Germination and growth of Glomus caledonius spores: The effects of inhibitors and nutrients

Spores of the vesicular-arbuscular mycorrhizal endophyte Glomus caledonius (Nicol. and Gerd.) Trappe and Gerdemann readily germinated in the absence of soil or host roots. Hyphal growth was improved by incorporation of nutrients into the medium and by the addition of pieces of cotyledon from boiled seeds, but was still dependent on the spore reserves. The response of ungerminated and pregerminated spores to inhibitors of protein and nucleic acid synthesis (cycloheximide, actinomycin D, proflavine hemisulphate, 5-fluorouracil and ethidium bromide) resembled those of saprophytic fungi more than other obligate biotrophs.