Pulse labeling of dissolved 13C-carbonate into tree xylem: developing a new method to determine the fate of recently fixed photosynthate
Pulse labeling of dissolved 13C-carbonate into tree xylem: developing a new method to determine the fate of recently fixed photosynthate
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DOI：
10.1002/rcm.4829
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发表时间：
2011-01-15
影响因子：
2
通讯作者：
Marshall, John D.
中科院分区：
文献类型：
--
作者：
Powers, Elizabeth M.;Marshall, John D.
稳定碳同位素常被用作植物和土壤系统中的示踪剂，以研究碳被森林冠层吸收，然后转移到土壤基质和土壤微生物中的命运和转化。本实验验证了一种新的C-13标记方法。我们将C-13-碳酸盐溶解于12 mL水中，并将其注入直径为6 cm的树的木质部中。同位素组成的叶子，茎CO2，韧皮部的内容进行了测量实验前和脉冲标签后两个星期。茎CO_2和韧皮部含量的同位素富集分别为6.1%和7.7%。未观察到大量树叶中的富集。在注射标签后5天，脉冲通过韧皮部，与基于通过树的运输速率的预期一致。这种木质部脉冲标记方法的应用可能会提供新的见解不稳定的固碳树木，甚至在更大的树木。此外，该方法可以应用于实验处理，将阐明机制控制最近固定的光合产物在森林中的命运和转化。版权所有（C）2010约翰威利父子有限公司
Stable carbon isotopes are often employed as tracers in plant and soil systems to study the fate and transformations of carbon as is it assimilated by the forest canopies and then translocated into the soil matrix and soil microorganisms. This experiment tested a new method of C-13-labeling. We dissolved C-13-carbonate into 12mL of water and injected it into the xylem of a 6-cm diameter tree. The isotopic composition of foliage, stem CO2, and phloem contents were measured before the experiment and up to two weeks after the pulse label. Isotopic enrichments of 6.1% and 7.7% were observed in stem CO2 and phloem contents, respectively. No enrichment in bulk foliage was observed. The pulse came through the phloem five days after the label was injected, consistent with expectations based on transport rates through the tree. The application of this xylem pulse-labeling method may provide new insights into labile carbon sequestration in trees, perhaps even in much larger trees. Furthermore, the method could be applied under experimental treatments that would elucidate the mechanisms controlling the fate and transformation of recently fixed photosynthate in forests. Copyright (C) 2010 John Wiley & Sons, Ltd.