Biology- Transpiration

Question

1) If you added salt to the beaker of water, indicate if the following would increase, decrease, or stay the same.

-water potential___________

-Slolute potential__________

-Pressure potential________

2) Calculate the pressure potential of a cell if water potential= -2.0MPa and solute potential= -5.2MPa.

Answer 1

1. Solutes decrease water potential. They make water potential more negative. Hence, decrease, decrease, stays the same.
2. Let Psi_w, Psi_s and Psi_p be water potential, solute potential and pressure potential.

Psi_w = Psi_p + Psi_s.

-2 MPa = Psi_p - 5.2 MPa

Psi_p = 3.2 MPa