Basic types of fungal nutrition (FOR UG/PG STUDENTS)

 

Different modes of nutrition in fungi

                     The fungi are chlorophyll less organisms which cannot synthesize their own food unlike green plants. They are so simple in structure that they cannot obtain inorganic food directly from the soil and therefare , they are always dependent for their food on some dead orgainic materials or living beings. The different modes of nutrition in fungi are as follows----

1. Parasitic mode: Fungi, which obtain food from living organisms are called parasitic fungi. The parasitic fungi absorbe their food material from the living tissue of host. They are quite harmful to their host and cause many serious diseases. Parasitic fungi may be ectoparasite i.e., grow out side the plant body (eg. Erysiphe); or may be endoparasite i.e., grow inside the plant body (eg. Phytophthora) parasitic fungi are farther classified as-----

(a) Obligate parasite: some fungi obtain their food entirely from the living protoplasm of the host and maintain their mode of nutrition throughout their life cycle only as parasite, known as obligate parasites.

eg. Puccinia, Peronospora

(b) Fucultative parasite: some fungi passing their mood of life as saprophytes in the beginning and later on, under certain conditions, they behave as parasite.

eg. Pertalotia, Fusarium, Pythium 

2. Saprophytic mode: The saprophytic fungi live on dead organic materials propduced by the decay of animal and plant tissue. They grow upon dead organic materials such as rotten fruits, ritten vegetables, moist wood, moist leather, jams, jallys, plants debris, dungs of domestic animals, most bread ect.

eg. Saprolegnia, Mucor, Rhizopus, Aspergillus, Agaricus ect.

                                                    The saprophatic fungi absorb their food from substratum by ordinary vegetative hyphae which penetrate the substratum.

3. Symbiotic mode: Some fungi grow in the association of other plants and are mutually beneficial. This association is called symbiosis and mode of the association is called symbiotic mode. The participants of symbiosis are called symbionts. Symbiotic modes generally appear as two farms-----

(a)Lichen: Lichen is the symbiosis of alogae and fungi. Generally some members of ascomycetes and basidiomycetes class live in this type of symbiotic association.

eg. Rocella tinctora here fungi absorbe water and algae produce food.

(b)Mycorrhiza: Mycorrhiza is the association of fungi with roots of higher plants. In a mycorrhizal association, the fungus may colonize the roots of host plants either inter- cellularly or extracelluarly. This mutualistic association provides the fungus with a renewable source of food through access to carbon from plant photosynthate. In return, fungi provide nutritions like phosphorous, Nitrogen, cobalt, zinc, Potasium ect.

eg. Glomus sp. colonizes with Cycas.

4. Predacious mode: Some fungi developed ingenious mechanisms far capturing small animal such as eel worm rotifers or protozoa which they use for food. These fungi are known as predacious fungi sence predacious fungal genera are Dactyllela, Arthrobotrys.