土壤汞污染胁迫对蚯蚓体内几种抗氧化酶活性的影响

汞是毒性较大的重金属,为了解土壤汞污染对蚯蚓抗氧化防御体系的影响,本文采用人工土壤法,研究了不同Hg暴露浓度水平下(1、2、4、8、16、24、32、50 mg/kg)赤子爱胜蚓(Eisenia foetida)的应激反应,分析了不同浓度Hg污染水平对蚯蚓体内3种抗氧化酶活性以及脂质过氧化最终产物丙二醛(MDA)含量的影响。结果表明,Hg暴露会对蚯蚓抗氧化防御系统产生较大影响。蚯蚓体内超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)和过氧化氢酶(CAT)在不同浓度的Hg暴露水平下,随时间变化呈现出不同的阶段性应激反应。总体上看,Hg暴露环境对赤子爱胜蚓SOD和GSH-PX活性有一定的抑制作用,但对CAT活性的影响无明显规律。Hg暴露对蚯蚓体内MDA含量有一定影响,在32和50 mg/kg的较高浓度水平下,赤子爱胜蚓体内MDA含量明显增加,可能是汞胁迫造成了蚯蚓机体细胞的氧化损伤。

Effects of Mercury Pollution Stress on Activity of Several Kinds of Antioxidant Enzymes in Earthworms

Mercury (Hg) is a heavy metal with great toxicity.In order to understand the impact of Hg pollutant on antioxidant defense system of earthworm,artificial soil experiment was adopted in this research.Stress responses to different Hg exposure levels (1,2,4,8,16,4,32,0 mg/kg) in earthworm (Eisenia foetida) were studied,and the effects on the contents of three antioxidant enzymes and lipid peroxidation (malondialdehyde,MDA) in different Hg exposure levels were analyzed as well.The results showed that Hg contaminated soil had great impact on the antioxidant defense system of Eisenia foetida.In different Hg concentrations,superoxide dismutase (SOD),glutathione peroxidase (GSH-PX) and catalase (CAT) of Eisenia foetida showed different stress response which changed over time.Hg exposure environment had certain inhibitory effect on the activity of SOD and GSH-Px in Eisenia foetida.However,no obvious patterns were observed on the influence of CAT.Hg exposure had a certain effect on the content of MDA of Eisenia foetida.Under the higher concentrations of 32 and 50 mg/ kg,the content of MDA in Eisenia foetida increased significantly and it was probably Hg stress that caused oxidative damage in earthworm body cells.