title: Hydraulic basis for the evolution of photosynthetic productivity.
abstract: Clarifying the evolution and mechanisms for photosynthetic productivity is a key to both improving crops and understanding plant evolution and habitat distributions. Current theory recognizes a role for the hydraulics of water transport as a potential determinant of photosynthetic productivity based on comparative data across disparate species. However, there has never been rigorous support for the maintenance of this relationship during an evolutionary radiation. We tested this theory for 30 species of Viburnum, diverse in leaf shape and photosynthetic anatomy, grown in a common garden. We found strong support for a fundamental requirement for leaf hydraulic capacity (Kleaf) in determining photosynthetic capacity (Amax), as these traits diversified across this lineage in tight coordination, with their proportionality modulated by the climate experienced in the species' range. Variation in Kleaf arose from differences in venation architecture that influenced xylem and especially outside-xylem flow pathways. These findings substantiate an evolutionary basis for the coordination of hydraulic and photosynthetic physiology across species, and their co-dependence on climate, establishing a fundamental role for water transport in the evolution of the photosynthetic rate.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, California 90095, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Scoffoni
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Box G-W, 80 Waterman St., Providence, Rhode Island 02912, USA.|Department of Ecology and Evolutionary Biology, Yale University, PO Box 208106, New Haven, Connecticut, 06520-8106, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Chatelet
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, California 90095, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Pasquet-Kok
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, California 90095, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rawls
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, PO Box 208106, New Haven, Connecticut, 06520-8106, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Donoghue
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, Box G-W, 80 Waterman St., Providence, Rhode Island 02912, USA.
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Edwards
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, California 90095, USA.
authors.forename: Lawren
authors.initials: L
authors.lastname: Sack
mesh_terms: D052818:Autotrophic Processes; D005075:Biological Evolution; D017753:Ecosystem; D010788:Photosynthesis; D018526:Plant Transpiration; D013045:Species Specificity; D027925:Viburnum / Q000502:physiology*