Testing hypotheses that link wood anatomy to cavitation resistance and hydraulic conductivity in the genus Acer

Authors

  • Frederic Lens,

    1. Laboratory of Plant Systematics, Institute of Botany and Microbiology, Kasteelpark Arenberg 31 Box 2437, K.U. Leuven, BE-3001 Leuven, Belgium
    2. Present address: Netherlands Centre for Biodiversity Naturalis (section NHN), Leiden University, PO Box 9514, NL-2300 RA, Leiden, the Netherlands
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  • John S. Sperry,

    1. Biology Department, University of Utah, 257S 1400E Salt Lake City, UT 84112, USA
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  • Mairgareth A. Christman,

    1. Biology Department, University of Utah, 257S 1400E Salt Lake City, UT 84112, USA
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  • Brendan Choat,

    1. Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
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  • David Rabaey,

    1. Laboratory of Plant Systematics, Institute of Botany and Microbiology, Kasteelpark Arenberg 31 Box 2437, K.U. Leuven, BE-3001 Leuven, Belgium
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  • Steven Jansen

    1. Institute for Systematic Botany and Ecology, Ulm University, Albert Einstein Allee 11, D-89081, Ulm, Germany
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  • Frederic Lens was awarded the 2010 New Phytologist Tansley Medal for excellence in plant science. The medal is in recognition of Frederic’s outstanding contribution to research in plant science, at an early stage in his career, as presented in this article; see the Editorial by Woodward & Hetherington, 190: 509.

Author for correspondence:
Frederic Lens
Tel: +32 16 32 86 37
Email: lens@nhn.leidenuniv.nl

Summary

  • Vulnerability to cavitation and conductive efficiency depend on xylem anatomy. We tested a large range of structure–function hypotheses, some for the first time, within a single genus to minimize phylogenetic ‘noise’ and maximize detection of functionally relevant variation.
  • This integrative study combined in-depth anatomical observations using light, scanning and transmission electron microscopy of seven Acer taxa, and compared these observations with empirical measures of xylem hydraulics.
  • Our results reveal a 2 MPa range in species’ mean cavitation pressure (MCP). MCP was strongly correlated with intervessel pit structure (membrane thickness and porosity, chamber depth), weakly correlated with pit number per vessel, and not related to pit area per vessel. At the tissue level, there was a strong correlation between MCP and mechanical strength parameters, and some of the first evidence is provided for the functional significance of vessel grouping and thickenings on inner vessel walls. In addition, a strong trade-off was observed between xylem-specific conductivity and MCP. Vessel length and intervessel wall characteristics were implicated in this safety–efficiency trade-off.
  • Cavitation resistance and hydraulic conductivity in Acer appear to be controlled by a very complex interaction between tissue, vessel network and pit characteristics.

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