What distinguishes endodermal cells in terms of water movement in roots?

Endodermal cells play a crucial role in regulating water movement into the vascular system of plant roots, particularly through the structure known as the Casparian strip. This strip is made up of suberin, a waxy substance that creates a barrier to free water movement. Therefore, water must pass through the plasma membranes of endodermal cells instead of traveling freely. This selective permeability allows the plant to control water uptake and maintain ion regulation, as the endodermis determines which substances can enter the vascular system. This is vital for the plant's ability to manage its internal environment, including nutrient uptake and overall hydration.