Dynamic biotic controls of leaf thermoregulation across the diel timescale

Leaf thermoregulation and consequent leaf-to-air temperature difference (Δ T ) are tightly linked to plant metabolic rates and health. Current knowledge mainly focus on the regulation of environmental conditions on Δ T , while an accurate assessment of biotic regulations with field data remains lacking. Here, we used a trait-based model that integrates a coupled photosynthesis-stomatal conductance model with a leaf energy balance model to explore how six leaf traits (i.e. leaf width, emissivity, visible and near-infrared light absorptance, photosynthetic capacity— V c,max25 , and stomatal slope— g 1 ) regulate Δ T variability across the diel timescale. We evaluated the model with field observations collected from temperate to tropical forests. Our results show that: (1) leaf traits mediate large Δ T variability, with the noon-time trait-mediated Δ T variability reaching c. 15.0 °C; (2) l…