The primary functions of roots in plants are to anchor the plants to the ground and to take in water and minerals from the soil. Substances usually enter the roots by diffusion, but facilitated diffusion may also occur. In addition, roots may be specialized for storage.
Various plants have different types of roots. A taproot is a root that grows straight downward and has strong lateral roots growing out of it. Dicots often have taproots. A fibrous root system, consisting of slender, branching roots, occurs in most monocots. Adventitious roots occur on the stems or leaves of some plants, such as corn.
An apical meristem forms the root’s tissues. Cells at the tip of the root form the root cap, which functions mainly for protection. Behind the root cap is the apical meristem, and behind the apical meristem is the region of elongation, followed by the region of maturation. Many of the epidermal cells of the root develop extensions called root hairs that increase the surface area of the root.