Is a sweet potato a root or a stem?

Generally speaking, sweet potatoes are roots, specifically classified as tuberous roots, which are a type of modified root. The detailed analysis is as follows:

Sweet potatoes lack nodes and internodes, as well as buds, and therefore do not possess the basic structural characteristics of stems. The primary function of sweet potatoes is to store large amounts of nutrients, which is a typical function of roots. During growth, the roots continuously absorb water and minerals from the soil, while transporting nutrients such as sugars produced through photosynthesis to the roots for storage, gradually expanding to form tuberous roots. This is different from the primary functions of stems, such as supporting the plant, transporting water and nutrients, and conducting photosynthesis.

In addition, sweet potatoes are also propagated using their tuberous roots. When these tuberous roots are buried in soil under suitable conditions, adventitious roots and shoots will develop from them, eventually growing into new plants.