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Diurnal depression of leaf hydraulic conductance in a tropical tree species


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Brodribb, TJ and Holbrook, NM (2004) Diurnal depression of leaf hydraulic conductance in a tropical tree species. Plant, Cell and Environment, 27 (7). pp. 820-827. ISSN 0140-7791

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Diurnal patterns of hydraulic conductance of the leaf lamina ( K leaf ) were monitored in a field-grown tropical tree species in an attempt to ascertain whether the dynamics of stomatal conductance ( g s ) and CO 2 uptake ( A leaf ) were associated with short-term changes in K leaf . On days of high evaporative demand mid-day depression of K leaf to between 40 and 50% of pre-dawn values was followed by a rapid recovery after 1500 h. Leaf water potential during the recovery stage was less than - 1 MPa implying a refilling mechanism, or that loss of K leaf was not linked to cavitation. Laboratory measurement of the response of K leaf to Y leaf confirmed that leaves in the field were operating at water potentials within the depressed region of the leaf ‘vulnerability curve’. Diurnal courses of K leaf and Y leaf predicted from measured transpiration, xylem water potential and the K leaf vulnerability function, yielded good agreement with observed trends in both leaf parameters. Close correlation between depression of K leaf , g s and A leaf suggests that xylem dysfunction in the leaf may lead to mid-day depression of gas exchange in this species.

Item Type: Article
Keywords: gas exchange; leaf hydraulic conductance; midday depression; stomata; water use.
Journal or Publication Title: Plant, Cell and Environment
Page Range: pp. 820-827
ISSN: 0140-7791
Identification Number - DOI: 10.1111/j.1365-3040.2004.01188.x
Additional Information: "The definitive version is available at"
Date Deposited: 30 Nov 2007 02:06
Last Modified: 18 Nov 2014 03:25
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