Morphogenesis of azygospores induced in Gibertella persicaria (plus) by imperfect hybridization with Rhizopus stolonifer (minus)

Morphogenesis of azygospores induced in Gilbertella persicaria (+) by the illegitimate cross of this species with Rhizopus stolonifer (−) was examined by light microscopy and transmission and scanning electron microscopy. Gametangia were formed only in G. persicaria. A continuous secondary azygospore wall was laid down within the original gametangial walls, and it was within this secondary wall that the conical, electron-opaque warts developed. Simultaneously, autophagic vacuoles filled the suspensor of R. stolonifer. Mature azygosporangia possessed a black outer ornamental layer consisting of connate truncate, conical warts. Azygosporangia were adjoined by intact fusion septa at their interface with a R. stolonifer progametangium. The significance of azygosporangia induced during imperfect hybridization was discussed in relation to the taxonomy and biology of the Mucorales.