Ultrastructural Observations of Meiosis Within Antheridia of Achlya Ambisexualis

SUMMARY

Antheridal production was induced by the addition of 1,000 units/ml of hormone A to hyphae of Achlya ambisexualis. Electron microscopy of nuclear divisions within hyphae demonstrated the presence of centrioles adjacent to somatic nuclei possessing intranuclear spindle fibers. The enlargement of antheridial nuclei, the presence of axial elements attached to the nuclear membrane prior to chromosome segregation, the reduced size of fertilization tube nuclei, and the double-membraned envelope around centrioles are considered indicators of antheridial meiosis.