endosperm

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Nutritive tissue in the seeds of most flowering plants. It surrounds the embryo and is produced by an unusual process that parallels the fertilization of the ovum by a male gamete. A second male gamete from the pollen grain fuses with two female nuclei within the embryo sac. Thus endosperm cells are triploid (having three sets of chromosomes); they contain food reserves such as starch, fat, and protein that are utilized by the developing seedling.

In ‘non-endospermic’ seeds, absorption of these food molecules by the embryo is completed early, so that the endosperm has disappeared by the time of germination.

White, blue, and red became known as the pan-Slavic colours, influencing many other Eastern European flags. White, blue, and red are also the colours of the arms of the Duchy of Moscow. Effective date: 11 December 1993. >>