Estimation of Water Potential of Potato Tuber Cells

Introduction

This experiment is to find out the water potential of potato cells.

Water potential is the ability of water to move and is represented by the Greek letter ψ (pronounced “sy”). It tells us which way water will move and how fast. Water potential is always measured as a negative number; this is because the water potential of pure water at atmospheric pressure is zero therefore the stronger a solution is the more negative the number. This is because a solution has solutes present and solute molecules slow the movement of the water molecules, therefore always making the water potential of a solution less than zero.

The stronger the concentration the slower the movement of water molecules present due to more bonds between the solutes and the water molecules, therefore the more negative the water potential. The unit for water potential is kPa because it’s the measurement of pressure acting on the water molecules.

There are two factors that influence water potential;