Question

Some fruits such as watermelon can be seedless although deriving from a flowering plant. Define this biological process and briefly explain how it is different from apomixis.

Answer 1

Q1 Some fruits such as watermelon can be seedless although deriving from a flowering plant. Define this biological process and briefly explain how it is different from apomixis.

Answer: The condition when any flowering plant develops or produces seedless fruits is known as APIRENY or PARTHENOCARPY. This condition appears when there is no fertilization/pollination or embryo development occurs in plants. Moreover, when there absence of pollination, this phenomenon is called as Vegetative parthenocarpy and the other condition where pollination takes place but plant do not undergo fertilization is known as Simulative parthenocarpy.

On the other hand, contrary to parthenocarpy the term Apomixis/Parthenogenesis involves the development of embryo by following asexual reproduction (agamospermy i.e. without involvement of male part) in plants.

There are two types of apomixis

Type -I where the megaspore mother cells follow meiotic division and results haploid embryo (either from egg or other gametophytic cells)

Type-II when seeds (developed embryos) are exactly similar to the mother plant's genome because of their development through unreduced or apomeiotic (no meiosis) egg cells. This type of apomixis is gametophytic apomixis which can further be of two types Diplospory or Apospory. When embryo sac develops from archesporial cells it is called Diplospory and when ebryo sac develops from other nucellus cells or non-archesporial cells it is known as Apospory.

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