- nutritive matter in seed-plant ovules, derived from the embryo sac.
Origin of endosperm
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- the tissue within the seed of a flowering plant that surrounds and nourishes the developing embryo
Word Origin and History for endosperm
Online Etymology Dictionary, © 2010 Douglas Harper
- The tissue that surrounds and provides nourishment to the embryo in the seeds of many angiosperms. The cells of the endosperm arise from a process similar to that of fertilization. The pollen of angiosperms contains two sperm, one of which fertilizes the egg cell in the female gametophyte. The second unites with two other nuclei in the female gametophyte, producing cells that are triploid (having three sets of chromosomes) and that develop into the endosperm. In some species of angiosperms, the endosperm is absorbed by the embryo before germination, while in others it is consumed during germination. Embyros that lack an endosperm (such as peas and beans) have absorbed most of their food storage tissues before becoming dormant and develop large, fleshy cotyledons.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.