title: Stomatal CO2responsiveness and photosynthetic capacity of tropical woody species in relation to taxonomy and functional traits.
abstract: Stomatal CO2responsiveness and photosynthetic capacity vary greatly among plant species, but the factors controlling these physiological leaf traits are often poorly understood. To explore if these traits are linked to taxonomic group identity and/or to other plant functional traits, we investigated the short-term stomatal CO2responses and the maximum rates of photosynthetic carboxylation (Vcmax) and electron transport (Jmax) in an evolutionary broad range of tropical woody plant species. The study included 21 species representing four major seed plant taxa: gymnosperms, monocots, rosids and asterids. We found that stomatal closure responses to increased CO2were stronger in angiosperms than in gymnosperms, and in monocots compared to dicots. Stomatal CO2responsiveness was not significantly related to any of the other functional traits investigated, while a parameter describing the relationship between photosynthesis and stomatal conductance in combined leaf gas exchange models (g1) was related to leaf area-specific plant hydraulic conductance. For photosynthesis, we found that the interspecific variation in Vcmaxand Jmaxwas related to within leaf nitrogen (N) allocation rather than to area-based total leaf N content. Within-leaf N allocation and water use were strongly co-ordinated (r2= 0.67), such that species with high fractional N investments into compounds maximizing photosynthetic capacity also had high stomatal conductance. We conclude that while stomatal CO2responsiveness of tropical woody species seems poorly related to other plant functional traits, photosynthetic capacity is linked to fractional within-leaf N allocation rather than total leaf N content and is closely co-ordinated with leaf water use.
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30, Gothenburg, Sweden.
authors.forename: Thomas B
authors.identifier: 0000-0002-9532-845X
authors.initials: TB
authors.lastname: Hasper
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30, Gothenburg, Sweden.|Department of Biology, University of Rwanda, University Avenue, PO Box 56, Huye, Rwanda.
authors.forename: Mirindi E
authors.initials: ME
authors.lastname: Dusenge
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30, Gothenburg, Sweden.
authors.forename: Friederike
authors.initials: F
authors.lastname: Breuer
authors.affiliation: Department of Biology, University of Rwanda, University Avenue, PO Box 56, Huye, Rwanda.
authors.forename: Félicien K
authors.initials: FK
authors.lastname: Uwizeye
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30, Gothenburg, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Wallin
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, 405 30, Gothenburg, Sweden. johan.uddling@bioenv.gu.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Uddling
mesh_terms: D002245:Carbon Dioxide; D009584:Nitrogen; D010788:Photosynthesis; D018515:Plant Leaves; D014197:Trees; D014934:Wood
chemical_list: D002245:Carbon Dioxide; D009584:Nitrogen
keywords: Carbon dioxide; Leaf traits; Stomatal patterning; Transpiration; Tropical trees