IN-VITRO MASS-PRODUCTION OF THE ARBUSCULAR MYCORRHIZAL FUNGUS, GLOMUSVERSIFORME, ASSOCIATED WITH RI T-DNA TRANSFORMED CARROT ROOTS

The rate of in vitro spore formation of the arbuscular mycorrhizal fun gus Glomus versiforme was followed in Petri dishes, using mycorrhizal root-segment inoculum associated with Ri T-DNA transformed carrot root s. Three phases of sporulation were observed: a lag phase, a period of intensive spore production and a plateau phase. An average of 9500 sp ores per Petri dish was produced after 5 months of dual culture. The r oot-organ culture system supported extensive root colonization, with m any arbuscules and vesicles being formed. The fungus, both within root -segments and as spores produced, was viable and able to complete its life cycle in vitro. The mycorrhizal root-segments, however, exhibited higher inoculum potential due to the numerous vesicles and extensive intraradical mycelium.