Question

Draw a labeled diagram of the mature embryo sac of angiosperms.

Answer 1

Embryo sac:

1. The female gametophyte or the embryo sac refers to an oval structure, which is found in the ovule of angiosperms.
2. It develops when the nucleus of the haploid megaspore differentiates. It comprises six haploid cells and two haploid nuclei.
3. The formation of the embryo sac takes place in two stages:

Stage 1:

1. In this, the process of megasporogenesis takes place, in which the haploid megaspore tetrad develops due to the meiosis of a single diploid mother cell.
2. Of these, three disintegrate, and one sustains that later develops into the embryo sac.

Stage 2:

1. In this stage, megagametogenesis takes place, in which the formation of the embryo sac takes place by the mitosis of the functional haploid megaspore to generate the 7-celled, 8-nucleate gametophyte.