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A study of the hyphal dynamics of tropical species of arbuscular mycorrhizal fungi (AMF) from 4 genera in association with a plant host

poster
BODDINGTON1, CLAIRE L. & JOHN C. DODD1
1International Institute for Biotechnology/Dept. of Biosciences, University of Kent, Canterbury, Kent. CT2 7YW. UK

ICOM1 Abstract
The extradradical mycelium (ERM) of AMF is the interface between the plant root system and the soil matrix. This mycelial network allows direct recycling of nutrients, e.g. P, and helps stabilise the soil structure. Information is required on the morphology and function of the ERM for effective application of AMF in ecosystem restoration projects. A study of fungal morphogenesis of 4 species of AMF from 4 genera: Glomus manihotis (INDO- 1), Gigaspora rosea (PHIL-INVAM), Scutellospora heterogama (BEG-35) and Acaulospora tuberculata (BEG- 47), has been made. Spores were placed between Millipore membranes in simple laboratory microcosms in the presence of a host root system. Results show clear differences in the hyphal architecture and dynamics between the 4 species following spore germination. The ecological relevance of these data will be discussed. The function of the ERM of 3 of these 4 species of AMF has been studied using inoculated Desmodium ovalifolium plants grown under tropical glasshouse conditions in an experimental pot system. A 37um mesh pouch was inserted into each pot to allow root-free hyphal growth. Hyphae were extracted from these pouches over 3 successive harvests during a 20-week time period. Hyphal lengths were compared for each species of AMf used, metabolic activity was measured using alkaline phosphatase stain (AP). The arbuscular colinisation of roots was quantified and stained for AP. The results of this work will be discussed.