Endosperm facts for kids
Endosperm is a special part inside the seeds of most flowering plants. Think of it as a food supply for the tiny baby plant, called an embryo, that's growing inside the seed. This food is usually in the form of starch, but it can also have oils and protein.
The endosperm from plants like cereals is a very important food source for people. For example, the endosperm of wheat is ground into flour to make bread. When you eat whole wheat bread, it means the outer layer of the seed, called the bran, is also included in the flour. Barley endosperm is mainly used to make beer.
Other examples of endosperm we eat include the 'meat' and 'water' from a coconut, and corn, which includes popcorn. Interestingly, some plants, like orchids, don't have endosperm in their seeds at all!
How Endosperm Forms
In simple flowering plants, seeds usually have a small baby plant (embryo) and a large amount of endosperm. As flowering plants have changed over time, many newer types of plants have seeds with little or no endosperm. In these plants, the baby plant takes up most of the seed. The food it needs is stored in special leaves called cotyledons, instead of in endosperm.
A Special Fertilization Process
Endosperm forms through a unique process called "double fertilization." This happens when two tiny parts from a pollen grain enter a part of the flower called an ovule.
One of these tiny parts joins with the egg cell, which then grows into the baby plant (embryo). The other tiny part usually joins with two other cells in the ovule. This special joining creates the very first endosperm cell. This cell then grows and multiplies to form the endosperm. Because it's formed by a separate joining process, the endosperm is like a separate "organism" next to the embryo within the seed.
Most flowering plants have endosperm cells that contain more than the usual two sets of chromosomes. Often, they have three sets of chromosomes, but the number can vary a lot!
See also
In Spanish: Endospermo para niños
