Question

What is monosporic development of the female gametophyte?

Answer 1

Hint: The cells in the body are made by the mitosis and meiosis. They will reduce the genetic content in them to make them less in ploidy. Meiosis occurs after the fertilization has taken place. This helps in the division of cells to form the gametes or cells for the next generation. The reduction of genetic material takes place.

Complete answer:
The female gametophyte is the female body of the plant which arises from the fertilized embryo after being implanted in the ovary of the flower. The pollen via style and stigma travel to the ovary to fertilize the ovule.

Megaspore is the first cell of the female body. Depending on what is the number of megaspores, the plant gametophyte can be of three types-monosporic, bisporic or tetrasporic.

Meiosis in the megaspore mother cells initiates the monosporic development, this will make the mother cell to form a dyad and then a tetrad.

One of these four cells/megaspores will be functional, this will undergo three continuous divisions to make 2, 4 and at last 8 nucleate and 7 celled embryo sac.

So this formation of the whole female gametophyte from a very small single megaspore is known as monosporic development. The 2 nucleated embryo sac is formed mitotically from the functional megaspore, by which the two nuclei move to the opposite poles.

Note: The female gametophyte originates from the ovules. It has 3 antipodal cells, two synergids and one central cell. The central cell fuses to form the desired embryo. While the two synergids fuse with pollen to make the triploid cell called endosperm.