PLant hormones and uses

• What is plant hormone stimulate growth ?

  Auxin
• What is geotropism and phototropism?


  Geo=respond to gravity Photo=Respond to light
• Why is it important to label the Petri dishes in the experiment?


  To differentiate between the different light conditions applied to each dish
• How should light be applied to the Petri dishes in the experiment?


  Shine a light onto one dish from above and two dishes from different directions
• What are some examples of variables to control in the cress seed experiment?


  • Number of seeds: use the same number in each dish
  • Type of seed: use seeds from the same packet
  • Temperature: keep dishes in a stable temperature
  • Water: use a measuring cylinder for the same amount
  • Light intensity: keep the distance from the bulb the same
• How can you investigate the effect of gravity on plant growth?


  Place four seedlings on damp cotton wool in a Petri dish with roots pointing in different directions
• What should be done with the Petri dish when investigating the effect of gravity on plant growth?


  Store the Petri dish vertically for a few days in the dark
• What is the expected outcome when seedlings are stored vertically in the dark?


  The roots of each seedling will grow downwards
• What does auxin do?

  Control plant growth
• What is Gibberellin?

  Plant growth hormone, like auxin. Stimulates seed germination, stem growth and flowering.
• What does gibberellin do to controlling dormancy?

  Germinate at specific times of year
• What does gibberellin do to induce flowering and bearing larger fruit

  Makes them flower when chosen and makes fruit grow larger
• How does ethene help ripen fruit?

  Control cell division, and stimulates enzymes. Commercially used to speed ripening, during transport

  ripening can be delayed in storage by adding chemicals
• Why are fruit picked unripen?

  So they are not damaged and then ripen with ethene on the way to the shops