Endosperm

Endosperm is the tissue produced inside the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This makes it an important resource for humans, who eat both the endosperm and the domesticated plants that produce it, such as wheat and corn.

Structure and Function

The endosperm is formed when the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte (or megagametophyte). One sperm nucleus fertilizes the egg cell, forming a zygote, while the other fuses with the two polar nuclei located at the center of the megagametophyte. The resulting cell is triploid, meaning it contains three sets of chromosomes.

The primary function of the endosperm is to nourish the developing embryo, though it can also help the seed to disperse and can aid in seed dormancy. In some species, the endosperm persists in the mature seed, while in others it is absorbed by the embryo as the seed matures.

Economic Importance

The endosperm is a major source of human nutrition, as it makes up the bulk of the edible portion of important cereal grains such as wheat, corn, and rice. It is also the source of flour in most types of bread and pastries.

See Also

• Seed
• Embryo
• Fertilization
• Cereal Grains
• Nutrition

Endosperm

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