2.81 Phototropism

POSITIVE - PHOTO - TROPISM
- photo --> light
- positive photo --> towards light
- tropism --> growth response
- positive phototropism :: growth response towards light
- even if the light is to the side of the plant ( unilateral light source ) the plant will bend over to catch the light
- Auxin is a hormone in the plant where cells divide and elongate.
- When the light hits only one side of the plant the Auxins which are usually evenly spread out in the plant move to the opposite side.
- Because Auxins is where the cells divide, the cells are only dividing on one side of the plant, the plant is only growing from one side.
- This is how it grows towards the sun.