What is double fertilization in an angiosperm?
Ok, after meiosis: In pistil: only ONE megaspore will be functional. This hapolid cell will divide mitotically three times to produce an embryo sac consisting eight haploid nuclei/cells: 1 egg (female gamete), 2 synergids, 2 polar nuclei and 3 antipodals. In anther: all (4) microspores are functional, each of which divides mitotically once to become a pollen consisting two cells: 1 generative cell and 1 vegetative cell (pollen tube cell). After pollination occur, pollen will germinate in the style and the generative cell divides mitotically to produce two funcional sperms (gametes). In double fertilizations: 1) One sperm/male gamete (n) fertilize an egg (n) to produce a zygote (2n), and 2) The other sperm (n) fertilize two polar nuclei 2(n) to produce primary endosperm/triploid nucleus (3n). In the further development of seed (divide mitotically many times), the zygote will become an embryo (2n) and the primary endosperm will become endosperm tissues (3n).
