Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, MA 02138, USA.
Max-Planck Institute for Biogeochemistry, Hans Knoll Str. 10, 07745 Jena, Germany.
Curr Opin Plant Biol. 2018 Jun;43:89-95. doi: 10.1016/j.pbi.2018.02.005. Epub 2018 Mar 6.
For trees to survive, they must allocate resources between sources and sinks to maintain proper function. The vertical transport pathway in tree stems is essential for carbohydrates and other solutes to move between the canopy and the root system. To date, research and models emphasize the role of tree stems as 'express' sugar highways. However, recent investigations using isotopic markers suggest that there is considerable storage and exchange of phloem-transported sugars with older carbon (C) reserves within the stem. Thus, we suggest that stems play an important role not only in long-distance transport, but also in the regulation of the tree's overall C balance. A quantitative partitioning of stem C inputs among storage and sinks, including tissue growth, respiration, and export to roots, is still lacking. Combining methods to better quantify the dynamics and controls of C storage and remobilization in the stem will help to resolve central questions of allocation and C balance in trees.
为了生存，树木必须在源和汇之间分配资源，以维持正常功能。树木茎中的垂直运输途径对于碳水化合物和其他溶质在树冠和根系之间移动至关重要。迄今为止，研究和模型强调了树干作为“表达”糖高速公路的作用。然而，最近使用同位素标记的调查表明，木质部运输的糖与茎内较老的碳（C）储备之间存在大量的储存和交换。因此，我们认为茎不仅在长途运输中起着重要作用，而且在调节树木的整体 C 平衡中也起着重要作用。茎中 C 输入在储存和汇之间的定量分配，包括组织生长、呼吸和向根系的输出，仍然缺乏。结合方法更好地量化 C 在茎中的储存和再移动的动态和控制，将有助于解决树木中分配和 C 平衡的核心问题。
