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Minimum hydraulic safety leads to maximum water-use efficiency in a forage grass


Holloway-Phillips, M and Brodribb, TJ, Minimum hydraulic safety leads to maximum water-use efficiency in a forage grass, Plant, Cell and Environment, 34, (2) pp. 302-313. ISSN 0140-7791 (2011) [Refereed Article]

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Copyright 2010 The definitive published version is available online at:

DOI: doi:10.1111/j.1365-3040.2010.02244.x


Understanding how water-use regulation relates to biomass accumulation is imperative for improving crop production in water-limited environments. Here, we examine how the vulnerability of xylem to water stress-induced cavitation and the coordination between water transport capacity and assimilation (A) influences diurnal water-use efficiency (WUE) and dry-matter production in Lolium perenne L. a commercial forage grass. Plants were exposed to a range of water stresses, causing up to 90% leaf death, by withholding water and then rewatering to observe the recovery process. Leaf hydraulic conductance (Kleaf) declined to 50% of maximum at a leaf water potential (yleaf) of -1 MPa, whereas complete stomatal closure occurred well after this point, at -2.35 MPa, providing no protection against hydraulic dysfunction. Instantaneous A remained maximal until >70% of hydraulic conductivity had been lost. Poststress rewatering showed that 95% loss of Kleaf could be incurred before the recovery of gas exchange exceeded 1 d, with a rapid transition to leaf death after this point. Plants exposed to sustained soil water deficits through restricted nightly watering regimes did not suffer cumulative losses in Kleaf; instead, yleaf and gas exchange recovered diurnally. The effect was improved WUE during the day and optimal yleaf during the night for the maintenance of growth.

Item Details

Item Type:Refereed Article
Keywords:grass; hydraulic conductivity; production; safety margin; stomatal regulation; water stress; water-use efficiency; xylem vulnerability.
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Biological adaptation
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Holloway-Phillips, M (Miss Meisha-Marika Holloway-Phillips)
UTAS Author:Brodribb, TJ (Professor Tim Brodribb)
ID Code:71954
Year Published:2011
Web of Science® Times Cited:41
Deposited By:Plant Science
Deposited On:2011-08-16
Last Modified:2012-06-18
Downloads:1 View Download Statistics

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