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How does endosperm nourish a developing angiosperm seed?

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Tall baobab trees with thick, cylindrical trunks and broad canopies line a dirt road in Madagascar, surrounded by green vegetation under a blue sky. — plant Grandidier's baobas (*Adansonia grandidieri*) in Madagascar.

The endosperm is a specialized, nutrient-rich tissue that serves as a vital food source for the developing embryo within an angiosperm seed.12

Its formation is a result of double fertilization, a process unique to flowering plants, where one sperm nucleus fuses with two polar nuclei to create a triploid endosperm nucleus. This nucleus then undergoes mitotic divisions to form the endosperm, which accumulates essential storage materials such as starch, sugars, fats, and proteins.23

The embryo utilizes these stored nutrients to support its growth and development. The role of the endosperm varies by species:2
* Persistent Endosperm: In some plants, such as wheat, the endosperm remains present until germination, at which point the cotyledons absorb the stored food to nourish the growing seedling.1
* Absorbed Endosperm: In other plants, like peas and beans, the endosperm is completely absorbed by the embryo during seed development, and the food is instead stored within the fleshy cotyledons.13