The Role of Hormone a During Sexual Conjugation in Achlya Ambisexualis

SUMMARY

Particles of polystyrene and polyvinyl plastic, on which hormone A had been adsorbed, were attractive to the antheridial branches produced on the mycelium of Achlya ambisexualis E87 in response to hormone A. The branches grew to the particles and wrapped around them. Antheridium-like structures were cut off by cross-walls on the branches initiated by hormone A. Thigmotropism did not appear to be involved in the formation of the cross-walls. It is suggested that hormone A may be the substance secreted by the oogonial initials that is responsible for the growth of the antheridial branches to the oogonial initial and for the formation of the antheridium.