TL;DR: Heterothallism was confirmed in Mortierella umbellata from Japan and anisogamic zygospore formation is described and illustrated with time-lapse light micrographs.
TL;DR: All the ± isolates originating from single zygospore, hyphal fragments, or sporangiospores produced azygospores, suggesting that azyGospores of this fungus are produced by mating-type heterokaryotic mycelia.
Abstract: Zygospore progeny from the cross between + and − isolates of Choanephora cucurbitarum consisted of +, −, and ± types. The + and − zygospore isolates were stable, giving rise to hyphal fragment cultures and sporangiospores with the same mating type as their respective parent. However, the ± zygospore isolates were unstable, segregating to +, −, and ± types during asexual propagations. During long-term storage, the + and − isolates were also very stable, but ± isolates were not. All the ± isolates originating from single zygospores, hyphal fragments, or sporangiospores produced azygospores, suggesting that azygospores of this fungus are produced by mating-type heterokaryotic mycelia. Keywords: azygospore, Choanephora cucurbitarum, germsporangiospore, germsporangium, zygospore germination.
TL;DR: No definite correlation could be established between the effect of nitrogen requirements for growth and sporulation of the fungi tested, and this indicates that requirement for zygospore and azygospore development are not similar.