Influence of leaf water potential on diurnal changes in CO<inf>2</inf> and water vapour fluxes

Yu, Q; Xu, S; Wang, J; Lee, X

Influence of leaf water potential on diurnal changes in CO<inf>2</inf> and water vapour fluxes

Yu, Q

Xu, S Wang, J Lee, X

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Publication Type:: Journal Article
Citation:: Boundary-Layer Meteorology, 2007, 124 (2), pp. 161 - 181
Issue Date:: 2007-08-01

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Field	Value	Language
dc.contributor.author	Yu, Q https://orcid.org/0000-0001-6950-1821	en_US
dc.contributor.author	Xu, S	en_US
dc.contributor.author	Wang, J	en_US
dc.contributor.author	Lee, X	en_US
dc.date.issued	2007-08-01	en_US
dc.identifier.citation	Boundary-Layer Meteorology, 2007, 124 (2), pp. 161 - 181	en_US
dc.identifier.issn	0006-8314	en_US
dc.identifier.uri	http://hdl.handle.net/10453/8525
dc.description.abstract	Mass and energy fluxes between the atmosphere and vegetation are driven by meteorological variables, and controlled by plant water status, which may change more markedly diurnally than soil water. We tested the hypothesis that integration of dynamic changes in leaf water potential may improve the simulation of CO2 and water fluxes over a wheat canopy. Simulation of leaf water potential was integrated into a comprehensive model (the ChinaAgrosys) of heat, water and CO2 fluxes and crop growth. Photosynthesis from individual leaves was integrated to the canopy by taking into consideration the attenuation of radiation when penetrating the canopy. Transpiration was calculated with the Shuttleworth-Wallace model in which canopy resistance was taken as a link between energy balance and physiological regulation. A revised version of the Ball-Woodrow-Berry stomatal model was applied to produce a new canopy resistance model, which was validated against measured CO2 and water vapour fluxes over winter wheat fields in Yucheng (36°57′ N, 116°36′ E, 28 m above sea level) in the North China Plain during 1997, 2001 and 2004. Leaf water potential played an important role in causing stomatal conductance to fall at midday, which caused diurnal changes in photosynthesis and transpiration. Changes in soil water potential were less important. Inclusion of the dynamics of leaf water potential can improve the precision of the simulation of CO2 and water vapour fluxes, especially in the afternoon under water stress conditions. © Springer Science+Business Media, B.V. 2007.	en_US
dc.relation.ispartof	Boundary-Layer Meteorology	en_US
dc.relation.isbasedon	10.1007/s10546-007-9164-y	en_US
dc.subject.classification	Meteorology & Atmospheric Sciences	en_US
dc.title	Influence of leaf water potential on diurnal changes in CO<inf>2</inf> and water vapour fluxes	en_US
dc.type	Journal Article
utslib.citation.volume	2	en_US
utslib.citation.volume	124	en_US
utslib.for	0401 Atmospheric Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	2	en_US
pubs.publication-status	Published	en_US
pubs.volume	124	en_US

Abstract:

Mass and energy fluxes between the atmosphere and vegetation are driven by meteorological variables, and controlled by plant water status, which may change more markedly diurnally than soil water. We tested the hypothesis that integration of dynamic changes in leaf water potential may improve the simulation of CO2 and water fluxes over a wheat canopy. Simulation of leaf water potential was integrated into a comprehensive model (the ChinaAgrosys) of heat, water and CO2 fluxes and crop growth. Photosynthesis from individual leaves was integrated to the canopy by taking into consideration the attenuation of radiation when penetrating the canopy. Transpiration was calculated with the Shuttleworth-Wallace model in which canopy resistance was taken as a link between energy balance and physiological regulation. A revised version of the Ball-Woodrow-Berry stomatal model was applied to produce a new canopy resistance model, which was validated against measured CO2 and water vapour fluxes over winter wheat fields in Yucheng (36°57′ N, 116°36′ E, 28 m above sea level) in the North China Plain during 1997, 2001 and 2004. Leaf water potential played an important role in causing stomatal conductance to fall at midday, which caused diurnal changes in photosynthesis and transpiration. Changes in soil water potential were less important. Inclusion of the dynamics of leaf water potential can improve the precision of the simulation of CO2 and water vapour fluxes, especially in the afternoon under water stress conditions. © Springer Science+Business Media, B.V. 2007.

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http://hdl.handle.net/10453/8525