Other plant hormones

• Gibberellins

  • cause elongation in the main stem
  • causes the the space between the internodes to lengthen
  • stimulates seed germination
  • encourages seeds to break out of their dormancy
• Do Gibberellins affect apical dominance? (yes/no)

  No
• What hormone stimulates seed germination?

  Gibberellins
• What hormone causes elongation in the mane stem?

  Gibberellins
• What hormone is a growth inhibitor?

  Abscisic acid
• What hormone causes stomata to close?

  Abscisic acid
• What hormone promotes dormancy in seeds and buds?

  Abscisic acid
• Two types of plant protection:

  • Chemical - substances made in leaves and stems making eating them difficult
  • Physical - often spines and thorns that make it difficult to eat them.
• Name THREE substances in the leaves of plants that chemically protects it.


  1. toxins
  2. digestive enzymes
  3. bitter tasting chemicals