Question

Agamospermy includes

• A. Adventive polyembryony
• B. Recurrent apomixis
• C. Nonrecurrent apomixis
• D. All the above

Answer 1

The correct option is D All the above

Agamospermy is a type of asexual reproduction in which plant propagation occurs by means of apomictic seeds (or asexual seeds). In Apomixis, there is seed formation without the fusion of gametes (syngamy) i.e., an embryo is formed within the seed coat without syngamy. In agamospermy, one or more sporophytic cells undergo stages of embryogeny and eventually grow into the mature embryo. Agamospermy is of three types:

1. Adventive polyembryony- Polyembryony is the occurrence of more than one embryo in a single seed. In adventive polyembryony, there is the formation of extra embryos due to sporophytic budding. One or more sporophytic cells, either nucellus or integuments undergo stages of embryogeny and eventually develop into mature embryos.

2. Recurrent apomixis- It includes apospory and diplospory. In apospory, nucellar cells divide mitotically and form an unreduced embryo sac i.e. diploid embryo sac. In diplospory, an unreduced megaspore mother cell divides by mitosis instead of meiosis and produces a diploid embryo sac.

3. Nonrecurrent apomixis- Here, the embryo develops directly from the egg cell without fertilisation and thus, the embryo is haploid.

Hence, agamospermy includes adventive polyembryony, recurrent apomixis, and nonrecurrent apomixis.

So, the correct answer is D.