The Body of Fungus

Explain the body of fungus?

THE BODY OF FUNGUS:

Mycelium:

The body of a fungus is called mycelium. (except yeasts which is non-hyphal unicellular fungi).

Hyphae:

Mycelium is composed of long slender, branched, tubular, thread like flaments called the hyphae (single hypha). Hyphae spread extensively over the surface of substratum. Their walls are composed of chitin, so their wall is more resistant to decay than are cellulose and lignin which is present in plant cell wall. Hyphae may be septate or non-septate.

Septate Hyphae:

Septate hyphae are divided by cross walls called septa (singular septum) into individual cells containing one or more nuclei. Septa of many septate fungi have pores through which ribosomes, mitochondria and even nuclei flow from cell to cell. Thus materials are carried to growing tips and enabling the hyphae to grow rapidly when food and water are abundant and temperature is favourable. Septate hyphae may be monokaryotic having one nucleus per cell or dikaryotic having two nuclei per cell.

Non-Septate Hyphae :

Non-septate hyphae lack septa and are not divided into individual cells. These are in the form of an elongated multinucleated large cells. Such hyphae are called coenocytic hyphae which consists of a continuous cytoplasmic mass with hundreds or thousands of nuclei. The coenocytic condition results from the repeated division of nuclei without cytoplasmic division.

Functions of Hyphae:

(i) Extensive spreading system of hyphae provides large surface area for absorption of nutrition, Parastitic fungi usually have some of their hyphae modified as haustoria, nutrient-absorbing hyphal tips that penetrate the tissue of the host.

(ii) Hyphae may be packed together and organized to form complex reproductive structures such as mushrooms, puff ball, morels etc., which can be expand rapidly. All fungal nuclei are haploid except for transient diploid zygote that forms during sexual reproduction.

A single mycelium may produce up to a kilometer of new hyphae in only one day. A circular clone of Armillaria, growing out from a central focus, has been measured up to 15 hectare (1 hectare = 10000m²) Armillaria is a pathogenic fungus afflicting conifers.