Turgor in root cells builds up root pressure. If you cut a well-watered pot plant (e.g. balsam) a few centimeters above the soil and immediately fix a glass tubing to it by means of a rubber. If you cut off the shoots of a plant, the water pushes out from the root stump. This is due to Root pressure.
Define Root Pressure
Root pressure is built up due to cell-to-cell osmosis in the root tissue. As one turgid cell presses the next cell, the force of the flow of water increases inward. When water reaches the xylem vessels , it enters the pores of their thick walls with considerable force.