Whole-plant capacitance, embolism resistance and slow transpiration rates all contribute to longer desiccation times in woody angiosperms from arid and wet habitats

Sean M. Gleason*, Chris J. Blackman, Alicia M. Cook, Claire A. Laws, Mark Westoby

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Low water potentials in xylem can result in damaging levels of cavitation, yet little is understood about which hydraulic traits have most influence in delaying the onset of hydraulic dysfunction during periods of drought. We examined three traits contributing to longer desiccation times in excised shoots of 11 species from two sites of contrasting aridity: (i) the amount of water released from plant tissues per decrease in xylem water potential (W Ψ); (ii) the minimum xylem water potential preceding acute water stress (defined as P50L; water potential at 50% loss of leaf conductance); and (iii) the integrated transpiration rate between the points of full hydration and P50L (Wtime). The time required for species to reach P50L varied markedly, ranging from 1.3h to nearly 3 days. WΨ, P50L and Wtime all contributed significantly to longer desiccation times, explaining 28, 22 and 50% of the variance in the time required to reach P50L. Interestingly, these three traits were nearly orthogonal to one another, suggesting that they do not represent alternative hydraulic strategies, but likely trade off with other ecological strategies not evaluated in this study. The majority of water lost during desiccation (60-91%) originated from leaves, suggesting an important role for leaf capacitance in small plants when xylem water potentials decrease below-2MPa.

Original languageEnglish
Pages (from-to)275-284
Number of pages10
JournalTree physiology
Volume34
Issue number3
DOIs
Publication statusPublished - Mar 2014

Keywords

  • cavitation
  • conductance
  • drought
  • saturated water content

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