2.81 phototropism

http://www.youtube.com/watch?v=tE4XMg4Y_d4

- photptroism is the growth with light
- positive phototropism isthe growth towards the light
- when the stem is hit by light rays the stem will grow up
- if the light is lateral, then the stem tip will grow to its side, this is an example of positive phototropism
- auxin is a hormon which causes cell division and then causes the cell to grow up, when the light rays hit the stem it causes the auxin to move to one side (the side which the light does not hit) and therefore bending it because its only growing on one side