Correct Answer - Option 2 : Air pollution
The correct answer is- Air pollution
Concept:
- The term ''Lichen'' was given by Theophrastus.
- Study of Lichens - Lichenology.
- Father of Lichenology - Erik acharius
- Lichen is a composite thalloid structure of algae & fungi.
- The algal part of Lichen is called phycobiont and the fungal part is called mycobiont. Both algae & fungi remain in symbiotic association i.e. they are beneficial for each other.
Explanation:
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Lichens are good indicators of air pollution – Lichens are sensitive towards SO2(sulphur dioxide). They die in more concentration of SO2. Therefore they are not found in those areas (polluted areas) where the concentration of SO2 is high.
Other ecological importance of Lichen:
- Many Lichens are used as food and fodder. Eg –Parmelia, used as food in South India. It is known as Rock Flower.
- It is also used as dyes. Eg – Litmus(Acid-base indicator) is obtained from many members of lichens like Roccella tinctoria.
- The crustose and foliose lichens grow on rocks and secrete different types of acids These acids break the rocks. In this way, these lichens help in soil formation.