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History of genetics
Learn introductory genetics with Braimy- B.Sc agriculture
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A. Vegetative Reproduction:

  • Vegetative reproduction occurs by the fragmentation method, in which a vegetative hypha breaks into few fragments which then develops into a new vegetative body.

B. Asexual Reproduction:

  • Firstly, the foot cell develops a small outgrowth by absorbing nutrients from the substratum.
  • Then, the foot cell gives rise to the long and slender hyphae called conidiophore.
  • After that, the conidiophore grows and enlarges at the apex by the nuclear division to form a vesicle.
  • The vesicle then grows and undergoes mitotic nuclear divisions to form sterigmata.
  • Sterigmata are uninucleate, which also undergoes mitotic division and transfers one nucleus to the secondary sterigmata.
  • These secondary sterigmata then form a chain of conidia in a basipetal arrangement.
  • After that, conidiospores gets detached from the hyphae either accidentally or through certain environmental factors and remains in the soil at dormant state.
  • When the spores get favorable conditions, they form a germ tube or undergo germination to form new vegetative hyphae.

What is Aspergillus? Structure, Features and Reproduction - Biology Reader

C. Sexual Reproduction:

  • The sexual reproduction rarely occurs only in the heterothallic species those contain both male and female hyphae.
  • The heterothallic hyphae consist of female hyphae called Ascogonium and the male hyphae called Antheridium.
  • First, the female and the male hyphae contacts with each other.
  • After that fusion occurs between the female and male hyphae, after which the antheridium contents go inside the ascogonium through the point of junction, Plasmogamy occurs in the ascogonium, after which a cytoplasmic division takes place.
  • After Plasmogamy, the ascogonium develops into the fruiting body called Ascocarp, where the karyogamy occurs. Then, 8 ascospores form inside the Asci (saclike structure), which are generally pear-shaped.
  • After the maturation of ascocarp, a protective layer (peridium) eventually forms.
  • Then by the maturation of the asci, the ascospores release out by the lysis of asci and then through the ascocarp wall.
  • The ascospores remain dormant in the environment and are unicellular, wheel-shaped and 5µm in diameter. Its wall differentiates into three layers, namely an outer layer (thick), a middle layer or epispore and an inner layer (thin).
  • On favorable conditions, they germinate new vegetative hyphae by the formation of a germ tube.

What is Aspergillus? Structure, Features and Reproduction - Biology Reader

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