Effects of Cr3+ on soil enzyme activity | Cr3+的土壤酶效应研究

Chinese. 研究Cr3+对土壤酶活性的影响，为建立土壤重金属铬污染评价的酶学指标提供依据。以我国常见的红壤（酸性土壤）及褐土和风沙土（碱性土壤）为供试土样，采用室内模拟方法,在供试土样中添加0，50，100，300，500，1 000，1 500，3 000 mg/kg Cr3+，研究不同Cr3+含量下土壤脲酶、磷酸酶、芳基硫酸酯酶、过氧化氢酶、脱氢酶和总体酶活性的变化规律。Cr3+显著或极显著地抑制了土壤脲酶、磷酸酶、芳基硫酸酯酶、过氧化氢酶和脱氢酶活性，且均为完全抑制作用（包括竞争性抑制和非竞争性抑制），供试土样中Cr3+轻度污染时的生态剂量（ED10）为 25 mg/kg；酸性土壤中脲酶、芳基硫酸酯酶和过氧化氢酶对Cr3+的毒害反应更敏感，碱性土壤中磷酸酶和脱氢酶的反应更敏感。土壤脲酶、磷酸酶、芳基硫酸酯酶、过氧化氢酶、脱氢酶活性及总体酶活性均可用来表征土壤Cr3+污染程度的大小；土壤pH、有机质含量对土壤酶与Cr3+的关系具有重要影响。

English. Influence of Cr3+ on soil enzymes was studied to provide a foundation for enzyme assessment index in soils polluted by heavy metals. Red soil, Cinnamonl and sandy soil, main soil types in China, were sampled. By simulative method, soil urease, phosohatase, arylsulphatase, catalase, dehydrogenase and total enzyme activities were studied under different Cr3+ concentrations 0, 50, 100, 300, 500, 1 000, 1 500, 3 000 mg/kg. Soil-urease, phosohatase, arylsulphatase, catalase, dehydrogenases enzymes significant or remarkably significant negative correlation with Cr3+ concentrations was obtained. And the reaction mechanism was complete inhibition (including competitive inhibition and noncompetitive inhibition). The critical Cr3+ concentration was 25 mg/kg when the soils were slightly polluted (ED10), arylsufatase and catalase were more sensitive to Cr3+ in acid soils, however, in alkalinen soil phosohatase and dehydrogenases were more sensitive. Soil urease, phosohatase, arylsulphatase, catalase, dehydrogenases enzymes and total enzyme activity could be index to monitor soils polluted by Cr3+, soil enzyme impact was up to soil physic-chemical properties, such as pH and organic matter content.