Predicting Transpiration Response to Climate Change: Insights on Physiological and Morphological Interactions that Modulate Water Exchange from Leaves to Canopies

Leaves are key factors in the global water exchange cycle. As the primary control interface involved in regulating water loss, understanding the relative influence of leaf morphological and physiological transpiration factors is critical to accurate evapotranspiration predictions. We parameterized a three-dimensional array model, MAESTRA, to establish a link from the leaf to canopy scale and attempted to isolate and understand the interplay among variation in morphological and physiological variables affecting transpiration. When physiological differences were accounted for, differences in leaf width (L-w) among Acer rubrum L. genotypes significantly affected leaf temperature and transpiration under slow to moderate wind velocities. In instances, L-w variation among genotypes resulted in a 25% difference in transpiration. This study demonstrates how simple morphological traits like L-w can provide useful selection criteria for plant breeders to consider in a changing climate.