What Are the Bulbs on the Potato Plant?

Tubers

• The part of the potato plant people eat is actually the plant's bulb or, more specifically, its "tuber." Bulbs are underground storage structures that provide nutrients for a plant's complete life cycle. A tuber is a specific type of underground storage structure and is an enlarged portion of an underground stem. A tuber is not a true "bulb," because it does not have either a basal plate at its bottom from which roots develop or a protective tunic covering.

Nodes

• Like other plant stems, tubers have nodes that produce buds. Potato "eyes" are the potato tuber's small nodes. Each has a cluster of buds that sprout when placed in a warm location.

Growth Cycle

• According to the University of Florida IFAS Extension, the potato's growth cycle is roughly like this: The potato eyes develop sprouts, which emerge from the soil; then leaves, stems, and the root system develop. Photosynthesis begins, and the plant prepares to store nutrients in tubers. Then tubers begin to form on the end of underground stems, usually before the plant flowers. The tubers enlarge; sugars and starches accumulate. Finally, the tubers reach full size, and the plant's top dries out and dies.