PAGS

Question 1

What are some precautions to take whilst setting up and using a potometer to ensure no air enters?

Answer 1

setting up:
• D cut stem under water
• D have apparatus under water
• D insert stem under water
• D joint(s) must be, sealed / tight
• E so no air can enter, stem / shoot / xylem /
apparatus
• E air / bubble, could block xylem
• E obtain a continuous column of water

whilst using:
• D do not allow the bubble to move too far
• D use syringe to move bubble
• E so air bubble does not enter, xylem / stem
• E so same air bubble can be re-used
• D place open end in water
• E so no, air / (new) bubble, introduced
• D keep shoot, still / supported
• E to avoid breaking, seal / water column
• E to measure transpiration accurately
• E ensure validity