The pollen tube delivers two haploid (n) sperm cells. An egg and two polar nuclei are located within the embryo sac of the ovary. Fertilization of the sperm cells and egg occurs within the ovary that is located at the base of the of the pistil. One of the sperm nucleus fertilizes the egg to form a diploid (2n) zygote. The other sperm nucleus fertilizes two polar nuclei to form the triploid (3n) endosperm that will later become the food source for the growing embryo.
After fertilization occurs, the zygote (fertilized egg) begins to divide via mitosis. Eventually, the zygote develops into an embryo. An embryo is the developing plant. The seed capsule encompasses the embryo. The embryo housed within the seed capsule remains dormant until the conditions within its environment are favorable for germination to begin.
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