Fungi

Basic features:

It belongs to the domain Eukarya. They are unicellular (yeast) as well as multicellular organism (filamentous fungi). Multicellular fungi are composed of filaments called hyphae (singular: hypha). Hyphae may contain internal cross walls, called septa, which divide the hyphae into separate cells. The hyphae may be branched. A mass of hyphae that is not a reproductive structure is called a mycelium. Fungi are saprophytic; absorb nutrients after degrading the organic matter and heterotrophs; require organic compounds. They have cell walls composed of chitin. The hyphae of some symbiotic fungi become specialized for penetrating the cells of the host. These hyphae are called haustoria. Reproduce both sexually and asexually, typically through the production of spores. Sexually produced spores are resting spores. In general, the life cycle involves the fusion of hyphae from two individuals, forming a mycelium that contains haploid nuclei of both individuals. The fusion of hyphae is called plasmogamy. The fused hyphae containing haploid nuclei from two individuals are heterokaryotic. In some cases, plasmogamy results in cells with one nucleus from each individual. This condition is called dikaryotic. It has been classified based on the mode of reprodouction

•  Lower fungi -

• Fungi belongs to this family are having nonseptate walls and spores contained in small sporangia. These classes of fungi include three groups: Chytridiomycota, Oomycota, Myxomycota

•  Higher fungi - true fungi (Kingdom Fungi)

• Fungi belongs to this family are having s
• eptate cross walls
• spores contained in complex structures

Include three groups: Zygomycota, Ascomycota, Basidiomycota

Asexual Spores

Produced by mitosis and cell division

• 1. Sporangiospore

  •  Spores form sac called sporangium

  •  Sporangium forms at end of aerial hyphae called a sporangiophore. Hundreds of sporangiospores in a single sporangium

• 2. Conidiospore

  •  Spores produced at the end of an aerial hyphae is called as conidiophore

  •  Conidia: chains of conidiospores on conidiophores

Sexual Spores

Sexual spores formed by fusion of two haploid nuclei into single diploid zygote. zygote then undergoes meiosis to generate haploid spores (usually multiples of four)

• 1. Zygospores

  One thick spore between two parent hyphae

2. Ascospores

Four spores in a sac called an ascus, at the end of one hyphae

3. Basidiospores

Four spores on the end of a basidium

 

Fungi organized into three Phyla based on the type of sexual spore: