Initial hydraulic failure followed by late-stage carbon starvation leads to drought-induced death in the tree Trema orientalis
Initial hydraulic failure followed by late-stage carbon starvation leads to drought-induced death in the tree Trema orientalis
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DOI：
10.1038/s42003-018-0256-7
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发表时间：
2019-01-07
影响因子：
5.9
通讯作者：
Aikawa, Shin-ichi
中科院分区：
文献类型：
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作者：
Kono, Yuri;Ishida, Atsushi;Aikawa, Shin-ichi
干旱导致的树木死亡已成为全球森林生态系统中的一个严重问题。两个非排他性的假设，液压故障和碳饥饿，已被提出来解释树木死亡。为了阐明机制，我们研究了干旱引起的树木死亡的幼树与对比胡伯值（边材面积/总叶面积）的生理过程。首先，在树木衰退的初始阶段，出现了水力衰竭和呼吸作用减弱，在最后阶段，碳饥饿导致树木死亡。健康树茎基部的碳水化合物储备较低，在衰退过程开始时由于韧皮部运输失败而积累，然后在死亡前下降。茎基部非结构性碳水化合物的浓度是树木受损的一个很好的指标。致命干旱期间发生的生理过程和碳汇-源动态为全球变暖条件下森林死亡的适应措施提供了重要的见解。
Drought-induced tree death has become a serious problem in global forest ecosystems. Two nonexclusive hypotheses, hydraulic failure and carbon starvation, have been proposed to explain tree die-offs. To clarify the mechanisms, we investigated the physiological processes of drought-induced tree death in saplings with contrasting Huber values (sapwood area/total leaf area). First, hydraulic failure and reduced respiration were found in the initial process of tree decline, and in the last stage carbon starvation led to tree death. The carbohydrate reserves at the stem bases, low in healthy trees, accumulated at the beginning of the declining process due to phloem transport failure, and then decreased just before dying. The concentrations of non-structural carbohydrates at the stem bases are a good indicator of tree damage. The physiological processes and carbon sink-source dynamics that occur during lethal drought provide important insights into the adaptive measures underlying forest die-offs under global warming conditions.