Download - Presentation Lichens
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Group 3
Debby Masteriana(4113111008)
Leni Anggraini(4113111026)
Mawaddah Nasution (4113312010)Ummi Khairunisa(411331209)
Yerni Silalahi (4113312016)
Yohannes (4113111083)
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LICHENS
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Why study lichens?
They grow just abouteverywhere
They tell us about the health
of our environment
They are very useful; - asrecyclers of nutrients,providing homes for insects,
humans extract dyes fromthem, eat them, use them asingredients in drugs andcosmetics
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What are lichens?
Unlike trees, grasses and flowers, lichens arenot a single plant
Composite Organisms created by arelationship between fungus and algae. Thefungus provides the body in which the alga canlive protected from light and drought. The algamakes the food for the fungus.
They are actually composed of two organismsliving together in a symbiotic relationship
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Grow on walls, rocks, tree bark, and otherplaces where neither fungus nor algaecould exist alone.
They grow very slowly.
They can withstand extreme heat and cold(but not smoke or fumes).
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Types
Leafy (foliose)
There are about 30,000 species of lichen worldwide, covering8% of the land surface. There are 3 main types
Shrubby (fruticose)
Crusty (crustose)
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Crustose (Crusty) Lichen:
Grows flat or may be embedded in thebark or rock surface.
The entire undersurface of this type isattached.
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Some Crustose Lichens
Caloplaca saxicola(Medlin)
Xanthoria elegans(Medlin)
Rhizocarpongeographicu
m(map lichen)
(Medlin)
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Foliose (leaf-like) Lichen:
Attached in spots with marginsor ridges that are often lobedand free. They curl up off of thesurface from which they grow,and look like crumbled leaves.
This type is attached to the
surface by many root-likethreads.
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Some Foliose Lichens
Cetraria arenaria,Medlin
Pulmonaria lobata, Medlin
Parmelia sulcata, Medlin Peltigera canina, Medlin
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Fruticose (treelike or shrubby)Lichen
Like a branched plant.
They grow upright or hang from the
surface from which they grow and areonly attached to the surface at thebase.
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Some Fruticose Lichens
Cladina rangiferina,Brodo
Cladina stellaris, Medlin
Usnea hirta, Medlin Teloschisteschr so hthalmus
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Squamulose
Similar to Crustose, but with Raised Edges which can be Folded or Lobe-
Like.
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Lichen internal structure
Lichens are natures biological monitors of pollution
and air qualityThalli act like spongesSome species more sensitive to pollutionWhich species are present can indicate air qualityMost resistant species can also be analyzed forpollutants, including bioaccumulation of heavymetals and radioactive isotopes
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Lichens and air quality
Lichens are very sensitive to sulphur dioxide(SO2) pollution in the air from industry andburning fossil fuels, especially coal
They absorb it dissolved in water
It destroys the chlorophyll in the algaepreventing it from photosynthesising and killing
the lichen.
Levels have fallen since the 1970s
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Nitrogen pollutants
Nitrogen compoundsfrom traffic on roadsand from intensive
farming (fertilisers)have become majorpollutants
Town and countryareas can be affected
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Bio-indicators
Lichens are widely used as environmentalor bio-indicators
If the air is clean, shrubby, hairy and leafylichens become abundant
If the air is polluted more tolerant crustylichens are present
In extreme cases of high pollution, theremay be no lichens at all (lichen deserts)
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Sexual Reproduction in Lichens
* Only the fungal partner undergoes sexual reproduction
* In the ascomycetous (i.e. most) lichens, ascospores areformed in sacs called asci, mixed with paraphyses to form ahymenium.
* Asci can be arranged on an open or convex or concave disk,when it is called an APOTHECIUM, or in an immersed, urn-shaped PERITHECIUM.
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Asexual reproduction in lichens
* Fragmentation of thallus when dry and brittle
* Detachment of isidia
* Loose dusty masses of soredia
* Pycnidia
A. Soredia burstingthrough thallus ofLobaria
B.External view ofsorediate mass
Pycnidium of Lecanora
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Human Uses of Lichens* Brown, purple and red fabric dyes (e.g. Scottish tweeds
and tartans)
* Indicators and stains (e.g. litmus and orcein)
* Emergency foods, e.g. rock tripe (Umbilicaria)
* Part of the daily diet, e.g. Lecanora esculenta(manna?)in Iran, flour from Cetraria islandica(Iceland moss) inScandinavian ships biscuits, Inuit nirukkaq - partlydigested lichens from caribou & muskox stomachs in winter
* Commercial production of sugar in Russia, WWII
* Iwatake (Umbilicaria esculanta) as delicacy in Japan
* Food additive io retard spoilage
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More uses of lichens - medicine,embalming and perfumery (see
Richardson for details)
* Many lichen extracts are inhibitory to the growth ofGram-positive bacteria
* Some are also effective against Mycobacteriumtuberculosus
*Oakmoss (Evernia prunastri) and Treemoss(Pseudoevernia furfuracea) are used in Europe to make
fixatives for perfumes and soaps.
* The antibiotic properties of lichens were exploited bythe ancient Egyptians in their embalming procedures
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Result Observation
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Thank Youfor
Your Attention
:D