NEET Biology Notes For Kingdom Fungi

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NEET Biology Notes For Kingdom Fungi

These are eukaryotic, heterotrophic, non-flowering, thalloid, mostly multicellular, decomposers, mineralizers of organic wastes, and help in the recycling of matter in the biosphere. The study of fungi is called mycology’. The term fungus was given by Gaspard Bauhin. Some important mycologists and their contributions/popularly known as

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Pier Antonio Micheli: Father or founder of mycology

E.M. Fries: Father of systematic mycology

H.A de Barry: Father of modem mycology

E.J. Butler: Father of Indian mycology

K.C. Menta: Famous for studying rust disease in wheat

Bessey: Defined fungi as chlorophyll-less. nonvascular Plants

NEET Biology Notes For Fungi General Characters

Fungi are mostly terrestrial and occur in soil. They may be aquatic, parasitic, saprotrophic, or symbiont (Lichen and Myconhiza). Saprophytic fungi are called vegetable vultures.

On the basis of habitat, fungi are classified as coprophilous (on dung), corticolous (on bark), epixylic (on wood), xerophilous (on burnt wood), lignicolous (on lignified wood), keratinophilic (on hairs, horns).

NEET Biology Notes For Fungi Somatic Structure

In most of fungi, the thallus consists of a mass of fine, tubular branching thread-like structures called hyphae which are usually woven into a network called mycelium.

Mycelium Is Of The Following Types:

  1. Primary Mycelium: Uninucleate, septate, for example, ascomycetes.
  2. Secondary Mycelium: Dikaryotic mycelium, for example, basidiomycetes.
  3. Coenocytic Mycelium: Multinucleate, aseptate, for example, oomycetes, zygomycetes.

NEET Biology Notes For Modifications Of Mycelium

  • Prosenchyma: Loosely arranged long elongated hyphae.
  • Pseudoparenchyma: Densely arranged hyphae giving a false appearance of parenchyma.
  • Sclerotium: Tough and hard perennating structure formed by a compact mass of hyphae, for example, Claviceps.
  • Rhizomorph: Dense mass of hyphae, running parallel. The hyphae lose their individuality; and subterranean nature; the growing tip looks like a root, for example, Agaricus.
  • Appressorium: Terminal swollen structure of germ tube for penetration and attachment.
  • Haustoria: Terminal swollen structure of germ tube for absorption of food.
  • Snares Or Hyphal Traps: Helps in capturing nematodes in preda¬ceous fungi such as Dactylaria and Arthrobotrys.

NEET Biology Notes For Fungi Cellular Structure

  • The cell wall is made of fungus cellulose/chitin, a polymer of TV-acetyl glucosamine (except oomycetes where cellulose occurs).
  • Presence of unicistemal Golgi bodies.
  • Karyochorisis type of mitosis occurs, it is mitosis with intranuclear spindle fibers formation.
  • Reserve food material is glycogen and oil.
  • Hyphae can be septate or aseptate. There are three types of septa in septate hyphae:
    • Complete septum,
    • Septum with simple pore (ascomycetes), and
    • Dolipore septum (basidiomycetes).

Fungi Nutrition: It is heterotrophic and absorptive.

NEET Biology Notes For Fungi Asexual Reproduction

Fungi Asexual Reproduction occurs by following asexual spores.

  1. Zoospore: Many fungi, especially aquatic fungi, produce this type of spore. It may be uniflagellate or biflagellate. The flagella are always heterokont type, i.e., of unequal length. Example. Saprolcgnia.
  2. Conidiosporcs Or Conidia: These are single-celled, double-celled, or many-celled structures borne on the sides of the hyphal structures called conidiophores. These are borne singly in chains.
  3. Chlamydospores: These are usually formed during unfavorable conditions and are thick-walled, single-celled spores that are highly resistant to adverse conditions, for example, Mucor.
  4. Sporangiospore: Noil-motile, multinucleate spore produced inside the sporangium, for example. Rhizopus.
  5. Oidia: Non-motile, thin-walled spores develop under the condition of excess sugar. The budding condition of oidia is called the tomla stage, for example, Mucor, and Rhizopus.

Fungi Sexual Reproduction: It involves plasmogamy, karyogamy, and meiosis. As a result of sexual reproduction, sexual spores are produced. However, these are fewer in number than the asexual spores. There are several types of sexual spores:

  • Ascospores: Usually, but not always, single-celled haploid spores are produced in a sac called an ascus (plural asci).
  • Basidiospores: Haploid spores produced exogenously by special structures called basidia (singular basidium)
  • Zygospores: Thick-walled diploid spores produced by tire fusion of entire gametangia.
  • Oospores: Formed within a special female structure, the oogonium as a result of fertilization of female oospheres by male gametes.

Plasmogamy is brought about by any one of the following methods:

  • Gametic Fusion Or Copulation: It may be isogamy, anisogamy, or oogamy, for example, Phytophthora.
  • Gametangial Contact: Fusion of female and amoeboid male gamete by fertilization tube, for example. Albugo, Pythium.
  • Gametangial Copulation: By fusion of gametangia, for example, Rhizopus, and Mucor.
  • Spermatization: Fusion between spennatia and receptive hyphae, for example, Puccinia.
  • Somatogamy: Fusion of somatic cells, for example, Agaricus.
    • The site of meiosis is zygospore/zygote/oospore, for example, oomycetes, or zygomycetes.
    • Site of meiosis is ascus, for example. ascomycetes.
    • Basidium, for example, basidiomycetes.

NEET Biology Notes For Classification Of Fungi

Humycota (true fungi) are classified into five classes:

  1. Oomycetes/Phycomycetes
  2. Zygomycetes
  3. Ascomycetes
  4. Basidiomycctcs
  5. Deutcromycetes

NEET Biology Notes For Fungi Oomycetes/Phycomycetes

  • Common Name: Algal fungi
  • Mycelium: Coenocylic
  • Cell Wall: Cellulosic
  • Asexual Spores: Zoosporcs/conidiosporangia
  • Sexual Reproduction: Gametic fusion and gametangial contact
  • Sexual Spore: Oospore
  • Aquatic phycomycetes are called water molds, for example, Saprolegnia, Plasmodiophora, etc.
  • Saprolegnia grows on dead bodies of insects, houseflies, tadpoles, and gills of fish causing salmon disease of gills in fishes. It shows diamagnetism, i.e., the formation of two types of zoospores-primary and secondary zoospores.

Common examples of oomycetes and diseases caused by them are as follows:

  • Synchytrium Endobioticum: Black wart disease of potato.
  • Phytophthora Infestens: Late blight disease of potato. The great Irish famine (1845-47) was caused by this fungus.
  • Albugo Candida: White rust of crucifers.
  • Pythium Debaiyanum: Damping off disease (seedlings).
  • Sclerospora Graminicola: Downy mildew of cereals

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