A Study on the Measurement of Urease, Phosphatase and Dehydrogenase Activities in Soils

土壤尿素酶、磷酯酶及去氫酶活性測定之研究

賴朝明(Chao-Ming Lai) ； 洪崑煌(Kun-Huang Houng)

《中央研究院化學研究所集刊》 35期 (1988/03) Pp. 79-96

https://doi.org/10.6522/BICAS.1988.35.10

摘要

本研究檢討臺灣主要耕地土壤尿素酶、磷酯酶及去氫酶之測定條件。結果顯示：尿素酶之適宜受質終濃度為35.7 mM urea，酸磷酯酶之適宜受質終濃度為12.5 mM PNP。風乾對此三種土壤酵素活性之測值無顯著影響，而田間新鮮土與風乾土酵素活性之測值間則有顯著相關。因此，如僅為比較酵素活性之相對高低，可使用風乾土樣測定。甲苯之添加（用以抑制微生物之活性）對尿素酶、酸磷酯酶活性之測值並無顯著影響。土壤尿素酶之適宜pH值為7.5~9.0，其K_m及V_(max)值分別為1.8~28×10^(-3)M urea及12~180×10^(-6) g urea N g^(-1) soil hr^(-1)。土壤磷酯酶之適宜pH值為6.5（酸性土）及11（鹼性土），酸磷酯酶之K_m及V_(max)值分別為1.1~4.9×10^-(3)M PNP及0.52~7.3×10^(-6)mol p-nitrophenol g^(-1) soil hr(-1)。

並列摘要

In this study, the measuring conditions for urease, phosphatase and dehydrogenase activities in major Taiwan agricultural soils were examined. It was shown that the optimum final concentration of the substrate for urease was 35.7 mM of urea, and that for soil phosphatase was 12.5 mM PNP in the reaction mixture. Air-drying the soil samples did not affect the measured activities appreciably, and there was a close correlation between the activities measured on field-moist and air-dry samples. Air-dry samples may be used for the purpose of comparison. For the purpose of suppressing microbial activities during the measurements, toluene may be added to the substrate solutions without significant effect. The results indicate that urease in the soil samples collected from major agricultural soils of Taiwan showed an optimum pH range of 7.5-9.0, K_m and V_(max) values had the range of 1.8-28×10^(-3) M urea and 12-180×10^(-6) g urea N g^(-1) soil hr^(-1), respectively. Optimum pH values for the soil phosphatase were 6.5 for acid soils and 11 for alkaline soils. The K_m and V_(max) values of soil phosphatase were 1.1-4.9x10^(-3) M and0.52-7.3x10^(-6) mole of p-nitrophenol g^(-1) soil hr(-1) , respectively.