Leaf habit affects the distribution of drought sensitivity but not water transport efficiency in the tropics

Abstract

<p>Considering the global intensification of aridity in tropical biomes due to climate change, we need to understand what shapes the distribution of drought sensitivity in tropical plants. We conducted a pantropical data synthesis representing 1117 species to test whether xylem-specific hydraulic conductivity (K<sub>S</sub>), water potential at leaf turgor loss (Ψ<sub>TLP</sub>), and water potential at 50% loss of K<sub>S</sub> (ΨP50) varied along climate gradients. The Ψ<sub>TLP</sub> and ΨP<sub>50</sub> increased with climatic moisture only for evergreen species, but K<sub>S</sub> did not. Species with high Ψ<sub>TLP</sub> and Ψ<sub>P50</sub> values were associated with both dry and wet environments. However, drought-deciduous species showed high Ψ<sub>TLP</sub> and ΨP<sub>50</sub> values regardless of water availability whereas evergreen species only in wet environments. All three traits showed a weak phylogenetic signal and a short half-life. These results suggest that environmental controls on trait variance, which in turn is modulated by leaf habit along climatic moisture gradients in the tropics.</p><p>Funding provided by: University of Minnesota<br>Crossref Funder Registry ID: https://ror.org/017zqws13<br>Award Number: Doctoral Dissertation Fellowship to GVG</p><p>Funding provided by: Interdisciplinary Center for the Study of Global Change, University of Minnesota*<br>Crossref Funder Registry ID: <br>Award Number: ICGC scholar fellowship to GVG</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: DEB-1753810</p><p>Funding provided by: United States Department of Energy<br>Crossref Funder Registry ID: https://ror.org/01bj3aw27<br>Award Number: DE-SC0020344</p&gt