Effects of elevated atmospheric (CO2) on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna

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dc.contributor.author Barton, Craig en_US
dc.contributor.author Duursma, Ra en_US
dc.contributor.author Medlyn, Belinda en_US
dc.contributor.author Ellsworth, David en_US
dc.contributor.author Eamus, Derek en_US
dc.contributor.author Tissue, David en_US
dc.contributor.author Adams, Mark en_US
dc.contributor.author Conroy, Jann en_US
dc.contributor.author Crous, Ky en_US
dc.contributor.author Liberloo, Marion en_US
dc.contributor.author Low, Marcus en_US
dc.contributor.author Linder, S en_US
dc.contributor.author Mcmurtrie, Ross en_US
dc.contributor.editor en_US
dc.date.accessioned 2012-10-12T03:33:17Z
dc.date.available 2012-10-12T03:33:17Z
dc.date.issued 2011 en_US
dc.identifier 2010005686 en_US
dc.identifier.citation Barton Craig et al. 2011, 'Effects of elevated atmospheric (CO2) on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna', Blackwell, vol. 17, en_US
dc.identifier.issn 1354-1013 en_US
dc.identifier.other C5 en_US
dc.identifier.uri http://hdl.handle.net/10453/18094
dc.description.abstract Rising atmospheric concentrations of CO2 (Ca) can reduce stomatal conductance and transpiration rate in trees, but the magnitude of this effect varies considerably among experiments. The theory of optimal stomatal behaviour predicts that the ratio of photosynthesis to transpiration (instantaneous transpiration efficiency, ITE) should increase in proportion to Ca. We hypothesized that plants regulate stomatal conductance optimally in response to rising Ca. We tested this hypothesis with data from young Eucalyptus saligna Sm. trees grown in 12 climate-controlled whole-tree chambers for 2 years at ambient and elevated Ca. Elevated Ca was ambient + 240 ppm, 60% higher than ambient Ca. Leaf-scale gas exchange was measured throughout the second year of the study and leaf-scale ITE increased by 60% under elevated Ca, as predicted. Values of leaf-scale ITE depended strongly on vapour pressure deficit (D) in both CO2 treatments. Whole-canopy CO2 and H2O fluxes were also monitored continuously for each chamber throughout the second year. There were small differences in D between Ca treatments, which had important effects on values of canopy-scale ITE. However, when Ca treatments were compared at the same D, canopy-scale ITE was consistently increased by 60%, again as predicted. Importantly, leaf and canopy-scale ITE were not significantly different, indicating that ITE was not scale-dependent. Observed changes in transpiration rate could be explained on the basis that ITE increased in proportion to Ca. The effect of elevated Ca on photosynthesis increased with rising D. At high D, Ca had a large effect on photosynthesis and a small effect on transpiration rate. At low D, in contrast, there was a small effect of Ca on photosynthesis, but a much larger effect on transpiration rate. If shown to be a general response, the proportionality of ITE with Ca will allow us to predict the effects of Ca on transpiration rate. en_US
dc.language en_US
dc.publisher Blackwell en_US
dc.relation.isbasedon http://dx.doi.org/10.1111/j.1365-2486.2011.02526.x en_US
dc.title Effects of elevated atmospheric (CO2) on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna en_US
dc.parent Global Change Biology en_US
dc.journal.volume 17 en_US
dc.journal.number en_US
dc.publocation UK en_US
dc.identifier.startpage en_US
dc.identifier.endpage en_US
dc.cauo.name SCI.Faculty of Science en_US
dc.conference Verified OK en_US
dc.for 050200 en_US
dc.personcode 0000022185 en_US
dc.personcode 0000064499 en_US
dc.personcode 0000028481 en_US
dc.personcode 0000064498 en_US
dc.personcode 0000027039 en_US
dc.personcode 0000070973 en_US
dc.personcode 0000027030 en_US
dc.personcode 0000069900 en_US
dc.personcode 0000070979 en_US
dc.personcode 0000070980 en_US
dc.personcode 0000064501 en_US
dc.personcode 0000027029 en_US
dc.percentage 100 en_US
dc.classification.name Environmental Science and Management en_US
dc.classification.type FOR-08 en_US
dc.edition en_US
dc.custom en_US
dc.date.activity en_US
dc.location.activity en_US
dc.description.keywords elevated carbon dioxide, Eucalyptus, transpiration efficiency, water-use efficiency, whole -tree chambers en_US

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