What Is a Plant Embryo?

The reproductive cycle of seed bearing plants has several stages. Plants flower, fruit, and produce new seeds. Inside each new seed there is a tiny plant embryo that looks like a tiny stem and leaves tucked into a kind of fetal position. The seed also contains enough nutrition for the new plant to use until it sprouts and begins to manufacture its own food by photosynthesis.

Identification

The word embryo, comes from a Greek word that can be translated: something that grows in a body. In botany, the plant embryo looks like a very small plant that is contained inside a seed or, in the case of mosses and ferns, inside an archegonium.

Features

The female reproductive organ of seed bearing plants, pistil, is found in the center of the flower. Ovules are located within the pistil. Ovules are covered by outer layers called integuments which hold a soft nucellus. This is the cavity in which the plant embryo sac fits.

Function

The plant is not mature enough for fertilization until a single large nucleus within the embryo sac divides to form an egg and two synergids. When the pollen tubes in the flower allow sperm cells to enter the embryo sac, the sperm cell unites with the egg. A double fertilization process happens when other sperm cells penetrate deeper into the nucleus.

Significance

The plant's fertilized egg is also called a zygote or embryo, which remains in and grows to fill the embryo sac. The cells that developed as a result of double fertilization become the endosperm. As the embryo grows, the endosperm surrounds it. The endosperm provides the stored nutrients to feed the plant from the time that it is planted until it sprouts.

Potential

Seeds are fully encased plant embryos surrounded by endosperms. You can tell that a seed is mature when the fruit of the plant is ripe. Each plant produces seeds that are unique in size, shape, color and texture. However, hybridized plants that grow from genetic engineering do not produce seeds that will grow. To find out specific planting instructions for particular seeds, consult the information in a seed catalog like Burpee's.

Resources

• Diagrams and explanation of the development of plant embryos
• Burpee seed catalog