In situ assessment of the velocity of carbon transfer by tracing 13C in trunk CO2 efflux after pulse labelling: variations among tree species and seasons

Authors

  • Masako Dannoura,

    1. INRA, UR1263 Ecologie Fonctionnelle et Physique de l’Environnement, F-33140 Villenave d’Ornon, France
    2. Laboratory of Forest Utilization, Department of Forest and Biomaterial Science, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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  • Pascale Maillard,

    1. Université Henri Poincaré, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, Nancy Université, F-54500 Vandoeuvre les Nancy, France
    2. INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
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  • Chantal Fresneau,

    1. Université Paris-Sud, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91405 Orsay, France
    2. CNRS, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91190 Gif-sur-Yvette, France
    3. AgroParisTech, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-75231 Paris, France
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  • Caroline Plain,

    1. Université Henri Poincaré, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, Nancy Université, F-54500 Vandoeuvre les Nancy, France
    2. INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
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  • Daniel Berveiller,

    1. Université Paris-Sud, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91405 Orsay, France
    2. CNRS, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91190 Gif-sur-Yvette, France
    3. AgroParisTech, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-75231 Paris, France
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  • Dominique Gerant,

    1. Université Henri Poincaré, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, Nancy Université, F-54500 Vandoeuvre les Nancy, France
    2. INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
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  • Christophe Chipeaux,

    1. INRA, UR1263 Ecologie Fonctionnelle et Physique de l’Environnement, F-33140 Villenave d’Ornon, France
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  • Alexandre Bosc,

    1. INRA, UR1263 Ecologie Fonctionnelle et Physique de l’Environnement, F-33140 Villenave d’Ornon, France
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  • Jérôme Ngao,

    1. Université Paris-Sud, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91405 Orsay, France
    2. CNRS, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91190 Gif-sur-Yvette, France
    3. AgroParisTech, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-75231 Paris, France
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  • Claire Damesin,

    1. Université Paris-Sud, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91405 Orsay, France
    2. CNRS, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-91190 Gif-sur-Yvette, France
    3. AgroParisTech, UMR 8079, Laboratoire Ecologie Systématique et Evolution, F-75231 Paris, France
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  • Denis Loustau,

    1. INRA, UR1263 Ecologie Fonctionnelle et Physique de l’Environnement, F-33140 Villenave d’Ornon, France
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  • Daniel Epron

    1. Université Henri Poincaré, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, Nancy Université, F-54500 Vandoeuvre les Nancy, France
    2. INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
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Author for correspondence:
Daniel Epron
Tel: +33 3 83684249
Email: daniel.epron@scbiol.uhp-nancy.fr

Summary

  • Phloem is the main pathway for transferring photosynthates belowground. In situ13C pulse labelling of trees 8–10 m tall was conducted in the field on 10 beech (Fagus sylvatica) trees, six sessile oak (Quercus petraea) trees and 10 maritime pine (Pinus pinaster) trees throughout the growing season.
  • Respired 13CO2 from trunks was tracked at different heights using tunable diode laser absorption spectrometry to determine time lags and the velocity of carbon transfer (V). The isotope composition of phloem extracts was measured on several occasions after labelling and used to estimate the rate constant of phloem sap outflux (kP).
  • Pulse labelling together with high-frequency measurement of the isotope composition of trunk CO2 efflux is a promising tool for studying phloem transport in the field. Seasonal variability in V was predicted in pine and oak by bivariate linear regressions with air temperature and soil water content. V differed among the three species consistently with known differences in phloem anatomy between broadleaf and coniferous trees.
  • V increased with tree diameter in oak and beech, reflecting a nonlinear increase in volumetric flow with increasing bark cross-sectional area, which suggests changes in allocation pattern with tree diameter in broadleaf species. Discrepancies between V and kP indicate vertical changes in functional phloem properties.

Ancillary