Answer
Root pressure is a positive pressure or force that helps to drive fluids to small heights via water-conducting xylem. Osmosis is the key to root pressure. Water outside the root system is greater than inside, thus water moves from higher concentration to lower that is from outside to inside the root system which is simply called osmosis. The water receiving cell becomes turgid and exerts pressure. This pressure allows the water to move towards the xylem and thus creates a continuous water column. Thus it is clear that xylem deals with the transportation of water.