可以参考如下(包括标准曲线):The dehydrogenase activity analysis, involved the measurement of triphenyl formazan (TPF) produced from the reduction of 2,3,5-triphenyltretrazolium (TTC) (Tabatabai, 1994). Samples of 5 g of air-dried soil were placed in 50-ml centrifuge tubes. To each tube, 1 ml of 3% TTC and 5 ml of deionized water were added. Then the samples were mixed on a vortex, the tubes were stoppered and incubated in the dark for 24 h at 37 ºC. After incubation, 10 ml of methanol were added, the samples were shaken and filtered (Fisherbrand Q8 paper filter). An additional 10 ml of methanol were added to wash the tubes. Then, for calibration, 7 standards of TPF were prepared (0.5, 1, 3, 5, 7, 10 and 15 μg of TPF ml-1). The red-colored complexes were measured within 1 h using the same spectrophotometer as for urease activity but at λ=485 nm.