title: Carbon Isotope Composition of Carbohydrates and Polyols in Leaf and Phloem Sap of Phaseolus vulgaris L. Influences Predictions of Plant Water Use Efficiency.
abstract: The use of carbon isotope abundance (δ(13)C) to assess plant carbon acquisition and water use has significant potential for use in crop management and plant improvement programs. Utilizing Phaseolus vulgaris L. as a model system, this study demonstrates the occurrence and sensitivity of carbon isotope fractionation during the onset of abiotic stresses between leaf and phloem carbon pools. In addition to gas exchange data, compound-specific measures of carbon isotope abundance and concentrations of soluble components of phloem sap were compared with major carbohydrate and sugar alcohol pools in leaf tissue. Differences in both δ(13)C and concentration of metabolites were found in leaf and phloem tissues, the magnitude of which responded to changing environmental conditions. These changes have inplications for the modeling of leaf-level gas exchange based upon δ(13)C natural abundance. Estimates of δ(13)C of low molecular weight carbohydrates and polyols increased the precision of predictions of water use efficiency compared with those based on bulk soluble carbon. The use of this technique requires consideration of the dynamics of the δ(13)C pool under investigation. Understanding the dynamics of changes in δ(13)C during movement and incorporation into heterotrophic tissues is vital for the continued development of tools that provide information on plant physiological performance relating to water use.
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture and Environment, The University of Sydney, Sydney NSW, Australia 2006.
authors.forename: Millicent
authors.initials: M
authors.lastname: Smith
authors.affiliation: Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria 1090.
authors.forename: Birgit
authors.initials: B
authors.lastname: Wild
authors.affiliation: Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria 1090.
authors.forename: Andreas
authors.initials: A
authors.lastname: Richter
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture and Environment, The University of Sydney, Sydney NSW, Australia 2006 Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Simonin
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture and Environment, The University of Sydney, Sydney NSW, Australia 2006 andrew.merchant@sydney.edu.au.
authors.forename: Andrew
authors.initials: A
authors.lastname: Merchant
mesh_terms: D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D002244:Carbon / Q000032:analysis / Q000378:metabolism; D002247:Carbon Isotopes / Q000032:analysis; D004777:Environment; D027805:Phaseolus / Q000737:chemistry / Q000378:metabolism*; D052585:Phloem / Q000737:chemistry / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D002247:Carbon Isotopes; D011108:Polymers; C024617:polyol; D014867:Water; D002244:Carbon
keywords: Carbon; Growth; Isotopes; Natural abundance; Water; Yield