Question

explain the development of a female gametophyte.

class12​

Answer 1

Answer:

One cell of nucellus of ovule inside ovary undergoes meiotic division and forms tetrad of megaspores.

One megaspore at chalazal end remains functional and other three degenerates.

Nucleus of functional megaspore undergoes three mitotic divisions without undergoing Cytokinesis.

Resulted 8 nuclei rearrange themselves into three at chalazal end forming antipodal cells and three at micropilar end forming two synergids and one egg cell.

remaining two nuclei comes together at centre and forms diploid polar nuclei.

all cells are haploid except polar nuclei.

This structure is female Gametophyte also called embryo sac...

please mark as brainleast answer..

Answer 2

DEVELOPMENT OF FEMALE GAMETOPHYTE

• Development of ovule upto the formation of megaspore is called megasporogenesis.

• Cell membrane and cell wall develops around all the nuclei, except the two at the centre.

• The three cells at the micropylar end of the embryo sac develops into egg apparatus.

• The central large cell of the egg apparatus is the female gamete or egg cell and the to either sides are synergids.

• The three cells at the chalazal end form three antipodals.

• The remaining two nuclei one from each poles move to the centre.

• They fuse to form a single diploid nucleus called diploid secondary nucleus or polar nuclei.

• The female gametophyte is generally eight-nuclei containing one egg cell and two synergids, three antipodals and two polar nuclei at the centre.