Diel variations in the carbon isotope composition of respired CO(2) and associated carbon sources: a review of dynamics and mechanisms
Diel variations in the carbon isotope composition of respired CO(2) and associated carbon sources: a review of dynamics and mechanisms
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DOI：
10.5194/bg-8-2437-2011
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发表时间：
2011-09
期刊：
影响因子：
4.9
通讯作者：
C. Werner;A. Gessler
中科院分区：
文献类型：
--
作者：
C. Werner;A. Gessler
抽象的。最近的进展改善了我们的方法和理论理解的光合作用后碳同位素分馏过程。然而，我们仍然缺乏一个清晰的图片的来源，短期变化的δ 13 C的呼吸CO2（δ 13 Cres）和有机碳组分的昼夜基础上。填补这一知识空白对于应用稳定同位素方法划分生态系统呼吸、追踪植物和生态系统中的碳流以及解开植物碳代谢中的关键生理过程至关重要。在这篇综述中，我们研究了在植物，土壤和生态系统尺度上的δ 13 Cres和假定的基质库的短期动态，并讨论了机制，这可能会驱动diel δ 13 Cres动态在每个尺度上。不同物种的干、根和叶的diel δ13Cres的最大变异分别为4.0、5.4和14.8 ‰，不同生物群落的土壤和生态系统尺度的diel δ13Cres的最大变异分别为12.5和8.1 ‰。光合作用后同位素分馏的时间变化与碳分配到不同代谢途径的变化有关，是对δ 13 Cres中观察到的昼夜动态的最合理的机制解释。此外，不同时间动态和同位素组成的组分通量的混合增加了土壤和生态系统水平上的δ13Cres变化。了解δ13Cres的短期变化对生态系统研究特别重要，因为δ13Cres包含呼吸基质的命运信息，因此可能提供一种非侵入性的方式来识别碳分配模式的变化。
Abstract. Recent advances have improved our methodological approaches and theoretical understanding of post-photosynthetic carbon isotope fractionation processes. Nevertheless we still lack a clear picture of the origin of short-term variability in δ13C of respired CO2 (δ13Cres) and organic carbon fractions on a diel basis. Closing this knowledge gap is essential for the application of stable isotope approaches for partitioning ecosystem respiration, tracing carbon flow through plants and ecosystems and disentangling key physiological processes in carbon metabolism of plants. In this review we examine the short-term dynamics in δ13Cres and putative substrate pools at the plant, soil and ecosystem scales and discuss mechanisms, which might drive diel δ13Cres dynamics at each scale. Maximum reported variation in diel δ13Cres is 4.0, 5.4 and 14.8 ‰ in trunks, roots and leaves of different species and 12.5 and 8.1 ‰ at the soil and ecosystem scale in different biomes. Temporal variation in post-photosynthetic isotope fractionation related to changes in carbon allocation to different metabolic pathways is the most plausible mechanistic explanation for observed diel dynamics in δ13Cres. In addition, mixing of component fluxes with different temporal dynamics and isotopic compositions add to the δ13Cres variation on the soil and ecosystem level. Understanding short-term variations in δ13Cres is particularly important for ecosystem studies, since δ13Cres contains information on the fate of respiratory substrates, and may, therefore, provide a non-intrusive way to identify changes in carbon allocation patterns.