With the help of a suitable diagram, describe internal structure of a monocot root.
Answers
1. Rhizodermis or epiblema
The outermost layer of parenchymatous cells without intercellular spaces. Stomata and cuticle are absent.
Root hairs are always single celled.
2. Cortex
The cortex is homogenous, consists of oval or rounded loosely arranged parenchymatous cells.
The function of cortical cells is storage.
3. Endodermis
It is made up of single layer of barrel shaped parenchymatous cells.
The radial and the inner tangential walls of endodermal cells are thickened with suberin. These thickenings are known as casparian strips.
But these casparian strips are absent in the endodermal cells which are located opposite to the protoxylem elements.
4. Stele: All the tissues present inside endodermis comprise the stele.
A. Pericycle:
A single layer of parenchymatous cells found inner to the endodermis. Lateral roots originate from the pericycle.
B. Vascular system
Vascular tissues are in radial arrangement.
Xylem and phloem are separated by sclerenchymatous conjunctive tissue.
Xylem shows exarch and polyarch condition.
Metaxylem vessels are generally circular in shape.
5. Pith:
The central portion is occupied by a large pith consist of thin walled parenchyma cells with intercellular spaces.
These cells are filled with abundant starch grain.
