Question

Polyarch and exarch condition are found in

• A. Monocot stem
• B. Monocot root
• C. Dicot stem
• D. Dicot root

Answer 1

The correct option is B Monocot root

Vascular bundles in monocot root are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch.
In monocot stem, xylem is described as endarch and presence of only two protoxylem and two metaxylem vessels in each bundle. So, it is not polyarch.
In dicot root, vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch.

Dicot stem vascular bundles. They are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch.
Thus, the correct answer is option B.