温带森林不同海拔土壤有机碳及相关胞外酶活性特征

研究测定了老秃顶子温带森林生态系统7个海拔土壤不同形态碳和相关水解酶、氧化还原酶活性,分析了土壤有机碳及相关酶活性沿海拔梯度的影响因素.结果表明: 随海拔升高,土壤有机碳(SOC)、颗粒有机碳(POC)和可溶性有机碳(DOC)含量显著增加,而在海拔825～1233 m之间没有显著变化,DOC/SOC则显著下降;土壤α葡萄糖苷酶、β葡萄糖苷酶、木糖苷酶和纤维二糖水解酶活性显著增加;土壤SOC、POC、DOC、全氮(TN)含量及土壤含水量(SMC)与土壤水解酶活性呈显著正相关;过氧化物酶(POD)活性在低海拔(675 m)落叶松人工林显著低于其他海拔,POD活性与土壤碳氮(SOC、TN、POC、DOC)含量及SMC呈显著正相关,而土壤多酚氧化酶(PPO)活性在海拔947 m落叶阔叶林带和海拔825 m红松林中较高,且仅与土壤pH呈显著正相关,表明土壤酸度是驱动PPO酶活性的主要因素.在温带森林生态系统中,土壤养分含量和含水量是影响土壤水解酶海拔分布的重要因素.

Characteristics of soil organic carbon and related exo-enzyme activities at different altitudes in temperate forests.

We measured soil organic carbon contents, hydrolase and oxidoreductase activities relating to carbon cycling at 7 different altitudes of Laotudingzi Mountain in temperate forest ecosystem, and studied the affecting factors of soil organic carbon contents and the related soil extracellular enzyme activities along the altitude. The results showed that soil organic carbon (SOC), particulate organic carbon (POC) and dissolved organic carbon (DOC) contents increased significantly with altitude except between 825-1233 m, and DOC/SOC decreased significantly with altitude. The activities of α-glucosidase, β-glucosidase, β-xylosidase and cellobiohydrolase increased significantly with altitude, and the hydrolase activities were significantly and positively correlated with SOC, POC, DOC, total nitrogen (TN) and soil moisture contents (SMC). Peroxidase (POD) activity was significantly lower at 675 m in Larix gmelinii plantation than at the other altitudes, and was positively correlated with soil nutrient contents (SOC, TN, POC, DOC) and soil moisture. Polyphenol oxidase (PPO) activity was higher in Korean pine plantation at 825 m and in deciduous broad-leaved forest at 947 m than at the other altitudes, and PPO activity was only positively correlated with soil pH, suggesting that soil acidity was a major factor influencing PPO activity. Soil nutrient and water contents were important factors that influenced the distribution of soil hydrolase along altitude in temperate forest ecosystem.