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| Titel |
Interactions between uptake of amino acids and inorganic nitrogen in wheat plants |
| VerfasserIn |
E. Gioseffi, A. Neergaard, J. K. Schjoerring |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2012-04-24), S.1509-1518 |
| Datensatznummer |
250006957
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| Publikation (Nr.) |
 copernicus.org/bg-9-1509-2012.pdf |
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| Zusammenfassung |
| Soil-borne amino acids may constitute a source of nitrogen (N) for plants in
various terrestrial ecosystems but their importance for total N nutrition is
unclear, particularly in nutrient-rich arable soils. One reason for this
uncertainty is lack of information on how the absorption of amino acids by
plant roots is affected by the simultaneous presence of inorganic N forms.
The objective of the present study was to study absorption of glycine (Gly)
and glutamine (Gln) by wheat roots and their interactions with nitrate
(NO3−) and ammonium (NH4+) during uptake. The underlying
hypothesis was that amino acids, when present in nutrient solution together
with inorganic N, may lead to down-regulation of the inorganic N uptake,
thereby resulting in similar total N uptake rates. Amino acids were enriched
with double-labelled 15N and 13C, while NO3− and
NH4+ acquisition was determined by their rate of removal from the
nutrient solution surrounding the roots. The uptake rates of NO3−
and NH4+ did not differ from each other and were generally about
twice as high as the uptake rate of organic N when the different N forms
were supplied separately in concentrations of 2 mM. Nevertheless,
replacement of 50% of the inorganic N with organic N was able to restore
the N uptake to the same level as that in the presence of only inorganic N.
Co-provision of NO3− did not affect glycine uptake, while the
presence of glycine down-regulated NO3− uptake. The ratio between
13C and 15N were lower in shoots than in roots and also lower than
the theoretical values, reflecting higher C losses via respiratory processes
compared to N losses. It is concluded that organic N can constitute a
significant N-source for wheat plants and that there is an interaction
between the uptake of inorganic and organic N. |
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