The Endodermis is one of the most important adaptations of terrestrial plants. In the absence of an endodermis plants would not be able to regulate water uptake by the roots and maintain the water balance of the plant.
Bryophytes lack an endodermis and they are unable to maintain large aerial systems.
Plants began to develop large shoots only after they developed this adaptation. I will try to illustrate how the endodermis regulates solute movement and consequently regulates water movement at an elementary level. Keep in mind that molecules move from areas of high concentration to areas of low concentration. This includes water. The sucrose molecules can't go anywhere, but the water molecules can cross the membrane.