2. ASEXUAL REPRODUCTION
• About 20% fungi propogate only by asexual means
• Also known as imperfect stage
• Technically called as anamorphic stage(without nuclear change)
• There is no union of nuclei / sex cells /sex organs
• Takes place during favourable condition by formation of a variety
of spores
• Such spores produced by asexual reproduction are called
mitospores
3. METHODS OF ASEXUAL REPRODUCTION
FRAGMENTATION
• Most common method
• In this method, a piece of the mycelium, the body of the fungus,
splits off. The resulting fragment can eventually produce a new
colony of fungi.
• The spores produced by fragmentation are called arthrospores or
oidia
• Sometimes,the contents of intercalary cells of hyphae rounded off
and surrounded by a thick wall and formed as chlamydospores
• Eg. Fusarium oxysporum, Ustilago tritici
•
4. FISSION
• The parent cell elongates, nucleus undergo mitotic division and
forms two nuclei
• Then the contents divide into equal halves by the formation of a
transverse septum and separates into two daughter cells
• Eg. Saccharomyces cerevisiae
5. BUDDING
• The parent cell puts out initially a
small outgrowth called bud / blastos
• As the bud is formed,nucleus of parent
cell divides and one daughter nucleus
migrates into the bud
• The bud increase in size while still
attached to parent cell and eventually
breaks off and forms a new individual
• The spores formed through budding
are called blastospores
• Eg: Saccharomyces cerevisiae
6. SPORULATION
• The process of production of spores is called sporulation
THEREARE TWO MAIN TYPESOF SPORES
❖SPORANGIOSPORES
• The sporangiospores are produced inside a sac-like structure
called sporangium
• The hypha bearing a sporangium is called sporangiophore
• They are characteristically branched
• A small sporangium with or without columella containing a
few or single spore is called as sporangiolum.
1) ENDOGENOUSSPORES
7. • Sporangium which is cylindrical in shape is
called as merosporangium. Eg. Saprolegnia
sp.
Sporangium with columella is called as
columellate sporangium. Eg. Rhizopus
stolonifer
In holocarphic thallus, the entire thallus
becomes sporangium
In eucarphic thallus, sporangia are produced
at the end of undifferentiated or on
specialized spore bearing structures called as
sporangiophores.
8. SPORANGIOSPORES ARE OF TWO TYPES
A)Zoospores / planospores
• Sporangiospores which are motile by
flagella
• Eg. Pythium, Phytophthora (Oomycota).
B)Aplanospores
• Sporangiospores which are non-motile without
flagella
• Eg. Rhizopus stolonifer, Mucor (Zygomycota).
9. TYPES OF FLAGELLA
UNIFLAGELLATE ZOOSPORE
• A zoospore with a single flagellum, may
be placed at anterior or posterior end of
spore
TTTINSEL
• It is a feathery structure
consisting of a long rachis with
lateral hair like projections called
mastigonemes or flimmers on all
sides along its entire length
BIFLAGELLATE ZOOSPORE
• Biflagellate zoospore: A zoospore with
two flagella, situated laterally or
anteriorly on zoospore
WWHIPLASH
• A flagellum with long, thick,
rigid basal portion and with a
short, narrow, flexible, upper
portion
10. 2)EXOGENOUS SPORE
A)THALLOSPORES
• They arise directly from a pre-existing segment of the
fungal thallus and detached from the parent hyphae and
not by astrictions.
B)ARTHROSPORE
• It is specialized uninucleate cells, which function as
spore. It is also called oidia
• Eg. Saccharomycopsis javanensis, Geotrichum candidum
11. C)CHLAMYDOPORES
• It is a thick-walled, non-deciduous, intercalary or terminal, asexual
spore formed by the rounding of a cell or cells of the hypha
• They do not detach from the parent hypha and remain viable even
after the hypha decays, with reserve food materials and possess
thick wall to withstand unfavourable conditions.
• The walls may often covered with dark melanin pigment
• Eg. Fusarium solani
12. D)CONIDIOSPORES
Conidia are non-motile asexual spores which
may arise directly from somatic hyphae or from
specialized conidiogenous cells or on
conidiophore
Conidia are produced freely on conidiophore ie.,
at the tips or sides of conidiophore or may be
produced in specialized asexual fruiting bodies
viz., pycnidium, acervulus, sporodochium and
synnemata.
13. CONIDIOSPORES BASED ON SEPTATION
AMEROSPORAE
• conidia non septate (single celled), spherical, ovoid to elongated, or short cylindric
DIDYMOSPORAE
• conidia ovoid to oblong, one septate (two celled)
PHRAGMOSPORAE
• conidia oblong, two to many septate (3 or more celled), only transverse septa present
DICTYOSPORAE
• conidia ovoid to oblong, both longitudinal and transverse septa present
SCOLECOSPORAE
• conidia thread like to worm like, filiform, septate or aseptate
HELICOSPORAE
• conidia spirally cylindrical, curved (allantoid), septate or aseptate
STAUROSPORAE
• conidia stellate (star shaped), radially lobed, septate or aseptate
14. COLOUR OF CONIDIA
A)HYALOSPORA
• cell wall of conidia hyaline
FRUITING BODIES(SHAPE)
A)PYCNIDIUM
• It is a globose or flask shaped fruiting body lined in side with
conidiophores which produce conidia
• It may be completely closed or may have an opening called ostiole.
• Eg. Phomopsis, Phoma, Macrophomina, Diplodia, Lasiodiplodia etc
B)PHAEOSPORAE
• cell wall of conidia coloured/ pigmented
15. B)ACERVELUS
A flat or saucer shaped fruiting body with a stromatic mat of hyphae producing conidia on
short conidiophores
An acervulus lacks a definite wall structure and not having an ostiole or definite line of
dehiscence
Eg. Colletotrichum, Pestalotiopsis
C)SPORODOCHIUM
• A cushion shaped asexual fruiting body
• Conidiophores arise from a central stroma and they are woven together
on a mass of hyphae and produce conidia
• . Eg. Fusarium,Epicoccum, Mycospherella, Tubercularia etc.
16. D)SYNNEMATA
• A group of conidiophores often united at the base and free at the top.
Conidia may be formed at its tip or along the length of synnema,
resembling a long handled feather duster.
• Eg. Ceratocystis, Graphium.
