Fusion of the male gamete and polar nucleus results in the formation of

Fusion of the male gamete and polar nucleus results in the formation of the Endosperm.
The endosperm is a tissue produced inside the seeds of most flowering plants following double fertilization.
It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven.
It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in animal diets.