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How does double fertilization help form a seed in flowering plants?
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pollination
Common carder bumblebee (Bombus pascuorum) pollinating a honeysuckle (Lonicera species) flower.
Double fertilization is a unique reproductive process in flowering plants that is essential for the formation of a seed. Following pollination, a pollen tube delivers two nonmotile sperm cells to the ovule, where two distinct fusion events occur:12
- Embryo Formation: One sperm cell fuses with the egg cell to create a diploid zygote. This zygote undergoes divisions to develop into the embryo, which will eventually grow into a new plant.12
- Endosperm Formation: The second sperm cell fuses with two polar nuclei in the embryo sac. This fusion produces a triploid nucleus that develops into the endosperm. The endosperm serves as a vital nutrient-rich tissue, providing the stored food—such as starch, proteins, and fats—necessary to nourish the developing embryo.132
Together, these processes ensure that the seed contains both the genetic blueprint for the next generation and the energy reserves required for its survival and germination.12