Syngamy and Triple Fusion
After traversing through the stylar region, the ultimate destination of the pollen tube is to reach the female gametophyte and release the male gametes that can ensure fertilization. In angiosperms, double fertilization is an important feature which involves fusion of one male gamete with the egg (syngamy) to from the zygote, the progenitor of next generation and the other male gamete fuses with the fusion product of the polar nuclei (secondary nucleus),resulting in triple fusion (haploid male gamete + two haploid polar nuclei = 3n), the primary endosperm nucleus.