11th Class Biology Biological Classification And System Of Classification / जैविक वर्गीकरण और वर्गीकरण की प्रणाली Nutrition

The fungi are achlorophyllous organisms and hence they can not prepare their food. They live as heterotrophs i.e., as parasites and saprophytes. Some forms live symbiotically with other green forms.

Parasites : They obtain their food from a living host. A parasite may be obligate or facultative. The obligate parasites thrive on a living host throughout their life. The facultative parasites are infact saprophytes which have secondarily become parasitic.

Some forms produce rhizoids for absorbing food. The parasitic fungi produce appressoria for adhering to the host. For absorbing food, the obligate parasites produce haustoria. The haustoria may be finger-like, knob-like or branched. Each haustorium is distinguishable into a base, stem and body.

Saprophytes : They derive their food from dead and decaying organic matter. The saprophytes may be obligate or facultative. An obligate saprophyte remains saprophytic throughout it's life. On the other hand, a facultative saprophyte is infect a parasite which has secondarily become saprophytic.

Symbionts : Some fungal forms grow in symbiotic association with the green or blue-green algae and constitute the lichen. A few fungal forms grow in association with the roots of higher plants. This association is called as mycorrhiza. They are two types – Ectotrophic mycorrhiza and Endotrophic mycorrhiza e.g., (VAM).