Mobile carbon supply in trees and shrubs at the alpine treeline ecotone
Mobile carbon supply in trees and shrubs at the alpine treeline ecotone
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高山林线交错带树木和灌木的移动碳供应
DOI：
10.1007/s11258-018-0809-3
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发表时间：
2018
期刊：
影响因子：
1.7
通讯作者：
Dai Limin
中科院分区：
文献类型：
--
作者：
Wang Qingwei;Liu Chengang;Zhou Wangming;Qi Lin;Zhou Li;Yu Dapao;Dai Limin
虽然生长限制假说（GLH）是最被接受的生理解释高山树线的形成，其形成机制的争论仍然存在争议，由于不同的研究结果相互矛盾。树木和高山矮灌木之间的功能差异可能会找到答案，因为灌木在较高海拔处生长良好。本文研究了长白山森林交错带的两种主要灌木（落叶笃斯越橘和常绿杜鹃）和落叶树带树种岳桦（Betula ermanii）的碳储量。我们确定的增长和非结构性碳水化合物（NSC）的浓度在器官中的海拔在生长中期增加。结果表明，在林线交错带，由于近地面空气动力学解耦不明显，土壤温度低于树冠空气温度。物种的生长一直随着海拔的增加而下降，而NSC浓度不同的树木和灌木之间的海拔高度。叶片和木质器官中的NSC分别呈上升和下降趋势。ermanii。各器官NSC含量随海拔升高而显著增加。而V.笃斯木属在林线上，灌木的值高于B。叶中可溶性糖与淀粉的比率，以及每面积叶质量。随着海拔的升高，白桦树的NSC的器官依赖性为GLH提供了部分支持，而R。金黄色的; Uliginosum分别为GLH和碳限制假说提供了强有力的支持。这些意味着高山灌木可能已经进化到比树木更有利的碳平衡和功能特征，以适应高海拔气候。
Although the growth limitation hypothesis (GLH) is the most accepted physiological explanation for alpine treeline formation, the debate about its formation mechanisms still remains controversial due to contradictory findings from different studies. The functional difference between trees and alpine low-stature shrubs may hold answers, as shrubs grow well at higher elevations. We investigated carbon (C) storage in deciduous treeline speciesBetula ermanii(Erman’s birch) and two dominant shrubs (deciduousVaccinium uliginosumand evergreenRhododendron aureum), which naturally grow next to each other at the treeline ecotone on Changbai Mountain, Northeast China. We determined growth and non-structural carbohydrate (NSC) concentrations in organs with increasing elevation at the mid-growing season. Results showed that in the treeline ecotone soil temperature was lower than tree canopy air temperature due to unobvious aerodynamic decoupling near the ground. Species growth consistently decreased with increasing elevation, while NSC concentrations responded differently to elevation between trees and shrubs. An elevational increase and decrease in NSC were observed in leaves and woody organs, respectively, ofB. ermanii. NSC concentrations in each organ significantly increased with increasing elevation forR. aureumbut decreased forV. uliginosum. At the treeline, shrubs had higher values thanB. ermaniiin NSC, ratios of soluble sugars to starch in leaves, and leaf mass per area. Organ dependence of NSC with increasing elevation inBetulatrees provided partial support for the GLH, whileR. aureumandV. uliginosumprovided strong support for the GLH and carbon limitation hypothesis, respectively. These imply that alpine shrubs may have evolved to maintain more advantageous C balance and functional features than did trees as an adaptation to higher-elevation climates.