重金属Cd、Zn、Cu、Pb对土壤微生物和酶活性的影响

采用室内培养实验(25℃),研究了不同培养时间下重金属Cd、Zn、Cu、Pb(浓度分别为50,800,400,800mg.kg-1)污染对土壤微生物和酶活性的影响。结果表明,土壤蔗糖酶、过氧化氢酶和脱氢酶活性随着培养时间的增加而显著下降,在培养20d的时候达到最小值,然后酶活性缓慢升高。Cu对脲酶活性以及Cd对酸性磷酸酶和脲酶活性的抑制作用随时间增加而增加。土壤微生物生物量碳、细菌、真菌和放线菌数量随培养时间的增加均表现出先降低后升高的变化趋势。Cd和Cu对微生物生物量氮的抑制作用则随着培养时间的增加而增强,在培养30d时微生物生物量氮到达最低值,分别较培养10天减少了12.6%和16.5%。

Effects of Cd,Zn,Cu and Pb on Soil Microbial Biomass and Enzyme Activities

Incubation experiment(25℃) was conducted to investigate the influence of cadmium,copper,zinc and lead(50,800,400,800 mg·kg-1) on soil microbes and soil enzyme activity at different incubation time.The results indicated that soil sucrase,catalase and dehydrogenase activities reduced first,then increased with increasing incubation days.The lowest of sucrase,catalase and dehydrogenase activities were observed at the 20th day of incubation experiment.Inhibition of copper on urease,inhibition of cadmium on urease and acid phosphatase increased with the increase of time.Microbial biomass carbon,amounts of bacteria,actinomyces and fungi also decreased first,then increased with increasing incubation days.Inhibition of cadmium and copper on microbial biomass nitrogen increased along with time.The lowest of microbial biomass nitrogen was observed at the 30th day of incubation experiment,decreased by 12.6% and 16.5% compared to that of the 10th day.