MSC 1st semester

1. ANJANA.K

2. A. Beneficial aspects
B . Harmful aspects
1.

3.  Lichens plays crucial roles in the ecology; it
serves as a crucial component of many
ecosystems.
 Some of the key ecological roles of lichens
include
 Biodiversity : Lichens are adverse group of
organisms that contribute to the overall
biodiversity of an ecosystem. They are found
in a wide range of habitats, including forests,
tundra, and even urban environments.

4. Lichens serve as indicators of air pollution
Since lichens are very sensitive to
environmental changes (pollution), their
presence in an area indicate a pollution free
environment.
 Lichens cannot survive in the areas air
pollution due to the occurrence of sulphur
dioxide .
 Thus, lichens can act as indicator species for
monitoring air quality and other
environmental parameters.

5. Lichens are the first serial community (pioneer community)
in a xerarch succession.
Sequence of stages in xerarch succession are as
follows: Lichen stage → Moss stage → Herb stage → Shrub
stage → Climax community
Example: Caloplaca and Lecanora

6.  Lichens release lichen acids which help in
the weathering of rock and organic matter
that leads to the formation of soil.

7.  Lichen that contain cyanobacteria, are
capable of fixing atmospheric nitrogen.
Nitrogen fixation is essential for maintaining
soil fertility.

8.  Lichens have been used as a source of staple
food, food colorant, and food preservative for
centuries in some traditional cultures,
particularly in arctic and sub-arctic regions.
 In some cultures, lichens are used as a staple
food and are collected, dried, and stored for
later use.
 Reindeer moss (Cladonia rangiferina) is a
common food source for indigenous peoples in
the Arctic and is eaten either raw or cooked.
 The thallus of Umbilicaria has been eaten in
arctic regions in danger of striation.

9.  Species of Lecanora have been used as food
in Western Asia and Northern Africa.
 Parmelia is used as flavouring agent in some
culinary preparations of South India.
 Some lichens are used as a flavor enhancer
in some traditional dishes. Example: Iceland
moss (Cetraria islandica) is used as a spice in
Scandinavian and Icelandic cuisine.
 Some lichens are used as natural food
colorants due to their bright and distinctive
pigments.

10.  Some lichens have antimicrobial properties,
making them useful as natural food
preservatives.
 Example: Usnic acid, extracted from Usnea,
has been used to preserve cheese and other
dairy products.
 In France lichen are used for making
chocolates, pastries.
 Endocarpon miniatum used as vegetables.

11.  Cetraria islandica (Ice land moss)
 Usnea

12.  Lichens also have been used for medicinal
purposes for centuries in traditional
medicine.
 Some of the most important medicinal uses
of lichens are listed below
 Anti-inflammatory: Some lichens contain
compounds that have anti- inflammatory
effects, making them useful in the treatment
of rheumatoid arthritis and inflammatory
bowel disease. Example Parmelia, Usnea.

13.  Antimicrobial: Lichens contain a variety of
antimicrobial compounds, including usnic acid
and barbatic acid, which are effective against
many pathogenic bacteria.
 Anti-oxidant activity: Experimental evidence
suggested that barbatic acid (extracted from
Usnea and Cladonia) has antioxidant properties.
 Anticancer: Some lichen compounds are
promising for the treatment of various types of
cancer, including breast and colon cancers.
 Example: Barbatic acid exhibits cytotoxic and
genotoxic activity against some tumour cell lines
and it has a pro-apoptotic property as well.

14.  Wound healing: Lichens have been used for
wound healing in traditional medicine.
 Immune system booster: Lichens have been
shown to have immuno stimulatory effects,
making them useful for boosting the immune
system and preventing infections.
 Parmelia is used in snake and scorpion bites.

15.  Some of the most important industrial uses of lichens
include
1.In tannin industry
Cetraria icelandica, Lobaria pulmonaria used as tannin
agent in leather industries.
2. In fermentation and distillation process: In Russia,
Sweden and Siberia liquors are manufactured by
fermentation and distillation of lichen like Cladonia
rangiferina and Ramalina fraxinea.
3.As culture media
 Lichens are important constituents of some culture media
for the culture of fungi and bacteria in laboratories.
4.Lichens are good source of dyes: Lichens have been used
for centuries as a source of natural dyes for textiles and
other products

16.  Litmus is a pH sensitive dye extracted from
many species of Roccella, Lepra, Parmotrema
and Parmelia. Litmus is used to test the pH.
 Orchil or Orcein is a bright purple dye
extracted from Roccella tinctoria. Orchil is
used to stain cloth and wood. Orchil can also
stain chromosomes.
 Cudbear is a purple dye extracted from
orchil lichens used for colouring wool and
silk.

17.  In cosmetic : Lichens have been used as an
ingredient in cosmetics and personal care
products due to their antimicrobial
properties
 Perfumery: Some lichens produce fragrant
compounds that have been used in
perfumery for centuries. For example,
oakmoss (Evernia prunastri), a lichen that
grows on oak trees, is a common ingredient
in perfumes and fragrances.

18.  Bioremediation: Lichens have been used in
bioremediation, the process of using
living organisms to clean up contaminated
environments.
 Some lichen species are capable of
breaking down toxic compounds, such as
heavy metals, making them useful in the
clean-up of contaminated sites.

19. Some of the most notable harmful aspects of lichens
include:
 Allergic reactions: Some people can develop allergic
reactions to lichens, especially when they are exposed to
large amounts of airborne lichen spores. Symptoms of
lichen allergies can include itching and sneezing
 Toxicity: Some lichen species contain toxic compounds,
such as usnic acid, which can be harmful to humans and
animals if ingested in large amounts. Ingestion of toxic
lichens can cause a range of symptoms, including vomiting,
diarrhea, and respiratory distress.
 Building damage: Some lichens can cause damage to
buildings and other structures if they are allowed to grow
unchecked. For example, lichens can break down roofing
materials, cause discoloration of paints

20.  Lichens cause loss of the surface of glasses
and marble stones.
 Long threads of pendant lichens like Usnea
are inflammable, thus help in spreading
forest fire.
 Lichen like Cladonia cause total destruction
to the colonies of mosses by direct parasitic
attack.

21.  Write a note on reproductive bodies of lichens.
 Explain thallus structure of lichen.
 Write note on classification of lichen.
 Write an account on asexual reproduction of
lichen.
 Write an account on different groups of lichen
based on thallus. Explain the vegetative
propagates and economic importance.
 Write an account on systematic , thallus
structure and ecological significance of lichen