title: Linking nonstructural carbohydrate dynamics to gas exchange and leaf hydraulic behavior in Pinus edulis and Juniperus monosperma.
abstract: Leaf hydraulics, gas exchange and carbon storage in Pinus edulis and Juniperus monosperma, two tree species on opposite ends of the isohydry-anisohydry spectrum, were analyzed to examine relationships between hydraulic function and carbohydrate dynamics. Leaf hydraulic vulnerability, leaf water potential (Ψl ), leaf hydraulic conductance (Kleaf ), photosynthesis (A), stomatal conductance (gs) and nonstructural carbohydrate (NSC) content were analyzed throughout the growing season. Leaf hydraulic vulnerability was significantly lower in the relatively anisohydric J. monosperma than in the more isohydric P. edulis. In P. edulis, Ψl dropped and stayed below 50% loss of leaf hydraulic conductance (P₅₀) early in the day during May, August and around midday in September, leading to sustained reductions in Kleaf . In J. monosperma, Ψl dropped below P₅₀ only during August, resulting in the maintenance of Kleaf during much of the growing season. Mean A and gs during September were significantly lower in P. edulis than in J. monosperma. Foliar total NSC was two to three times greater in J. monosperma than in P. edulis in June, August and September. Consistently lower levels of total NSC in P. edulis suggest that its isohydric strategy pushes it towards the exhaustion of carbon reserves during much of the growing season.
authors.affiliation: USDA Forest Service, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Woodruff
authors.affiliation: USDA Forest Service, PNW Research Station, 3200 SW Jefferson Way, Corvallis, OR, 97331, USA.
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Meinzer
authors.affiliation: College for Forestry, Oregon State University, Corvallis, OR, 97331, USA.
authors.forename: Danielle E
authors.initials: DE
authors.lastname: Marias
authors.affiliation: Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
authors.forename: Sanna
authors.initials: S
authors.lastname: Sevanto
authors.affiliation: Department of Environmental Studies, University of California, Santa Cruz, CA, 95064, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Jenkins
authors.affiliation: Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
authors.forename: Nate G
authors.initials: NG
authors.lastname: McDowell
mesh_terms: D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism; D018653:Juniperus / Q000502:physiology*; D010788:Photosynthesis; D028223:Pinus / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology*; D012621:Seasons; D014197:Trees; D014867:Water / Q000502:physiology
chemical_list: D014867:Water; D002244:Carbon
keywords: Juniperus monosperma; Pinus edulis; carbon starvation; carbon storage; drought; growth limitation; leaf hydraulics; nonstructural carbohydrate (NSC)