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University of Kent at Canterbury (1999)

Ecology of arbuscular mycorrhizal fungi from a desertified ecosystem

Craven-Griffiths, A

Titre : Ecology of arbuscular mycorrhizal fungi from a desertified ecosystem

Auteur : Craven-Griffiths, A

Université de soutenance : University of Kent at Canterbury

Grade : Doctor of Philosophy (PhD) 1999

Résumé
This investigation examined the effects of environmental factors on the inoculum potential of indigenous AMF from a semi-arid ecosystem in the Rambia Honda in southern Spain and also the effects of inoculation with AMF on 2 indigenous desert plants. Trap cultures, using soils taken from Rambla Honda, revealed the presence of at least 12 species of AMF with 10 species of Glomus, 1 species of Acaulospora and 1 species of Scutellospora being identified. Of these, Glomus coronatum BEG49 G.microaggregatum BEG51, G.viscosum BEG50, G.constrictum BEG130 and Acaulospora longula BEG52 were established in pure culture.Incubation temperatures within a range from 23 to 37°C did not affect % germination of spores of G.coronatum BEG49, G.constrictum BEG130 or the exotic isolate G. mosseae BEG25. However, the optimum temperatures for hyphal extension of G.coronatum BEG49 and G.microaggregatum BEG56 were 25°Cand 30°C respectively. When spores were pre-exposed to 35°C, 45°C or 55°C for 3 hours before incubation at 24 8°C germination of spores, was significantly reduced. Pre-exposure of spores to 55°C for 3 days did not affect hyphal growth of these isolates.Storage of mixed inoculum (colonised root fragments, spores and hyphate) of G.coronatum BEG49 and A.longula BEG52, at either 4°C or room temperature, over 12 months increased infectivity of leek compared with freshly harvested inoculum. However, the isolates differed in their response, which was further modified by storage conditions. If inoculum was stored at room temperature, colonisation by G.coronatum BEG49 increased significantly, peaking at 3 (67%) and 9 months (67%), and was still significantly greater than from fresh/unstored inoculum after 12 months of storage (52%). In contrast, if inoculum was stored at 4°C, colonisation by G.coronatum BEG49 was only greater than from fresh/unstored inoculum after 12 months of storage (45%).

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