Question

Dicot root differs from monocot root in
a. Fewer number of radial vascular bundles with small pith
b. Large number of radial vascular bundles with large pith
c. Fewer number of radial vascular bundles with large pith
d. Large number of radial vascular bundles with small pith

Answer 1

Hint: Dicots have their own vascular bundles in ring arrangement. Monocots have most of their vascular bundles near the outside edge of the stem. Vascular bundle is a part of the transport system in vascular plants. Xylem and phloem are two vascular tissues, both of which are present in vascular bundles.

Complete answer:
Dicot root and monocot root are different because monocots tend to have “fibrous roots’’ that are webbed in many directions and these roots occupy upper level
soil as compared with the dicot roots occupy a deeper level of soil and have thicker systems. Dicot root contains one main root called taproot. Dicot root differs from monocot root in the number of xylem strands, the presence of medulla, activity of pericycle and activity of conjunctive tissue.

> Option A - Fewer number of radial vascular bundles with small pith: In dicot root, 2 to 4 vascular bundles are found, pericycle (a thin layer of plant tissue between the endodermis and phloem) is involved in secondary growth and small pith ( or medulla, is a tissue in the stems of vascular plants.) as compared to monocot root.

> Option B - Large number of radial vascular bundles with large pith: Large number of radial vascular bundles are found in monocot not in dicots and pith in dicots are small.

> Option C - Fewer number of radial vascular bundles with large pith: Dicots root have fewer vascular bundles i.e. 2 to 4 and have small pith as compared to monocot root but piths in dicot are small than that of monocot root.

> Option D - Large number of radial vascular bundles with small pith: Dicots doesn’t have a large number of radial vascular bundles it contains fewer vascular bundles with small piths.

Hence, the correct answer is option (A).

Note: Other few differences between monocot and dicot roots are:
- The cortex area is narrow in dicot root and wide in monocot root.
- Older dicot roots have a covering of cork whereas older monocot roots show a covering of exodermis.
- Passage cells are absent in dicot and present in monocot.
- The conjunctive tissue is parenchymatous and it forms the cambium and secondary growth is absent in the monocot root.
- Pith is reduced or absent and reduced pith is usually small and at the other hand pith is well developed in monocot roots.