关键词: hydraulic conductance hydraulic resistance leaf surface liquid flux vapour diffusion water absorption

Mesh : Abscisic Acid / metabolism pharmacology Glycosides / pharmacology Kinetics Microscopy, Electron, Scanning Plant Leaves / metabolism ultrastructure Plant Stomata / drug effects physiology ultrastructure Prunus dulcis / metabolism Pyrus / metabolism Water / metabolism

来  源:   DOI:10.1111/pce.14041   PDF(Sci-hub)

Abstract:
Plants can absorb water through their leaf surfaces, a phenomenon commonly referred to as foliar water uptake (FWU). Despite the physiological importance of FWU, the pathways and mechanisms underlying the process are not well known. Using a novel experimental approach, we parsed out the contribution of the stomata and the cuticle to FWU in two species with Mediterranean (Prunus dulcis) and temperate (Pyrus communis) origin. The hydraulic parameters of FWU were derived by analysing mass and water potential changes of leaves placed in a fog chamber. Leaves were previously treated with abscisic acid to force stomata to remain closed, with fusicoccin to remain open, and with water (control). Leaves with open stomata rehydrated two times faster than leaves with closed stomata and attained approximately three times higher maximum fluxes and hydraulic conductance. Based on FWU rates, we propose that rehydration through stomata occurs primarily via diffusion of water vapour rather than in liquid form even when leaf surfaces are covered with a water film. We discuss the potential mechanisms of FWU and the significance of both stomatal and cuticular pathways for plant productivity and survival.
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