plant response

• plants respond to what they need for photosynthesis
• plants grow in direction most likely to find sunlight (leaves grow up) and water (roots grow down)
• response with growth in plants called?

  tropisms
• response to light?

  phototrophism
• response to gravity?

  geotrophism
• shoots grow towards sun = positive phototropism
• roots grow away from sun = negative phototrophism
• towards = positive
• away = negative
• roots grow towards gravity?

  positive geotropism
• shoots grow away from gravity?

  negative geotroopism
• phototropism auxins?

  make shoot cells grow longer

  moves away from light = shoots in dark grow longer as have more auxins

  dark side grows longer = shoots bends towards light
• geotropism auxins?

  auxins make root cells slow their growth - shorter cells

  auxins move to lowest side of root and slow the growth = root bend downwards