Asexual reproduction : It occurs through spores. These are single celled specialized structures which separate from the organism , get dispersed and germinate to produce new mycelium after falling on suitable substrate. The spores produced during asexual reproduction in fungi are formed by mitotic division and are thus termed, mitospores.
The various means of asexual reproduction are as follows :
- a) Zoospore : Many fungi, especially aquatic members produce these type of spores. Zoospore may be uniflagellate, e.g., Synchytrium or biflagellate, e.g., Saprolegnia, Pythium and are naked uninucleate structures formed in zoosporangia. They geminate to give rise to new mycelium Biflagellate zoospores are of two kinds (e.g., Saprolegnia) pear shaped or pyriform with 2 flagella placed at anterior end (primary zoospore ) and kidney shaped or bean shaped , bearing two laterally inserted flagella (secondary zoospore). This phenomenon of having two types of zoospores is called diplanetism.
- b) Sporangiospore : Sporngiospores are thing walled non-motile spores produced endogenously in a sporangium during faourable conditions, which after liberation give rise to new mycelium e.g., Rhizopus, Mucor.
- c) Conidia : Conidia are non motile, thin walled exogenous spores produced at the tips of erect hyphae called conidiophore. They are arranged in chains upon the conidiophores, e.g., Aspergillus and Penicillium.
- d) Chlamydospore : In some fungi the hyphae under unfavourable conditions, forms thick walled resting resistant spores which later get separated from each other. They may be terminal or intercalary. They may remain viable for several years. On return to favourable conditions they germinate to give rise to new individuals. Thus, chlamydospores are structures for perennation also, e.g., Rhizopus.
- e) Oidia : Non- motile thin walled spores developing under sugar rich conditions in medium. Their budding condition is called torula stage.