乙草胺铜离子复合污染对黑土农田生态系统中土著细菌群落的影响

Joint effects of acetochlor and Cu^(2+) on indigenous bacterial communities in phaeozem

采用传统毒性评价手段和现代分子生物学技术相结合的方法 ,研究乙草胺和金属铜的复合污染对黑土农田生态系统中土著细菌群落的影响 .结果表明 ,乙草胺 铜复合污染比其单一污染更能降低细菌总数以及固氮菌、硅酸盐细菌和矿化磷细菌活菌量和土壤脱氢酶的活性 ,更能促进土壤呼吸强度的增加 ;利用以 16SrDNA为基础的变性梯度凝胶电泳 (DGGE)分析各处理样品间的相似程度 ,发现复合污染明显影响微生物群落结构 .由相似系数结果表明 :长期未施农药土壤、农药单一与复合污染土壤 3者间存在细菌群落的显著差异 ,并且乙草胺 Cu2 + 复合污染土壤与长期施用农药土壤具有较高相似性 (相似系数达 74 1% ) .

Jointly toxic effects of acetochlor and Cu^(2+) on indigenous bacterial communities in phaeozem were studied using the traditional toxicity assessment methods combined with the modern molecular techniques. It was indicated that acetochlor and Cu^(2+) had a synergic inhibitory effect on the amount of culture-dependent viable bacteria including nitrogen-fixing bacteria, silicate bacteria and phosphorus-mineralization bacteria, as well as the activity of soil dehydrogenase. The increase in the substrate-induced respiration (SIR) was significantly promoted by the two pollutants. Analyzing the similarity and the banding patterns by the denaturing gradient gel electrophoresis (DGGE) revealed that the joint toxicity of acetochlor and Cu^(2+) can significantly affect bacterial community structure. Microbial structures of the polluted soils and the clean soil without pesticide application were different, but there was a similarity in microbial structures between the soil with long-term pesticide application and the soil treated simultaneously with acetochlor and Cu^(2+) under the experimental condition, of which the similarity coefficient was up to 74.1%.