外源Cd对中国不同类型土壤酶活性的影响

【目的】研究国家土壤环境质量二级镉（Cd）污染标准下，中国不同类型土壤的酶活性变化，初步探讨其间的关系，了解土壤酶作为污染程度监测指标及污染标准的可行性。【方法】采用模拟盆栽试验，设置对照、低浓度、高浓度3个水平，分析Cd污染玉米收获后不同类型土壤中7种酶活性的变化。【结果】Cd胁迫对不同土壤酶效应有所差别，在供试Cd浓度范围内，土壤酸性磷酸酶、过氧化氢酶对Cd胁迫反应不敏感；转化酶、FDA水解酶和脱氢酶活性显著受到抑制，而激活了脲酶和碱性磷酸酶；当Cd浓度达到国家土壤环境质量二级标准，Cd对土壤FDA水解酶和脱氢酶的平均抑制率分别达34.03%和31.14%；主成份分析构建的土壤酶、土壤酶-理化性质-Cd信息系统与总体酶活性达极显著正相关，可较好反映土壤Cd污染的影响。【结论】土壤脱氢酶、FDA水解酶、总体酶活性对土壤Cd较为敏感，可作为监测辅助指标之一；土壤酶与Cd间关系受到酶种类、土壤性质等的影响，其中尤以土壤有机质和pH影响最重要。

Response of Soil Enzyme Activity in Different Type of Soils to Cadmium Exposure in China

【Objective】The objective of this study was to clarify the soil enzyme of different type soils affected by Cd under soil environmental quality standards in China, to explore the relationship between soil enzyme and Cd, and discuss the feasibility of soil enzyme acted as an indicator of soil Cd pollution.【Method】The influences of Cd addition to soil enzyme activities in different types of soils were studied by a traditional pot incubation experiment with three Cd concentrations.【Result】The results indicated that the soil acid phosphatase and catalase activity were not sensitive to Cd, Cd could remarkably inhibit soil FDA hydrolase and dehydrogenase activity, but activated the urease and alkaline phosphatase activity. Under the soil environmental quality standards for agricultural soils, the average inhibition rate of soil FDA hydrolase and dehydrogenase was 34.03% and 31.14% respectively. Soil enzymes, soil enzymes-physicochemical properties-Cd information system showed significant positive correlations with soil total enzymatic activities, which suggested they may indicate the Cd contamination.【Conclusion】Soil FDA hydrolase, dehydrogenase and soil total enzymatic activities are sensitive to soil Cd, which can be used as a assisted monitoring indicator. The relationship between soil enzymes and Cd is influenced by many factors such as enzyme types and soil properties, and soil organic matter and pH play a matter role.