Initial hydraulic failure followed by late-stage carbon starvation leads to drought-induced death in the tree Trema orientalis
乾燥を受けた樹木が枯死に至る生理過程を解明 --地球温暖化の森林への影響を高精度に予測する道を開く成果--. 京都大学プレスリリース. 2019-01-28.
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.
- Communications Biology
Communications Biology (2), 2019-01-07