How do seeds and fruits form after fertilization in flowering plants?

In flowering plants, or angiosperms, the formation of seeds and fruits is triggered by a unique process known as double fertilization.12

Seed Formation

Following pollination, a pollen tube grows toward the ovule and discharges two sperm nuclei. One sperm nucleus fuses with the egg cell to form a diploid zygote, which develops into the embryo. The second sperm nucleus fuses with two polar nuclei to create a triploid nucleus, which develops into the endosperm—a nutrient-rich tissue that supports the growing embryo. As these developments occur, the ovule's protective integuments harden and dehydrate to become the seed coat.12

Fruit Formation

Simultaneously, the ovary surrounding the ovules undergoes rapid enlargement and maturation to become the fruit. While the ovary wall typically forms the fruit, in some species, adjacent floral structures may also contribute to its development. This process of fruit maturation involves complex metabolic changes, including cell division and enlargement, which ultimately protect the developing seeds and facilitate their eventual dispersal.134