In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order:

Explanation

The root system of a plant develops from the hypocotyl of the embryo of a seed. The root shows the following four regions these usually merge into one another, without distinct boundaries between them. The zones, successively from the apex to the base are: (i) Root cap zone: The apex of each root is covered by a cushion of thin-walled cells known as a root cap. (ii) Region of cell division: It lies just behind the root cap. It is the main growing region of the root where active cell divisions take place. (iii) Region of elongation: The region of elongation is responsible for the growth in length of the root. (iv) Region of maturation: Epidermal cells of this region give out small, thin, cylindrical unicellular outgrowths, known as root hairs. These are the main absorbing organs of the root.