transpiration and stomata

• what controls he opening of the stomata?


  guard cells - they open the stomata when turgid and close stomata when flaccid
• what affects transpiration rate?

  • light intensity
  • temperature
  • air flow
  • humidity
• how might temperature affect the rate of transpiration?


  it will cause an increase as water molecules have more energy o evaporate and diffuse out of the stomata
• why might light intensity affect transpiration rate?


  brighter the light = greater the transpiration rate, stomata closes as it gets darker meaning photosynthesis can't happen so co2 doesn't need to be let in. therefore very little water can escape
• what shape are guard cells?

  kidney shape
• what happens when plants have a lot of water?


  guard cells fill with water and go plump and turgid - this makes the stomata open so gases can be exchanged for photosynthesis
• what happens when the plant is short of water?


  guard cells loose water and become flaccid - making the stomata close - this helps stop water vapour from escaping
• what are guard cells adapted for?


  for gas exchange and controlling water loss within a leaf