Question

T.S. of a material exhibits conjoint collateral endarch and closed bundles scattered in a ground tissue. What should be the material?

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

Answer 1

The correct option is C Monocot stem

Monocot stem vascular bundles are found irregularly scattered in the ground tissue. Towards the periphery, the bundles are smaller in size while towards the centre, they are larger in size. The smaller bundles are younger, while the larger ones are older. Hence, the arrangement is described as endarch.

Each vascular bundle has a covering called bundle sheath formed by a single layer of sclerenchyma cells. The vascular bundle encloses both xylem and phloem. Xylem is found towards the inner surface and phloem towards the outer surface. Cambium is absent. Hence the vascular bundles are described as conjoint, collateral and closed.

Dicot stem vascular bundles 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.

Dicot root vascular bundles are described as radial, open and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch.

Monocot root vascular bundles 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.