllum demersum L

采用静态模拟方法,研究了金鱼藻(Ceratophyllum demersum L)在不同浓度(0、0.05、0.1、0.15、0.25 mg/L)百草枯胁迫下叶绿素含量、可溶性蛋白含量、超氧化物歧化酶(SOD)和多酚氧化酶(PPO)活性的变化。结果表明:在百草枯胁迫下,叶绿素和可溶性蛋白含量受到强烈抑制,0.25 mg/L实验组与对照组比较,叶绿素含量下降了60.23%,可溶性蛋白含量下降了67.76%;PPO和SOD均为氧化还原酶,金鱼藻受百草枯胁迫程度较轻时,为抵御外界胁迫PPO和SOD活性升高;当胁迫程度超过机体抗氧化防御能力时,酶活性下降,于是呈现"低促高抑"的变化趋势。

A static simulation method was conducted to study the changes of chlorophyll content,soluble protein content,superoxide dismutase（ SOD） and polyphenol oxidase（ PPO） activity of Ceratophyllum demersum under toxic effects of different concentration（ 0,0. 05,0. 1,0. 15,0. 25 mg / L）Paraquat. The results showed that under Paraquat stress,chlorophyll and soluble protein contents were strongly inhibited,for example,compared with control group,the chlorophyll and soluble protein contents in the 0. 25 mg / L experimental group decreased by 60. 23% and 67. 76% respectively.When Ceratophyllum demersum L. was exposed to lower concentration of Paraquat,PPO and SOD,a kind of oxidoreductases would show higher activity in order to resist the external stress; while for higher concentration of Paraquat,which presented stress exceeding PPO and SOD ＇s antioxidant capacity,the activity would decrease,thus activity of PPO and SOD would be promoted under low stress,and suppressed under high stress.