Common mycorrhizal networks amplify size inequality in Andropogon gerardii monocultures

Joanna Weremijewicz, David P. Janos

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)203-213
Number of pages11
JournalNew Phytologist
Issue number1
StatePublished - Apr 2013


  • Andropogon gerardii
  • Arbuscular mycorrhizal (AM) fungi
  • Gini coefficient
  • Intraspecific competition
  • Manganese
  • Size hierarchy

ASJC Scopus subject areas

  • Plant Science
  • Physiology


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