Fungi Phycomycetes Ascomycetes Basidiomycetes

Fungi Phycomycetes Ascomycetes Basidiomycetes

INTRODUCTION: In this chapter, Fungi Phycomycetes Ascomycetes Basidiomycetes we will discuss in detail. Fungi is Non-vascular, achlorophyllous, spore-forming.

• Fungi is cosmopolitan.
• Present in water, air, and living organisms.
• Fungi contain chitin.
• Its food reserve is Glycogen.
• Mycology: Study of fungi.
• The mode of nutrition is Heterotrophs.
• Chlorophyll is absent hence not able to prepare their food.
• Saprotrophic fungi obtain food from dead and waste material.

Image 1: Fungi

Fungal Structure: 

• The Body having tubular filaments i.e., Hyphae.
• The filamentous hyphae or mass of hyphae is known as mycelium.
• In yeast mycelium is absent.
• Fungi have vegetative and reproductive phases.

Image 2: Formation of Mycelium

See Also: Protista Photosynthetic Dinoflagellates Euglenoids

Protista Protozoan Plasmodium

Tissue and Cell Structure:  

• When hyphae are held together called Plectenchyma it contains Prosenchyma ( loosely hyphae),  and Pseudoparenchyma ( closely packed hyphae).
• When single nuclei are present condition is monokaryotic.
• When two nuclei are present condition is dikaryotic.
• Chitin is made up of acetyl glucosamine.
• Plastids are absent.
• Mitochondria, Endoplasmic reticulum, ribosomes, microtubules, etc. are present.
• Food reserve is glycogen and oil.

Image 3: Rhizopus

Reproduction: 

1. Sexual reproduction: Involves Karyogamy, plasmogamy, and meiosis.

• Homothallic: when mating occurs between the genetically are similar.
• Heterothallic: when mating occurs between two genetically are different.
• Union of cytoplasm i.e., Plasmogamy, and union of Nuclei i.e., Karyogamy.
• The stage between plasmogamy and karyogamy contains two nuclei (dikaryon).
• Sexual reproduction methods: Plano gametic Copulation: Heterogamous fusion can be Oogamy and anisogamy.
• Gametangial Contact: Male gamete antheridia transfer to female gamete oogonia by fertilization tube.
• Gametangial Copulation: Formation of zygospore.
• Spermatogamy: Male cell carried to the receptive region of the female sex organ.
• Somatogamy: Reproduction occurs by the fusion of two hyphae.

Image 4: Sexual Reproduction in Fungi

2. Vegetative Reproduction:

• Budding: Bud is arising on the parent body. Budding occurs in yeast and many other fungi.
• Fragmentation: By mechanical reason or much other reason parent body breaks up into two or several segments and form a complete organism. Fragmentation occurs in Rhizopus.
• Fission: Yeast divide two or more daughters identical to the parent.

Image 5: Vegetative Reproduction in fungi

3. Asexual Reproduction: 

• Occurs by the formation of spores. They can be motile or non-motile. Sexually produced spores are ascospores, basidiospores and others are asexually produced spores.
• Zoospores: Spores are naked and motile. Flagella help in swimming. Examples: Phytophthora, Albugo, etc.
• Sporangiospores: They are non-flagellate and dispersed by air. Examples: Mucor, Rhizopus, etc.
• Conidia: Spores are non-motile and develop by special hyphae. Example: Penicillium, Aspergillus, etc.
• Chlamydospores: Spores are thick-walled and develop by the accumulation of protoplasm.
• Basidiospores: They are non-motile and develop from basidium.
• Oidia: Produce during excess water and particular salts. Example: Rhizopus etc.
• Ascospores: Spores are non-motile and produce inside asci.

Image 6: Fungal Spores

Fungus Classification:

Image 7: Kingdom Fungi

PHYCOMYCETES: 

• Sexual and Asexual reproduction occurs.
• Phycomycetes divide into two groups i.e., oomycetes and zygomycetes.

1. Oomycetes: Mycelium is multinucleate and aseptate.

• Spore formation occurs by asexual reproduction.
• Biflagellate zoospores, non-flagellate gametes, and smooth flagella are present.
•  Antheridium passes into oogonium by a fertilization tube.
• Examples: the late blight of potato caused by➡ Phytophthora infestans.

2. Zygomycetes: Mycelium is multinucleate and aseptate.

• Mostly saprotrophic, zoospores are absent.
• Non motile Mitospores are present.
• Gametangial copulation for the sexual reproduction.
• Gametes are multinucleate.
• Examples: Soft rot of Apple, strawberry is due to Rhizopus.

