Plants

• Plant features to increase rateof diffusion

  -Large SA- many points of contact with air or water

  -Thin- short diffusiin distance

  -Movement of air or water over gas exhannge surface - to keep diffusion gradients high
• What is a xerophyte

  Plants adapted to dry, warm or windy climates e.g if little water is available or if there is a high rate of water loss
• Xerophytes- features and explanations

  -Sunken stomata- increases diffusion distance- redues transpiration rate

  -Stomatal hairs- reduces water potential gradient as it traps water vapour- redues transpiration rate

  -Rolled leaves- reduces water potential gradient as it traps water vapour- reduces transpiration rate

  -Small leaf surface area (spikes/needles)- less stomata- reduces transpiration rate

  -Waxy/thick cuticle- increases diffusion distance- reduces transpiration rate