Question

Which among the following is not a character of apomixis?

• A. Does not involve gamete formation
• B. A type of asexual reproduction
• C. Unreduced egg cell develops parthenogenetically into an embryo
• D. Fosters the propagation of new genes in a population

Answer 1

The correct option is D Fosters the propagation of new genes in a population

Apomixis is a special mechanism of producing seeds without fertilisation. It is a form of asexual reproduction which does not involve syngamy/fertilisation and meiosis as well. As there is no meiosis. there will not be any mixing of genes and hence the offspring formed will be identical to the parents. This is shown by many kinds of grass and some members of the Asteraceae family.

There are two main forms of apomixis: (1) sporophytic and (2) gametophytic.

Sporophytic apomixis involves the direct formation of an embryo from a somatic cell in the ovule.

In gametophytic apomixis the embryo sac is obtained via apospory and diplospory. In apospory, the embryo sac originates from cells other megaspore mother cells (e.g. nucellar cells). It is the most common mechanism of apomixis in higher plants. In diplospory, the gametophyte arises directly from the megaspore mother cell.

In both cases (gametophytic and sporophytic apomixis), the unreduced egg cell develops parthenogenetically into an embryo.