Microbiology Lichens Quiz

Lichen

a colony of two (or usually more) organisms living in a symbiotic

relationship with each other

microbiont

fungal organism in the lichen

photobiont

photosynthetic organism in the lichen

phycobiont

photosynthetic organism in the lichen that is specifically an algae

epiphyte

organism capable of growing on another plant (many belong to ascomycota and some belong to basidiomycota)

Lichen Morphology

crustose, foliose, fruticose, squamulose

important functions of lichens

• nitrogen fixation

• soil production through erosion

• pioneer species in ecological

succession

• winter food source for animals

• potential medicinal uses (many

produce antimicrobial compounds)

thallus

the lichen body

cortex

an upper and lower tightly packed protective fungal layer

medulla

lower loosely packed fungal layer

rhizines

bundles of hyphae that bind to surfaces

S reproduction

fungus produces spores→ spores germinate→ form association with photosynthetic component→spores envelop the photobiont with hyphae

vegetative (clonal) reproduction

both fungus and photobiont together form vegetative propagules→ propagules are dispersed via wind, rain etc→ must land in suitable environment to develop in lichens

Lichen Habitats

specific needs: air, nutrients, light, substrates, water

poikilohydry

the inability of an organism to regulate water retention and release via homeostatic mechanisms