In situ 13CO2 pulse-labelling of upland grassland demonstrates a rapid pathway of carbon flux from arbuscular mycorrhizal mycelia to the soil

David Johnson, J. R. Leake, N. Ostle, P. Ineson, David Read

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Abstract

The flux of pulse-derived C-13 from upland pasture plants to the external mycelium of their arbuscular mycorrhizal (AM) symbionts was traced and quantified over a 7-d post-labelling period.

Mesh cores, which allowed in-growth of native AM mycelium but were impenetrable to roots, were inserted into unlimed and limed plots and the surrounding vegetation was exposed to (CO2)-C-13 at ambient CO2 concentrations.

Release of (CO2)-C-13 from cores colonized by AM mycelium peaked 9-14 h after labelling and declined within 24 h after severance of mycelial connections to roots. Between 5 and 8% of carbon lost by plants was respired by AM mycelium over the first 21 h after labelling. Liming increased the amount of carbon fixed by plants and subsequently allocated to fine roots and AM mycelium.

The results demonstrate for the first time under field conditions that AM mycelia provide a rapid and important pathway of carbon flux from plants to the soil and atmosphere.

Original languageEnglish
Pages (from-to)327-334
Number of pages7
JournalNew Phytologist
Volume153
Issue number2
DOIs
Publication statusPublished - Feb 2002

Keywords

  • C-13
  • stable isotope
  • liming
  • carbon flow
  • carbon cycling
  • respiration
  • arbuscular mycorrhiza
  • mesh cores
  • EXTERNAL HYPHAE
  • PLANTS
  • ROOTS
  • FLOW
  • RHIZOSPHERE
  • PHOSPHORUS
  • INFECTION
  • CUCUMBER
  • TURNOVER
  • SYSTEMS

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