LICHEN

PRERNA FOR IAS

         Mehnat Aapki, Guidance Humari

         Roz ki Prelims Practice — Experts ke Saath

LICHEN

1. Lichen

Lichen is a unique symbiotic association between an alga (or cyanobacterium) and a fungus. In this partnership, the alga performs photosynthesis and prepares food, while the fungus provides water, minerals, protection, and support. Lichens grow on rocks, tree bark, soil, and old walls, often in harsh environments where other plants cannot survive. They are slow-growing organisms and are highly sensitive to air pollution, making them excellent bioindicators of environmental quality. Lichens contribute to soil formation by breaking down rocks and play important ecological roles. Some species are also used in dyes, perfumes, medicines, and traditional remedies.

2. Industrial Products Obtained from Fungi

Fungi are economically important microorganisms that produce many valuable industrial products through fermentation and biotechnology. They are used to manufacture citric acid, gluconic acid, enzymes, vitamins, organic acids, and alcoholic beverages such as beer and wine. Certain fungi also produce yeast, which is widely used in baking and brewing industries. Some species are used in cheese production and food processing. Industrial fermentation using fungi has become an essential part of pharmaceutical, food, and chemical industries because fungal products are cost-effective, environmentally friendly, and can be produced on a large scale under controlled conditions.

3. Antibiotics Produced by Fungi

Many fungi produce antibiotics, which are chemical substances that inhibit or kill harmful bacteria. The most famous example is Penicillin, discovered from Penicillium notatum by Alexander Fleming in 1928. Other fungal antibiotics include Cephalosporins, Griseofulvin, and several antifungal compounds. These medicines are widely used to treat bacterial and fungal infections in humans and animals. Antibiotics derived from fungi have revolutionized modern medicine by reducing deaths from infectious diseases and making complex surgeries safer. However, the misuse of antibiotics can lead to antibiotic resistance, making responsible use essential for effective treatment.

4. Plant Diseases Caused by Fungi

Fungi cause several serious diseases in crops, reducing agricultural productivity and economic returns. Common fungal diseases include rust of wheat, smut of maize, red rot of sugarcane, late blight of potato, powdery mildew, and rice blast. These pathogens infect leaves, stems, roots, fruits, or seeds, leading to poor growth and lower yields. Some fungal epidemics have caused severe famines, such as the Irish Potato Famine. Farmers manage fungal diseases through resistant crop varieties, crop rotation, fungicides, proper irrigation, and good field sanitation. Effective disease control is essential for ensuring food security and sustainable agriculture.

5. Human Diseases Caused by Fungi

Fungi can infect humans and cause diseases known as mycoses. Common fungal infections include ringworm, athlete’s foot, candidiasis (thrush), aspergillosis, and histoplasmosis. These infections may affect the skin, nails, hair, mouth, lungs, or other organs, especially in people with weakened immune systems. Fungal diseases spread through direct contact, contaminated surfaces, or inhalation of fungal spores. Most superficial infections can be treated with antifungal creams or medicines, while severe infections require specialized treatment. Maintaining personal hygiene, keeping the skin dry, and avoiding contaminated environments help prevent many fungal infections.

6. Kingdom Plantae

Kingdom Plantae includes multicellular, eukaryotic organisms that possess chlorophyll and prepare their own food through photosynthesis. Plant cells have cellulose cell walls, large vacuoles, and chloroplasts. Plants play a vital role in maintaining ecological balance by producing oxygen, absorbing carbon dioxide, preventing soil erosion, and providing food, medicine, timber, and fibres. The kingdom includes algae, bryophytes, pteridophytes, gymnosperms, and angiosperms. Plants reproduce sexually and asexually and exhibit alternation of generations in their life cycle. They form the primary producers of ecosystems and are essential for sustaining life on Earth through energy transfer and nutrient cycling.