Fig. 38.4
1. The 2N megasporocyte
nucleus undergoes
meiosis to produce
haploid nuclei.
2. One of these 1N nuclei
divides multiple times
by mitosis, producing
several 1N clones. (The
function of most of
these cells is unknown.)
3. Double fertilization
produces a 2N zygote
and 3N endosperm
Kingdom Fungi
Characteristics of Fungi
• Fungi are NOT plants
Justify this statement…
• Absorptive heterotrophs
• Reproduce by spores
* reproductive bodies are
often the most visible
• “Ecologically active”
* hyphae = tubular units
of construction
* secrete exoenzymes
Briefly describe an
example in each of the
following fungal lifestyles:
•decomposers
•parasites
•symbionts
Fig 31.1
fruiting bodies
both are
composed
of hyphae
mycelium
?
(Protista)
Fig 32.2
Proposed Phylogeny of Eukaryotes
Fig 28.8
Fig 31.4
zygosporangia
asci
basidia
Where do chytrids live?
motile spores
Classification in these three phyla is
based on sexual reproductive structures
Hyphae
•
•
•
•
tubular
hard wall of chitin
around the cell
membrane
septa (perforated crosswalls) may form
compartments (± cells)
multinucleate
Septate hypha
Coenocytic hypha
Haustoria*
*80% of plant diseases are caused by fungi
What do you think is the purpose of perforated cross-walls?
Hyphal growth
Where would you find the hyphae of most fungi?
• Hyphae grow from their tips
• Mycelium = extensive, feeding web of hyphae
Why is SA important?
• Mycelia are the ecologically active bodies of
fungi
This wall is rigid
Only the tip wall is plastic and stretches
What does absorptive
heterotrophic nutrition look like?
•
•
Fungi get their energy and raw materials from
organic sources in their environment
The products of digestion diffuse back into
hyphae
Nucleus “hangs back”
and directs metabolism
Products diffuses back
into hyphae for use
Modifications of hyphae
Fig 30.2 (don’t worry
about the terms we don’t
discuss in class)
Reproduction by spores
•
•
Spores are reproductive cells
* Sexual
* Asexual
Produced
Classification of fungi is
based on which mode of
spore production?
What is the primary
purpose of spores?
* fruiting bodies
* inside sporangia
* directly on hyphae
Penicillium hyphae
(Ascomycota)
Amanita fruiting body
(Basidomycota)
Pilobolus sporangia
(Zygomycota)
Fungal Ecology
• Saprobes
* Decomposers
* Mostly of plants, some animals
• Parasites
* Harm host
* Mostly on plants, some animals
• Mutualists
* Lichens
* Mycorrhizas
Zygomycota – “zygote fungi”
•
•
•
•
Sexual - zygosporangia
Asexual spores common
Hyphae have no cross
walls
Grow rapidly
Fig 31.6 Rhizopus on strawberries
Sexual zygsporangium
with one zygospore
Asexual sporangium
with spores inside
Fig. 31.7
Fig 31.7 Life cycle of Rhizopus
You are not responsible for the details of
this life cycle. Life cycle is predominantly
haploid
Ascomycota – “sac fungi”
•
•
•
•
•
•
Sex. – asci
Asex. – common
Cup fungi, morels,
truffles
Important plant
parasites & saprobes
Yeast - Saccharomyces
Most lichens
A cluster of asci with spores inside
Ascomycota –
“sac fungi”
1 cm
Aleuria
Fig 31.9b Tuber melanosporum
The black french truffle
Basidiomycota – “club fungi”
•
•
•
•
•
•
•
Sex – basidia
Asex – not so common
Long-lived mycelia
Rusts & smuts – primitive
plant parasites
Mushrooms, puffballs
Enzymes decompose wood
Mycorrhizas
SEM of basidia and spores
See Fig. 31.12
Marasmius oreades - “Fairy Ring”
From: http://botit.botany.wisc.edu/toms_fungi/mar2003.html
A rust growing
on a currant leaf
0.5 cm
Amanita, “death angel”
Inocybe, contains muscarine
Boletus edulis
Cantharellus, the chanterelle
Fomitopsis
Hyphal fusion mycelium and fruiting
of haploid
body are dikaryotic
mycelia
haploid
mycelium
Mushroom
Life Cycle
N
Meiosis
2N
N+N
Nuclear
fusion in
basidium
young basidia - the
only diploid cells
Fig 31.12
“Alternative” fungal lifestyles
•
•
•
•
Yeasts
Molds
Mycorrhizas
Lichens
Yeasts
•
•
Single celled fungi
Adapted to liquids
* Plant saps
* Water films
* Moist animal tissues
Saccharomyces
Candida
Molds
•
•
•
Rapidly growth
Asexual spores
Many of human
importance
* Food spoilage
* Food products
* Antibiotics, etc.
Noble Rot - Botrytis
Fig 31.21 Antibiotic activity
Mycorrhizas
•
•
“Fungus roots”
Mutualism between:
* Fungus (nutrient & water uptake for plant)
* Plant (carbohydrate for fungus)
•
Several kinds
* Zygomycota – hyphae invade root cells
* Ascomycota & Basidiomycota – hyphae invade root but
don’t penetrate cells
•
Extremely important ecological role of fungi!
Lichens
• “Mutualism” between
* Fungus – structure
* Alga or
cyanobacterium –
provides food
By what process do these symbionts
produce food for the fungus?
• Form a thallus
* Foliose
* Fruticose
* Crustose
Fig 31.16
Lichen internal
structure
Lobaria
What do the fungi provide in
this symbiotic relationship?
Fig 31.17
Lichens as biomonitors
• Thalli act like sponges
* Airborne dust, minerals, etc. adsorb to the
lichen surface
• Some species more sensitive
• Which species are present can indicate air
•
quality
Most resistant species can also be analyzed
for pollutants
Lichen
diversity
These photos taken by
Fred Rhoades
Visit: Fred Rhoade's
Lichen Page
Caloplaca &
Verrucaria
Two species in the fruticose lichen of the genus, Cladonia
Peltigera
1 cm
Basidiomycote lichen, Omphalina