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Meiosis in Flowering Plants Plant Reproductive Structures Plant Sperm production Pollination and Fertilization After landing on the stigma of a flower (pollination), the tube cell elongates to produce a pollen tube, which grows from the stigma through the style and through the micropyle to the egg. The generative cell will divide by mitosis to produce two sperm. As in gymnosperms, the sperm of angiosperms are contained within the pollen tube and therefore do not require water. Fertilization Fertilization Double Fertilization: One sperm fertilizes the egg the other one combines with the two polar nuclei forming a triploid (3N) cell. The zygote grows by mitosis to form an embryo. The 3N cell divides by mitosis and becomes endosperm, a food-containing material for the developing embryo. The ovary, sometimes with other floral parts, develops into a fruit. It usually contains seeds. Summary During pollination, the pollen grain sticks to the stigma. Guided by the pollen tube nucleus , the pollen tube grows through the micropyle near the base of the ovule. The generative nucleus in the pollen grain divides by mitosis. The two nuclei move into the embryo sac where one fertilizes the polar nucleus to produce a triploid endosperm nucleus and the other fertilizes the egg nucleus to form a zygote.