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Seasonal trends in carbon assimilation, stomatal conductance, pre-dawn leaf water potential and growth in Terminalia ferdinandiana, a deciduous tree of northern Australian savannas

Citation

Prior, LD and Eamus, D and Duff, GA, Seasonal trends in carbon assimilation, stomatal conductance, pre-dawn leaf water potential and growth in Terminalia ferdinandiana, a deciduous tree of northern Australian savannas, Australian Journal of Botany, 45, (1) pp. 53-69. ISSN 0067-1924 (1997) [Refereed Article]


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Copyright Statement

Copyright © 1997 CSIRO

DOI: doi:10.1071/BT96065

Abstract

Seasonal trends in pre-dawn leaf water potential and morning and afternoon rates of light-saturated assimilation and stomatal conductance were studied in saplings of the deciduous tree Terminalia ferdinandiana Excell. Mean daily maximum assimilation rates ranged from 11 µmol m-2 s-1 in the wet season to 8 µmol m-2 s-1 during the transition from the wet to the dry season. Saplings were without leaves from June to October inclusive (dry season). There was a log–linear relationship between stomatal conductance and pre-dawn leaf water potential (r = 0.76, n = 325), and a weak linear relationship between daily maximum assimilation and pre-dawn leaf water potential (r = 0.39, n = 184). Assimilation rates were higher in the morning than in the afternoon in April and May, but were similar throughout the day from December to March. Seasonal trends in assimilation could be attributed primarily to stomatal closure, but diurnal differences could not. High leaf temperatures may have been responsible for observed lower assimilation rates in the afternoon in April and May. Assimilation and stomatal conductance decreased when leaf temperatures rose above 38˚C and/or the leaf-to-air vapour pressure difference exceeded 4–4.5 kPa. Pre-dawn leaf water potentials decreased more quickly, and stomatal conductance was more sensitive to this decrease, in T. ferdinandiana saplings than in saplings of Eucalyptus tetrodonta F.Muell. a co-occurring evergreen tree. Specific leaf area and assimilation per unit dry weight were higher in T. ferdinandiana than in E. tetrodonta which is consistent with other studies of costs and benefits of deciduousness.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Forest and Woodlands Flora, Fauna and Biodiversity
Author:Prior, LD (Dr Lynda Prior)
ID Code:72718
Year Published:1997
Web of Science® Times Cited:50
Deposited By:Research Division
Deposited On:2011-08-31
Last Modified:2011-09-29
Downloads:2 View Download Statistics

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