戴云山土壤微生物碳源利用效率的海拔变异规律及影响因素

微生物碳源利用效率（CUE）是指微生物将吸收的碳（C）转化为自身生物量C的效率，土壤微生物CUE的研究对深入认识土壤C循环过程十分重要.利用¹⁸ O-H₂ O-DNA标记法，研究戴云山不同海拔（980~1765 m）天然林土壤微生物CUE、微生物生长速率（C_growth）和呼吸速率（C_respiration）的变化特征和影响机制.结果表明，微生物CUE在0.1~0.4之间变化，并随海拔升高而增加；微生物CUE与C_growth、C_respiration和单位微生物生长正相关，而与呼吸熵负相关，说明随海拔的增加，微生物通过增加个体生长和抑制个体呼吸来提高CUE；温度是影响CUE的主要因素，微生物CUE与温度负相关，说明随海拔增加，温度下降是促进土壤微生物CUE升高的关键因素.

Elevational Pattern and Control Factors of Soil Microbial Carbon Use Efficiency in the Daiyun Mountain

Microbial carbon use efficiency (CUE) refers to the C transformation to microbial biomass from C uptake. The study of soil microbial CUE is very important for understanding the soil C cycle. Here, CUE, C_growth, and C_respiration were measured using the ¹⁸O-H₂O-DNA labeling method at six elevational sites (980-1765 m) in Daiyun Mountain, a subtropical montane forest, to understand the variation characteristics and influencing mechanisms. The results showed that:CUE varied from 0.1 to 0.4 and increased linearly with elevation; CUE was positively correlated with C_growth, C_respiration, and q_growth but negatively correlated with qCO₂, indicating that CUE increased with elevation by increasing microbial growth and inhibiting respiration; and temperature was the first controlling factor for the elevation variation in microbial CUE in the subtropical forest ecosystem.