Suppose two living plant cells are in contact with each other so that water, but not solutes, can pass between them. The cells have the same water potential. One cell has ψP = 0.3 MPa and ψS = -0.5 MPa, while the other cell has ψS = -0.3 MPa. What is the ψP of the second cell?

Question

Quizplus · Accepted Answer

Since the water potential (ψ) is the same for both cells, ψP + ψS must be equal for both. For the first cell, ψ = 0.3 MPa + (-0.5 MPa) = -0.2 MPa. For the second cell, ψS = -0.3 MPa, so ψP must be 0.1 MPa to also have ψ = -0.2 MPa.

Suppose Two Living Plant Cells Are in Contact with Each