ovulesfertilization

Ovulesfertilization, commonly called ovule fertilization, is the process by which a male gamete fuses with a female gametophyte within an ovule to initiate seed development in seed plants. The ovule is a structure inside the ovary that ultimately becomes a seed after fertilization and maturation.

In angiosperms (flowering plants), fertilization typically involves a sequence that begins with pollination, when a pollen grain lands on a receptive stigma. The pollen grain germinates and forms a pollen tube that grows through the style to reach the ovule. Inside the embryo sac of the ovule, two sperm cells are delivered. One sperm fertilizes the egg cell to form the zygote, which develops into the embryo. A second sperm fuses with the central cell to form the triploid endosperm, providing nutrition to the developing embryo. This phenomenon, known as double fertilization, is a distinctive feature of angiosperms.

In gymnosperms and other non-flowering seed plants, fertilization also involves the delivery of sperm to the female gametophyte within the ovule, but there is typically only a single fertilization event that forms the zygote. The nutritive tissue that supports the embryo in gymnosperms originates from the female gametophyte rather than forming a distinct triploid endosperm.

Following fertilization, the zygote develops into an embryo, and the surrounding tissues differentiate to form the seed coat and, in flowering plants, the fruit. Ovulesfertilization is therefore a central step in plant reproduction and seed formation.