polar nucleus

plant anatomy

Also known as: polar nuclei

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Last updated

July 1, 2026

Quick Summary

In flowering plants, the polar nuclei are two nuclei found within the embryo sac. These nuclei play a crucial role in the process of double fertilization, which is unique to flowering plants.12

During double fertilization, one sperm cell from a pollen grain fuses with the egg cell to form a zygote, which develops into the embryo. Simultaneously, a second sperm cell fuses with the two polar nuclei. This fusion creates a triploid nucleus that develops into the endosperm, a nutrient-rich tissue that nourishes the developing seed. This process ensures that the seed contains both an embryo and its food source.23

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plant reproductive system
Angiosperms
…with the two nuclei (polar nuclei) within the large central cell of the female gametophyte. The resultant nucleus, which has three sets of chromosomes, is the primary endosperm nucleus. This process, double fertilization, occurs only in angiosperms.
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…with the two nuclei (polar nuclei) within the large central cell of the female gametophyte. The resultant nucleus, which has three sets of chromosomes, is the primary endosperm nucleus. This process, double fertilization, occurs only in angiosperms.
Read More

seed
Angiosperm seeds
…centre are referred to as polar nuclei; the egg cell, or oosphere, is situated near the micropylar (“open”) end of the ovule.
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…centre are referred to as polar nuclei; the egg cell, or oosphere, is situated near the micropylar (“open”) end of the ovule.
Read More