Tracing in situ amino acid uptake in plants and microbes with15N13C labelled compounds
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- Abstract volume
Final published version, 1.34 MB, Word document
Though measurements of amino acids (the 20 essential; HPLC) yielded low concentrations in the soil pore water (~ 1% of dissolved organic nitrogen) and showed seasonal variations, the 15N13C tracer experiment revealed high plant and microbial enrichment, suggesting a significant cycling of amino acids. Furthermore, the influence of colonisation and type of mycorrhizal association (ericoid and arbuscular) of the roots on amino acid uptake was investigated. Mineralization (decarboxylation) of the 13C labelled amino acids at uptake (through mycorrhizae or directly through root) and after xylem transport decreased the 13C enrichment of plant shoots, which therefore may not necessarily reflect root acquisition of intact amino acids. Furthermore, tannin addition tended to reduce plant uptake of label.
By combining data on 15N recovery after 1 day in shoots and roots (fine and coarse) of the dominant heathland plants: the evergreen dwarf shrub Calluna vulgaris and the graminoid Deschampsia flexuosa, in soil microorganisms (chloroform fumigation extraction) and in soil water, we discuss the relative importance of free amino acids and ammonium as plant nutrients and microbial substrates in natural N-limited ecosystems with a high proportion of soil N held in tannin-N complexes.
|Publication status||Published - 2006|
|Event||The 5th International Conference on Applications of Stable Isotope Techniques to Ecological Studies - Belfast, United Kingdom|
Duration: 13 Aug 2006 → 18 Aug 2006
|Conference||The 5th International Conference on Applications of Stable Isotope Techniques to Ecological Studies|
|Period||13/08/2006 → 18/08/2006|
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