Photosynthetic physiology of eucalypts along a sub-continental rainfall gradient in northern Australia

Photosynthetic physiology of eucalypts along a sub-continental rainfall gradient in northern Australia

Title
Publication TypeJournal Article
Year of Publication2011
AuthorsCernusak, LA, Cernusak, LA, Assoc Prof Hutley, LB, Beringer, J, Holtum, JAM, Turner, BL
JournalAgricultural and Forest Meteorology
Volume151
Pagination1462-1470
ISBN Number0168-1923
Keywordscarbon-isotope discrimination, Leaf mass per area, Photosynthetic capacity, rainfall gradient, savanna
Abstract

Leaf-level photosynthetic parameters of species in the closely related genera Eucalyptus and Corymbia were assessed along a strong rainfall gradient in northern Australia. Both instantaneous gas exchange measurements and leaf carbon isotope discrimination indicated little variation in intercellular CO2 concentrations during photosynthesis (ci) in response to a decrease in mean annual precipitation from ∼1700 mm to ∼300 mm. Correlation between stomatal conductance and photosynthetic capacity contributed toward the maintenance of relatively constant ci among the sampled leaves, when assessed at ambient CO2 concentration and photon irradiance similar to full sunlight. Leaf mass per area was the most plastic leaf trait along the rainfall gradient, showing a linear increase in response to decreasing mean annual precipitation. The maximum Rubisco carboxylation velocity, Vcmax, expressed on a leaf-area basis, showed a modest increase in response to decreasing rainfall. This modest increase in Vcmax was associated with the strongly expressed increase in leaf mass per area. These results suggest that variation in ecosystem-level gas exchange during the dry season in north-Australian savannas will likely be dominated by changes in leaf area index in response to increasing aridity, rather than by changes in photosynthetic performance per unit leaf area.

Publications

RIEL Headlines

Pages

Jump to NRBL themeJump to CMEM themeJump to FEM themeJump to SMWC themeJump to TRF themeJump to RIEL home

Innovative Research University

© 2011-2013 Charles Darwin University
Research Institute for the Environment and Livelihoods
Privacy Policy
CRICOS Provider No. 00300K | RTO Provider No. 0373

Phone (+61) 8 8946 6413
Email riel@cdu.edu.au