Question

What is a basic difference in the organization of vascular tissue in eudicots when you compare root and shoot tissues?

Answer 1

Answer:

• Roots: Protostele formed by xylem, cambium, and phloem. There is no medulla. Pericycle, endodermis, and Caspary band surrounds the protostele.

• Shoots: Eustele formed by all the vascular bundles that surround the medulla. Each bundle is composed of xylem, cambium, and phloem.

Explanation:

The vascular and fundamental tissues of shoots normally show a more complex organization than those of the roots.

In dicots´ root, transversal cut shows a protostele which is a solid vascular cylinder surrounded by cortex. The xylem is in the center of the protostele, surrounded by phloem. There are xylem lobules that extend between phloem. Two cell layers are surrounding the protostele, called pericycle and endodermis. Next to the endodermis, there is the Caspary Band, composed of suberin and lignin.

In dicots´ shoots, the vascular system forms independent vascular bundles composed of xylem and phloem. In each bundle, xylem is facing to the center of the shoot, and phloem is facing the exterior of the shoot. All the vascular bundles form a circle around the medulla which is always in the center of the shoot. This organization is known as eustele.  The cortex surrounds the vascular system.