title: The effect of plant water storage on water fluxes within the coupled soil-plant system.
abstract: 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 (Fe,night) on hydraulic redistribution (HR) in the soil. The model results suggest that daytime PWS usage and Fe,night generate a residual water potential gradient (Δψp,night) along the plant vascular system overnight. This Δψp,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.
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Huang
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.|Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, 33175, Gradignan Cedex, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Domec
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ward
authors.affiliation: Department of Biological Sciences, Rutgers University, Newark, NJ, 07102, USA.
authors.forename: Tomer
authors.initials: T
authors.lastname: Duman
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Manoli
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, Marquette University, Milwaukee, WI, 53233, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Parolari
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.|Department of Civil and Environmental Engineering, Duke University, Durham, NC, 27708, USA.
authors.forename: Gabriel G
authors.initials: GG
authors.lastname: Katul
mesh_terms: D002244:Carbon / Q000378:metabolism; D008954:Models, Biological; D018517:Plant Roots / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000502:physiology
chemical_list: D012987:Soil; D014867:Water; D002244:Carbon
keywords: drought resilience; hydraulic redistribution; leaf-level gas exchange; nocturnal transpiration; plant water storage; root water uptake