HOMEOSTASIS AND RESPONSE

• what are plant hormones?

  Plants produce hormones that allow them to respond to changes in the external environment
• what is ethene?Ethene is a gas that controls cell division and the ripening of fruits.
• what is ethene?


  ethene is a hydrocarbon gas which controls cell division and the ripening of fruits
• what are Gibberellins?


  important in starting off the seed germination (sprouting) process. they trigger the breakdown of the food stores at the start of germination and stimulater the growth of shoots
• what are Auxins?


  auxins change growth patterns to allow roots and shoots to move either towards or away from stimulus (change in conditions). the response to stimuli that involve direction are called tropisms
• what are negative/positive phototropism?

  negative- responses that involve growth AWAY from a light source positive- responses that involve growth TOWARDS a light source
• what are negative and positive gravitropisms?

  positive- responses that involve growth TOWARDS the direction of gravity negative- responses that involve growth AWAY from the direction of gravity
• how does the distribution of auxin work in phototropism?


  • 1 side of the shoot is exposed to more light.
  • Auxin is redistributed within the shoot so that the concentration is greater on the shaded side.
  • This unequal auxin distribution will result in increased cell elongation (grows longer) on the shaded side.
  • In shoots, auxins promote the elongation of cells. 
  • However, in roots, auxins prevent the elongation of cells.
• what can be used to increase fruit size?

  gibberellins
• what can plant hormones also be used for?

  control the growth of plants for farming and gardening purposes
• what can auxins also be used for?

  weed killers, rooting powders (growth supplement) and to promote growth in tissue culture
• what else can ethene be used for?

  control the ripening of the fruit during storage and transport