The document summarizes the development of the female gametophyte in flowering plants. A diploid megaspore mother cell in the nucellus of an ovule undergoes meiosis to form four haploid megaspores arranged in a linear tetrad. The lower chalazal megaspore develops into the functional female gametophyte through three rounds of mitotic division, forming an eight-nucleate, seven-celled structure called the embryo sac containing an egg cell, synergid cells, and antipodal cells with a secondary nucleus formed by fusion of two polar nuclei.

1. Female Gametophyte
Department Of Botany
Prepared by
Dr. P. B. Cholke
(Assistant Professor in Botany)
Pune District Education Association’s
Anantrao Pawar College ,Pirangut,
Tal-Mulshi, Dist-Pune- 412115

2. DEVELOPMENT OF FEMALE GAMETOPHYTE IN
A FLOWERING PLANT
• Female gametophyte is developed in the nucellus of
the ovule.
• In the nucellus of a developing ovule, one diploid cell
develops into a diploid megaspore mother cell.
• This megaspore mother cell divides by meiosis to
produce four haploid megaspores which are arranged
in a linear tetrad.
• Of these, the upper three degenerate and the lower
chalazal megaspore is functional to produce the female
gametophyte (embryo sac).
• The nucleus of the functional megaspore divides
mitotically into two nuclei.

4. • These are called primary micropylar and primary
chalazal nuclei.
• The second division produces one pair of nuclei
at the micropylar end and one pair of nuclei at
the chalazal end. The third division results in the
formation of 4 nuclei at each pole.
• One nucleus from each pole then migrates
towards the centre to become polar nuclei, which
fuse together and give rise to the secondary
nucleus (2n).

5. • Out of these, the central one is the egg cell while
the two lateral cells are called synergids.
• The three nuclei towards the chalazal end also
get organized into three thin walled cells called
antipodal cells.
• The structure containing egg apparatus,
secondary nucleus and antipodals is called
female gametophyte or embryo sac.
• It is a seven-celled and eight-nucleate structure.