土壤脲酶活性的测定有多种方法,其中靛酚蓝比色法由于测量结果精确性较高,重现性较好,应用最为广泛。但也有培养后土壤过滤液浑浊、带色、脲酶活性受底物浓度影响较大等缺点。以此方法为基础,针对过滤方式、培养时间、底物浓度及缓冲液选择等4个重要参数进行了对比试验,以期进一步改进靛酚蓝比色法的测定准确性。结果表明,培养时选择5%的底物浓度、pH10.0的硼酸盐缓冲液、培养24 h后再经KCl溶液浸提过滤比色测定,其结果比传统靛酚蓝比色法高约2.46倍,改良靛酚蓝比色法的测定结果更接近土壤真实脲酶活性。

Among all the measurement methods on activity of urease, indophenol blue colorimetric method, higher accuracy of the measurement results and better reproducibility, is the most widely used measurement method on activity of urease. However, this kind of method also owns some drawbacks, for examples, filtered fluid of cultivated soil is muddy and concentration of substrate has a great influence on the activity of urease. Based on the former measurement methods, four crucial parameters was taken to, such as method of filtration, time of cultivation, concentration of substrate and choice of buffer solution, the comparative tests in order to improve the accuracy of the measurement results of indophenol blue colorimetric method. The result of improved method is closer to the real activity of urease in soil with the conditions that choosing 5% concentration of substrate and pH10.0 borate buffer solution during the cultivation, extracting and filtrating with potassium chloride solution after 24-hours cultivation. The result of improved indophenol blue colorimetric method is 2.46 times better than the traditional method.

国家自然科学基金(50909019、51079029) ;东南大学创新基金(3205001503)