Potatoes and sweet potatoes are tubers, and radishes are roots. Tuber is a botanical term. It is a kind of metamorphosis of plant stem, which is blocky, hence the name tuber. Since it is a stem, it has the main characteristics of plant stems, such as buds and leaf scars. The potato we often eat is the most typical tuber.

One of the underground improved underground stems is a horizontal stem, which has short internodes and different shapes, and is often irregular and massive in meat quality, and stores carbohydrates such as starch and sugar. For next year's growth again. Root system occurs from the bottom of tuber, and the nodes are sunken downwards, such as eye socket, where buds are born, but the scales degenerate or fall off early, such as Pinellia ternata, Gastrodia elata and potato.

Extended data

The end of the underground stem forms an enlarged irregular block, which is a metamorphosed stem suitable for storing nutrients and wintering. The top is hypertrophy, the parenchyma is developed, and rich nutrients are stored. There are many bud eyes on the surface of tuber, which are generally arranged in a spiral shape. There are 2 ~ 3 axillary buds in the bud eye, and only one axillary bud can germinate easily and grow new branches, so tuber can be used for propagation.

A tuber, such as a potato tuber, has a terminal bud at the top. The underground branches of potatoes crawl in the soil layer, and when they extend 9 ~ 12 cm, the ends swell and form thick tubers with short internodes. On the growing tuber, there is periderm on the surface and a few lenticels on it. On the cross section of tuber, it can be divided into cortex, outer phloem, xylem, inner phloem and central pith. From the appearance or structure, it can be explained that it is an abnormal situation of terrier.