Features of Internal structure of young root of gram

A transverse section of the young root of gram (Cicer arietinum) shows the following features:-

(i) Epiblema or piliferous layer:

The cross section shows almost a circular margin. Epiblema con­tains one layer of thin walled cells. Some of the cells produce unicellular hairs. Cuticle is not present.

(ii) Cortex:

It is a broad homogenous zone of parenchymatous cells. The cells are loosely ar­ranged with intercellular spaces.

(iii) Endodermis:

It is the inner most layer of cortex containing a layer of barrel shaped cells. The thickenings (Casparian thicken­ings) are also marked on the ra­dial walls. Thin-walled rounded passage cells are seen opposite to the protoxylem points.

(iv) Pericycle:

It is  a layer of thin­ walled parenchyma inner to the endodermis.

(v) Vascular tissues:

The vascular bundles are ra­dial with xylem and phloem tissues alternating with each other and oc­cupy different radii. There are four xylem patches and four phloem patches. Hence, the stele is tetrach. The parenchyma tissue lying between xylem and phloem is the conjunctive tissue. Vascular bundles are closed as there is no cambium and exarch in nature. The protoxylem points correspond to the location of passage cells in the endodermis.

(vi) Pith:

Pith is a very narrow zone of parenchyma. In old roots pith is not seen.