What Contains Food for the Plant Embryo?

An apple is a plant's ovary that has expanded to protect seeds.

The development of seeds was an important step in the evolution of land plants. Seeds have certain characteristics, such as their hard outer coat, that provide protection for embryo plants until the right conditions exist for them to germinate.

Endosperm

Seeds also contain a supply of nutrients for embryo plants in a tissue called endosperm. Endosperm stores proteins and carbohydrates for use until the young plant is able to begin photosynthesis. As well as nourishing the young plant, endosperm contains hormones that prompt the embryo to grow.

Endosperm Creation

Endosperm is created at the same time a plant's ovule, or egg, is fertilized. Pollen contains two sperms: One sperm unites with an egg cell to produce the embryo, and the other sperm unites with two nuclei from the egg cell to create the endosperm.

Cotyledons

In some plant seeds, most of the embryo plant's nutrients are stored in a seed leaf, called a cotyledon. Plants with one seed leaf are called monocotyledon and those with two seed leaves, dicotyledon. The monocotyledons, which include grains such as wheat, and flowers like lilies and irises, generally store nutrients in endosperm, with nutrients transferred to the cotyledon when needed. Some dicots, which includes rose and bean plants, store most of the embryo plant's nutrients in the cotyledons, resulting in the endosperm being a thin, papery coating around the embryo plant.

References

• East Stroudsburg University; Seeds and Fruit; Raymond G. Milews; 2008
• Michigan State University van Nocker lab: Endosperm Development
• University of Cincinnati Clermont College Department of Biology; Angiosperms; J.S. Carter; 2004

Resources

• Teachers' Domain; Life Cycle of a Seed Plant; August 2007