土壤呼吸组分对气候变暖的响应研究进展

Research progress on the responses of soil respiration components to climatic warming

气候变暖正在深刻地改变全球碳循环过程.土壤呼吸作为全球碳循环的重要环节,连接着植物-土壤-微生物之间的碳转移过程.土壤呼吸可分为异养呼吸和根源呼吸(根系呼吸和根际微生物呼吸)等组分.土壤呼吸各组分的发生部位与利用的有机碳源不同,其对气候变暖的响应可能存在显著差异.然而,目前的研究还不能完全实现土壤呼吸各组分的精确区分和量化,气候变暖对土壤呼吸各组分的影响及其具体机制仍存在很多悬而未决的问题,这极大地限制了人们对土壤碳循环评估的精确性以及对气候变暖背景下陆地生态系统碳收支格局变化的认识.本文系统综述了目前国内外土壤呼吸组分区分技术,分析了土壤呼吸组分区分的研究结果,并论述了土壤呼吸各组分对气候变暖的响应研究进展.提出仍需发展新的土壤呼吸组分区分技术或者改进和创新现有技术,未来的研究重点应放在精确区分野外条件下根源呼吸组分,同时开展土壤呼吸组分对多种环境因子变化的响应研究,以期更全面地认识土壤碳循环过程以及全球变化背景下陆地生态系统碳收支的变化趋势.

Global carbon cycle is being profoundly altered by climate change. As an important component of the global carbon cycle,soil respiration is tightly linked to the carbon transfer among plants-soil-microbes. Soil respiration can be divided into the heterotrophic respiration and root-derived respiration（ i.e.,actual root respiration and rhizomicrobial respiration）. Responses of soil respiration to climate warming may be different,since its components differ in occurrence sites and sources of soil organic carbon. However,the current literatures can not fully clarify the precise partition and quantification of soil respiration components. The influences of climate warming on soil respiration and related mechanisms are still unclear,which greatly limits our understanding of the accurate assessments of soil carbon cycle as well as the changes in the carbon balance of terrestrial ecosystems under climate change. We systematically summarized the progress of partitioning techniques of soil respiration components,and compared the results of partitioning of soil respiration components using different techniques. We further discussed the progress on the responses of soil respiration components to climate warming. To exactly distinguish and quantify soil respiration components,we proposed that the present techniques should be modified. Furthermore,future studies should focus on how to accurately partitioning root-derived respiration in the field for comprehensively understand soil carbon cycle and the changes of carbon budget in terrestrial ecosystems under global change. Moreover,more attention should be paid on the responses of soil respiration components to various environmental factors.