中文摘要：

目的 研究钒对土壤微生物生物量和酶活性的影响。 方法 采用盆栽试验，设置6个水平的外源钒添加处理（0、50、100、150、250，500mg／kg），测定不同钒浓度在油菜（Brassicajunca L）生长的不同阶段对土壤微生物生物量和酶活性的影响。 结果 多酚氧化酶活性随钒浓度增加而显著增加，且各处理间差异显著fP〈0．05），特别是在50mg／kg钒浓度处理下，土壤多酚氧化酶活性迅速减少为对照组的56％；试验中虽然土壤过氧化氢酶、脲酶和蔗糖酶活性因钒的存在增加不明显，但三者的酶活性在油菜结实期均高于苗期，表明油菜生长减轻了钒对酶活性的影响。同时，土壤微生物生物量C、P在一定钒浓度范周内随钒浓度增加而增加，且土壤微生物生物最C、P间存在显著正相关（P〈0．05）．表明除钒的影响以外，其他外加因素 如植物）也会影响土壤微生物生物量C、P的含量。 结论 该试验表明土壤多酚氧化酶活性可作为评价土壤钒污染的指标，同时发现钒浓度变化对土壤微生物产生了一定的影响．但由于两者的关系十分复杂，其机理还需要进一步研究。

英文摘要：

[Objective] This study aimed to investigate the impact of vanadium at dif- ferent concentration on enzyme activity and microbial biomass in soils. [Method] Us- ing pot experiments in the growth cabinet, we would like to investigate the changes of the soil enzyme activity and microbial biomass at different growing stages of rape （Brassica juncea L.） at different soil vanadium concentrations （soil background value was 147 mg/kg, spiked with 0, 50, 100, 150, 250 and 500 mg/kg of exogenous vanadium）. [Result] Among all enzymes examined, polyphenol oxidase was most sensitive to soil vanadium. Addition of 50 mg/kg vanadium decreased its activity up to 56% of the control probably due to the vanadium toxicity. In comparison, the ac- tivities of sucrase, urease and catalase was less affected by soil vanadium. Surpris- ingly, the activity of sucrase, urease and catalase at the rape seedling stage differed significantly from at the maturity stage, highlighting the potential impact of plant growth on the vanadium-soil enzyme interaction. Different soil vanadium concentra- tions led to increases of microbial biomass to different extents. However, the corre- lation between soil microbial biomass carbon and phosphorus with vanadium con- centrations was insignificant. This revealed that the presence of additional factors （eg. plant） affected soil microbial biomass carbon and phosphorus aside from soil vanadium. [Conclusion] Polyphenol oxidase may be considered as an indicator of soil vanadium contamination. Due to the highly complicated interaction between vanadium and soil biological activities during plant growth, more investigations are required to reveal the mechanisms beyond our findings here.