Question

Vascular bundle in dicot stem are

A. Conjoint and collateral

B. Conjoint and closed

C. Conjoint, collateral and open

D. Collateral and open

Answer 1

Hint:  The vascular bundles are the type of transporting system in vascular plants. There are two vascular tissues present in plants and they are xylem and phloem and they play an important role in the transportation of minerals, nutrients, food etc. throughout the plants. 

Complete answer:

The vascular bundle is a longitudinal arrangement of strands of xylem and phloem, and sometimes cambium, which forms the channels for the conduction of liquid in vascular tissue into the rhizomes, stems, and leaf veins of vascular plants. There are different types of arrangement in different types of plant. There are two types of vascular bundles present. 

Open vascular bundles are the vascular bundles which consist of cambium and which can form secondary xylem and phloem and it include dicot stem while the closed vascular bundles do not consist of cambium in them and they include monitor stem. 

In the case of dicot stem, the vascular bundles are arranged in a ring, with pith and are intense at the core of the stem instead of being dispersed throughout the internal parts of the plants. In each vascular bundle, the xylem and phloem are separated by a material known as vascular cambium. In the dicot stem, the vascular bundles are ‘conjoint, collateral and open’. In the case of monocot stems, the vascular bundles are arranged in the bundles of xylem and phloem and are dispersed throughout the ground tissue. The vascular bundle in the monocot stem is conjoint, bicollateral and open. 

Hence, the correct answer is C. Conjoint, collateral and open.

Note:  In dicot stem, the cells of the endodermis are rich in starch grains and the layer is known as the starch sheath. The ring arrangement of the vascular bundle is a characteristic of the dicot stem. The vascular bundles of monocot stem consist of water containing cavities.