Question

What is the functional role of the endodermis in the root?

Answer 1

Endodermis is the innermost layer of root of plant. After endodermis there is one more inner layer known as stele( xylem and phloem). The radial wall of these endodermal cells have casparian strip made up of suberin forces trasported substances to enter into symplast as they cannot cross casparian strip through apoplast movement.

Radial movement of water and minerals occurs through root by apoplast and symplast route. Water and minerals forst enter through root hair cells then move to epidermis, from epidermis to cortex, cortex to endodermis, endodermis to pericycle and from pericycle to xylem and phloem. In symplast movement occurs in interconnected cells through plasmodesmeta. Apoplast on the other hand occurs through intercellular spaces.Radial movement of water through root is shown in below image

Endodermis play important role in regulating the movement of water and minerals into the vascular system of xylem and phloem. It prevents movement of minerals and water through apoplast. It also stores strarch. It also protect plant by not allowing toxic substances to move inside through xylem and phloem. They also doesn't let the bubble form in water column.