title: Significant Difference in Hydrogen Isotope Composition Between Xylem and Tissue Water in Populus Euphratica.
abstract: Deuterium depletions between stem water and source water have been observed in coastal halophyte plants and in multiple species under greenhouse conditions. However, the location(s) of the isotope fractionation is not clear yet and it is uncertain whether deuterium fractionation appears in other natural environments. In this study, through two extensive field campaigns utilizing a common dryland riparian tree species Populus euphratica Oliv., we showed that no significant δ(18) O differences were found between water source and various plant components, in accord with previous studies. We also found that no deuterium fractionation occurred during P. euphratica water uptake by comparing the deuterium composition (δD) of groundwater and xylem sap. However, remarkable δD differences (up to 26.4‰) between xylem sap and twig water, root water and core water provided direct evidence that deuterium fractionation occurred between xylem sap and root or stem tissue water. This study indicates that deuterium fractionation could be a common phenomenon in drylands, which has important implications in plant water source identification, palaeoclimate reconstruction based on wood cellulose and evapotranspiration partitioning using δD of stem water.
authors.affiliation: College of Urban and Environmental Sciences, Northwest University, Xi'an, 710069, China.|Key Laboratory of Ecohydrology and Integrated River Basin Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Liangju
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN, 46202, USA.
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Marine and Environmental Sciences, James Cook University, Cairns, Queensland, Australia.
authors.forename: Lucas A
authors.initials: LA
authors.lastname: Cernusak
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ecohydrology and Integrated River Basin Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Honglang
authors.initials: H
authors.lastname: Xiao
authors.affiliation: School of Agriculture and Forestry Economics and Management, Lanzhou University of Finance and Economics, Lanzhou, 730101, China.
authors.forename: Maoxian
authors.initials: M
authors.lastname: Zhou
authors.affiliation: College of Urban and Environmental Sciences, Northwest University, Xi'an, 710069, China.
authors.forename: Shiqiang
authors.initials: S
authors.lastname: Zhang
mesh_terms: D003903:Deuterium / Q000378:metabolism*; D060587:Groundwater / Q000737:chemistry; D010103:Oxygen Isotopes / Q000032:analysis / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D032107:Populus / Q000378:metabolism*; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism*
chemical_list: D010103:Oxygen Isotopes; D014867:Water; D003903:Deuterium
keywords: drylands; groundwater; hydrogen isotope; oxygen isotope; water source; xylem sap