Question

In a fully turgid cell

• A. ${\Psi }_s$ is negative and ${\Psi }_p$ is positive
• B. ${\Psi }_p$ is negative and ${\Psi }_s$ is positive
• C. Both ${\Psi }_p$ and ${\Psi }_s$ are positive
• D. Both ${\Psi }_s$ and ${\Psi }_p$ are negative

Answer 1

The correct option is A ${\Psi }_s$ is negative and ${\Psi }_p$ is positive

In a fully turgid cell the protoplast exerts a pressure on cell wall. This pressure is called turgor pressure or pressure potential (${\Psi }_p$) and is always positive. The cell has some solute concentration, which reduces the water potential from zero (the water potential of pure water). Hence the solute potential (${\Psi }_s$) is negative.