Question

Radial vascular bundles are the ones in which the xylem and phloem occurs on
A. Same radius
B. Alternate radii
C. Xylem outside and phloem inside
D. Phloem outside and xylem inside

Answer 1

Hint: The vascular system in plants is made up of phloem and the xylem. Radial type of vascular bundles is not arranged along the same line or radius.

Complete Answer:
- The plant tissues are divided into two main types- meristematic and permanent tissues based on whether the cells being formed are capable of dividing or not. The meristematic tissues are those that are the site of active division. Permanent tissues in plants are those that are no longer undergoing division.

- There are three types of tissue systems in plants on the basis of their structure and location. They are the epidermal tissue system, the ground tissue system and the vascular tissue system.

- The xylem and phloem are types of complex permanent tissues. They form the vascular bundles or conduct tissues in plants. If xylem and phloem are arranged alternately along different radii within a vascular bundle, the arrangement is known as radial.

- In conjoint types of vascular bundles, the xylem and phloem are located around the same radius of vascular bundles. These vascular bundles are typically seen in the stems and leaves. The phloem in conjoint vascular bundles is located only on the outer side of xylem.

Thus, the correct answer is option B, i.e., alternate radii.

Note: Dicotyledons have cambium located between phloem and xylem. These vascular bundles are capable of forming secondary xylem and phloem tissues and are often referred to as open vascular bundles. The monocots have closed vascular bundles, that is, cambium is not present in the vascular bundles.