Temperate woody angiosperm (Acer, Ilex, Magnolia) drought tolerance (TLP, xylem embolism) data, Arnold Arboretum and Scott Arboretum, MA/PA, USA, 2019-22

Understanding the capacity of temperate trees to acclimate to limited soil water has become essential in the face of increasing drought risk due to climate change. We documented seasonal – or phenological – patterns in acclimation to water deficit stress in stems and leaves of tree species spanning the angiosperm phylogeny.

Over three years of field observations carried out in two U.S. arboreta, we measured stem vulnerability to embolism (36 individuals of 7 Species) and turgor loss point (119 individuals of 27 species) over the growing season. We also conducted a growth chamber experiment on 20 individuals of one species to assess the mechanistic relationship between soil water restriction and acclimation.

In three quarters of species measured, plants became less vulnerable to embolism and/or loss of turgor over the growing season. We were able to stimulate this acclimatory effect by withholding water in the growth chamber experiment.

Temperate angiosperms are capable of acclimation to soil water deficit stress, showing maximum vulnerability to soil water deficits following budbreak and becoming more resilient to damage over the course of the growing season or in response to simulated drought. The species-specific tempo and extent of this acclimatory potential constitutes preadaptive climate change resilience.

面对气候变化导致的干旱风险日益加剧的现状，解析温带树木适应土壤水分受限的能力已成为至关重要的研究课题。本研究针对覆盖被子植物系统发育范围的多个树种，记录了其茎、叶组织对水分亏缺胁迫的季节（即物候）响应模式。
本研究于两处美国树木园开展了为期三年的野外观测，在整个生长季内测定了7个树种共36株个体的茎栓塞脆弱性（vulnerability to embolism），以及27个树种共119株个体的膨压丧失点（turgor loss point）。此外，我们针对1个树种的20株个体开展了人工气候室实验，以解析土壤水分限制与驯化过程之间的机制性关联。
在被测定的树种中，有四分之三的植物在生长季内表现出对栓塞和/或膨压丧失的脆弱性降低。我们通过人工气候室中的控水实验，成功诱导出了这种驯化效应。
温带被子植物具备对土壤水分亏缺胁迫的适应能力：其在芽萌动后对土壤水分亏缺的脆弱性达到峰值，随后在生长季进程中或响应模拟干旱时，抗损伤能力逐步提升。这种驯化潜力的物种特异性节奏与程度，构成了预适应气候变化的抗逆能力。