Control And Coordination

• plants produce hormones ro coordinate and control growth and responses to light (phototropism) and gravity (gravitropism or geotropism).
• unequal distributions of auxin cause unequal growth rates in plant roots and hoots
• gibberellins are important in initiating seed germination
• ethene controls cell division and the ripening of fruits
• Investigating plant growth responses:

  1. put 10 cress seeds into three different Petri dishes, each lined with moist filter paper
  2. label dishes
  3. shine a light onto one of the dishes from above and two of the dishes from two directions
  4. leave your cress seeds alone for one week until you can observe their responses
  5. the seeds will grow toward the light `````````````````````````````````````