铅对赤子爱胜蚓抗氧化酶活性的影响

研究了老化和未经老化土壤中Pb(NO₃)₂对赤子爱胜蚓(Eisenia fetida)体内SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、POD(过氧化物酶)活性的影响. 结果表明:在测试范围(w〔Pb(NO₃)₂〕为200~1000 mg/kg)内,Pb(NO₃)₂对蚯蚓体内3种抗氧化酶的活性均有显著性影响. 暴露于未经老化土壤1、14、21d时,蚯蚓体内SOD和CAT活性均随土壤中w〔Pb(NO₃)₂〕的增加而降低,高w〔Pb(NO₃)₂〕下,与对照组相比这2种抗氧化酶活性均降低了约40%. POD活性除第1、3天在高w〔Pb(NO₃)₂〕中显著变化外,其他暴露时间、暴露水平中均无显著性变化. 暴露于老化(28d)土壤1d后,蚯蚓体内SOD、POD、CAT活性均随土壤中w〔Pb(NO₃)₂〕的增加而升高,高w〔Pb(NO₃)₂〕下,与对照组相比这3种抗氧化酶活性分别升高了359%、147%和233%；然而,随着暴露时间的延长,3种抗氧化酶活性又呈显著降低趋势. 总体上,蚯蚓体内CAT和SOD活性变化趋势基本一致. 研究显示,土壤老化对铅毒性产生了影响,因此在进行毒性试验时应予以考虑. 

Effects of Lead Ion on Activities of Three Antioxidant Enzymes from the Eearthworm, Eisenia fetida

Effects of Pb(NO₃)_2on activities of three antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in the earthworm, Eisenia fetida, were investigated with both freshly spiked and aged soils. The results showed that Pb(NO₃)₂ caused a significant effect on activities of three antioxidative enzymes at 200-1000mg/kg. When toxicity tests were carried with freshly spiked soils, the SOD and CAT activities decreased with the exposed dose of Pb(NO₃)_2in creased at the 1st, the 14th, the 21st day and the inhibition rates were about 40% with the treatments with high concentrations. The POD activity was basically not affected except for the 1st and the 3rd day. When toxicity tests were carried with aged soils, the SOD, POD and CAT activities increased with exposed dose of Pb(NO₃)_2increased in the first day, and the simulation rates at higher concentrations were 359%, 147% and 233%, respectively. However, the three enzymes significantly decreased at the 3rd, the 7th, the 14th and the 21st day. In addition, the activity trend of SOD was generally in accord with that of the activity of CAT for both freshly spiked and aged soils. All these indicated that the soil aging leads to effects on the toxicity of Pb(NO₃)₂ and it should be taken into consideration when toxicity tests of Pb(NO₃)_2were carried out.