Every plant is a biological system integrating different and often conflicting signals from the environment into the expression of enlargement, development, and differentiation we call growth. To say that a plant grows is to describe a process in which the visible changes in size and structure are carried on by a continual increase in the number, size, and differentiation of plant cells. Growth is irreversible in that there can be no reduction in these changes except through processes that bring about decay and death of the plant. The rootUs function is to absorb water and nutrients, and to act as a store house for manufactured food. The root also provides the wide spreading system that anchors the plant and supports the stem and crown.
Roots extend themselves through the soil by creating new cells in the apical meristem.
Behind this area, the cells are enlarging, and, further back, they have differentiated and matured into specialized tissue cells that include the origins of the vascular system. Also in this area, the outside cells develop long protrusions called root hairs. Absorption of water and minerals occur mainly in the root-hair zone. New root hairs are constantly forming at the tip to replace the older ones dying further back. Root branching occurs irregularly.