Question

Formation of gametophyte directly from spore mother cell, without meiosis is called as
a. Apospory
b. Apogamy
c. Apomictic
d. Apomixis

Answer 1

Hint: Gameto means ‘gametes’ and phyte means ‘plants’. The plants which form gametes are called gametophytes. Plants produce gametes with the help of their sex organs.

Complete answer:
Plants produce gametes with the help of their sex organs. Plants such as Bryophyte, Angiosperms, Gymnosperms, Algae, etc go through this process. For example, algae produce simple and non-metallic gametes inside its body.
Apomixis is often found in higher plants, like in maize, wheat etc.

There are three types of apomixis: -
• Apospory.
• Diplospory.
• Adventitious embryonic.

Apospory: It is defined as the formation of 2n gametophyte without the process of meiosis from vegetative cells of sporophytes in it. An apomictic embryo sac is developed from the nuclear cells. It produces diploid gametophytes like in Anthoceros. After they differentiate then enter mitotic cell division to produce an embryo sac. Some ovules can also contain several embryo sacs and also depending upon the plant’s species, the form of the embryo sac may be different from that which is seen in the process of sexual reproduction. The initiating apospory embryo sac can occur alongside a sexual embryo sac or it can obstruct the formation of sexual embryo sac.

Hence, the correct answer is option (A).

Note: Apomixis can be defined as the formation of a zygote or seed without the fusion of male and female gametes. Apospory is defined as a type of apomixis where nuclear cells give rise to the apomictic embryo sac. Apogamy denotes the development of male gametes or sporophytes without the fusion of gametes.