碳同位素示踪技术及其在陆地生态系统碳循环研究中的应用与展望

葛体达,王东东,祝贞科,魏亮,魏晓梦,吴金水

Tracing technology of carbon isotope and its applications to studies of carbon cycling in terrestrial ecosystem

GE Ti-Da,WANG Dong-Dong,ZHU Zhen-Ke,WEI Liang,WEI Xiao-Meng,WU Jin-Shui

表1 脉冲和连续标记在根际沉积碳(C)输入土壤应用中的比较

Table 1 Comparison of pulse and continuous labeling method in the study of rhizosphere deposition carbon (C) input to soil

	脉冲标记 Pulse labeling	连续标记 Continuous labeling
1. 标记持续时间 Labeling duration	短(小时或天) Very short (hours or days)	植物生长的全部时期 Entire duration of plant growth
2. CO₂输入的同位素组成变化 Changes in the isotopic composition of the CO₂ input	时间短而丰度高 Short time and high abundance	时间长(不一定需要高丰度); 长期持续富集 Long time (not necessarily high abundance), constant enrichment over a long period
3. 应用 Application	简单 Simple	复杂 Complicated
4. 成本 Cost	便宜 Cheap	昂贵 Expensive
5. 目的 Aim	不同生长阶段植物-土壤系统的C流动力学 Dynamics of C flow in the plant, soil, and CO₂ at various growth stages	可以达到脉冲标记的所有目的 All the aims of pulse labeling can be achieved
	地下C分配 Belowground C allocation	植物C在CO₂, 微生物生物量碳(MBC), 可溶性有机质(DOM)和土壤有机质(SOM)等中的分配 Partitioning of plant derived C in CO₂, microbial biomass C (MBC), dissolved organic matter (DOM), soil organic matter (SOM), etc.
	净C同化 Net C assimilation	植物C分配的季节动态 Seasonal dynamics of plant C partitioning
	植物根系和土壤呼吸 Root-soil respiration	根际激发效应 Rhizosphere-priming effects
	新同化C的命运(分配和运输) Fate of newly assimilated C
	C转移速度 Speed of C transfer
6. C输入到土壤中 C input into the soil	在特定的植物生长阶段 At specific plant development stages	在植物生长的整个时期 Over the whole growth period
7. 缺点 Disadvantage	特定生长阶段不能代表整个生长时期, 同位素丰度在植物整株中分布不均匀 A specific growth stage cannot be transferred for the whole growth period, isotope abundance is unequal across plant parts	需要特殊设备长期标记植物 Requires special equipment for exposing the plant over a long period
7. 缺点 Disadvantage	同位素丰度随时间变化 Isotope abundance in pools change over time	为保证空气湿度, 需要良好的温度控制和空气循环系统 Temperature control and good air circulation are necessary to maintain air humidity