Tropisms and Auxins

• What is the focus of today's video?

  The role of auxins in plant responses
• Why do plants need to respond to stimuli?

  To survive in their environment
• How do plants sense light?

  By growing their shoots towards it
• What is the purpose of roots growing downwards?

  To fix into the soil and find water
• What do some plants do in response to touch?

  They climb around other objects
• How do plants rely on hormones compared to animals?

  Plants rely entirely on hormones, no nervous system
• What are auxins?

  Plant hormones that control growth
• Where do auxins accumulate in shoots?

  On the shaded side of the shoot
• What is phototropism?

  A response of plants to light
• What is geotropism?

  A response of plants to gravity
• How do shoots respond to light?

  They grow towards the light
• How do shoots respond to gravity?

  They grow away from the ground
• How does auxin accumulation affect shoot growth?

  It causes faster growth on the shaded side
• What happens to the shoot when auxins accumulate on one side?

  The shoot curves towards the light
• How do roots respond to light?

  They grow away from the light
• What happens when roots are exposed to light?

  Auxins accumulate on the lower side
• How do auxins affect root growth?

  They inhibit growth in roots
• How does gravity affect root growth?

  Auxins accumulate on the lower side
• What is the result of auxin accumulation in roots?

  The upper side grows faster, curving downwards
• What are the key responses of plants to environmental stimuli?

  • Phototropism: response to light
  • Geotropism (gravitropism): response to gravity
  • Touch response: climbing around objects
• What are the differences in auxin effects on shoots and roots?

  • Shoots: Auxins stimulate growth
  • Roots: Auxins inhibit growth