Name__________________________________Date____________________Period________ Introduction to Water Potential Water potential (): The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure. Water always moves from an area of higher water potential to an area of lower water potential. Water potential is calculated using the following formula: Water potential = pressure potential () + solute potential () = + Pressure potential ():In a plant cell, pressure exerted by the rigid cell wall that limits further water uptake. Pressure is zero in an open system. Solute potential (): The effect of solute concentration. Solute potential () = –iCRT Pure water at atmospheric pressure has a solute potential of zero. As solute is added, the value for solute potential becomes more negative. This causes water potential to decrease also. In sum, as solute is added, the water potential of a solution drops, and water will tend to move into the solution. We use bars as the unit of measure for water potential; 1 bar = approximately 1 atmosphere.