title: Evidence of a universal scaling relationship for leaf CO2 drawdown along an aridity gradient.
abstract: The leaf carbon isotope ratio (δ(13) C) of C3 plants is inversely related to the drawdown of CO2 concentration during photosynthesis, which increases towards drier environments. We aimed to discriminate between the hypothesis of universal scaling, which predicts between-species responses of δ(13) C to aridity similar to within-species responses, and biotic homoeostasis, which predicts offsets in the δ(13) C of species occupying adjacent ranges. The Northeast China Transect spans 130-900 mm annual precipitation within a narrow latitude and temperature range. Leaves of 171 species were sampled at 33 sites along the transect (18 at ≥ 5 sites) for dry matter, carbon (C) and nitrogen (N) content, specific leaf area (SLA) and δ(13) C. The δ(13) C of species generally followed a common relationship with the climatic moisture index (MI). Offsets between adjacent species were not observed. Trees and forbs diverged slightly at high MI. In C3 plants, δ(13) C predicted N per unit leaf area (Narea) better than MI. The δ(13) C of C4 plants was invariant with MI. SLA declined and Narea increased towards low MI in both C3 and C4 plants. The data are consistent with optimal stomatal regulation with respect to atmospheric dryness. They provide evidence for universal scaling of CO2 drawdown with aridity in C3 plants.
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.|Grantham Institute and Division of Biology, Imperial College, Silwood Park, Ascot SL5 7PY, UK.|State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.
authors.forename: I Colin
authors.initials: IC
authors.lastname: Prentice
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Meng
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.|State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.|State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.|School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK.
authors.forename: Sandy P
authors.initials: SP
authors.lastname: Harrison
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.|Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany.
authors.forename: Jian
authors.initials: J
authors.lastname: Ni
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan Nanxincun 20, 100093 Beijing, China.
authors.forename: Guohong
authors.initials: G
authors.lastname: Wang
mesh_terms: D018533:Biomass; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes; D002681:China; D002980:Climate; D003889:Desert Climate; D005843:Geography; D006813:Humidity; D018515:Plant Leaves / Q000502:physiology*; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D013045:Species Specificity; D013696:Temperature; D014867:Water
chemical_list: D002247:Carbon Isotopes; D014867:Water; D002245:Carbon Dioxide; D002244:Carbon