外源重金属Cr、Cu、Se和Zn对土娄土酶活性的影响

Influences of different concentrations of exterior heavy metals Cr,Cu,Se and Zn on three soil enzymes in Lou soil

【目的】研究外源重金属Cr、Cu、Se和Zn对土娄土土壤酶活性的影响,为建立土娄土重金属污染评价的酶学指标提供依据。【方法】通过施入不同剂量的重金属来模拟不同污染程度的土壤,采用温室平衡培养并结合室内化学分析,研究了不同质量浓度外源重金属(Cr、Cu、Se和Zn)污染对土壤过氧化氢酶、碱性磷酸酶和脲酶活性的影响。【结果】在试验浓度范围内,随着土壤中Cr、Cu质量浓度的增加,其对过氧化氢酶产生了明显激活效应,而对碱性磷酸酶和脲酶却表现出显著的抑制效应;3种土壤酶均随土壤中Se质量浓度的增加呈现不同程度的激活效应;土壤过氧化氢酶和碱性磷酸酶活性随着土壤中Zn质量浓度的增加而增大;但不同质量浓度Zn对土壤脲酶的活性影响有差异,当Zn质量浓度低于100 mg/kg时有一定激活作用,大于200 mg/kg则表现为抑制效应。【结论】虽然不同重金属元素对土壤酶活性的影响差异较大,但很难用某一专有土壤酶来反映特定重金属的污染,而且关于酶系统与重金属以及土壤自身和外界环境因素的相互作用机制尚不清楚,所以土壤重金属酶学指标的建立还需做大量的研究工作。

[Objective] Influences of adding heavy metal （Cr,Cu,Se and Zn） on soil enzymes was studied to provide a fundamental groundwork for foundation of enzymology assessment index of Lou soil pollu- ted by Heavy metals. [Method] Soil was mixed evenly with different types of tested metals with different concentrations and incubated in greenhouse for two months. Soil was sampled and soil catalase,alk-phosphatase and urease were analyzed. [Result] Under the experimental concentrations range, Cr and Cu had activation effect on soil catalase activities, while they had remarkable inhibitory effects on the soil alk-phosphatase and urease activities with their adding concentrations increased. There were activation effects on all these three soil enzymes in Se polluted soil. However, Zn had a positive effect on catalase and alk-phosphatase activities as its adding concentration raised. But it had exhibited sensitive reactions to soil urease activity with different Zn concentrations in soil, soil urease activity was activated when Zn concentration was 100 mg/kg and it was restrained when Zn concentration exceeded 200 mg/kg. [Conclusion] Although there were different influences on these soil enzymes for different metals,it was difficult to find a special soil enzyme to index a single heavy metal pollution in soil. Also,little was known about the interwork of heavey metals,soil enzymes and soil conditions. Therefore,lots of research will be needed to accomplish the foundation of enzymes indexes for assessing heavy metals pollution in soil.