5 Xylem Water Potential 1. In lab two we became familiar with the concept of water potential and estimated the water potential of potato tissues. Today we will measure the water potential of whole plant organs under different environmental conditions.
Water moves axially through the xylem from roots to leaves following gradients of water potential.
The Osmotic component of water potential in xylem is very small because xylem water is very diluted. This is because xylem elements are dead and have no living membranes across which osmotic gradients can be established. We will measure the water potential of stems and leaves of plants under different environmental conditions. First, we will have a set of plants well watered the night before and compare the leaf water potential to the one in plants that have been water stressed. We will keep a set of well-watered plants under ambient conditions and another set under a warm fan.