Plant hormones

• What is a tropism?

  Plant response to stimulus
• A tropism is the response of a plant to a specific stimulus
• What is phototropism?

  Response to light
• Phototropism is the response of a plant's shoot or root to light
• What is gravitropism?

  Response to gravity
• Gravitropism is the response of a plant's shoot or root to gravity
• Auxin is a hormone that controls plant growth.
• How do plant shoots show positive phototropism?

  Bend towards light
• In positive phototropism, the cells on the shaded side of the shoot are stimulated to grow
• Positive phototropism allows photosynthesis to occur at a faster rate.
• How do plant shoots show negative gravitropism?

  Bend away from gravity
• In negative gravitropism, the cells on the lower side of the shoot grow more due to auxin
• Negative gravitropism ensures more light for photosynthesis.
• How do plant roots show positive gravitropism?

  Bend towards gravity
• In positive gravitropism, auxin accumulates in the lower side of the root, causing cells to grow less
• Positive gravitropism in roots ensures access to more water and nutrients.
• What are gibberellins involved in?

  Seed germination
• Gibberellins are a type of plant hormone involved in seed germination
• What is ethene involved in?

  Cell division and ripening
• Ethene is a plant hormone involved in cell division and ripening
• Match the plant hormone with its use:

  Auxins ↔️ Rooting powder

  Ethene ↔️ Food ripening

  Gibberellins ↔️ Seed dormancy termination
• Ethene is used in the food industry to control fruit ripening.
• What are the uses of gibberellins in plants?

  Seed dormancy termination
• Gibberellins promote flowering and increase fruit size