THE FUNGI & LICHENS Flashcards
Lichens occur in three general growth forms:
foliose
crustose
fruticose
symbiosis of algae or cyanobacteria living among filaments of multiple fungi species
are traditionally grouped based on these vegetative growth forms.
may reproduce both sexually and asexually.
Lichens
leaf-like thallus
foliose
crust-like thallus
crustose
with an erect or pendant, usually much branched thallus with tissues that tend to form cylinders
but may also be flattened
fruticose
Sexual reproduction is carried out through the formation of _____ depending on the fungal component of the lichen
ascocarp or basidiocarp
Hence, lichens may further be described as ______ based on their fruiting bodies.
ascolichen or basidiolichen
They are hard to the touch and each has an outer layer of cortex-like
tissue, enclosing an inner layer consisting of loosely packed hyphae and algal cells. They are narrowed at the base and quite easily become detached. the short, sometimes branched outgrowths of the surface of the thallus are usually colored red, black, brown, green or orange. lichens
ISIDIA
consist of a few photobionts enveloped by a loose, spherical
mantle of hyphae in lichens. powdery
They are formed by the proliferation of the medulla and algal cells and may occur diffusely on the surface of the thallus
Soredia
delimited areas that produce soredia
soralia
Soredia bearing lichen
Ramalina nervulosa
ISIDIA bearing lichen
Cladonia sp
fruticose lichen
Cladonia sp, Ramalina. Nervulosa
foliose lichen
Parmelia
five divisions,of fungi
Chrytridiomycota (chytrids), Zygomycota (zygote fungi),
Glomeromycota (arbuscular mycorrhizal fungi), Ascomycota (sac fungi) and Basidiomycota (club fungi).
All fungi lacking or at least with yet to be known sexual reproduction have been traditionally lumped into a group called
Deuteromycota (imperfect fungi)
They have chitinous cell wall and form spores as reproductive structures. They are achlorophyllous and lack any plastid. They digest food outside their bodies and release enzymes (exoenzymes) into the surrounding environment, breaking down organic matter into a form they can absorb. This makes them very important decomposers of organic materials. While majority are opportunistic
saprobes (or decomposers), other fungi live as parasites or symbionts of other organisms.
fungi
multicellular filaments
hyphae
hyphae thathave septa or cross-walls within the cells
Septate hyphae
lack these cross-walls and the cells are continuous, i.e. one-large branched cytoplasm with many nuclei
Nonseptate hyphae
A connected mass of hyphae
This makes–up the thallus, the fungal vegetative body.
mycelium
Certain fungi grow in association with green algae or cyanobacteria
lichen
Most species grow as molds on bread, fruits or rootcrops causing them to rot on storage. Some occur as parasites or symbionts of animals. The hyphae are coenocytic, with septa found only where reproductive cells are formed. repdocues both asexually and sexual
Division Zygomycota (zygote fungi)
the photobiont (green algae or cyanobacteria) synthesizes carbohydrates and other food substances while the mycobiont (fungal partner) absorbs and provides moisture. These mycobionts, which are either sac or club fungi, are obligate symbionts whereas the photobionts, are facultative symbionts frequently found independent of the
lichen symbiosis.
lichen
develop at the tips of the upright hyphae and may contain hundreds of haploid sporangiospores.
sporangia
sporangia may contain hundreds of
haploid sporangiospores.
If the mold consumes all its food or the environmental conditions deteriorate, it may reproduce
sexually.
sexually reproducing zygomycota
Hyphae from opposite mating types unite and form zygosporangia which are resistant to environmental
extremes. Mating types possess different chemical markers but may appear identical. When conditions
improve, the zygosporangia germinate into new mycelia.
behave as roots, anchoring the fungus into its substrate, releasing digestive enzymes, and absorbing nutrients for the fungus
rhizoids
are special horizontal strands of hyphae connecting the fungal bodies
Stolons
are upright growing hyphae which bear sporangia at their tips.
Sporangiophores
Certain compatible hyphae form zygosporangium containing a thick-walled resting spore called
zygospore
is suspended on both sides of these hyphae with suspensor cells.
zygosporangium
This is the most diverse group of fungi with approx. 65,000 known species from a wide range of marine,
freshwater and terrestrial habitats. The group is defined by the production of sexual spores (ascospores) in
saclike asci (sing. ascus).
Division Ascomycota (sac fungi)
, ascomycetes develop fruiting bodies called
during sexual stage
ascocarps
Most common forms of ascocarp
apothecium, cleistothecium and perithecium
Most common forms of ascocarp
are stalked and either disc-like, saucer-shaped, or cup-shaped with exposed asci.
Apothecia
Most common forms of ascocarp
spherical and must rupture or disintegrate to release their ascospores.
Cleistothecia
are globular or flask-shaped with an apical opening for discharge of ascospores.
Perithecia
Ascomycetes reproduce asexually by producing asexual spores called
conidia
conidia are formed externally at the tips of specialized hyphae, called the
conidiophores
Ascomycetes include both unicellular
and filamentous species.
true
for ascomycota, filaments are septate and become dikaryotic (i.e. each cell of the filament
contains two separate haploid nuclei) after plasmogamy or fusion of the hyphae from different mating types.
true
unicellular ascomycete, used in the production of various food stuff, wines and beers. The cells are globose and ellipsoid to elongate in shape.
Saccharomyces cerevisiae
Saccharomyces cerevisiae reproduction
Multilateral (multipolar) budding is typical, producing blastoconidia or blastospores
form globose ascospores in asci, which do not rupture at maturity.
yeast
Each yeast ascus contains_____
ascospores.
1-4
a cup fungus that produces apothecium usually attached on decaying wood. ascomycete
Peziza
shows a mycelium constructed of loose dikaryotic hyphae underneath, with tightly packed spore
producing structures (called asci) on top.
Peziza
fertile layer consisting of asci
hymenium
sexual spores within asci
ascopores
thin layer of interwoven hyphae immediately below
the hymenium of an apothecium
hypothecium
outer layer of the apothecium
ectal excipulum
inner layer of the apothecium
medullary excipulum
form long chains of conidia at the tip of phialides
organization of the phialides at the tips of the conidiophores is very typical. They form brush-like clusters
which are also referred to as “penicilli”
Penicillium
conidia (2.5-5μm in diameter) are round, unicellular, and
appear like unbranching chains at the tips of the phialides.
Penicillium
are flask-shaped structures carried on secondary branches (metulae) that form on conidiophores.
phialides
form long chains of conidia at the tip of phialides
conidiophores originate from the basal foot cell located on the supporting hyphae and
terminate in a vesicle
Aspergillus
is the typical formation for the genus Aspergillus
Vesicle
Covering the surface of
the vesicle entirely (“radiate” head) or partially only at the upper surface (“columnar” head) are the flask
shaped phialides which are either uniseriate and attached to the vesicle directly or are biseriate and
attached to the vesicle via a supporting cell, metula Over the phialides are the round conidia (2-5 μm in diameter) forming radial chains.
Aspergillus
