Causes of tree death due to drought; hydraulic failure and carbon starvation

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K07492
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Forest Research and Management Organization
• Principal Investigator: Harayama Hisanori 国立研究開発法人森林研究・整備機構, 森林総合研究所, 主任研究員 等 (60353819)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 乾燥ストレス / 通水阻害 / 炭素欠乏 / エンボリズム / キャビテーション / 枯死

Outline of Final Research Achievements

An increase of tree mortality due to drought is expected as global warming is progressing. However, the mechanisms of drought-induced mortality remain poorly understood. I studied hydraulic failure and carbon starvation as core traits involved in the stress response mechanisms in Japanese larch (Larix kaempferi) and Todo fir (Abies sachalinensis) saplings. Needles were more vulnerable to hydraulic failure than stems in both species. The hydraulic failure in needles was associated with a decrease in the photosynthetic rate but not with plant death. Under rapid soil drying conditions, plants died when stem hydraulic conductivity decreased by 88 %. Transformation from starch to sugar was observed in saplings just before death induced by rapid drought, whereas the total amount of starch and sugar did not decrease significantly, suggesting carbon starvation was not an important cause of death.

Free Research Field

樹木生態生理学