中文摘要：

对森林生态系统的土壤呼吸组分进行分离和量化，确定不同组分CO2释放速率的控制因子，是估测局域和区域森林生态系统碳平衡研究中必不可少的内容。采用挖壕法和红外气体分析法测定无根和有根样地的土壤表面CO2通量（Rs），确定东北东部6种典型森林生态系统Rs中异养呼吸（RH）和根系自养呼吸（RA）的贡献量及其影响因子。具体研究目标包括：（1）量化各种生态系统的RH及其与主要环境影响因子的关系；（2）量化各种生态系统Rs中根系呼吸贡献率（RC）的季节动态；（3）比较6种森林生态系统RH和RA的年通量。土壤温度、土壤含水量及其交互作用显著地影响森林生态系统的RH（R^2=0．465-0．788），但其影响程度因森林生态系统类型而异。硬阔叶林和落叶松人工林的RH主要受土壤温度控制，其他生态系统RH受土壤温度和含水量的联合影响。各个森林生态系统类型的RC变化范围依次为：硬阔叶林32．40％-51．44％；杨桦林39．72％-46．65％；杂木林17．94％-47．74％；蒙古栎林34．31％-37．36％；红松人工林33．78％-37．02％；落叶松人工林14．39％-35．75％。每个生态系统类型RH年通量都显著高于心年通量，其变化范围分别为337-540gC·m^-2·a^-1和88-331gC·m^-2·a^-1。不同生态系统间的RH和RA也存在着显著性差异。

英文摘要：

Quantifying soil respiration components and their relations to environmental controls is essential to estimates of both local and regional carbon budgets of forest ecosystems. In this study, we used trenching-plot and infrared gas exchange analyzer approaches to determine heterotrophic （ RH ） and autotrophic respiration （ RA ） in soil surface CO2 flux for six major temperate forest ecosystems in northeastern China. The ecosystems were： Mongolian oak forest （dominated by Quercus mongolica）, poplarbirch forest （dominated by Populous davidiana and Betula platyphylla ）, mixed-wood forest （ composed of P. davidiana, B. platyphylla, Fraxinus mandshurica, Tilia amurensis , Acer amono , etc. ）, hard-wood forest （dominated by F. mandshurica, Juglans mandshurica , and Pliellodendron amurense ）, Korean pine （ Pinus koraiensis ） and Dahurian larch （ Larix gmelinii ） plantations, representing typical secondary forest ecosystems in this region. Our specific objectives were to： （1） quantify RH and its relationships with environmental factors for the forest ecosystems, （2） characterize seasonal dynamics in the contribution of root respiration to total soil surface CO2 flux （RC）, and （3） compare annual CO2 fluxes from RH and Ra among the six forest ecosystems. Soil temperature, Soil water content, and their interactions significantly affected RH in the ecosystems, and explained 46.5% - 78.8% variations in RH. However, the environmental controlling factors of RH varied with ecosystem types： soil temperature in hardwood and Dahurian larch forest ecosystems, soil temperature and water content in the others. The RC for hardwood, poplar-birch, mixed-wood, Mongolian oak, Korean pine and Dahurian larch forest ecosystems varied between 32.40% -51.44%, 39.72%-46.65%, 17.94% -47.74%, 34.31%- 37.36%, 33.78%-37.02%, 14.39% -35.75%, respectively. The annual CO2 fluxes from Ru were significantly greater than that from RA for all the ecosystems, ranging from 337 -540 gC·m^- 2· a^-1 and 88