What is the casparian strip? why is it important?

Answer and Explanation:

Most young roots have two main regions. An outer cortex and a central cylinder containing the vascular bundles.

The endodermis also referred to as starch sheath. Its cells have a casparian strip which is made up of an impervious waxy deposit on the radial and cross walls. It controls entry of water and dissolved salts into the vascular bundle.