Local Adaptation Drives Leaf Thermoregulation in Tropical Rainforest Trees

作者：Kali Middleby, Rebecca Jordan, Alexander W. Cheesman, Maurizio Rossetto, Martin F. Breed, Darren M. Crayn, Lucas A. Cernusak · 发表于：Global Change Biology · 年份：2025 · DOI：10.1111/gcb.70461 · 被引用次数：6 · 研究领域：Ecology and Vegetation Dynamics Studies、Species Distribution and Climate Change、Plant Water Relations and Carbon Dynamics

ABSTRACT Tropical forests play a critical role in biodiversity, carbon sequestration, and climate regulation, but are increasingly affected by heatwaves and droughts. Vulnerability to warming may vary within and between species because of phenotypic divergence. Leaf trait variation can affect leaf operating temperatures—a phenomenon termed ‘limited homeothermy’ when it helps avoid heat damage in warmer conditions. However, evidence for this capacity and the relative roles of acclimation or adaptation remain limited. We measured photosynthetic heat tolerance and leaf thermal traits of three co‐occurring rainforest tree species across a thermal gradient in the Australian Wet Tropics. Using a leaf energy balance model parameterised with field‐measured traits, we predicted variation in leaf‐to‐air temperature differences (∆ T trait ) and resulting thermal safety margins. We combined this with individual‐based genome‐wide data to detect signals of adaptive divergence and validated findings in a glasshouse trial with provenances grown under contrasting temperature and humidity conditions. Intraspecific trait variation reduced ∆ T trait and increased heat tolerance in warmer sites for Darlingia darlingiana and Elaeocarpus grandis, but not Cardwellia sublimis . As a result, thermal safety margins declined less steeply with increasing growth temperature in species capable of increased heat tolerance and avoidance, indicating these strategies can effectively buffer warming. All species...