碳同位素在草地土壤呼吸区分中的应用

Application of the Carbon Isotope in the Partitioning of Soil Respiration in Grassland

草地生态系统在区域气候变化及全球碳循环中扮演着重要的角色,草地土壤呼吸的区分是定量评价草地植被和土壤碳平衡的基础,有助于理解和预测草地生态系统对气候变化的响应。文章中论述了稳定碳同位素13C和放射性碳同位素14C在草地土壤呼吸区分中的应用。用于区分土壤微生物呼吸和根呼吸的方法主要有:13C自然丰度法、FACE实验法、13C脉冲标记法;用于区分纯根呼吸和根际微生物呼吸的方法主要有:同位素稀释法、模拟根际沉积物法、14CO2动态模型法、根系分泌物洗涤法。碳同位素法几乎不对草地土壤和植物根系产生干扰,可提高对土壤呼吸各组分的测算精度,在区分草地土壤微生物呼吸、纯根呼吸和根际微生物呼吸等组分方面有较大的应用前景。

Grassland ecosystem plays an important role in regional climate changes and global carbon cycle. The partitioning of soil respiration in grassland ecosystem is the foundation of quantitative evaluation of grassland vegetation and soil carbon balance, which could help to improve understanding and prediction of the responses of grassland ecosystem to climate changes. In this paper, several methods for separating soil respiration in grassland ecosystem by the application of stable carbon isotope 13C and radioactive carbon isotope 14C were reviewed. Methods for the separation of SOM-derived respiration and root-derived respiration mainly include： 13C natural abundance method, FACE experiment, 13C pulse labeling. Also, the methods for the separation of root and rhizomicrobial respiration mainly include： isotope dilution method, model rhizodeposition method, modeling of 14CO2 effiux dynamics method, and exudates elution method. Carbon isotope methods are novel methods that involve less disturbances to soil-plant system, which ultimately enhance the accuracy of estimation. Overall, carbon isotope methods have a great potential in the study of partitioning of soil respiration in grassland ecosystem.