Introduction to Lichens
- 2. LICHENS Prepared By: Asad Khan Roll No: B-01 5th Semester BS Botany
- 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.
- 8. CRUSTOSE • Flattened • Scale-like • No lower surface • Tightly bound to substratum
- 10. FOLIOSE • Flattened • Leaf-like • Branching lobes loosely attached to the substratum • Have upper and lower surfaces • Anatomically similar to Angiosperm leaf.
- 16. FRUTICOSE • Branched • Strap-shaped or Thread- like Thallus • Upright or Hanging
- 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.
- 23. BASIDIOLICHENS • The fungal member of this lichen belongs to Basidiomycota. • e.g. Dictyonema and Corella.
- 24. DEUTEROLICHEN • The fungal partner belongs to Deuteromycota.
- 25. REPRODUCTION
- 27. ASEXUAL REPRODUCTION 1. Soridia Formation o fine powdery granules 2. Isidia Formation o minute outgrowths from the thallus
- 28. SEXUAL REPRODUCTION • Perform by fungal component. • Ascospores and Basidiospore formation • Ascospore and Basidiospore germinate and make contact with algal cells.
- 29. Scanning electron micrograph (SEM) of a lichen. APOTHCI A
- 31. HARMFUL EFFECTS
- 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.
- 33. USEFUL EFFECTS
- 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.
- 36. INDUSTRIAL USE • Brewery and Distillation • Preparation of Dye
- 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.
- 39. REFERENCE • www.biologydiscussion.com/lichens-2/lichens-definition-structure-and-reproduction- with-diagram/69697 • https://biologyboom.com/lichens/ • www.Britannica.com/science/lichen • https://en.wikipedia.org/wiki/lichen
- 40. THE END
- 41. THANKS