Question

The osmotic potential and pressure potential of three cells (A, B, C) located in different parts of an actively transpiring plant are as following.

$\begin{array}{ccc}\text{Cell}& \text{Osmotic potential (MPa)}& \text{Pressure potential(MPa)}\\ A.& -0.87& 0.44\\ B.& -0.92& 0.34\\ C.& -0.68& 0.27\end{array}$

Which of the cells (A, B, C) have the highest water potential?

• A. A
• B. B
• C. C
• D. All of these.

Answer 1

The correct option is C

C

Water potential = Osmotic potential + Pressure potential
The following are the water potential values:
A: -0.87 + 0.44 = -0.43 MPa
B: -0.92 + 0.34 = -0.58 MPa
C: -0.68 + 0.27 = -0.41 MPa
Hence, C has the highest water potential.