Transport of root-respired CO2 via the transpiration stream affects aboveground carbon assimilation and CO2 efflux in trees
Transport of root-respired CO2 via the transpiration stream affects aboveground carbon assimilation and CO2 efflux in trees
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DOI：
10.1111/j.1469-8137.2012.04366.x
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发表时间：
2013-01-01
期刊：
影响因子：
9.4
通讯作者：
Steppe, Kathy
中科院分区：
文献类型：
--
作者：
Bloemen, Jasper;McGuire, Mary Anne;Steppe, Kathy
树干通过蒸腾流将CO2从地下向上输送到地上组织。尽管对我们理解植物生理学具有潜在的重要意义，我们将（CO2）-C-13标记的水溶液注入7年生的野外生长的东部棉白杨的基部，（Populus deltoides）树木，以调查木质部-C-13标记物在整个树体内运输并检测到。高达17%的注入标签被同化，而其余的通过茎和分支流出扩散到大气中。分支木质组织中C-13的同化量最大，而叶中只有少量。叶柄中C-13的含量比其他叶组织中的含量高，我们的结果证实了呼吸CO2的循环途径，并表明来自根系的CO2的内部运输可能会混淆对木质组织呼吸和碳水化合物分配模式的基于流出的估计的解释。
Upward transport of CO2 via the transpiration stream from belowground to aboveground tissues occurs in tree stems. Despite potentially important implications for our understanding of plant physiology, the fate of internally transported CO2 derived from autotrophic respiratory processes remains unclear.We infused a (CO2)-C-13-labeled aqueous solution into the base of 7-yr-old field-grown eastern cottonwood (Populus deltoides) trees to investigate the effect of xylem-transported CO2 derived from the root system on aboveground carbon assimilation and CO2 efflux.The C-13 label was transported internally and detected throughout the tree. Up to 17% of the infused label was assimilated, while the remainder diffused to the atmosphere via stem and branch efflux. The largest amount of assimilated C-13 was found in branch woody tissues, while only a small quantity was assimilated in the foliage. Petioles were more highly enriched in C-13 than other leaf tissues.Ourresults confirm a recycling pathway for respired CO2 and indicate that internal transport of CO2 from the root system may confound the interpretation of efflux-based estimates of woody tissue respiration and patterns of carbohydrate allocation.