Ex.No. 2
ASEXUAL REPRODUCTION IN FUNGI
Fungi reproduce both asexually and
sexually. Asexual reproduction is repeated several times in the life cycle of a
fungus while sexual reproduction occur only once in its life cycle. The
reproduction in fungi takes place by the fallowing methods. 1. Asexual reproduction 2. Sexual
reproduction
Asexual
reproduction (Without nuclear change)
It is otherwise called as
vegetative phase or somatic production. The spores produced by asexual
reproduction are called as Mitospores.
Methods
of asexual reproduction
Fragmentation
(Fragment – Segment): Spores produced by hyphae breaking up into separate
cells. They are called as Arthrospores / Oidia Ex. Oidium species
Fission:
The cell is split into two daughter cells by constriction and formation of a
cell wall.
Budding:
Small outgrowth (bud) is produced from parent cell. The nucleus of the parent
cell divides and one daughter nucleus migrates into the bud. The nud increases
in size, ultimately breaks off and forms a new individual. Ex. Yeast
Production
of asexual spores: 1. Lower fungi asexual spore - Sporangiospores
(Motile sporangiospore – Planospore/ Zoospore) (Non motile sporangiospore –
Aplanospore)
Ex. Zoospore – Pythium
: Aplanospore – Rhizopus
2. Higher fungi asexual spore –
Conidia
Asexual
fruiting bodies of fungi : Fruiting bodies are
otherwise called as Sporocarp. The asexual fruiting bodies are
Pycnidium
: It’s a hollow or globose / flask shaped structure whose pseudoparenchymatous
cells are lined with Pycnidiophore with an anterior opening called as Ostiole.
Ex. Septoria, Macrophoma, Macrophomina,
Phyllostictina musarum, Diplodia, Botryodiplodia
Sporodochium:
The conidiophores are cemented together to form sporodochium. In this
conidiophores arise from the surface of a cushion shaped stroma. Ex. Fusarium, Tubercularia, Volutella, Epicoccum
Acervuli/
Acervulus: It is a saucer shaped and short
conidiophores are closely packed arise forming a bed like structure. Ex. Colletotrichum, Pestalotia
Synnema: It is a group
of conidiophores are cemented together to form an elongated spore bearing
structure. Sometimes, resembling like a feather cluster. Ex. Ceratocystis, Graphium, Haplographium,
Briosia, Trichurus
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