Carbon dynamics in the deciduous broadleaf tree Erman's birch (Betula ermanii) at the subalpine treeline on Changbai Mountain, Northeast China
Carbon dynamics in the deciduous broadleaf tree Erman's birch (Betula ermanii) at the subalpine treeline on Changbai Mountain, Northeast China
复制标题
中国东北长白山亚高山林线落叶阔叶树埃尔曼桦 (Betula ermanii) 的碳动态
DOI：
10.1002/ajb2.1006
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发表时间：
2018
影响因子：
3
通讯作者：
Dai Limin
中科院分区：
文献类型：
--
作者：
Wang Qing-Wei;Qi Lin;Zhou Wangming;Liu. Chenggang;Yu Dapao;Dai Limin
生长限制假说（GLH）和碳限制假说（CLH）是两种解释树线形成的主要假说。GLH提出，低温通过限制碳汇而不是碳源来驱动树线，它预测非结构性碳水化合物（NSC）水平是静态的或随海拔升高而增加。虽然GLH已收到全球万年青树木的大力支持，仍然没有达成共识的落叶树木，经历了巨大的供应和需求之间的一年四季。MethodsWe调查的增长和生长季节的C动态在一个共同的落叶树种，厄尔曼的桦树（桦），沿着海拔梯度从封闭的森林的树线上长白山，中国东北。从发育器官（叶和树枝）和主要存储器官（茎和根）NSC analysis.Key ResultsTree生长随海拔的增加而下降，NSC浓度不同海拔，器官和采样时间显着。特别是，NSC水平略有变化，在生长季节的叶，高峰期在生长季节的中间，在树枝和茎，并不断增加，在整个生长季节的根。神经干细胞也倾向于增加或略有不同，在发展中的器官，但在成熟的器官，随着海拔的增加elevation.ConclusionsThe神经干细胞与海拔在主要存储器官的减少表示支持CLH，而在新的发展中的器官的增加或静态的趋势表示支持GLH。我们的研究结果表明，生长限制理论可能不适用于落叶树种的生长比万年青树种。
Premise of the StudyThe growth limitation hypothesis (GLH) and carbon limitation hypothesis (CLH) are two dominant explanations for treeline formation. The GLH proposes that low temperature drives the treeline through constraining C sinks more than C sources, and it predicts that non‐structural carbohydrate (NSC) levels are static or increase with elevation. Although the GLH has received strong support globally for evergreen treelines, there is still no consensus for deciduous treelines, which experience great asynchrony between supply and demand throughout the year.MethodsWe investigated growth and the growing‐season C dynamics in a common deciduous species, Erman's birch (Betula ermanii), along an elevational gradient from the closed forest to the treeline on Changbai Mountain, Northeast China. Samples were collected from developing organs (leaves and twigs) and main storage organs (stems and roots) for NSC analysis.Key ResultsTree growth decreased with increasing elevation, and NSC concentrations differed significantly among elevations, organs, and sampling times. In particular, NSC levels varied slightly during the growing season in leaves, peaked in the middle of the growing season in twigs and stems, and increased continuously throughout the growing season in roots. NSCs also tended to increase or vary slightly in developing organs but decreased significantly in mature organs with increasing elevation.ConclusionsThe decrease in NSCs with elevation in main storage organs indicates support for the CLH, while the increasing or static trends in new developing organs indicate support for the GLH. Our results suggest that the growth limitation theory may be less applicable to deciduous species' growth than to that of evergreen species.