Common mycorrhizal networks amplify size inequality in Andropogon gerardii monocultures
Article first published online: 29 JAN 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 198, Issue 1, pages 203–213, April 2013
How to Cite
Weremijewicz, J. and Janos, D. P. (2013), Common mycorrhizal networks amplify size inequality in Andropogon gerardii monocultures. New Phytologist, 198: 203–213. doi: 10.1111/nph.12125
- Issue published online: 25 FEB 2013
- Article first published online: 29 JAN 2013
- Manuscript Accepted: 3 DEC 2012
- Manuscript Received: 22 SEP 2012
- University of Miami Department of Biology Curtis Fellowship
- College of Arts and Sciences Cooper Fellowship
- Andropogon gerardii ;
- arbuscular mycorrhizal (AM) fungi;
- Gini coefficient;
- intraspecific competition;
- size hierarchy
- Arbuscular mycorrhizal fungi can interconnect plant root systems through hyphal common mycorrhizal networks, which may influence the distribution of limiting mineral nutrients among interconnected individuals, potentially affecting competition and consequent size inequality. Using a microcosm model system, we investigated whether the members of Andropogon gerardii monocultures compete via common mycorrhizal networks.
- We grew A. gerardii seedlings with isolated root systems in individual, adjacent containers while preventing, disrupting or allowing common mycorrhizal networks among them. Fertile soil was placed within the containers, which were embedded within infertile sand. We assessed mycorrhizas, leaf tissue mineral nutrient concentrations, size hierarchies and the growth of nearest neighbors.
- Plants interconnected by common mycorrhizal networks had 8% greater colonized root length, 12% higher phosphorus and 35% higher manganese concentrations than plants severed from common mycorrhizal networks. Interconnected plants were, on average, 15% larger and had 32% greater size inequality, as reflected by Gini coefficients, than those with severed connections. Only with intact common mycorrhizal networks were whole-plant dry weights negatively associated with those of their neighbors.
- In the absence of root system overlap, common mycorrhizal networks likely promote asymmetric competition below ground, thereby exaggerating size inequality within A. gerardii populations.