Plant hormones and response

• Geotropism: The response to gravity
• Phototropism: The response to light
• What affects the growth of the shoots?


  • Positive phototropism
  • Negative geotropism
  • Auxins stimulate growth
• What affects the growth of shoots?

  • Negative phototropism
  • Positive geotropism
  • Auxins inhibit growth
• Why do shoots bend?

  1. Light diffuses auxins to shaded side
  2. Side with most auxins grows in that direction faster by cell elongation
  3. Shoot grows towards the sun to the side with less auxins bending shoot

  
• Why do roots bend down?

  1. Gravity diffuses auxins down on lower half of roots
  2. The side with most auxins inhibits growth so side with less auxins grows faster causing it to bend

  
• Where are auxins located in the shoots?

  The tip of the shoots