BARBETA, Adrià; GIMENO, Teresa; CLAVÉ, Laura; FRÉJAVILLE, Bastien; JONES, Sam; DELVIGNE, Camille; WINGATE, Lisa; OGÉE, Jérôme

doi:10.1111/nph.16564

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BARBETA, Adrià
Interactions Sol Plante Atmosphère [UMR ISPA]
Universitat de Barcelona [UB]

GIMENO, Teresa
Interactions Sol Plante Atmosphère [UMR ISPA]
Ikerbasque - Basque Foundation for Science

CLAVÉ, Laura
Interactions Sol Plante Atmosphère [UMR ISPA]

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Article de revue

Ce document a été publié dans

New Phytologist. 2020-08, vol. 227, n° 3, p. 766-779

Wiley

Résumé en anglais

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 delta H-2 and delta O-18 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 delta H-2 were similar only near permanent wilting point. Under moister conditions, stem water delta H-2 was 11 +/- 3 parts per thousand more negative than soil water delta H-2, coherent with field studies. Under drier conditions, stem water delta H-2 became progressively more enriched than soil water delta H-2. Although stem water delta O-18 broadly reflected that of soil water, soil-stem delta H-2 and delta O-18 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.< Réduire

Mots clés en anglais

plant water sources

root water uptake

water isotopes

ecohydrology

Fagus sylvatica

URI

https://oskar-bordeaux.fr/handle/20.500.12278/195465

DOI

http://dx.doi.org/10.1111/nph.16564

Project ANR

COntinental To coastal Ecosystems: evolution, adaptability and governance - ANR-10-LABX-0045
Etude des mécanismes de régulation de l'anhydrase carbonique et des flux de COS et CO18O dans les écosystèmes terrestres - ANR-13-BS06-0005

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Importé de hal

Unités de recherche

Interactions Soil Plant Atmosphere (ISPA) - UMR 1391