The effect of plant water storage on water fluxes within the coupled soil–plant system. Issue 3 (21st November 2016)

• Record Type: Journal Article
• Authors: Huang, Cheng‐Wei; Domec, Jean‐Christophe; Ward, Eric J.; Duman, Tomer; Manoli, Gabriele; Parolari, Anthony J.; Katul, Gabriel G.
• Is Part Of: New phytologist. Volume 213:Issue 3(2017)
• Page Start: 1093
• Page End: 1106
• Publication Date: 2016-11-21
• Subjects: drought resilience -- hydraulic redistribution -- leaf‐level gas exchange -- nocturnal transpiration -- plant water storage -- root water uptake; Botany -- Periodicals; 580
• DOI: 10.1111/nph.14273
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: In addition to buffering plants from water stress during severe droughts, plant water storage (PWS) alters many features of the spatio‐temporal dynamics of water movement in the soil–plant system. How PWS impacts water dynamics and drought resilience is explored using a multi‐layer porous media model. The model numerically resolves soil–plant hydrodynamics by coupling them to leaf‐level gas exchange and soil–root interfacial layers. Novel features of the model are the considerations of a coordinated relationship between stomatal aperture variation and whole‐system hydraulics and of the effects of PWS and nocturnal transpiration ( F e, night ) on hydraulic redistribution (HR) in the soil. The model results suggest that daytime PWS usage and F e, night generate a residual water potential gradient ( Δ ψ p, night ) along the plant vascular system overnight. This Δ ψ p, night represents a non‐negligible competing sink strength that diminishes the significance of HR. Considering the co‐occurrence of PWS usage and HR during a single extended dry‐down, a wide range of plant attributes and environmental/soil conditions selected to enhance or suppress plant drought resilience is discussed. When compared with HR, model calculations suggest that increased root water influx into plant conducting‐tissues overnight maintains a more favorable water status at the leaf, thereby delaying the onset of drought stress.