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Stadler, Jutta ; Gebauer, Gerhard ; Schulze, Ernst-Detlef:
The influence of ammonium on nitrate uptake and assimilation in 2-year-old ash and oak trees - a tracer study with 15N.
In: Isotopes in Environmental and Health Studies.
Bd. 29
(1993)
Heft 1-2
.
- S. 85-92.
ISSN 1477-2639
DOI: https://doi.org/10.1080/10256019308046139
Abstract
Interactions between ammonium and nitrate as competitive N sources depend on various biotic and abiotic factors. The preference for one of these N sources and the influence of ammonium on nitrate uptake and nitrate reductase activity was investigated in a 15N labelling experiment using 2-year-old potted plants of ash (Fraxinus excelsior L.) and oak (Quercus robur L.) under greenhouse conditions.Seedlings of both tree species use ammonium and nitrate in equal amounts when both N forms are supplied in a 1:1 ratio (1.5 mM NH4+ + 1.5 mM NO3-), although there is a slight tendency that ammonium is preferred. In both species total N uptake is higher if ammonium. and nitrate are supplied simultaneously when compared with uptake of nitrate alone (3 mM nitrate). If nitrate is the sole N source N uptake is only half as high as if ammonium and nitrate are supplied in a ratio of 1:1.The distribution of nitrate reductase between shoot and roots is not influenced by the N-form: nitrate reductase activity is always highest in the roots of both species under the conditions of this experiment.Xylem sap analyses showed that both species transport higher concentrations of amino acids than of nitrate from the roots to the shoot. The amino acid composition is independent of the type of N source. Furthermore, ash trees contain more nitrate in the xylem sap than oak trees, reflecting the higher N uptake and the higher nitrate reductase activity in the leaves of this species.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER36655 |
| Institutionen der Universität: | Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 12 Feb 2016 07:15 |
| Letzte Änderung: | 12 Feb 2016 07:15 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/30717 |