Image 8: Zygomycetes

Rhizopus:

• Rhizopus is a black bread mold.
• It is saprotrophic.
• Hyphae are rhizoidal, sporangiophores, stoloniferous, and zygophores.
• Rhizoidal hyphae are branched, sporangiophores are unbranched, stoloniferous are unbranched and zygophores are subaerial.
• Fragmentation for vegetative reproduction.
• Asexual reproduction by sporangiospores, chlamydospores, and oidia.
• Sporangiospores: Sporangiophore develops ➡ sporangium.
• chlamydospores: chlamydospores rise ➡ new mycelium.
• Oidia: They multiply by➡ budding.
• Sexual reproduction: Rhizopus stolonifer is heterothallic. Trisporic acids help in the formation of zygophores. Two gametangia are dissolves and two coenogametes form diploid zygote and zygospore. Germ sporangium develops germ spores.

ASCOMYCETES:

• They are pigmented moulds.
• Septate hyphae are present.
• Cell wall having chitin.
• Budding and fission for asexual reproduction.
• Conidiophores can be branched or unbranched.
• Sexual reproduction by sex cells, gametangial between antheridium and ascogonium.
• Plasmogamy and karyogamy for fertilization.
• Ascospores produce an ascus. The asci form ascocarps. 

Yeast: 

• They are nonmycelial or pseudomycelial.
• Mode of asexual reproduction in yeasts: Fission yeasts, budding yeasts, and halobial yeasts.
• Ascus formation is known in yeasts.
• Yeasts are unicellular and form temporary chains during rapid growth.
• It contains chitin and mannan β glucan.
• The mode of nutrition is saprotrophic.
• Budding and fission occur in asexual reproduction.

Image 9: Life cycle of Yeast

Economic importance of Yeast:

• Saccharomyces cerevisiae is used in baking food.
• Saccharomyces ellipsoidens are used in the brewing industry.
• Yeast is also used in vitaminized food.
• Some yeast is used in the silk industry.

Aspergillus:

• It contaminates bread, jellies, cheese, and laboratory cultures.
• It is rotting the cigars, figs, and many fruits.
• It also causes ear infections.

Penicillium:

• It is commercial antibiotics.
• It spoils citrus food, paper, apple, and other products.
• It helps in the formation of organic acids.

BASIDIOMYCETES:

• It is club fungi.
• Motile cells are not present.
• Primary and Secondary mycelia are present.
• Sex organs do not involve during sexual reproduction.
• Primary mycelium and Secondary mycelium are monokaryotic, dikaryotic respectively.
• Basidium can be septate or aseptate.
• A basidium produces four basidiospores.

Image 10: Basidiomycetes

Mushroom:

• Agaricus campestris is edible.
• The mode of nutrition is saprotrophic.
• Primary mycelium and Secondary mycelium are present but secondary is long-lived.
• Clamp connections show by secondary mycelium.
• Secondary mycelium gives rise mass of hyphae during favorable conditions.
• Stipe is fleshy and its base is swollen.
• Pilus is circular, looking like an umbrella.
• Basidiocarp produces several spores.

Toadstools:

• They are non-edible.
• Toadstools contain poison.
• Having white spores.
• Example: Amanita muscaria etc.

Smuts:

• They produce black spores known as smut spores.
• Spores are exposed in loose smut and spores are not exposed in covered smut.

DEUTEROMYCETES:

• The sexual stage is not known in this class.
• They are unicellular.
• Conidia help for asexual reproduction.
• Examples: Trichoderma, Early blight, Wilts, Arthrobotrys, Red rot, Tikka disease, etc.

Tikka Disease:

• Black and brown spots occur in groundnut leaves.
• Filamentous and septate conidia are present.

Red Rot:

• Midribs of leaf and canes effects by Colletotrichum falcatum, cause red rot in sugarcane.
• It decreases the juice content.

Wilts:

• Banana, Potato, Cotton wilts by Fusarium.
• Chlamydospores, macroconidia, and microconidia spores show by Fusarium oxysporum.

Early Blight:

• Causes occur in Potato and Tomato.
• Causal organism is Alternaria solani.
• Brown spots develop in the leaf.
• Branch and leaf are falls.

Lichens:

• It is the association of fungus and alga.
• The algal partner is a cyanobacterium.
• Lichen grows in alpines, tree bark, roofs, etc.
• Lichen's colors have green, orange, greyish, black, or brown.
• Alga performs photosynthesis activity.
• The fungus has minerals and water that are used by alga for the preparation of food. 

Image 11: Lichens

Importance of Lichens:

• They are used in dyes.
• Ramalina is used in Perfumes.
• Lichen use as colonisers.
• Usnea and Cladonia are used for medicinal purposes.

Mycorrhizae:

• Mutual beneficial of fungus and Root of higher plants.
• Absence of Root hairs and Root cap in these plants.
• Ecto mycorrhizae lie on the Root surface in bulk.
• Endo mycorrhizae lie on the Root surface in little.

Image 12: Mycorrhizae of Pinus

Conclusion:  It is cosmopolitan found in air, water, and soil. Fungi contain fungal cellulose and the food reserve as glycogen.

 This article contains Fungi Phycomycetes Ascomycetes Basidiomycetes with images for better understanding

See Also: Diversity Living World