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Abstract

• Hydraulic dysfunction in leaves determines key aspects of whole-plant responses
to water stress; however, our understanding of the physiology of hydraulic dysfunction
and its relationships to leaf structure and ecological strategy remains
incomplete.
• Here, we studied a morphologically and ecologically diverse sample of angiosperms
to test whether the water potential inducing a 50% loss in leaf hydraulic
conductance (P50leaf) is predicted by properties of leaf xylem relating to water
tension-induced conduit collapse.We also assessed the relationships between P50leaf
and other traits considered to reflect drought resistance and ecological strategy.
• Across species, P50leaf was strongly correlated with a theoretical predictor of vulnerability
to cell collapse in minor veins (the cubed ratio of the conduit wall thickness
to the conduit lumen breadth). P50leaf was also correlated with mesophyll
traits known to be related to drought resistance, but unrelated to traits associated
with carbon economy.
• Our data indicate a link between the structural mechanics of leaf xylem and
hydraulic function under water stress. Although it is possible that collapse may
contribute directly to dysfunction, this relationship may also be a secondary product
of vascular economics, suggesting that leaf xylem is dimensioned to avoid wall
collapse.

Item Type:	Article
Authors/Creators:	Blackman, CJ and Brodribb, TJ and Jordan, GJ
Journal or Publication Title:	New Phytologist
ISSN:	0028-646X
DOI / ID Number:	https://doi.org/10.1111/j.1469-8137.2010.03439.x
Additional Information:	The definitive published version is available online at: http://onlinelibrary.wiley.com/
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