Question

Mention the various regions of root.

Answer 1

The apical region of roots of any root system shows the same zones or regions. 

A longitudinal section of root apex shows the following structures:

1. Root cap region

It is a thimble-like structure produced by meristematic (rapidly dividing) zone and protects the tender apex (apical meristem) from harsh soil particles. As the root grows further down in soil, root cap wears out but it is constantly renewed. In aquatic plants (Pistia and water hyacinth) root cap is like a loose thimble, called root pocket.

2. Region of meristematic cells

It is a small region of actively dividing cells called the apical meristem. It consists of:

(i) Dermatogen (outermost layer whose cells mature into epiblema and root cap
(ii) Periblem (inner to dermatogen whose cells mature into cortex)
(iii) Plerome (central region whose cells mature into stele). In monocots, cap is formed by independent group of cells known as Calyptrogen.

3. Region of elongation

This is situated next to the meristematic region, wherein, the cells elongate and enlarge to make the root grow in length.

4. Region of maturation

This is next to the region of elongation, wherein the cells mature and differentiate into various tissues constituting

(i) Root hair or piliferous region having unicellular hairs which absorb water and mineral salts from the soil
(ii) Permanent region which lies behind the root hair zone and is without hairs. It produces lateral roots, anchors the plant in soil and conducts water and minerals upwards.