spermatisation results in plasmogamy. Karyogamy is delayed and dikaryotic phase is prolonged. Karyogamy takes place in basidium and it is immediately followed by meiotic division. • The four nuclei thus formed are transformed into basidiospores which are borne on sterigmata outside the basidium (Exogenous ).
The basidium is club shaped with four basidiospores, thus this group of fungi is popularly called “Club fungi”. The fruit body formed is called Basidiocarp . Deuteromycetes or Fungi Imperfecti (b) Acervulus - Colletotrichum Conidiophore Seta Conidium Conidia (c) Synnema - Graphium Figure . : Reproduction in Deuteromycetes Pycniospore (a) Pycnidium - Phoma The fungi belonging to this group lack sexual reproduction and are called imperfect fungi.
A large number of species live as saprophytes in soil and many are plant and animal parasites. Asexual reproduction takes place by the production of conidia, chlamydospores, budding, oidia etc., Conidia are also produced in special structures called pycnidium , acervulus , sporodochium and synnemata (Figure . ). Parasexual cycle operates in this group of fungi.
This brings genetic variation among the species. . . Economic importance Fungi provide delicious and nutritious food called mushrooms.
They recycle the minerals by decomposing the litter thus adding fertility to the soil. Dairy industry is based on a single celled fungus called yeast. They deteriorate the timber. Fungi cause food poisoning due the production of toxins.
The Beneficial and harmful activities of fungi are discussed below: Beneficial activities Food Mushrooms like Lentinus edodes, Agaricus bisporus, Volvariella volvaceae are consumed for their high nutritive value. Yeasts provide vitamin B and Eremothecium ashbyii is a rich source of Vitamin B . Medicine Fungi produce antibiotics which arrest the growth or destroy the bacteria. Some of the antibiotics produced by fungi include Peni- cillin ( Penicillium notatum ) Cephalosporins ( Acremonium chrysogenum ) Griseofulvin ( Penicillium griseofulvum ).
Ergot alkaloids (Ergotamine) produced by Claviceps purpurea is used as vasoconstrictors. Industries Production of Organic acid: For the commercial production of organic acids fungi are employed in the Industries. Some of the organic acids and fungi which help in the production of organic acids are: citric acid and