Question

Agamospermous embryo sac develops from:
(A) Pollen
(B) Egg
(C) Ovum
(D) Megaspore mother cell

Answer 1

Hint: Agamospermous embryo sac develops from megaspore mother cell. It is a form of asexual reproduction produced without fertilisation or meiosis.

Complete Step by Step Answer:
In plants, a megaspore mother cell, also known as a megasporocyte, is a diploid cell that will undergo meiosis, giving rise to four haploid megaspores. One of the spores at the very least becomes a haploid female gametophyte. Within the megasporangium tissue, the megaspore mother cell develops. The megaspore is created inside the megasporangium during megasporogenesis. One meiosis division is completed by a megaspore mother, who then produces four haploid cells. Four one-nucleate megaspores are produced during meiosis, three of which degenerate, and one of which is still functioning. The massive gametogenesis process then begins.

A single functional megaspore goes through three cycles of mitotic division in this procedure, yielding an eight-nucleate cell. These eight nuclei are divided into two groups, each of which has a nucleus at the cell's center. The three nuclei at the end of the cell combine before the core cell is fertilized to form the egg apparatus, which consists of an egg cell in the center and two synergids. An embryo sac is created when a cell wall forms around the nuclei on the opposite end of the cell, forming the antipodal.

So, Agamospermous embryo sac develops from megaspore mother cell. So, option (D) is correct.

Note: The development of an embryo sac happens in two steps. Megasporogenesis is the process by which the megaspores are created in the megasporangium through meiotic division, and mega gametogenesis is the process by which the megaspores evolve into the megagametophyte.