Symbioses: Plant, Animal, and Microbe Interactions
Southworth, Darlene , Frank, Jonathan , Anglin, Sara , Taylor, David , Carrington, Elizabeth , Viratos, Brea .
Dispersal of Mycorrhizal Inoculum to Quercus garryana Seedlings: Limitations on Plant Dispersal.
According to the Janzen-Connell hypothesis, seeds dispersed greater distances from parent plants survive better because they escape seed and seedling predators. Because oaks are ectomycorrhizal, dispersal requires two vectors: one to carry acorns away from the parent tree, and one to carry mycorrhizal inoculum to reach seedling roots. Hypogeous fungi comprise a significant component of the Quercus garryana mycorrhizal community. To assess availability of ectomycorrhizal inoculum as a function of distance from mature oaks, we trapped small mammals to obtain fecal pellets in shrublands and grasslands, collected soil cores to obtain ectomycorrhizal roots, and planted acorns as bioprobes. Spores of 14 species of hypogeous fungi were found in fecal pellets at distances up to 35 m from mature trees. DNA sequences of the ITS region were used to identify spores and mycorrhizas. More animals entered traps in shrublands than in grasslands. Mycorrhizas were present in soil cores 5 m from parent trees, but soil cores farther away lacked mycorrhizas. Only those seedlings within the root zone of mature trees formed mycorrhizas in the first growing season. Hypogeous fungi were found in fecal pellets and on roots of seedlings. The requirement for mycorrhizal inoculum limits the distance from mature trees at which seedlings can survive. Dispersal of mycorrhizal inoculum affects restoration of oak habitats, natural regeneration of oak communities, and the possibilities for range expansion with global warming.
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1 - Southern Oregon University, Department of Biology, 1250 Siskiyou Blvd, Ashland, Oregon, 97520-5010, USA
2 - Southern Oregon University, Biology, Ashland, OR, 97520, USA
3 - Southern Oregon University, Geology, Ashland, OR, 97520, USA
Oregon white oak
Presentation Type: Oral Paper:Papers for Topics
Location: Blair A/Gage
Date: Tuesday, July 29th, 2008
Time: 11:15 AM