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Differential Niche Response of Bouteloua gracilis and Pascopyrum smithii to VA Mycorrhizae

1984; Torrey Botanical Society; Volume: 111; Issue: 3 Linguagem: Inglês

10.2307/2995917

2325-8055

Michael F. Allen, Edith B. Allen, Peter D. Stahl,

Peatlands and Wetlands Ecology

ALLEN, M. F., (Dept. Biology, UMC 45, Utah State Univ., Logan, UT 84322) E. B. ALLEN (Dept. Range Science, UMC 52, Utah State Univ., Logan, UT 84322), AND P. D. ST AHL (Dept. Botany, Univ. Wyoming, Laramie, WY 82071). Differential niche response of Boutelouagracilis and Pascopyrum smithii to VA mycorrhizae. Bull. Torrey Bot. Club 111: 361-365. 1984.-The seasonality of Glomus fasciculatum associated with Bouteloua gracilis and Pascopyrum smithii was contrasted in the field, as well as the effects of this vesicular-arbuscular mycorrhizal (VAM) fungus on physiological parameters of these grasses in the greenhouse. Arbuscule formation was earlier in P. smithii, which has C3 photophysiology, than in the C.4 B. gracilis. Soil spore densities were highest in fall samples of both grasses. Both grasses exhibited lower stomatal resistance and increased photosynthesis with VAM formation, but these changes were 36% greater for B. gracilis. B. gracilis has a greater percentage of VAM infection than P. smithii in the field, but % of the root length infected in the two grasses was similar in the greenhouse. We hypothesize that the greater niche response of B. gracilis than P. smithii to VAM, coupled with their differing phenologies, enable coexistence of the two grasses.