title: A test of the 'one-point method' for estimating maximum carboxylation capacity from field-measured, light-saturated photosynthesis.
abstract: Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate (Vcmax ). Estimating this parameter using A-Ci curves (net photosynthesis, A, vs intercellular CO2 concentration, Ci ) is laborious, which limits availability of Vcmax data. However, many multispecies field datasets include net photosynthetic rate at saturating irradiance and at ambient atmospheric CO2 concentration (Asat ) measurements, from which Vcmax can be extracted using a 'one-point method'. We used a global dataset of A-Ci curves (564 species from 46 field sites, covering a range of plant functional types) to test the validity of an alternative approach to estimate Vcmax from Asat via this 'one-point method'. If leaf respiration during the day (Rday ) is known exactly, Vcmax can be estimated with an r(2) value of 0.98 and a root-mean-squared error (RMSE) of 8.19 μmol m(-2) s(-1) . However, Rday typically must be estimated. Estimating Rday as 1.5% of Vcmax, we found that Vcmax could be estimated with an r(2) of 0.95 and an RMSE of 17.1 μmol m(-2) s(-1) . The one-point method provides a robust means to expand current databases of field-measured Vcmax , giving new potential to improve vegetation models and quantify the environmental drivers of Vcmax variation.
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Martin G
authors.initials: MG
authors.lastname: De Kauwe
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Yan-Shih
authors.identifier: http://orcid.org/0000-0003-3177-5186
authors.initials: YS
authors.lastname: Lin
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Wright
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
authors.forename: Belinda E
authors.initials: BE
authors.lastname: Medlyn
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.|Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, B15 2TT, UK.
authors.forename: Kristine Y
authors.initials: KY
authors.lastname: Crous
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
authors.forename: David S
authors.initials: DS
authors.lastname: Ellsworth
authors.affiliation: Université du Québec à Trois-Rivières, Trois-Rivières, QC, G9A 5H7, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Maire
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.|AXA Chair of Biosphere and Climate Impacts, Grand Challenges in Ecosystems and the Environment and Grantham Institute - Climate Change and the Environment, Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK.
authors.forename: I Colin
authors.initials: IC
authors.lastname: Prentice
authors.affiliation: ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Building 134, Canberra, ACT, 2601, Australia.
authors.forename: Owen K
authors.initials: OK
authors.lastname: Atkin
authors.affiliation: Biological, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.
authors.forename: Alistair
authors.initials: A
authors.lastname: Rogers
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia.|Estonian Academy of Sciences, Kohtu 6, 10130, Tallinn, Estonia.
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Niinemets
authors.affiliation: Biological, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.
authors.forename: Shawn P
authors.initials: SP
authors.lastname: Serbin
authors.affiliation: Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia.|School of Geosciences, University of Edinburgh, Edinburgh, EH9 3JN, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Meir
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, SE-40530, Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Uddling
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia.|Terrestrial Ecosystem Research Network, Ecosystem Modelling and Scaling Infrastructure, The University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Henrique F
authors.initials: HF
authors.lastname: Togashi
authors.affiliation: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83, Umeå, Sweden.
authors.forename: Lasse
authors.initials: L
authors.lastname: Tarvainen
authors.affiliation: ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Building 134, Canberra, ACT, 2601, Australia.|Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400, Sri Lanka.
authors.forename: Lasantha K
authors.initials: LK
authors.lastname: Weerasinghe
authors.affiliation: Terrestrial Ecosystem Research Network, Ecosystem Modelling and Scaling Infrastructure, The University of Sydney, Sydney, NSW, 2006, Australia.|Department of Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Evans
authors.affiliation: College of Marine and Environmental Sciences, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, 4870, Australia.
authors.forename: F Yoko
authors.initials: FY
authors.lastname: Ishida
authors.affiliation: Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av Bandeirantes, 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Tomas F
authors.initials: TF
authors.lastname: Domingues
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D019069:Cell Respiration; D019992:Databases as Topic; D007700:Kinetics; D008027:Light; D010788:Photosynthesis / Q000528:radiation effects*; D054046:Plant Stomata / Q000502:physiology; D010944:Plants / Q000378:metabolism*; D013696:Temperature
chemical_list: D002245:Carbon Dioxide
keywords: A-Ci curve; leaf respiration during the day (Rday); maximum carboxylation rate (Vcmax); net photosynthetic rate at saturating irradiance and at ambient atmospheric CO2 concentration (Asat)