Pressure potential

• what happens when water enters a plant cell by osmosis?

  • it expands the vacuole and pushes the cytoplasm against the cell wall
  • the cell wall can only expand a little and so pressure outwards builds up, resisting the entry of more water, making the cell turgid
  • this pressure is the pressure potential, and as its a push outwards it has a positive sign
• what does turgid mean?

  a plant cell that holds as much water as possible - further entry of water is prevented as the cell wall can’t expand further
• what is this a diagram of?

  solute and water potential

  
• what is pressure potential?

  the hydrostatic pressure exerted by the cell contents on the cell wall - its equal and opposite to the pressure exerted by the cell wall on the cell contents
• what does this symbol mean?

  it stands for pressure potential