Learning Exercise

Connecting Concepts: Plant Biology Water Relations http://www.merlot.org/merlot/viewMaterial.htm?id=83578 a. For the Water Potential Equation you learned in this lesson, think of the pneumonic “WaSP” where the total water potential (W) in a small or average sized plant is equal to the solute potential (S) plus the pressure potential (P). b. What conditions for each of these variables contribute to the value? In other words, what makes S positive or negative? What makes P positive or negative? c. When these values (S and P) are added together, the total (W) will be positive or negative. What does that mean with respect to the flow of water? d. What is the biggest factor (numerically speaking, what is the biggest value) driving the flow of water from roots to shoots? (At what point in the flow of water is the W value so large that it drives the entire process?)