辛硫磷对土壤微生物种群结构的影响

采用室内培养法研究了土壤中200～1000mg／kg三种不同质量分数的辛硫磷对好氧性细菌、真菌和放线菌三大主要微生物种群数量及其优势菌生长速率的影响。结果表明，土壤中各微生物种群对不同质量分数的辛硫磷具有各自不同的反应。辛硫磷对细菌种群数量及优势细菌生长速率的影响表现为明显的刺激效应，且随加药质量分数的提高刺激效应越明显，而且对种群数量的刺激效应随加药时间延长趋势越明显；对放线菌种群数量的影响表现为抑制效应，且随药剂质量分数的提高抑制效应越明显。但随着加药时间的延长，这种抑制效应又趋于减弱．逐渐恢复到正常水平。但对优势放线菌生长速率的影响却表现为刺激效应；对真菌种群数量及优势真菌生长速率的影响也表现为抑制效应，且随药剂质量分数的提高和加药时间的延长抑制效应越明显。因此，有望从土壤中筛选到能降解辛硫磷的细菌，同时真菌可以作为土壤受辛硫磷污染的敏感指示菌。

Effect of Phoxim on Microbial Community Structure in Soil

The effects of phoxim on the microbial community amount and the growth of ascendent bacteria, funguses and actinomyces in soil at 200-1 000 mg/kg three different concentrations were studied by indoor culture method. It was found that the effect of phoxim varied on different cultivable microbial community in soil. The bacteria community amount and the growth of ascendent bacteria were stimuted. The stimulating trend was more obvious with concentra-tion increasing of the insecticide. And that, the stimulating trend of the bacteria community ammount was more obvious with the prolonging of time. However, the actinomyces community amount was restrained. The restraining trend was more obvious with concentration increasing of the insecticide. The trend was weakened with the prolonging of time. But the growth of ascendent actinomyces was stimuted. The fungi community amount and the growth of ascendent fungi were also restrained. And the trend was more obvious with concentration increasing of the insecticide and the prolonging of time. Accordingly, the phoxim-degrading bacterial strain may bescreened from phoxim's contami-native soil. The fungi and actinomyces community may be used as sensitive indicator in phoxim's contaminative soil.