The fungi and Lichens

The fungi constitute a unique kingdom of heterotrophic organisms. They show a great diversity in morphology and habitat. Fungi are cosmopolitan and occur in air, water, soil and on animals and plants. They prefer to grow in warm and humid places. Food is kept in the refrigerators to prevent food from going bad due to bacterial or fungal infections.

• The bread develops a mould or orange rots because of fungi. 
• The common mushroom and toadstools are also fungi. 
• White spots seen on mustard leaves are due to a parasitic fungus. 
• Some unicellular fungi, e.g., yeast are used to make bread and beer. 
• Other fungi cause diseases in plants and animals; wheat rust-causing Puccinia is an important example. 
• Some are the source of antibiotics, e.g., Penicillium. 
• Most fungi are heterotrophic and absorb soluble organic matter from dead substrates and hence are called saprophytes. 
• Those that depend on living plants and animals are called parasites. 
• They can also live as symbionts – in association with algae as lichens and with roots of higher plants as mycorrhiza. 
• Reproduction in fungi can take place by vegetative means – fragmentation, fission and budding.
• With the exception of yeasts which are unicellular, fungi are filamentous. Their bodies consist of long, slender thread-like structures. 

Lichens: Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi. The algal component is known as phycobiont and fungal component as mycobiont, which are autotrophic and heterotrophic, respectively. Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients and water for its partner. So close is their association that if one saw a lichen in nature one would never imagine that they had two different organisms within them. Lichens are very good pollution indicators – they do not grow in polluted areas.