Question

Conjoint and closed vascular bundles with no phloem parenchyma are observed in:

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

Answer 1

The correct option is A Monocot stem

The vascular bundles are formed by xylem and phloem. It can be radial or conjoint based on the arrangement of xylem and phloem.
When xylem and phloem are arranged in an alternate manner along different radii, the arrangement is known as a radial vascular bundle. It is found in roots.


When the xylem and phloem together are along the same radius of vascular bundles, the arrangement is known as a conjoint vascular bundle. It is found in stems and leaves. The conjoint vascular bundle can be open or closed based on the presence of cambium. In monocots, cambium is not present in between the xylem and phloem. Hence, it is known as a closed vascular bundle. Hence, monocot stem will have conjoint and closed vascular bundles. In dicots, the cambium is present in between the xylem and phloem. Hence, it is known as the open vascular bundle. The open vascular bundle in dicots is responsible for the increase in the girth of the dicot plants which is known as secondary growth.