Question

A conjoint vascular bundle is one in which the xylem and phloem are
A. Joined together
B. Separate
C. On same radii
D. On alternate radii

Answer 1

The conjoint vascular bundles is the arrangement where the vascular bundles like xylem and phloem are arranged with each other. It is mainly seen in leaves and stem.

Complete answer:
The vascular bundle is the arrangement of xylem and phloem and sometimes cambium which forms the channel for the conduction of liquid of vascular tissue in the rhizomes, stems and leaf veins of vascular plants, there are distinct types of arrangement in distinct types of plant.
The conjoint vascular bundle shows the arrangement of vascular bundle xylem and phloem together in the same radius. In this type of vascular bundle arrangement of xylem is interior side and phloem is present towards the exterior side.

These are of types:
-Collateral: is a type of arrangement where the xylem is arranged towards the interior side and phloem towards the exterior. The xylem and phloem are seen in sides with the radii same. In the collateral vascular bundles, only a single patch of xylem and single patch of phloem are there. It can be open or closed.
Open: In this the xylem is found in the internal side and the phloem is seen in the outer side. Cambium is present between the xylem and phloem. Closed: In this xylem is found in the internal side and phloem is found in the outer side and there is no cambium between them.
-Bi-collateral: The xylem is placed in the centre and there are two patches of phloem and cambium tissues at each side. These types of vascular bundles are seen in the family of Solanaceae, Convolvulaceae.

Hence, the correct answer is option (A).

Note: Vascular tissues containing xylem and phloem are organized into different strands called vascular bundles. The function of xylem is to transport water and minerals from the roots to distinct parts of the plant body whereas phloem transports the food to the parts of the body.