| Pollen grains germinate on the stigma and form pollen tubes that grow through the style to the ovarium, carrying each a pair of sperm cells to the ovarium. The ovarium hosts ovules that contain each one egg cell. In a process called double fertilization, one of the two sperm nuclei fuses with the egg cell and forms a zygote from which the embryo further develops, whereas the other sperm nucleus fuses with two other nuclei in the embryo sac to form the endosperm. |
