Mycorrhiza

, Volume 19, Issue 4, pp 239–246

The arbuscular mycorrhizal symbiosis links N mineralization to plant demand

Original Paper

DOI: 10.1007/s00572-008-0215-0

Cite this article as:
Atul-Nayyar, A., Hamel, C., Hanson, K. et al. Mycorrhiza (2009) 19: 239. doi:10.1007/s00572-008-0215-0

Abstract

Arbuscular mycorrhizal (AM) fungi facilitate inorganic N (NH4+ or NO3) uptake by plants, but their role in N mobilization from organic sources is unclear. We hypothesized that arbuscular mycorrhizae enhance the ability of a plant to use organic residues (ORs) as a source of N. This was tested under controlled glasshouse conditions by burying a patch of OR in soil separated by 20-μm nylon mesh so that only fungal hyphae can pass through it. The fate of the N contained in the OR patch, as influenced by Glomus claroideum, Glomus clarum, or Glomus intraradices over 24 weeks, was determined using 15N as a tracer. AM fungal species enhanced N mineralization from OR to different levels. N recovery and translocation to Russian wild rye by hyphae reached 25% of mineralized N in G. clarum, which was most effective despite its smaller extraradical development in soil. Mobilization of N by G. clarum relieved plant N deficiency and enhanced plant growth. We show that AM hyphae modify soil functioning by linking plant growth to N mineralization from OR. AM species enhance N mineralization differentially leading to species-specific changes in the quality of the soil environment (soil C-to-N ratio) and structure of the soil microbial community.

Keywords

Arbuscular mycorrhizal fungiOrganic residue decompositionN mineralizationN mobilizationSoil microbial community composition

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • A. Atul-Nayyar
    • 1
    • 2
  • C. Hamel
    • 1
    • 2
  • K. Hanson
    • 1
  • J. Germida
    • 2
  1. 1.Semiarid Prairie Agricultural Research CentreAgriculture and Agri-Food CanadaSaskatchewanCanada
  2. 2.Department of Soil ScienceUniversity of SaskatchewanSaskatoonCanada