基于不同基质测定土壤碱性磷酸酶活性的比较

Comparison of Soil Alkaline Phosphatase Activity Determined with Different Substrates

土壤磷酸酶对有机磷的矿化及植物的磷素营养有重要影响。目前测定土壤磷酸酶活性采用的基质主要有磷酸苯二钠(CAS编号:3279-54-7)和对硝基苯磷酸二钠(CAS编号:4264-83-9)两种。国际上对土壤磷酸酶活性的测定普遍采用对硝基苯磷酸二钠,而国内大部分学者主要采用磷酸苯二钠。由于不同类型的基质对磷酸酶活性的测定结果有很大影响,所以选择适宜的基质种类对磷酸酶活性进行测定有很大的不确定性。为探讨碱性磷酸酶活性的测定方法,以磷酸苯二钠和对硝基苯磷酸二钠为基质,选用酸性、中性和碱性土壤各10个土样,比较了依据《土壤酶及其研究法》(DPP1),《Method in Soil Biology》(DPP2)和《Methods of Soil Enzymology》(PNPP)书中所介绍的测定方法所获结果之间的差异。结果表明:三种方法所测的三种类型土壤磷酸酶活性的变化趋势基本一致,但不同土壤之间差异性的变化幅度有明显不同。在酸性土壤和碱性土壤中,DPP1和DPP2所测十个土样碱性磷酸酶活性之间的变异系数属于中度变异,而PNPP则属于高度变异;在中性土壤中,DPP1和DPP2属于低度变异,PNPP属于中度变异。总的来看,PNPP比DPP1和DPP2敏感。此外,由于PNPP具有高精确度、培养时间短和实验操作简便等优点,我们建议采用PNPP进行碱性磷酸酶活性的测定。

Soil phosphatase had important role in the mineralization of organic phosphorus and plant phosphorus nutrition. Now phenyl phosphate disodium salt and disodium p- Nitrophenyl phosphate tetrahydrate were the main substrates for measuring soil phosphatase activity. Disodium p- Nitrophenyl phosphate tetrahydrate was widely used in the world, but phenyl phosphate disodium salt was almost used in China. The obvious differences were found by opting different substrates to determine soil phosphatase activity. How to choose the kinds of substrates was difficult for researchers. In order to study the optimal methods for measuring soil alkaline phosphatase activity, alkaline phosphatase activity of 10 samples from acid, neutral and alkaline soil were measured with three different methods which was described in the book of 'Soil enzymes and its Method'(DPP1), 'Method in Soil Biology'(DPP2) and 'Methods of Soil Enzymology'(PNPP), respectively. Results showed that the change tendency of phosphatase activity was similar in three soil types measured with three methods, but the shift range of difference among different soils was obviously different. In acid and alkaline soils, the coefficient of variation of soil alkaline phosphatase activity of 10 soil samples measured with DPP1 and DPP2 was moderate, and that measured with PNPP was high; Whereas in neutral soils, the coefficient of variation of soil alkaline phosphatase activity measured with DPP1 and DPP2 was low, and that measured with PNPP was moderate. In short, PNPP was more sensitive than DPP1 and DPP2. Additionally, PNPP was with the characteristic of high precision, short incubation time, easy operation, and so on. So PNPP was advised to determine soil alkaline phosphatase activity.