Give a comparative account
of the classes of Kingdom Fungi under the following: (i) mode of nutrition (ii)
mode of reproduction.
Mode of nutrition: Fungi do not contain any chlorophyll in their body. So for nutrition they are dependent upon others. Mainly three types of nutritional status is being observed in fungi.
1. Saprotroph: saprophytic fungi grow on dead bodies of plants and animals. They secret specific types of enzymes-hydrolytic and cellulase. These enzymes breakdown the tissue of dead animals and convert complex organic molecules into simple molecules. Then it is uptake by the hyphae into the fungi body. E.g. oyster mushroom etc.
2. Paratroph: In this type of nutrition Fungi grow on host body and take their food from the host. Parasitic nature causes sometime harm to the host.
3. Mutualism: in this type of nutrition fungus serve mutualist relationship with other organisms. And both of them dependent on each other for their nutrition. E.g. mycorrhiza is a symbiosis between fungi and root of plant. It provides plant nitrogenous salt and make the soil fertile. Lichens also show this type of nutrition.
Mode of Reproduction:
In fungi three types of reproduction are observed. They are –
Vegetative reproduction: Occurs by fragmentation, fission, budding, rhizomatous, sclerotia.
Asexual reproduction: Accomplished by different spores in different situations. They are conidia, oidia, chlamydospores , endospore , pycniospore , ascospores , basidiospores , uredospores , teleutospores .
Sexual reproduction: It varies from isogamy, anisogamy , oogamy. It occurs by planogametic copulation ( fusion of motile gametes), gametangial contact (fusion of egg and amoebids male gamete), spermatozoon or spermatogamy ( male structure called spermatia are carried by insects ,water etc.)
According to mode of reproduction fungi can be divided into different groups:
Phycomycetes (egg fungi):
Mycelium is coenocytic, hyphal wall may contain chitin or cellulose. Asexual reproduction occurs with the help of conidio-sporangia. In moist environment they produce zoospores and in dry sporangia directly function as conidia. Sexual reproduction is oogamous. It occurs by the contact of gametangia where male nucleus enter the polonium through a conjugation tube.E.g. Phytopthora infestans.
Zygomycetes (conjugation fungi):
Mycelium coenocytic,hyphal wall contains chitin.Motile stage absent. Sporangiospres are born inside sporangia. Sexual reproduction involves fusion of coenogametes through conjugation. E.g rhizopus, mucor.
Ascomycetes (sac fungi):
Asexual reproduction occurs by means of exogenously produced conidia. Sexual reproduction by ascogonium (female) and antheridium (male) produces dikaryophase because karyogamy is delayed with plasmogamy .E.g. yeast,penicillium.
Basidiomycetes (club fungi):
Most advanced and best decomposer of woods. Primary mycelium is inconspicuous, haploid with monokaryotic cell. Secondary mycelium is Produced by fusion of two spores ( monokaryotic cell) . E.g. Agaricus, Puccinia.
Deuteromycetes (fungi imperfecti):
The group include fungi where sexual or perfect stage in not known. Mycelium is made of septate hyphae. Asexual reproduction is occur by conidia. E.g. Microsporum, Trychophyton.
Questions and Answers on Classes of Kingdom Fungi:
1. Which fungus causes early blight of potato?
2. Name the species causes Athlete's foot.
3. Name two predator fungi.
Dactylella bembicoides; D.ellipsospora.
4. Name two drug producing fungi.
Penicillium notatum– penicillin
5. What is Hyphae?
Body of fungus consists of microscopic threads or filament like structure is called hyphae.
6. What is mycelium?
Fungal body is a web of hyphae called mycelium.