Whole-tree dynamics of non-structural carbohydrate and nitrogen pools across different seasons and in response to girdling in two temperate trees
Whole-tree dynamics of non-structural carbohydrate and nitrogen pools across different seasons and in response to girdling in two temperate trees
复制标题
不同季节非结构碳水化合物和氮库的全树动态以及两棵温带树木对环剥的响应
DOI：
10.1007/s00442-014-3186-1
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发表时间：
2015-02-01
期刊：
影响因子：
2.7
通讯作者：
Guo, Dali
中科院分区：
文献类型：
--
作者：
Mei, Li;Xiong, Yanmei;Guo, Dali
尽管对非结构性碳水化合物（NSC）和氮（N）浓度的季节动态进行了广泛的研究，但对不同树木器官的NSC和N库的大小和相对贡献还没有很好的了解。以落叶松（Larix gmelinii）和水曲柳（Fraxinus mandshurica）为试材，对环剥和对照树的叶、枝、茎和根分支顺序的NSC和N浓度进行了逐月测定。还测定了每个植物隔室的生物量，以计算NSC和N库的大小。在这两个物种中，13- 37%的NSC和N库在生长季节开始时被动员。在动员库中，落叶松和水曲柳的茎和非吸收根（分支4-9级）分别是最大的NSC源，而分支则是最大的N源。落叶松和水曲柳在环剥后，分别有22%和50%的根系NSC被调动起来维持生长季的根系活力。树木死亡后1年环剥，在这个时候仍然有一个丰富的NSC库的根。结果表明：（1）不同贮藏器官在生长季初期对新组织生长的贡献不同，贮藏器官中NSC或N库的含量高的器官不一定是动员NSC或N较多的器官;（3）非吸收性根系的C储存对维持树木在地上源光合产物流停止后的存活起着重要作用。
Despite extensive research on the seasonal dynamics of non-structural carbohydrate (NSC) and nitrogen (N) concentrations, the size and relative contributions of NSC and N pools across different tree organs are not well understood. We have measured the changes in NSC and N concentrations in leaves, branches, stems and all root branch orders at monthly intervals in control and girdled trees of larch (Larix gmelinii) and ash (Fraxinus mandshurica). The biomass of each plant compartment was also determined to calculate the size of the NSC and N pools. In both species, 13–37 % of the NSC and N pools were mobilized at the beginning of the growing season. Among the mobilized pools, stems and non-absorptive roots (branch orders 4–9) acted as the largest NSC sources in larch and ash, respectively, while branches served as the largest N source in both species. After stem girdling, 22 and 50 % of the root NSC stores in larch and ash, respectively, were mobilized to maintain root activities during the growing season. Tree mortality was observed 1 year after girdling, at which time there was still an abundant NSC pool in the roots. We conclude that (1) different storage organs differ in their contribution to new tissue growth at the beginning of the growing season and that those storage organs holding higher fractions of the NSC or N pool are not necessarily those which mobilize more NSC or N; (2) tree growth may not be limited by carbon (C) availability; (3) C storage in non-absorptive roots plays an important role in maintaining tree survival after the termination of photosynthate flow from aboveground sources.