Phototropism & How It Works Flashcards
1
Q
What is phototropsim?
A
When plants respond to light by changing directions in which way they grow
2
Q
Which way do the plants grow?
A
They grow towards a light source as they need light to survive
3
Q
Where is auxin produced?
A
At the shoot tip
4
Q
Which direction does the auxin move?
A
It moves down the shoot, causing cells further down the shoot to grow
5
Q
What happens when light shine on a shoot?
A
Auxin near the light source is slowly destroyed, so there’s more auxin on the far side away from the light. This causes these cells to lengthen faster than those near the light, so the shoot bends towards light.
6
Q
What is the first step of phototropism?
A
- When a light source is directly overhead;
- auxin is evenly spread through the shoot
- the shoot grows straight up
7
Q
What is the second step of phototropism?
A
- When a light source is at an angle;
- auxin is destroyed nearest to the light source
- the auxin is concentrated on the side furthest away from the light
- the shoot bends towards the light
8
Q
What is the third step of phototropism?
A
- If the tip of the shoot is removed or covered in opaque materials, then the plant will continue to grow upwards - as if the light source isn’t there
9
Q
What is the fourth step of phototropism?
A
- If the tip is covered with a transparent cap, then it will still grow towards the light source. The same thing will happen if an opaque cylinder is wrapped around the stem, leaving the tip exposed.
