土壤酶动力学与热力学特征对于揭示土壤生物化学过程及其对环境变化的响应具有重要意义。本文采用微孔板荧光法，分析了川西高寒森林土壤中磷酸单酯酶(PME)、β-葡萄糖苷酶(BG)、β-N-乙酰氨基葡萄糖酶(NAG)、纤维二糖水解酶(CBH)的动力学及热力学特征。结果表明，在酶动力学方面，这4种酶活性均随底物浓度(0 ~0.28 mmol/L)的增加而升高，当底物浓度为0.28 mmol/L时，PME、BG、CBH和NAG活性分别达到109.01、52.53、6.51和6.63 μmol/(g·h)；土壤酶热力学方面，这4种土壤酶活性随着温度升高呈现出两种变化趋势，即持续增长型(NAG)和先升高后稳定型(PME、BG、CBH)；4种酶的温度敏感性(Q₁₀值)随着温度升高而降低，在10 ~20 ℃时Q₁₀最高，PME、BG、CBH、NAG 的最大Q₁₀值分别为3.25、3.80、10.22和6.31。高寒土壤这4种酶在低温区间(0 ~20 ℃)具有较高的温度敏感性，土壤升温将导致酶活性显著升高，因此全球变暖导致的高寒土壤升温，将对这些酶参与的相关土壤生态与生化过程产生重要影响。

Alpine soil in the Tibetan Plateau is thought to be sensitive to global climate change, and characteristics of soil enzyme kinetic and thermodynamic are of great significance due to its crucial role in alpine soil ecological and biochemical processes. The activities of phosphomonoesterase(PME), β-glucosidase(BG), cellobiohydrolase(CBH) and β-N-Acetyl- glucosaminidase (NAG) in topsoil ((0-10 cm) of the alpine treeline in the western Sichuan were determined by microplate fluorimetric method. The results showed that the activities of the four studied enzymes increased with increasing of substrate concentration(0-0.28 mmol/L), and activity of PME, BG, CBH and NAG were 109.01, 52.53, 6.51 and 6.63 μmol/(g·h), respectively, when initial concentration of substrate was 0.28 mmol/L. The temperature sensitivity(Q₁₀ values) of PME, BG, CBH and NAG were reduced as temperature increased, and all the Q₁₀maximum values of four enzymes appeared at 10-20℃. In addition, NAG activity was increased with temperature elevation, while PME, BG and CBHactivities increased just before 25 ℃.Therefore, all the four soil enzymes are more sensitive to temperature elevation under lower temperature conditions(0-20℃) than higher temperature, and the soil ecological and biochemical processes related these enzymes maybe impacted significantly when alpine soil warming, especially in warm season.

S155.2+94；S154.2

国家自然科学基金项目(41271094)资助。