Endosperm is a nutritive tissue produced inside the seed of angiosperms (most flowering plants) during the time of fertilization. It surrounds the embryo with the purpose of providing nutrition in the form of starch and often proteins and oils.
Encyclopedia Britanica states that the induction of endosperm necessitates the bond of at least one nucleus in the embryo sac with a sperm nucleus from the pollen grain. The process of endosperm varies from types of angiosperms. For example, in seeds such as peas and beans, the endosperm is completely absorbed at maturity. In others, such as wheat, the endosperm is apparent until germination. It is noted that endosperm accounts for the economic importance of cereal grains and oil seeds.
PlantCell confirms the notion that endosperm represents a vital source of food, feed and industrial raw materials for mankind. Yet, despite this claim, it further goes on to state that the origin and process involved in endosperms' development remains unclear. However, there are two views regarding the advancement of endosperm which manifested after the discovery of double-fertilization. In one postulation, it is theorized that endosperm is a derivative of a benevolent twin embryo. In the other, it is suggested that endosperm is the result of the extended development of the megagametophyte (the female gametophyte in seed plants), which is thought to advance when the central cell is fertilized by the second male gamete. Despite the ambivalence of its origination, the predominate function of endosperms is to surround and nourish a developing embryo.