Which specialized cell structures in roots form a waterproof barrier called the Casparian strip, forcing water and minerals to pass through the plasma membrane?

💡 Solution & Explanation

The endodermal cell walls in plant roots are impregnated with suberin to form the Casparian strip, which acts as a waterproof seal blocking the apoplastic movement of water and solutes. This forces water to cross the selectively permeable plasma membrane of endodermal cells for internal regulation.