Plant hormones

• What is a hormone?

  Chemical that causes a change
• Hormones are found in:

  • Roots/shoots
  • Leaf fall
  • Seed germination
  • Bud formation
• Phototropism 


  Plant's growth response to light
• Geotropism

  Plant's growth response to earth's gravitational field
• Hydrotropism 


  Plant's growth response to moisture
• In phototropism...

  • Shoots will grow towards light
  • Roots will grow away from light
• In geotropism...

  • Shoots will grow away from gravity
  • Roots will grow towards gravity
• In hydrotropism...

  • Shoots have no response
  • Roots will grow towards water
• Hormone name

  Auxin
• If they have a high concentration of Auxin...

  • Cells in stems grow more
  • Cells in roots grow less
• Vascular bundle

  • Xylem - Transports water from roots to leaves (transpiration)
  • Phloem - Transports sugar + nutrients both ways (translocation)