Fertilization - Full Process

After pollination on the stigma pollen grains start forming a pollen tube. The pollen tube pierces through tissue of the style and reaches the ovule in the ovary. Generally, the tip of the pollen tube enters the embryo sac of the ovule through micropyle. The pollen tube releases two male gametes. One of the male gametes fuses with the egg cell forming a diploid zygote or oospore. This fusion of male and female gamete is called fertilization. 

The second male gamete fuses with nuclei of two polar bodies called definitive nucleus and a triploid endosperm nucleus is formed. This phenomenon is called double fertilization.

 Zygote divides many times to form the embryo and the endosperm nucleus (definite nucleus) forms the endosperm of the seed. The sepals, petals, stamens, style and stigma of the flower fall off. The ovule develops into seed and ovary develops into fruits.