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Incontinence in aging leaves: Deteriorating water relations with leaf age in Agastachys odorata (Proteaceae), a shrub with very long-lived leaves

Citation

Jordan, GJ and Brodribb, TJ, Incontinence in aging leaves: Deteriorating water relations with leaf age in Agastachys odorata (Proteaceae), a shrub with very long-lived leaves, Functional Plant Biology, 34, (10) pp. 918-924. ISSN 1445-4408 (2007) [Refereed Article]

DOI: doi:10.1071/FP07166

Abstract

This paper examines physiological characteristics of the leaves of Agastachys odorata R.Br., a wet-climate sclerophyllous shrub with very long-lived leaves. It addresses the hypothesis that cuticles become leakier to water vapour as leaves age. Astomatous cuticular conductance, whole-leaf minimum epidermal conductance, leaf damage and accumulation of epiphylls all increased several-fold with leaf age from first year growth to 10 years of age. Maximum carbon assimilation peaked 1 year after full leaf expansion, then declined. Intrinsic water use efficiency was highest in mid-aged leaves and declined markedly in the oldest leaves. Stomatal density, stomatal size and cuticle thickness did not vary significantly among ages. The older leaves were less effective at controlling water loss, resulting in decreases in water use efficiency. A differential increase in the conductance of the stomatal surface of the leaves relative to astomatous surface suggested that stomatal leakiness was significant in leaves over five years old. Although data for other species is ambiguous, the deterioration in A. odorata appears to be consistent with changes in the oldest leaves of other species. Thus, decreasing ability to use water efficiently appears to be a consequence of accumulated damage and may contribute to the need for leaf senescence in evergreen species with little self shading. © CSIRO 2007.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Jordan, GJ (Associate Professor Greg Jordan)
Author:Brodribb, TJ (Dr Tim Brodribb)
ID Code:50197
Year Published:2007
Web of Science® Times Cited:8
Deposited By:Plant Science
Deposited On:2007-08-01
Last Modified:2008-05-17
Downloads:0

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