title: The relationship of leaf photosynthetic traits - V cmax and J max - to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modeling study.
abstract: Great uncertainty exists in the global exchange of carbon between the atmosphere and the terrestrial biosphere. An important source of this uncertainty lies in the dependency of photosynthesis on the maximum rate of carboxylation (V cmax) and the maximum rate of electron transport (J max). Understanding and making accurate prediction of C fluxes thus requires accurate characterization of these rates and their relationship with plant nutrient status over large geographic scales. Plant nutrient status is indicated by the traits: leaf nitrogen (N), leaf phosphorus (P), and specific leaf area (SLA). Correlations between V cmax and J max and leaf nitrogen (N) are typically derived from local to global scales, while correlations with leaf phosphorus (P) and specific leaf area (SLA) have typically been derived at a local scale. Thus, there is no global-scale relationship between V cmax and J max and P or SLA limiting the ability of global-scale carbon flux models do not account for P or SLA. We gathered published data from 24 studies to reveal global relationships of V cmax and J max with leaf N, P, and SLA. V cmax was strongly related to leaf N, and increasing leaf P substantially increased the sensitivity of V cmax to leaf N. J max was strongly related to V cmax, and neither leaf N, P, or SLA had a substantial impact on the relationship. Although more data are needed to expand the applicability of the relationship, we show leaf P is a globally important determinant of photosynthetic rates. In a model of photosynthesis, we showed that at high leaf N (3 gm(-2)), increasing leaf P from 0.05 to 0.22 gm(-2) nearly doubled assimilation rates. Finally, we show that plants may employ a conservative strategy of J max to V cmax coordination that restricts photoinhibition when carboxylation is limiting at the expense of maximizing photosynthetic rates when light is limiting.
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield Alfred Denny Building, Western Bank, Sheffield, S10 2TN, UK ; Environmental Sciences Division, Climate Change Science Institute, Oak Ridge National Laboratory Oak Ridge, Tennessee, 37831-6301.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Walker
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield Alfred Denny Building, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Beckerman
authors.affiliation: Environmental Sciences Division, Climate Change Science Institute, Oak Ridge National Laboratory Oak Ridge, Tennessee, 37831-6301.
authors.forename: Lianhong
authors.initials: L
authors.lastname: Gu
authors.affiliation: Max Plank Institute for Biogeochemistry Jena, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kattge
authors.affiliation: Department of Marine and Tropical Biology Cairns, James Cook University Cairns, Queensland, 4878, Australia.
authors.forename: Lucas A
authors.initials: LA
authors.lastname: Cernusak
authors.affiliation: Depto. de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto Av. Bandeirantes, 3900 - CEP, 14040-901, Ribeirão Preto, Brasil.
authors.forename: Tomas F
authors.initials: TF
authors.lastname: Domingues
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research Harpenden, Herts, AL5 2JQ, UK.
authors.forename: Joanna C
authors.initials: JC
authors.lastname: Scales
authors.affiliation: University of Innsbruck, Institute of Ecology Sternwartestrasse 15, 6020, Innsbruck, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Wohlfahrt
authors.affiliation: Environmental Sciences Division, Climate Change Science Institute, Oak Ridge National Laboratory Oak Ridge, Tennessee, 37831-6301.
authors.forename: Stan D
authors.initials: SD
authors.lastname: Wullschleger
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield Alfred Denny Building, Western Bank, Sheffield, S10 2TN, UK.
authors.forename: F Ian
authors.initials: FI
authors.lastname: Woodward
keywords: Carbon assimilation; DGVM; Farquhar model; TBM; carbon cycle; carboxylation; electron transport; land surface model; meta-analysis; mixed-effect multiple regression; noncarbon photosynthesis