Question

Sequence of development during the formation of embryo sac is
A.Archesporial cell, Megaspore, Megaspore mother cell, Embryo Sac
B.Megasporocyte, Archesporial cell, Megaspore, Embryo Sac
C.Megaspore, Megaspore mother cell, Archesporial cell, Embryo Sac
D.Archesporial cell, Megaspore mother cell, Megaspore, Embryo Sac

Answer 1

Hint: The embryo sac is also known as the female gametophyte present in the ovule of flowering plants having the oval structure.The ovule in plants is that structure which encloses the reproductive cells in females also contains the nucleus and the female gametophyte.

Complete answer:
The embryo sac formation completes into two stages: megasporogenesis and megagametogenesis.
Megasporogenesis : The haploid megaspore group forms due to the meiosis of a single diploid mother cell. From these three disintegrates, and one sustains develops into the embryo sac. In the nucellus a single hypodermal cell in the ovule or megasporangium which is known as the archesporium cell acts as a megaspore mother cell.
This megaspore mother cell matures within the ovule and by meiosis, it leads to formation of haploid megaspores and this process is called megasporogenesis. Only one remains functional and the other three degenerate.
This one functional megaspore grows into embryo sac by the process of megagametogenesis.
Megagametogenesis: The embryo sac is formed due to mitosis. Haploid megaspore to produce 8-nucleate, 7-celled gametophyte. One of the polar molecules comes out and from the single diploid cells. The polar nuclei move to the centre out of all the eight nuclei to combine and generate a single diploid cell at that location (centre). Then these single diploid cells combine with the sperm to produce the triploid endosperm.

Hence, the correct answer is option (D)

Note: The embryo sac is also known as the egg producing unit or megagametophyte. It is a female gametophyte that comprises various components such as one egg cell, two synergids, three antipodal cells, and polar nuclei.