Rate of transpiration

• What does the rate of transpiration depend on?


  Environmental conditions
• What are the four main factors affecting transpiration rate?


  • Light Intensity
  • Temperature
  • Air Flow
  • Humidity
• How does light intensity affect the transpiration rate?


  The brighter the light, the greater the transpiration rate
• What happens to stomata as it gets darker?


  Stomata begin to close
• Why do stomata close in the dark?


  Photosynthesis can't happen in the dark, so they don't need to be open
• What is the effect of closed stomata on water escape?


  Very little water can escape
• How does temperature affect transpiration?


  The warmer it is, the faster transpiration happens
• Why does transpiration happen faster in warmer conditions?


  Water particles have more energy to evaporate and diffuse out
• How does air flow influence transpiration rate?


  The better the air flow around a leaf, the greater the transpiration rate
• What happens to water vapor if air flow around a leaf is poor?


  Water vapor surrounds the leaf and doesn't move away
• What is the consequence of high water vapor concentration around a leaf?


  Diffusion doesn't happen as quickly
• How does good air flow affect transpiration?


  It sweeps away water vapor, maintaining a low concentration outside the leaf
• What is the relationship between concentration gradients and diffusion?


  Diffusion happens from an area of higher concentration to an area of lower concentration
• How does humidity affect the rate of transpiration?


  The drier the air around a leaf, the faster transpiration happens
• What happens when the air is humid around a leaf?


  There's not much difference between the inside and outside of the leaf
• Why does diffusion happen fastest with high concentration differences?


  Because there's a really high concentration in one place and a really low concentration in another
• Summarize the factors affecting transpiration rate and their effects.


  • Light Intensity: Brighter light increases transpiration; stomata close in darkness.
  • Temperature: Warmer conditions increase transpiration due to higher energy of water particles.
  • Air Flow: Better air flow increases transpiration; poor air flow leads to high water vapor concentration.
  • Humidity: Drier air increases transpiration; humid air decreases it due to low concentration differences.