Plant growth depressions in arbuscular mycorrhizal symbioses: not just caused by carbon drain?
Article first published online: 12 MAR 2008
© The Authors (2008). Journal compilation © New Phytologist (2008)
Volume 178, Issue 4, pages 852–862, June 2008
How to Cite
Li, H., Smith, F. A., Dickson, S., Holloway, R. E. and Smith, S. E. (2008), Plant growth depressions in arbuscular mycorrhizal symbioses: not just caused by carbon drain?. New Phytologist, 178: 852–862. doi: 10.1111/j.1469-8137.2008.02410.x
- Issue published online: 12 MAR 2008
- Article first published online: 12 MAR 2008
- Received: 9 December 2007Accepted: 20 January 2008
- arbuscular mycorrhizal (AM) fungi;
- intraspecific plant competition;
- plant growth depression;
- phosphorus uptake;
- wheat (Triticum aestivum)
- • This study investigated effects of plant density and arbuscular mycorrhizal (AM) colonization on growth and phosphorus (P) nutrition of a cultivar of wheat (Triticum aestivum) that often shows early AM-induced growth depressions.
- • Two experiments were conducted. Expt 1 had three plant densities and one soil P concentration. Expt 2 had two plant densities and two P concentrations. Plants were grown in calcareous P-fixing soil, inoculated with Glomus intraradices or Gigaspora margarita, or noninoculated (nonmycorrhizal (NM)). Glomus intraradices colonized well and caused a growth depression only in Expt 1. Gigaspora margarita caused large growth depressions in both experiments even though it colonized poorly.
- • The results showed that growth depressions were mitigated by changes in relative competition for soil P by NM and AM plants, and probably by decreasing carbon costs of the fungi.
- • The different effects of the two fungi appear to be attributable to differences in the balance between P uptake by the fungal pathway and direct uptake via the roots. These differences may be important in other AM symbioses that result in growth depressions. The results show that mycorrhizal growth responses of plants grown singly may not apply at the population or community level.