Question

Monocot root has
A.Conjoint, collateral, open, polyarch vascular bundles
B.Suberized exodermis, casparian strip, passage cells, cambium
C.Suberized exodermis, polyarch xylem, exarch xylem and pith
D.Exodermis, endarch, tetrarch vascular bundles

Answer 1

Hint: Roots are the part of the vascular plants. Roots are modified to provide anchorage for the plant. Roots with the help of root hairs absorb water and minerals. Roots generally present below the ground surface but they can be aerial which grows above the ground surface.

Complete answer:
Monocot root:
The roots of the monocot plants are composed of an epidermis, cortex, endodermis, pericycle, xylem, phloem and a pith.
1.Epidermis – It is the outermost layer of the root which has thin walled cells. Some of the cells give rise to the root hairs. Monocot roots have a gummy pectic layer on the outside which is used for cementing with soil particles and retaining water. Both epidermis and root hairs are devoid of the cuticle.

2.Cortex – Cortex is the wide region of the parenchymatous cells that have intercellular spaces for the exchange of gases. The cells within the cortex store food. In the older roots the layer of the cortex becomes thick walled and suberized. It constitutes the exodermis which is protective in nature and also absorptive in function.

3.Endodermis – Endodermis is single layered. Endodermis is made of barrel shaped cells that do not have intercellular spaces. The young endodermal cells possess an internal strip of suberin and lignin which is called as the casparian strips.

4.Pericycle – Pericycle is the outer boundary of the vascular bundles which lies below the endodermis. Pericycle may be single layered or may be multi layered. The pericycle is composed of thin walled parenchymatous cells.

5.Xylem – The xylem bundles of monocot roots are exarch which means the protoxylem lies towards the outside while the meta xylem lies toward inside. There are numerous xylem bundles present and also exarch condition exists in the xylem due to which the xylem of monocot roots is polyarch. The vessels of the meta xylem are larger than that of the protoxylem.

6.Phloem – Phloem bundles are alternate with the xylem bundles in monocot roots. The phloem bundles and xylem bundles are separated by the means of narrow strips of a type of tissue called conjunctive tissue.
Pith – The centre of the monocot root is occupied by the pith. Pith consist of the parenchymatous cells which may be rounded or angular. There are intercellular spaces
present between the cells of the pith.

Therefore, it has been clear from the above discussion that Monocot root has suberized exodermis, polyarch xylem, exarch xylem and pith.

Hence the correct answer is OPTION(C)

Note: Monocots are the plants in which the seeds contain only one embryonic leaf or cotyledon. Example – ginger, maize, grass, onions, etc. While dicots plants are the plants in which the seeds contain two embryonic leaves or cotyledons. Example – legumes, pea, lentils, etc.