Question

A typical monocotyledonous root is characterized by
A. Usually more than six xylem bundles
B. Large and well-developed pith
C. No secondary growth
D. All of the above

Answer 1

Hint: The roots of monocots cannot grow in diameter due to the lack of vascular cambium. In dicots, there is secondary growth which makes the plants have woody stems.

Complete answer: Monocot roots are characterized by the presence of (8 or more in number) alternate and radial xylem and phloem bundles.
This condition of the xylem is known as polyarch condition.
The central portion of the cross-section of a monocot root is occupied by a large pith consisting of thin-walled parenchyma cells spaced with intercellular spaces.
These cells may be round or angular in shape and are filled with abundant starch grain.
The vascular bundles are arranged in the form of a ring around the well-developed central pith.
Monocots don’t undergo secondary growth throughout their life cycle, instead, they grow more roots at the shoot and send out typical creeping shoots known as runners or rhizomes.

So, the correct answer is option D. All of the above.

Note: There is no distinction between a young and an old root of the monocotyledonous plant. This is due to the absence of secondary growth in the monocot roots.