this presentation is about lichen. in these slides we will study about lichen which is a symbiotic association between algae and fungi. it consist of the following studies introduction to lichens, its History, Distribution, External Structure of Thallus (Shapes of Lichens), Internal Structure of Thallus, Classification, Reproduction, Harmful Effects, Economic Importance etc.
3. CONTENTS
1. Introduction
2. History
3. Distribution
4. External Structure of Thallus (Shapes of Lichens)
5. Internal Structure of Thallus
6. Classification
7. Reproduction
8. Harmful Effects
9. Economic Importance
4. INTRODUCTION
• Beneficial Association or combination of Algae and Fungi.
• Dual Organism
• Algal Component ---- Phycobiont (e.g. Trebouxia)
• Fungal Component – Mycobiont
5. HISTORY
• The term lichen is used by Theophrastus in History of Plant.
• Lichen is a word of Greek origin which means “any superficial growth on the bark of
trees”.
6. DISTRIBUTION
• 400 genera and 15000 spp.
• Cosmopolitan
• Found in Temperate and Tropical regions.
• Grow on soil, rocks, trees, marine.
• Also in Arid to Moist.
10. FOLIOSE
• Flattened
• Leaf-like
• Branching lobes loosely
attached to the substratum
• Have upper and lower surfaces
• Anatomically similar to
Angiosperm leaf.
19. HOMOISOMEROUS
• Fungal hyphae and the algal cells are
uniformly distributed throughout the
thallus.
• Both the partners intermingle and
form thin outer protective layer.
• Found in Crustose Lichens.
20. HETEROMEROUS
• Thallus is differentiated into four distinct
layers .
1. Upper Cortex
2. Algal Zone
3. Medulla
4. Lower Cortex
• Foliose and Fruticose Lichens
22. ASCOLICHENS
• Fungal member of this lichen
belongs to Ascomycota.
• Form two type of Fruiting bodies.
1. Apothecia (Disc-Shaped)
2. Perithecia (Flasked-Shaped)
• e.g. Parmelia and Dermatocarport.
28. SEXUAL REPRODUCTION
• Perform by fungal component.
• Ascospores and Basidiospore
formation
• Ascospore and Basidiospore
germinate and make contact with
algal cells.
32. .
• Amphiloma and Cladonia parasitize on mosses
(Reindeer moss) and cause total destruction of
moss colonies.
• Different lichens, mainly crustose type, cause
serious damage to window glasses and marble
stones of old buildings.
• Lichens like Letharia vulpina (wolf moss) are
highly poisonous. Vulpinic acid is the poisonous
substance present in this lichen.
34. AS FOOD AND FODDER
• Used as food by human being in many
parts of the world .
• Also by different animals such as Snails,
Slugs and Termites etc.
• Contain polysaccharide, lichenin,
cellulose, vitamin and certain enzymes.
35. AS MEDICINE
• Used in the treatment of Diarrhoea,
Fevers, Epilepsy, Hydrophobia and
Skin diseases.
37. COSMETICS AND PERFUMERY
• The aromatic compounds available in
lichen thallus are extracted and used in
the preparation of cosmetic articles and
perfumes.
• Essential oils extracted from species of
Ramalina and Evernia are used in the
manufacture of cosmetic soap.
