title: A leaf gas exchange model that accounts for intra-canopy variability by considering leaf nitrogen content and local acclimation to radiation in grapevine (Vitis vinifera L.).
abstract: Understanding the distribution of gas exchange within a plant is a prerequisite for scaling up from leaves to canopies. We evaluated whether leaf traits were reliable predictors of the effects of leaf ageing and leaf irradiance on leaf photosynthetic capacity (V(cmax) , J(max) ) in field-grown vines (Vitis vinifera L). Simultaneously, we measured gas exchange, leaf mass per area (LMA) and nitrogen content (N(m) ) of leaves at different positions within the canopy and at different phenological stages. Daily mean leaf irradiance cumulated over 10 d (PPFD(10) ) was obtained by 3D modelling of the canopy structure. N(m) decreased over the season in parallel to leaf ageing while LMA was mainly affected by leaf position. PPFD(10) explained 66, 28 and 73% of the variation of LMA, N(m) and nitrogen content per area (N(a) ), respectively. Nitrogen content per unit area (N(a) = LMA × N(m) ) was the best predictor of the intra-canopy variability of leaf photosynthetic capacity. Finally, we developed a classical photosynthesis-stomatal conductance submodel and by introducing N(a) as an input, the model accurately simulated the daily pattern of gas exchange for leaves at different positions in the canopy and at different phenological stages during the season.
authors.affiliation: INRA Montpellier SupAgro, UMR759 LEPSE, 2 place Viala, F-34060 Montpellier Cedex 01, France. jprieto@mendoza.inta.gov.ar
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Prieto
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Louarn
authors.forename: Jorge
authors.initials: J
authors.lastname: Perez Peña
authors.forename: Hernán
authors.initials: H
authors.lastname: Ojeda
authors.forename: Thierry
authors.initials: T
authors.lastname: Simonneau
authors.forename: Eric
authors.initials: E
authors.lastname: Lebon
mesh_terms: D000064:Acclimatization; D008954:Models, Biological; D009584:Nitrogen / Q000032:analysis*; D010788:Photosynthesis; D018515:Plant Leaves / Q000528:radiation effects*; D054046:Plant Stomata / Q000528:radiation effects; D018526:Plant Transpiration; D027843:Vitis / Q000528:radiation effects*
chemical_list: D009584:Nitrogen