中文摘要：

土壤呼吸对温度的敏感性是影响全球气候变暖不确定性的因素之一。为了解在排除其他生态因子的影响下天然阔叶林和人工针叶林土壤呼吸对温度敏感性的差异，选择了苏南丘陵次生栎林和火炬松人工林为研究对象，采集2种林分0～10cm表层土壤，分别进行了5℃、15℃、25℃和35℃的室内恒温培养实验。用传统的密闭气室碱液吸收法测定它们的CO2释放量的动态变化，并测定土壤理化性质。结果表明：次生栎林对温度的敏感性即Q10值大于火炬松人工林；在5℃、15℃和25℃培养时2种林分土壤呼吸累积释放CO2量的差异不显著，并且土壤释放co：的动态变化一致，而35℃时，次生栎林显著大于火炬松人工林；在25℃培养时，次生栎林土壤呼吸累积释放co：量与5℃和15℃相比并没有显著增加，反而低于火炬松人工林；次生栎林的全碳、全氮、全钙、全磷含量以及碳氮比显著大于火炬松人工林。模拟结果表明，在全球气候变暖背景下，天然阔叶林可能比人工针叶林释放更多的CO2。

英文摘要：

The sensitivity of soil respiration to temperature is one of the uncertain factors affecting global warming. In order to understand the difference of this sensitivity in natural broadleaf forest and artificial coniferous forest with the exclusion of other factors＇ influence, a laboratory simula- tion was conducted with the soil samples （0-10 cm） collected from a Quercus variabilis seconda- ry forest and a Pinus taeda plantation in Jiangsu Province of Southeastern China. The samples were incubated in closed-jars in laboratory at 5 ℃, 15 ℃, 25 ℃, and 35 ℃, respectively, and alkali-absorption method was applied to measure soil respiration. Soil physical and chemical properties were also measured. The results showed that the sensitivity of soil respiration to tem- perature （Q10 value） was larger in Q. variabilis secondary forest than in P. taeda plantation. At 5 ℃, 15 ℃, and 25 ℃, there was no significant difference in the amount of cumulative CO2 released from soil respiration in the two forest stands, and the dynamic changes of soil CO2 release were similar. At 35 ℃, the amount of cumulative CO2 released from soil respiration was signifi- cantly higher in Q. variabilis secondary forest than in P. taeda plantation ; while at 25 ℃, it was in adverse. The soil total carbon, nitrogen, calcium and phosphorus contents and C/N ratio were higher in Q. variabilis secondary forest than in P. taeda plantation. It was suggested that under the predicted global warming scenarios, natural broadleaf forests might release more CO2 than artificial coniferous forests.