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| Titel |
Multi-isotope labelling of organic matter by diffusion of 2H/18O-H2O vapour and 13C-CO2 into the leaves and its distribution within the plant |
| VerfasserIn |
M. S. Studer, R. T. W. Siegwolf, M. Leuenberger, S. Abiven |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 6 ; Nr. 12, no. 6 (2015-03-20), S.1865-1879 |
| Datensatznummer |
250117873
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| Publikation (Nr.) |
 copernicus.org/bg-12-1865-2015.pdf |
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| Zusammenfassung |
Isotope labelling is a powerful tool to study elemental cycling within
terrestrial ecosystems. Here we describe a new multi-isotope technique to
label organic matter (OM).
We exposed poplars (Populus deltoides × nigra) for
14 days to an atmosphere enriched in 13CO2 and depleted in
2H218O. After 1 week, the water-soluble leaf OM
(δ13C = 1346 ± 162‰) and the leaf water were
strongly labelled (δ18O = −63 ± 8, δ2H =
−156 ± 15‰). The leaf water isotopic composition was between
the atmospheric and stem water, indicating a considerable back-diffusion of
vapour into the leaves (58–69%) in the opposite direction to the net
transpiration flow. The atomic ratios of the labels recovered
(18O/13C, 2H/13C) were 2–4 times higher in
leaves than in the stems and roots. This could be an indication of the
synthesis of more condensed compounds in roots and stems (e.g. lignin vs.
cellulose) or might be the result of O and H exchange and fractionation
processes during phloem transport and biosynthesis.
We demonstrate that the three major OM elements (C, O, H) can be labelled
and traced simultaneously within the plant. This approach could be of
interdisciplinary interest in the fields of plant physiology, palaeoclimatic
reconstruction or soil science. |
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