红壤磷酸单酯酶活性测定方法的改进

以甘油磷酸钠为底物,通过添加适量无机磷减少土壤吸附作用对磷酸单酯酶活性测定的影响,探讨红壤磷酸单酯酶活性测定方法的改进.在4个红壤样品的测试结果中,与Rogers法相比,RSD从≤10.2%降为≤3.2%;省去了HCl浸提步骤:耗时从19 h左右变为2 h左右.与对硝基苯磷酸盐法相比,底物更具代表性:所测磷酸单酯酶活性为P4.4～6.8 μmol/(g土·h),比对硝基苯磷酸盐法的测定值P 0.8～2.2 μmol/(g土·h)更大,更灵敏.

Improvement of phosphomonoesterase activity determination in red soils

A method was improved for the determination of phosphomonoesterase activity in red soils by determining inorganic phosphate released from soil incubated with Na-β-glycerophosphate as substrate. The influence of inorganic P adsorption on soil can be greatly minimized by the pretreatment that the substrate was mixed with appropriate inorganic P before being added into the soil for incubation. The proposed method successfully determined phosphomonoesterase activities in 4 red soils. The results showed that the precision of the proposed method (RSD < 3.7%) was greater than that of Rogers method (RSD ≤ 10.2%). Compared with Rogers method, the proposed method avoided HCl extraction procedure and shorted analytical time from 19 hours to 2 hours. In addition, phosphomonoesterase activity obtained with the proposed method (P 4.4 - 6.8 μmol/(g soil·h)).