Elevated growth temperatures alter hydraulic characteristics in trembling aspen (Populus tremuloides) seedlings: implications for tree drought tolerance

Authors

  • DANIELLE A. WAY,

    Corresponding author
    1. Department of Biology
    2. Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, USA
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    • Current address: Department of Biology, University of Western Ontario, London, ON, Canada.

  • JEAN-CHRISTOPHE DOMEC,

    1. Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, USA
    2. University of Bordeaux, Bordeaux Sciences AGRO, UMR 1220 TCEM INRA, 1 Cours du général de Gaulle, 33175 Gradignan Cedex, France
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  • ROBERT B. JACKSON

    1. Department of Biology
    2. Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, USA
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D. A. Way. Fax: +1 919 613 8741; e-mail: danielle.way@duke.edu

ABSTRACT

Although climate change will alter both soil water availability and evaporative demand, our understanding of how future climate conditions will alter tree hydraulic architecture is limited. Here, we demonstrate that growth at elevated temperatures (ambient +5 °C) affects hydraulic traits in seedlings of the deciduous boreal tree species Populus tremuloides, with the strength of the effect varying with the plant organ studied. Temperature altered the partitioning of hydraulic resistance, with greater resistance attributed to stems and less to roots in warm-grown seedlings (P < 0.02), and a 46% (but marginally significant, P = 0.08) increase in whole plant conductance at elevated temperature. Vulnerability to cavitation was greater in leaves grown at high than at ambient temperatures, but vulnerability in stems was similar between treatments. A soil–plant–atmosphere (SPA) model suggests that these coordinated changes in hydraulic physiology would lead to more frequent drought stress and reduced water-use efficiency in aspen that develop at warmer temperatures. Tissue-specific trade-offs in hydraulic traits in response to high growth temperatures would be difficult to detect when relying solely on whole plant measurements, but may have large-scale ecological implications for plant water use, carbon cycling and, possibly, plant drought survival.

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