Mycelial uptake, translocation and assimilation of 15N-labelled nitrogen by ectomycorrhizal Pinus sylvestris plants

Abstract

Mycelial uptake, translocation and assimilation of15N-labelled ammonium was followed inPinus sylvestrisplants infected with the ectomycorrhizal fungus.Paxillus involutus. The distribution of labelled compounds within the systems was examined using gas chromatography / mass spectrometry. Labelled nitrogen was incorporated into a range of free amino acids in the fungal mycelium, the principal sinks being alanine and glutamate/glutamine. Levels of15N enrichment declined throughout the transport pathway from 30–45% in the mycelium and mycorrhizal root tips to 3–11% in the plant shoots. A significant proportion of the total assimilated nitrogen (27%) was incorporated into proteinaceous material and the proportion of label present in this fraction increased from 27% in the mycelium to 32% and 58% in the plant roots and needles respectively. The protein-incorporated amino acids showed a wider spectrum of labelling with significant amounts of15N incorporated into valine, isoleucine, phenylalanine and lysine.

Published in

Agriculture, Ecosystems and Environment
1990, volume: 28, number: 1-4, pages: 133-137
Publisher: Elsevier Masson

SLU Authors

• Finlay, Roger

  • Lund University

UKÄ Subject classification

Microbiology
Ecology

Publication identifier

• DOI: https://doi.org/10.1016/0167-8809(90)90028-C

Permanent link to this page (URI)

https://res.slu.se/id/publ/38979