Lichens Flashcards
What makes up a lichen
Ascomycete, basidiomycete yeast, and a photosynthesis partner (algae or Cyanobacteria)
2 microbionts and 1 photobiont
Can fungi and algae within lichens grow independently?
Yes
Microbiont cells often grow slowly, don’t reproduce, lack morphology of lichen thallus.
Photobiont cells multiply and reproduce easily in pure culture
Taxonomy of lichen is based on ____ morphology
Mycrobiont
Who proposed that the algae and fungus grow Independently within a lichen
Beatrix potter
Benefits of the lichen symbiont relationship
-lichens able to expand habitat into rocks and trees where there is more solar radiation
-mycobiont may absorb minerals from substrate and may absorb nutrients from the atmosphere (N2) from the algae
-protections for algae within the fungal strucure-chemical, solar and physical protection
Upper cortex of lichens can screen ____% of solar radiation
50
3 forms of lichens
Crutose
Foliose
Fruiticose
Crutose lichen
Form cheats that grow so closely to substrate that they can not be removed without damage to substrate
Foliose lichen
Leaf-like, composed of lobes, loosely attached to substrate by rhizines
Fruticose lichen
3D in structure, branched and round in cross section
Lichens as bio indicators
Are extremely vulnerable to habitat alteration. More lichens=less disturbances
Macrobiotic crusts
Intimate association between lichens, mosses and Cyanobacteria.
Stabilize soil against erosion by wind and water
Free-living Cyanobacteria and the Cyanobacteria in lichens, fix nitrogen allowing for nitrogen into habitats
Lichens as colonizers
Primary succession
Nicknamed nature’s pioneers because they have the ability to colonize bare rock and are often the first plant-like forms to become established on newly exposed surfaces
Brings in Nitrogen, carbon, invertebrates, traps seeds
Boreal lichen woodlands
Boreal forest covers a large part of the northern hemisphere.
Lichen ground cover is 50-90%
Preserve soil moisture, reflect heat, add organic matter, trap seeds
Lichens and Caribou
-lichens on ground are primary winter food for caribou (90%)
-rumen microorganisms help metabolize usnic acid in lichens
-partially digested lichens in gut where eat by indigenous people
Most serious threat to the continued health of lichens is …….
Increased air pollution
Lichens absorb minerals in rain, and the presence of pollutants, including sulphur, will result in the decline of the thallus.
Species of lichens vary in sensitivity to air pollution-> bio indicator species of pollution intensity (Chernobyl)
Lichen dyes
Lichens are a common source of natural dyes. They are extracted by either boiling water or “ammonia fermentation”
Ammonia fermentation involves letting the lichen steep in ammonia for at least 2-3 weeks
Lichens for medicine
Estimated that 50% of all lichen species have antibiotic properties. One of the most potent lichen antibiotics is usnic acid as a result the species is commonly used in traditional medicine
