Zhang Rui, Zhao Yu, He Hong Bo, Zhang Xu Dong
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Ying Yong Sheng Tai Xue Bao. 2017 Jul 18;28(7):2379-2388. doi: 10.13287/j.1001-9332.201707.034.
Elevated atmospheric CO affects plant photosynthesis process and biomass accumulation, furthermore alters the distribution of photosynthetic carbon (C) above- and below-ground. The formation and turnover of soil organic carbon (SOC) depends on the input of photosynthetic C, so the change of plant physiology and metabolism caused by increasing CO concentration will further affect the balance of SOC pool. Therefore, stable isotope C technique is powerful for clarifying the influence of elevated atmospheric CO on C cycling in plant-soil system, including the distribution of photosynthetic C among plant organs, and the transformation and accumulation of photosynthetic C in soil. This review summarized research focused on the effects of elevated atmospheric CO on C cycling in terrestrial ecosystems based on C natural abundance or C tracing technique, including: 1) isotopic fractionation effect in plant photosynthesis; 2) the distribution of photosynthetic C in plant organs; 3) the transformation and stabilization of photosynthetic C in SOC driven by microbial process. Clarifying the above processes and controlling mechanisms is essential to predict long-term influence of elevated CO on C cycling and evaluate the source-sink function of SOC in terrestrial ecosystems.
大气中二氧化碳浓度升高会影响植物光合作用过程和生物量积累，进而改变光合碳在地上和地下的分配。土壤有机碳（SOC）的形成和周转取决于光合碳的输入，因此二氧化碳浓度升高引起的植物生理和代谢变化将进一步影响土壤有机碳库的平衡。因此，稳定同位素碳技术对于阐明大气中二氧化碳浓度升高对植物 - 土壤系统中碳循环的影响具有重要作用，包括光合碳在植物器官间的分配以及光合碳在土壤中的转化和积累。本综述基于碳自然丰度或碳示踪技术，总结了关于大气中二氧化碳浓度升高对陆地生态系统碳循环影响的研究，包括：1）植物光合作用中的同位素分馏效应；2）光合碳在植物器官中的分配；3）微生物过程驱动的光合碳在土壤有机碳中的转化和稳定。阐明上述过程及其控制机制对于预测二氧化碳浓度升高对碳循环的长期影响以及评估陆地生态系统中土壤有机碳的源汇功能至关重要。
