Question

Vascular bundles in dicot stem are

• A. Open, collateral, endarch
• B. Closed, collateral, endarch
• C. Open, collateral, exarch
• D. Closed, collateral, exarch

Answer 1

The correct option is A Open, collateral, endarch

Vascular bundles of dicot stem 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.

Vascular bundles of dicot stem are open, because of presence of cambium. Endarch is used when there is more than one strand of primary xylem in a stem or root and the xylem develops from the inside outwards towards the periphery, i.e., centrifugally. The protoxylem is thus closest to the center of the stem or root and the metaxylem closest to the periphery. The stems of seed plants typically have endarch development. The roots of vascular plants are normally considered to have exarch development. Closed vascular bundles are present in monocots. Thus, option A is correct.