An explanation for the isotopic offset between soil and stem water in a temperate tree species

Autor: Lisa Wingate, Bastien Fréjaville, Adrià Barbeta, Sam P. Jones, Laura Clavé, Camille Delvigne, Teresa E. Gimeno, Jérôme Ogée
Přispěvatelé: Interactions Sol Plante Atmosphère (UMR ISPA), Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Barcelonne, Ikerbasque - Basque Foundation for Science, ANR-10-LABX-0045,COTE,COntinental To coastal Ecosystems: evolution, adaptability and governance(2010), ANR-13-BS06-0005,ORCA,Etude des mécanismes de régulation de l'anhydrase carbonique et des flux de COS et CO18O dans les écosystèmes terrestres(2013), European Commission, Aquitaine Region, French national research agency, FP7/2007, French national programme EC2CO-Biohefect, European Research Council, IdEx Bordeaux, EU Seventh Framework Program, ANR-13-BS06-0005-01
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: New Phytologist
New Phytologist, Wiley, 2020, 227 (3), pp.766-779. ⟨10.1111/nph.16564⟩
Addi. Archivo Digital para la Docencia y la Investigación
instname
Addi: Archivo Digital para la Docencia y la Investigación
Universidad del País Vasco
ISSN: 0028-646X
1469-8137
DOI: 10.1111/nph.16564⟩
Popis: A growing number of field studies report isotopic offsets between stem water and its potential sources that prevent the unambiguous identification of plant water origin using water isotopes. We explored the causes of this isotopic offset by conducting a controlled experiment on the temperate tree species Fagus sylvatica. We measured d2H and d18O of soil and stem water from potted saplings growing on three soil substrates and subjected to two watering regimes. Regardless of substrate, soil and stem water d2H were similar only near permanent wilting point. Under moister conditions, stem water d2H was 11 ± 3 more negative than soil water d2H, coherent with field studies. Under drier conditions, stem water d2H became progressively more enriched than soil water d2H. Although stem water d18O broadly reflected that of soil water, soil stem d2H and d18O differences were correlated (r = 0.76) and increased with transpiration rates indicated by proxies. Soil stem isotopic offsets are more likely to be caused by water isotope heterogeneities within the soil pore and stem tissues, which would be masked under drier conditions as a result of evaporative enrichment, than by fractionation under root water uptake. Our results challenge our current understanding of isotopic signals in the soil plant continuum. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trust This work was supported by the French national programme EC2CO-Biohefect (RootWater), the French national research agency (projects Hydrobeech, Climbeech and Micromic within the Cluster of Excellence COTE with grant agreement ANR-10-LABX-45; project ORCA with grant agreement ANR-13-BS06-0005-01), the European Research Council (ERC) under the EU Seventh Framework Program (FP7/2007-2013, with grant agreement no. 338264, awarded to LW) and the Aquitaine Region (project Athene with grant agreement 2016-1R20301-00007218). AB also acknowledges an IdEx Bordeaux postdoctoral fellowship from the Universite de Bordeaux (contract no. 22001162).
Databáze: OpenAIRE
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