<P> Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower . The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style . The tip of the pollen tube then enters the ovary and penetrates through the micropyle opening in the ovule . The pollen tube proceeds to release the two sperm in the megagametophyte . </P> <P> The ovules are 8 in number and arranged in the form of 3 + 2 + 3 (from top to bottom) i.e 2 synergids & 1 egg cell, 2 polar central cells, 3 antipodal cells . One sperm fertilizes the egg cell and the other sperm combines with the two polar nuclei of the large central cell of the megagametophyte . The haploid sperm and haploid egg combine to form a diploid zygote, the process being called syngamy, while the other sperm and the two haploid polar nuclei of the large central cell of the megagametophyte form a triploid nucleus (triple fusion). Some plants may form polyploid nuclei . The large cell of the gametophyte will then develop into the endosperm, a nutrient - rich tissue which provides nourishment to the developing embryo . The ovary, surrounding the ovules, develops into the fruit, which protects the seeds and may function to disperse them . </P> <P> The two central cell maternal nuclei (polar nuclei) that contribute to the endosperm, arise by mitosis from the same single meiotic product that gave rise to the egg . The maternal contribution to the genetic constitution of the triploid endosperm is double that of the embryo . </P>

Write the fate of egg cell and polar nuclei after fertilization