Interdependence of phosphorus, nitrogen, potassium and magnesium translocation by the ectomycorrhizal fungus Paxillus involutus

Authors

  • Georg Jentschke,

    Corresponding author
    1. School of Agricultural and Forest Sciences, University of Wales Bangor, Bangor, Gwynedd LL57 2UW, UK;
    2. Forest Ecosystem Research Centre, Institute of Forest Botany, University of Göttingen, Büsgenweg 2, D-37077 Göttingen, Germany;
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  • Bettina Brandes,

    1. Forest Ecosystem Research Centre, Institute of Forest Botany, University of Göttingen, Büsgenweg 2, D-37077 Göttingen, Germany;
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  • Arnd J. Kuhn,

    1. Institute for Biological Information Processing, Research Centre Jülich, D-52425 Jülich, Germany
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  • Walter H. Schröder,

    1. Institute for Biological Information Processing, Research Centre Jülich, D-52425 Jülich, Germany
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  • Douglas L. Godbold

    1. School of Agricultural and Forest Sciences, University of Wales Bangor, Bangor, Gwynedd LL57 2UW, UK;
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Author for correspondence: G. Jentschke Tel: +49–5507–1469 Fax: +49 551392705Email: gjentsc@gwdg.de

Abstract

  •  Translocation is shown of phosphorus, nitrogen, potassium and magnesium to a P-deficient host from ectomycorrhizal fungal hyphae.
  • • Mycorrhizal (with Paxillus involutus) and nonmycorrhizal P-deficient spruce (P. abies) seedlings were grown in a two-compartment sand-culture system. Hyphal translocation of nutrients from the inner compartment (penetrated only by hyphae) to the host was measured using mass balance (for N, P and K) or stable isotope (15N and 25Mg) methods.
  • • Addition of P to the hyphal compartment strongly stimulated hyphal growth, and this also increased both seedling P status and growth. Hyphae translocated nonlimiting elements in addition to P, contributing 52, 17, 5 and 3–4%, respectively, to total P, N, K or Mg plant uptake. The potential role of the ectomycorrhizal mycelium in K acquisition was demonstrated. Translocation to mycorrhizal seedings of N, K and Mg was strongly reduced when hyphal P-fluxes ceased; this translocation of nonlimiting nutrients depended on simultaneous translocation of P.
  •  The ectomycorrhizal mycelium has an active role in P acquisition from sources not available to roots. Nutrient fluxes within fungal hyphae are interdependent and strong coupling of N, K and Mg fluxes with long-distance P translocation in the mycorrhizal mycelium occurs.

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