Acclimation of interacting leaf surface traits affects foliar water uptake.

This article investigates the mechanisms and environmental responsiveness of foliar water uptake in Sequoia sempervirens (coast redwood) leaves, focusing on how leaf surface traits influence water absorption. Experimental evidence demonstrates that water primarily enters Sequoia leaves through the cuticle on the stomata-free adaxial surface rather than through stomata, as confirmed by fluorescent dye tracing and stomatal occlusion experiments. The study identifies abaxial wax coverage and stomatal density as key leaf surface traits negatively associated with water uptake capacity, both of which exhibit developmental plasticity influenced by climatic conditions. These findings suggest that climatic variation can induce acclimation in leaf surface traits, altering foliar water uptake kinetics and potentially affecting tree water relations and forest hydrology. The authors provide protocols for measuring these traits, highlighting their suitability for large-scale ecological monitoring and conservation physiology research.