Stomata and transpiration

• What are stomata?

  Tiny pores on the surface of a plant
• Where are stomata mostly found on a plant?

  On the lower surface of leaves
• What gases do stomata allow to diffuse in and out of a leaf?

  CO₂ and oxygen
• What is transpiration in plants?

  Water vapor escaping from leaves
• Why does water escape from leaves during transpiration?

  More water inside the plant than outside
• What surrounds stomata to control their size?

  Guard cells
• What happens to stomata when guard cells are turgid?

  Stomata are open
• What happens to stomata when guard cells are flaccid?

  Stomata are closed
• What environmental factors affect transpiration rate?

  1. Light intensity
  2. Temperature
  3. Air flow
• How does light intensity affect transpiration rate?

  Higher light increases transpiration rate
• What happens to stomata as it gets darker?

  Stomata begin to close
• How does temperature affect transpiration?

  Warmer temperatures increase transpiration
• Why does transpiration happen faster in warm conditions?

  Water particles have more energy to evaporate
• How does air flow affect transpiration rate?

  Good air flow increases transpiration rate
• What happens to water vapor diffusion with good air flow?

  Water vapor is removed more quickly
• How can you estimate transpiration rate using a potometer?

  1. Set up the potometer apparatus
  2. Record starting position of air bubble
  3. Measure distance moved by bubble over time
• What does a potometer measure to estimate transpiration rate?

  Water uptake by a plant
• If a bubble moved 25 mm in 10 minutes, what is the transpiration rate?

  $2.5 \text{ mm min}^{-1}$
• What should you remember when changing variables in transpiration experiments?

  Change one variable at a time
• What are the ideal conditions for transpiration?

  Sunny, warm, and windy
• What is the main purpose of stomata in plants?

  Gas exchange
• How does low light intensity affect water uptake by a plant?

  Stomata close, reducing water loss