Ectomycorrhizal transfer of amino acid-nitrogen to the alpine sedge Kobresia myosuroides

David A. Lipson, Christopher W. Schadt, Steven K. Schmidt, Russell K. Monson

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Previous work in the Colorado alpine ecosystem has shown that amino acids are a potentially important N source for the sedge, Kobresia myosuroides. This plant is the only known sedge to harbour associations with ectomycorrhizal fungi. The aim of the present work was to test the hypothesis that these ectomycorrhizas transfer N from amino acids in the soil solution to the host plant, and thereby have an important role in the N nutrition of this species. We used a two-chamber system (rhizoboxes) in which K. myosuroides plants were separated from a soil chamber by nylon mesh that allowed fungal hyphae, but not plant roots, to cross it. Injections of [15N, 2-13C]glycine were made into the soil chamber. The hyphal crossings on half of the rhizoboxes were regularly disrupted to control for leakage of label across the barrier. Plants in the intact rhizoboxes showed significantly higher 15N enrichment than those in controls, and mycorrhizal root tips were significantly more enriched than bulk roots. The mycorrhizas transferred an average of 1.3% of the added 15N label to plants, a figure comparable to those obtained in previous studies in which plant roots were directly exposed to label. We conclude that fungal associations have an important role in the N nutrition of K. myosuroides by transferring N from amino acids to their hosts.

Original languageEnglish (US)
Pages (from-to)163-167
Number of pages5
JournalNew Phytologist
Volume142
Issue number1
DOIs
StatePublished - Apr 1999

Keywords

  • Alpine
  • Amino acid
  • Cyperaceae
  • Ectomycorrhizas
  • Kobresia myosuroides
  • Nitrogen
  • Sedge

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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