Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-22T20:42:27.381Z Has data issue: false hasContentIssue false

Interactive effects of arbuscular mycorrhizal symbiosis, intraspecific competition and resource availability on Trifolium subterraneum cv. Mt. Barker

Published online by Cambridge University Press:  01 March 1999

E. FACELLI
Affiliation:
The Centre for Plant Root Symbioses, The University of Adelaide, Adelaide, SA 5005, Australia Department of Soil Science, The University of Adelaide, Glen Osmond, SA 5064, Australia
J. M. FACELLI
Affiliation:
The Centre for Plant Root Symbioses, The University of Adelaide, Adelaide, SA 5005, Australia Department of Botany, The University of Adelaide, Adelaide, SA 5005, Australia
S. E. SMITH
Affiliation:
The Centre for Plant Root Symbioses, The University of Adelaide, Adelaide, SA 5005, Australia Department of Soil Science, The University of Adelaide, Glen Osmond, SA 5064, Australia
M. J. MCLAUGHLIN
Affiliation:
CSIRO Land and Water, Glen Osmond, SA 5064, Australia
Get access

Abstract

We performed two glasshouse experiments to determine whether the presence of arbuscular mycorrhizal symbiosis reduces the intensity of intraspecific competition at low concentrations of available phosphorus (P), and whether this effect is modified by a reduction in light intensity. In the first experiment, Trifolium subterraneum cv. Mt. Barker was grown at different densities in controlled conditions of light and temperature, and half of the pots were inoculated with spores of the arbuscular mycorrhizal fungus, Gigaspora margarita. In the second experiment, the plants were grown in similar controlled conditions but the light intensity received by half of the pots was reduced by >50%. The biomass and P content of individual mycorrhizal plants and the biomass response to mycorrhizal infection were drastically reduced as plant density increased. The effects of density on percentage infection, shoot and root P concentrations, and root: shoot ratios were inconsistent. Generally reduction in light intensity did not alter these effects. Mycorrhizal symbiosis increased intraspecific competition intensity through an increase in the availability of soil P. This increase in competition was reflected in the greater size inequality of low density mycorrhizal treatments. Our results emphasize that the main effects of mycorrhizas at the individual level cannot be expected to be apparent at the population level, because they are overridden by density-dependent processes.

Type
Research Article
Copyright
© Trustees of New Phytologist 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)