Effects of association between dual plant hosts and an arbuscular mycorrhizal fungus.
Golubski, Antonio*,, Lussenhop, John,
ABSTRACT- Arbuscular mycorrhizal (AM) associations are ubiquitous in many terrestrial plant communities, and it is recognized that both the plants and fungi involved may associate with multiple partners of the other guild simultaneously. Little experimental information is available, however, on the interactions between participants in such scenarios. Here plants of big bluestem (Andropogon gerardii) and indiangrass (Sorghastrum nutans) were grown in two-plant pots, with either an individual of the same species or an individual of the opposite species as a neighbor. Pots were inoculated with either Glomus claroideum or Scutellospora fulgida, and plants were separated by a root-free compartment to minimize direct interaction between neighbors. Inoculation with Scutellospora led to higher total root masses and lengths than inoculation with Glomus in pots with Bluestem (whether two bluestem neighbors or one bluestem with an indiangrass neighbor), but not in pots with only Indiangrass. Conversely, total pot root length per root mass was lower with Scutellospora than with Glomus in pots with conspecific neighbors of either species, but not in pots with heterospecific neighbors. In general, the effects of inoculation by Glomus depended more on plant species and on the species of neighbor the plant shared a pot with than did effects of inoculation by Scutellospora. These results highlight interactions between AM fungal mutualists and neighbors in their effects on plant traits and shed further light on how multiple partner associations might affect the ecology of species involved in AM associations.
Key words: arbuscular mycorrhizae, multiple partners, mutualism, root free compartment
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