FUNGI #2 Zygomycetes

Introduction :

•  The class zygomycetes includes  those members  in which the resting pores or zygospores develop by the fusion of two  gametangia.
• Motile zoopores are absent.
• Members are saprophytic or weak parasite.
• Plant body is branched, filamentous, coenocytic.
• Cell wall is made up of chitin.
• Asexual reproduction takes place by aplanospores or chlamydospores or oidia.
• Sexual reproduction takes place by means of gametangial copulation which result in formation of  zygospores.

Vegetative Reproduction :

Vegetative reproduction takes place by the following ways :

1. Fragmentation
2. Chlamydospore formation
3. Oidia
4. Fission
5. Aplanospore
6. Budding

Asexual Reproduction :

• If fungi reproduces only by asexual spore then it is known as anamorphs.
• If fungi reproduces only by sexual spore  then it is known as telomorphs.
• If fungi reproduces by both asexual and sexual spore then it is known as holomorphs.
• If some fungi produces more than one type of spores then it is known as pleomorphic or polymorphic.
• If spore produces inside the sporophores then it is known as endogenous spores.
• If spore produces outside the sporophores then it is known as exogenous spores. 

Endogenous spores :-  

• Producing spores within the sporangium.
• Sporangia are born on sporophores called  sporangiophores
• Examples - Zoospores,Aplanospores

Exogenous spores :-

• Born on conidia.
• Examples - Only conidia 

 

Sexual Reproduction :

• Sexual reproduction involves fusion of sex cells called gametes, which are formed in special structure called gametangia.
• In monoecious species, fusion of gametes occur on same hyphae.
• In dioecious species fusion of gametes occurs on different hyphae.
• Fungi having monoecious mycelia are homothallic and fungi having dioecious mycelia are heterothallic.
• Sexual reproduction involoves three stages 

1. Plasmogamy - Fusion of protoplast
2. Karyogamy - Fusionn of nucleus
3. Meiosis - Required to complete the lif cycle