Zygomycetes : The Conjugation Fungi | Structures & Characteristics

 

1. It is class of terrestrial fungi which are mostly saprotrophic and rarely parasitic.
2. Hyphal wall contains chitin or fungal cellulose.
3. The mycelium is coenocytic (multinucleate, aseptate) like the one found in Oomycetes.
4. Motile cells (zoospores or planogametes) are absent.
5. Mitospores are non motile. They are called sporangiospores as the spores are formed inside sporangia that are borne at the tips of special hyphae called sporangiophores.
6. Sexual reproduction occurs through gametangial copulation or conjugation. Because of it, zygomycetes are also called conjugation fungi.
7. The gametes are commonly multinucleate and are called coenogametes.
8. Sexual reproduction produces a resting diploid spore called zygospore. Because of the presence of zygospore, the group of fungi is called zygomycetes. Zygospore differs from oospore in that, for its formation a distinct food laden, non motile, large female gamete is not produced.
9. Zygospore is the site of meiosis and does not give rise to new mycelium directily. Instead it produces a new sporangium called germ sporangium (previously called zygosporangium). Germ sporangium forms meiospores called germ spores.
10. Sometimes, gametangia fail to fuse. Gametangia become surrounded by a thick wall resulting in formation of azygospore (parthenogenetically produced zygospore).

Knowledge Cloud

Rhizopus stolonifer (= R. nigricans) is popularly known as black bread mould. M. mucedo is called dung mould or pin mould. Rhizopus and Mucor are the common saprotrophic fungi that attack a variety of food stuffs. Soft rot or leek disease of strawberry, apple, jack fruit, sweet potato etc. is due to Rhizopus. Mucor pusillus causes infection of internal organs in human beings. Absidia corymbifera causes bronchomycosis. Ramysin (antibiotic) is obtained from Mucor ramannianus.