What is "megaspore mother cell"

n. A cell that forms four megaspores by meiosis; a megasporocyte.

A megaspore mother cell, or megasporocyte, is a diploid cell in plants in which meiosis will occur, resulting in the production of four megaspores, the spores that develop into female gametophytes.

In angiosperms or flowering plants, the megasporocyte produces a megaspore that develops into a megagametophyte (sometimes called the embryo sac) through two distinct processes – megasporogenesis (formation of the megaspore in the nucellus, or megasporangium), and megagametogenesis (development of the megaspore into the megagametophyte).

Generally, within each sporangium, meiosis of a megaspore mother cell produces four haploid megaspores. In gymnosperms and angiosperms, only one of these four megaspores is functional at maturity, and the other three soon degenerate. The megaspore that remains divides mitotically and develops into the female gametophyte (megagametophyte) which eventually produces one or more eggs.