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Introduction to systematic eukaryotes (Reproduction of Fungi) (Sexual…
Introduction to systematic eukaryotes (Reproduction of Fungi)
Asexual Reproduction
Sporulation
there can be more than one mitosporic state for each species of fungus
asexual spores are formed during a phase of the fungal life cycle termed/called the mitosporic or anamorphic phase
Fragmentation
a cork bore taken from a colonized donor plate - cut mycelium tips do not regenerate but the branches may form some distance away from the damaged point
cork borer - used to cut a hole in the cork
any mycelium that is fragmented/disrupted can grow into a new colony -
thus, normally used as a common sub-culturing method for fungi (hyphal-fragment technique)
Buds formation in yeasts
a mitosis process
1)
development of a ring of chitin around the point of budding
2)
enzymatic activity to weaken and extrude the cell wall
3)
new cell wall material is combined/incorporated during this stage
4)
cell content is forced into the progeny cell
5)
at the end of mitosis, a cell plate is formed (marks the end of mitosis)
Sexual Reproduction
In the case of the two haploid nuclei (n+n), they must
fuse to form a diploid first, but once fused the
nuclei undergo meiosis. These events are followed
by the formation of spores, which in most cases
are spores can withstand harsh
conditions.
2 mating type -haploid nuclei or a diploid nucleus
introduces the possibility of variation in a population
Types of reproduction
can be sexual or asexual reproduction
but many fungi can have both types of reproduction :mushroom:
onset of reproduction is controlled by environmental factors
(nutrient levels, carbon dioxide and light levels) and the
internal time clock- circadian rhythms
circadian rhythms
- a physical, behavioral, mental changes that occur within 24 hours responding to the change in light and darkness of the environment
Morphology of spores (Chlamydospores)
a thick-walled big resting spore
(cells/spores surrounded by thick walls
) of several kinds of fungi including
Ascomycota, Basidiomycota and several Mortierellales species
a life-stage that survives unfavourable conditions such as wet and dry weather/ seasons
normally dark-coloured, spherical and have a smooth surface
Sporangiospores
development of spores within a sac at the hyphal tip
(endogenous - formed and contained within a sporangium)
two main types: Zoospores (motile) and Aplanospores (non-motile)
formed as a
result of cleavage of protoplasm around the nuclei
and sometimes formation of wall around each nucleated portion of the cleavaged protoplasm
Arthrospores
formed due to the fragmentation of hyphae - formed cells called arthroconidia or arthrospores
(Hyphae wall thicken but does not expand)
asexual spore (
conidium- a spore produced asexually by various fungi at speciallised hyphae (conidia
) formed by the conversion of a pre-existing hypha
Conidiospores
normally, asexual reproduction in Ascomycota where the spores are formed on specialized stalks called Conidiophores
not enclosed in a sac but produced at the sides or tips of a hyphae
(normally known s the conidia)
can develop into new organisms if conditions are favourable and serve in biological dispersal
also called the
mitospores
because they are
produced through mitosis
- therefore, the 2 new haploid daughter cells are similar to the haploid mother cell
Blastospores
example:
Candidia albicans
- a dimorphic fungi that grows as yeasts and fillamentous cells that can cause disease in humans
spores produced from mother cells by budding and also known as the Blastoconidium
produced by fungi in the phylum Glomeromycota
