Question

what purpose does the female gametophyte serve in the gymnosperm seed?

Answer 1

Plants alternate between two generations during their life cycle: the diploid sporophyte and the haploid male and female gametophytes, in which gametes are generated. In angiosperms, the male gametophytes (the pollen grains) develop within the anthers and the female gametophytes (megagametophytes or embryo sacs) develop within the ovule. There has been over a century of developmental studies on gametophyte development in a large number of diverse plant species. In most flowering plants, including Arabidopsis and maize, the embryo sac has a characteristic organization called the Polygonum-type, containing seven cells of four distinct cell types.

The female gametophyte plays a critical role in essentially every step of the reproductive process. During pollen tube growth, the female gametophyte participates in directing the pollen tube to the ovule. During fertilization, cytoskeletal components within the female gametophyte direct the sperm cells to the egg cell and the central cell. Upon fertilization, female gametophyte–expressed genes control the initiation of seed development. During seed development, female gametophyte–expressed gene products play a role in controlling embryo and endosperm development