Plant hormones

• what is phototropism?


  Growth of a plant in response to light.

  Shoots are positively phototropic - grow towards light

  Roots are negatively phototropic - grow away from light
• what is geotropism (gravitropism)?


  growth of a plant in response to gravity

  shoots are negatively geotropic - grow up

  roots are positively geotropic - grow down
• what is hydrotropism?

  plant growth in response to water.

  Roots are positively hydrotropic
• what is thermotropism?


  plant growth in response to temperature
• what is thigmotropism?


  plant growth in response to contact with an object
• How do carrots respond to low temperatures?


  produce antifreeze proteins

  which bind to ice crystals and lower the temperature water freezes at, stopping more ice crystals from growing