Seed Coat

• The coating on seeds varies depending upon the environment in which the plant typically grows. The coat controls the dormancy of the seed and determines when it germinates. It also contains genes that may form part of the plant's defense system.
  
  

Embryo

• The embryo is a tiny version of the plant, containing all the parts of a fully grown plant including leaves and roots. The embryo is dormant and, in some species, may remain in suspended animation for years before favorable conditions trigger germination.
  
  

Endosperm

• Endosperm provides food for the seed embryo. In some species, such as beans, the growing embryo absorbs the entire endosperm by the time the seed reaches maturity. In other species, including all the cereals, the endosperm remains in the seed until it germinates. Two thirds of all the calories consumed by humans come from the endosperm of seeds, including rice, oats, wheat, barley and maize.