Describe development of endosperm after double fertilization?

Development of Endosperm

The primary endosperm nucleus repeatedly divides to give rise to free nuclei. This stage of development is called free nuclear endosperm. Cell wall formation occurs next, resulting in a cellular endosperm. The endosperm may either be fully consumed by the growing embryo (as in pea and beans) or retained in the mature seed (as in coconut and castor).

The endosperm develops before the embryo because the cells of the endosperm provide nutrition to the developing embryo.