Leaf respiratory CO2 is 13 C-enriched relative to leaf organic components in five species of C3 plants.
Leaf respiratory CO2 is 13 C-enriched relative to leaf organic components in five species of C3 plants.
复制标题
相对于五种 C3 植物的叶子有机成分，叶子呼吸性 CO2 富含 13 C。
作者：
Chengyuan Xu;Guangxin Lin;K. Griffin;R. Sambrotto
·在这里，我们比较了生长在温室和生物圈2号内的五种C3植物的叶片呼吸CO2（δ13 CR）和叶片有机组分（可溶性糖，水溶性组分，淀粉，蛋白质和散装有机物）的碳同位素比率。 一个物种，美洲黑杨，生长在三个不同的CO2浓度。·将Keeling作图法应用于叶片尺度以测量叶片δ13 CR，并将这些结果与叶片有机组分的δ13 C进行比较。 ·在所有情况下，叶片呼吸CO2比叶片有机组分更富含13C。 13 C富集量具有明显的种特异性，CO2处理对美洲黑杨的影响不显著。在C3植物叶片中，富含13 C的呼吸CO2似乎广泛存在。 在目前推测的机制，促成这一现象，非统计碳同位素分布在糖基板似乎最有可能。然而，在生态系统尺度上通过放大叶片δ13 CR与叶片有机组分δ13 C之间的关系来预测叶片呼吸CO2 δ13 C时应谨慎。
• Here, we compared the carbon isotope ratios of leaf respiratory CO2 (δ13 CR ) and leaf organic components (soluble sugar, water soluble fraction, starch, protein and bulk organic matter) in five C3 plants grown in a glasshouse and inside Biosphere 2. One species, Populus deltoides, was grown under three different CO2 concentrations. • The Keeling plot approach was applied to the leaf scale to measure leaf δ13 CR and these results were compared with the δ13 C of leaf organic components. • In all cases, leaf respiratory CO2 was more 13 C-enriched than leaf organic components. The amount of 13 C enrichment displayed a significant species-specific pattern, but the effect of CO2 treatment was not significant on P. deltoides. • In C3 plant leaves, 13 C-enriched respiratory CO2 appears widespread. Among currently hypothesized mechanisms contributing to this phenomenon, non-statistical carbon isotope distribution within the sugar substrates seems most likely. However, caution should be taken when attempting to predict the δ13 C of leaf respiratory CO2 at the ecosystem scale by upscaling the relationship between leaf δ13 CR and δ13 C of leaf organic components.