What is double fertilization?

Double fertilization is unique to flowering plants (angiosperms) two male nuclei from the same pollen grain fertilize different cells simultaneously.

Male nucleus 1 + Egg cell → Zygote (2n) → Embryo
Male nucleus 2 + 2 Polar nuclei → Endosperm (3n) → Food reserve

• Discovered by Nawaschin (1898).
• Ensures efficient seed development embryo gets both genetic material and nourishment.

Summary: Double fertilization in flowering plants produces both the embryo and the nutritive endosperm from a single pollen grain.