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 y _P = 0.3 MPa and y _S = - 0.5 MPa, while the other cell has y _S = - 0.3 MPa. What is the y _P of the second cell?

Question

Quizplus · Accepted Answer

The water potential (Ψ) is the sum of pressure potential (ΨP) and solute potential (ΨS). For the first cell, Ψ = 0.3 MPa + (-0.5 MPa) = -0.2 MPa. Since the cells have the same water potential, the second cell must also have Ψ = -0.2 MPa. Given ΨS = -0.3 MPa for the second cell, ΨP must be 0.1 MPa to satisfy Ψ = ΨP + ΨS = -0.2 MPa.

Suppose Two Living Plant Cells Are in Contact with Each