Last Updated: September 24, 2018

Definition - What does Endosperm mean?

Endosperm is a nutritive tissue found in the seeds of nearly all the flowering plants after fertilization. The endosperm is normally formed in the process of double fertilization.

Although an endosperm can contain oil and protein, it mainly contains starch. The starch surrounds the embryo and provides it with nutrients. Due to the abundance of starch in the endosperm, it is a food source for humans and other animals.

MaximumYield explains Endosperm

Endosperm is formed when the separated nuclei in a pollen grain connect with a female gametophyte or the embryo sac. While one of the male nuclei fertilizes the female egg to form a zygote, the other nuclei normally connects with two nuclei in the embryonic sac to form the endosperm. In some plants the endosperm is entirely engrossed by the embryo prior to germination, while in others it is the source of food during germination. Embryos consume their endosperm entirely before they develop; examples include beans and peas, which normally absorb most of their food storing tissues before developing big, fleshy cotyledons. Some plants such as the orchids lack endosperms in their seeds.

In most species the endosperm facilitates the transfer of nutrients from the plant to the embryo, aborts seeds produced from mismatched parents, and acts as a location for gene imprinting. Also in most species the endosperm is responsible for seed dormancy.

For many flowering species, the endosperm has become a source of nutrition for the human diet. For example, in maize the endosperm is ground to form maize flour, and in wheat it is pulverized to form wheat flour. In barley the endosperm is the main source of sugar from which beer is made.

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