Consequences of nocturnal water loss: a synthesis of regulating factors and implications for capacitance, embolism and use in models

M. J. B. Zeppel*, J. D. Lewis, N. G. Phillips, D. T. Tissue

*Corresponding author for this work

    Research output: Contribution to journalReview articlepeer-review

    93 Citations (Scopus)

    Abstract

    Total daily water use is a key factor influencing the growth of many terrestrial plants, and reflects both day-time and nocturnal water fluxes. However, while nocturnal sap flow (En) and stomatal conductance (gs,n) have been reported across a range of species, ecosystems and microclimatic conditions, the regulation of these fluxes remains poorly understood. Here, we present a framework describing the role of abiotic and biotic factors in regulating Enand gs,nhighlighting recent developments in this field. Across ecosystems, Enand gs,ngenerally increased with increasing soil water content and vapor pressure deficit, but the interactive effects of these factors and the potential roles of wind speed and other abiotic factors remain unclear. On average, gs,n and En are higher in broad-leaved compared with needle-leaved plants, in C3compared with C4 plants, and in tropical compared with temperate species. We discuss the impacts of leaf age, elevated [CO2] and refilling of capacitance on night-time water loss, and how nocturnal gs,nmay be included in vegetation models. Younger leaves may have higher gs,n than older leaves. Embolism refilling and recharge of capacitance may affect sap flow such that total plant water loss at night may be less than estimated solely from En measurements. Our estimates of gs,n for typical plant functional types, based on the published literature, suggest that nocturnal water loss may be a significant fraction (10-25%) of total daily water loss. Counter-intuitively, elevated [CO2] may increase nocturnal water loss. Assumptions in process-based ecophysiological models and dynamic global vegetation models that gs is zero when solar radiation is zero are likely to be incorrect. Consequently, failure to adequately consider nocturnal water loss may lead to substantial under-estimation of total plant water use and inaccurate estimation of ecosystem level water balance.

    Original languageEnglish
    Pages (from-to)1047-1055
    Number of pages9
    JournalTree physiology
    Volume34
    Issue number10
    DOIs
    Publication statusPublished - 1 Oct 2014

    Keywords

    • Climate change
    • Dynamic global vegetation models
    • Elevated co
    • Embolism refilling
    • Hydraulic redistribution
    • Night-time sap flow
    • Nocturnal stomatal conductance

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