Question

What is the composition of the embryo sac?

Answer 1

Embryo sac:

1. It is the fully developed female gametophyte.
2. It is multicellular and haploid.
3. It consists of eight nuclei.
4. Of the eight nuclei, four are at the micropylar end while the other four are at the chalazal end.
5. The components of the embryo sac are egg apparatus, antipodal cells, and central nuclei.

Egg apparatus:

1. It contains a group of three micropylar cells.
2. The central cell is called the egg cell and the cells on its side are called synergids.

Antipodal cells:

1. These cells are located at the chalazal end of the embryo sac
2. They possess enzymes, starch, lipids, and proteins.
3. It plays an active part in absorbing nourishment from the nucellus.

Central cell:

1. The two polar nuclei in the center often fuse to form a single diploid secondary nucleus.
2. It is a diploid structure.
3. It gives rise to a primary endosperm cell.

Figure showing embryo sac: