Positive steps against hunger and toward self-sufficiency.

Kathy Wingard

Mushroom is a living organism and biologically known as fungus (pl. fungi). Its body is made up of cells that take the form of long filaments, known as hyphae (sing. hypha), and its structure as well as chemistry distinguishes it from other­ Kingdoms of Living World like Animal, Plant, Protista and Monera. Fungi, numbering about 200,000 species and distributed all over the world, have now earned the distinction of a separate Kingdom.

Mushroom is a fungus but every fungus is not a mushroom. Large macroscopic fleshy fungi are known as mushrooms. In the Kingdom of Fungi, the most species are microscopic and they do not come under the category of mushrooms. The larger fungi, which reproduce by forming mushrooms, flourish best in moist and shady habitats and biologically belong to the two sub-divisions of Ascomycotina and Basidiomycotina, either is characterised by the formation of a special type of sexual spore, the ascospore and the basidiospore respectively. Each of these two sub-divisions of the fungi is further divided into a number of Classes, Orders, Families, Genera and Species. Mushroom growers in India are, however, concerned with only three specific genera of the sub-division of Basidiomycotina for commercial exploitation of the technology of mushroom cultivation. These genera include Agaricus, Pleurotus and Volvariella. Agaricus is commonly known as button mushroom, Pleurotus as oyster mushroom and Volvariella as paddy-straw mushroom. The cultivation of mushrooms in India has earned some considerable popularity in recent years with reference to the two Agaricus species (Agaricus bisporus and Agaricus bitorquis), the two Pleurotus species (Pleurotus sajor-caju and Pleurotus citrinopileatus) and the two Volvariella species (Volvariella diplasia and Volvariella volvacea).

In each of these cultivated species, the fruiting body (commonly known as mushroom) consists of an umbrella-shaped cap (also known as pileus) that is supported on a stalk (also known as stipe) that is produced through aggregation of mycelia in the substratum. A ring-like structure, known as annulus, is found on the stipe of Agaricus, and a cup-like structure, known as volva, is noticed at the base of the stipe of Volvariella. Neither annulus nor volva is present in Pleurotus. The two faces of the gills (also known as lamellae) which are situated underside of the pileus and radiated from the apex of the stipe to the margin of the pileus bear enormous number of spores which are released at intervals and germinate in a suitable substratum to produce a hypha. Each individual hypha is a filament that grows by extension at the apex. While growing in the substratum, it produces enzymes that effect a breaking down of complicated substances into simple molecules. These molecules are 'absorbed by the hypha to provide energy for further growth. The hypha branches out and produces a number of hyphae. These hyphae in the substratum do not behave independently but act as a colony. The interwoven hypha forms a fluffy mass, known as mycelium (pl. mycelia), which gradually spreads throughout the substratum. Under favourable conditions the mycelia aggregate to form small knot-like buds, the beginning of a fruiting body (also known as primordia). It quickly expands and emerges out form the substratum as a fully-grown fruiting body (also known as carpophore or fructification).