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Plant hormones

  • There are five general classes of hormones: auxins, cytokinins, gibberellins, ethylene, and abscisic acid. for more details see plant biology


  • movement in response to light.
  • shoots grow toward light and are positively phototropic; roots grow away from light and are negatively phototropic.
  • IAA increase in shaded side → plant curve toward light
  • wavelengths less than 500μm—is most effective in producing a growth response.


  • response to gravity


  • reaction to a solid object
  • eg. tendrils of climbing plants wrapping around a support
  • IAA (lengthening) and ethylene (contracting) are probably involved
  • plant_movement.1211896715.txt.gz
  • Last modified: 2008-05-27 13:58
  • by nik