Mycorrhizae Lichens

Lichens are

a symbiosis of fungus and algae, the dominant food source for reindeer and important pioneer organisms

characteristics of ghost ploant or indian pipe

lacks chlorophyll, perennial wildflower, pollinating relationship with bees, nutrients from fungi

ghost plant or indian pipe

monotropa uniflora

pinesap

monotropa hypopithys

characteristcs of pinesap (monotropa hypopithys)

perennial, temperate regions

tuber melanogaster and other truffles

ectomycorrhizal, form crucial symbiotic relationships with tree roots, such as oak, hazel, beech and pine

aminita muscaria

ectomycorrhizal

orchids

• mycoheterotrophs

• deoends on mycorrhizae for seed germination and subsequent growth

• seeds are small and do not have enough substance for germination

• specialized parasitism mycorrhizal relationship

chracteristics of mycorrhizae

• most plants are considered this

• not organisms (more considered an interation)

• important for absorbing nutrients from soils

• less dependency for fertilizer

groups of mycorrhizae

ectomycorrhizae and endomycorrhizae

ectomycorrhizae

• no direct penetration of plant root cells

• sheath protects plant roots

• material is absorbed by fungus and can cross cell walls to be absorbed by host plant

• large diversity of fungal agents, low diversity of plants affected

examples of ectomycorrhizae

• tuber melanogaster and other truffles

• aminita muscaria

• cantharellus

endomycorrhizae (arbuscular mycorrhizae)

• more common than ecto

• has hyphae that penetrate into cell

• obligate biotrophs

• low diversity of fungal agents, high diversity of plants affected

• played a role in plant evolution

how did endomycorrhizae play a role in plant evolution

• fossilized plant material formed around 400 million years ago had contained arbuscules

• molecular analysis suggests AM originated 460-350 MYA, when plants diversified on earth

benefits of mycorrhizae

• increased absorptive SA for better uptake of water and nutrients

• selective acquisition of some elements, especially phosphorus

• improved tolerance of poor soils

  • high pH

  • dry

  • chemical contaminants

• protection form soil-borne pathogens

  • fungi

  • nematodes

  • with mycorrhizae, seedlings have robust root systems

characteristics of lichens

• symbiotic unions of fungi and algae/ fungi and photosynthetic cyanobateria

• fungus gets food from algal (or cyanobacterial partner)

• algal partner gets protection from fungus

• symbiotic relationship allows both partners to colonize habitats, where separately they would be rare or non-existent

• reproduce by sexual propagules

• associated with primary succession

• used as food

• lichen acids dissolve rocks and concrete

• nitrogen fixation

• household usses

• used as indicators of air polution

how do lichens have household uses

medicine, dyes, perfume industry

sub-groups of lichens

• crustose

• foliose

• fruticose

crustose

tightly attached to substrate and flat on or beneath rock or tree surfaces

foliose

partially attached to substrate, flat but layered and leaf-like structure'; rounded or angular lobe

fruticose

partially attached to the substrate, upright with stalks and branches, bush-like

examples of fruticose

british soldiers and reindeer moss

what evidence suppors the hypothesis that fungi are parasitizing the algal partner

• a typical lichen is about 95% fungus tissue, the rest is algal

• fungus cannot live (in nature) without alga, but alga can live without fungus

• specialized fungus cells in algal cells resemble those of plant pathogens