The first step in the production of seeds by a flowering plant is the formation of gametes (sex cells). Through pollination gametes are brought together so that fertilization may occur. From this fertilization a seed eventually develops.
The Formation of Gametes
Sexual reproduction, whether in plant or animal, is basically the fusion of male and female gametes – sperm or pollen and egg – to produce a zygote, which will develop into a new individual.
Gametes are unique cells because they are haploid. That is, they contain only half a set of genes. Other body cells are diploid. That is, they contain a full set of genes. In plants, when the haploid pollen (1/2 set) fertilizes the haploid egg (1/2 set), the zygote that results is diploid (full set).