Mycorrhizal colonization of American chestnut seedlings from sites exposed to prescribed fire and/or overstory thinning. (Plant Biology 09:00 AM, Saturday, April 5, 2003 Brewer/Frost Science 142 Dr. Sarah E. Wyatt-Presiding).

McQuattie, Carolyn J. ; McCament, Corinne ; McCarthy, Brian 等

10:45

The potential for establishment of blight-resistant American chestnut (Castanea dentata) in Ohio forests has led to renewed interest in chestnut seedling growth and survival. Mycorrhizal fungal colonization of roots, which usually results in increased nutrient uptake, may improve seedling survival on disturbed forest sites. In May 2002, 400 chestnut seeds were planted in Vinton County, OH on four treatment sites: undisturbed site, control (C); overstory thinned by 29% (T); forest floor exposed to a prescribed burn in spring 2001 (B); combination of burned plus thinned (B+T). The study objectives were to describe mycorrhizal root morphology and to determine percent colonization of seedling roots after one growing season. In October 2002, three representative lateral roots from each of three seedlings per treatment were chemically preserved. All short roots on each lateral root were examined for mycorrhizal colonization. Root tips were subsequently embedded in epoxy resin and sectioned to verify mycorrhizal root structure. Chestnut roots from each treatment were ectomycorrhizal, with definite hyphal mantle and Hartig net development. Percent colonization of short roots varied by treatment: C, 36%; T, 53%; B, 71%; T+B, 78% (p = 0.10). Greater mycorrhizal colonization of roots associated with treatments may be related to micro-site changes such as increased light levels (T), altered soil temperatures, moisture or nutrient levels (B), or some combination (T+B). Additional root collections are planned over the next several years to monitor longer term effects of treatments on mycorrhizal associations.

CAROLYN J. MCQUATTIE (1) [email protected], CORINNE MCCAMENT (2) [email protected], BRIAN MCCARTHY (2) [email protected], (1) USDA FOREST SERVICE, 359 MAIN RD, DELAWARE OH 43015, AND OHIO UNIVERSITY