Plant Hormones Flashcards
What is an auxin
A plant growth hormone
What do plant roots do
Grow in the direction of gravity
What do plant shoots do
Grow towards the light
What is a phototropism
Response of a plant to light
What is a positive phototropism
When the plants grows towards the light
What is a geotropism
Response of a plant to gravity
What is a positive geotropism
When a plant grown in the direction of gravity
Explain a positive phototropism
1 Shoots of the plants have auxins in the tip
2 The light hits the shoot from one direction, destroying the auxins on that area
3 Auxins are left on the shaded side and so grow on that side
4 The shoot grows only on the shaded side meaning it grows towards the light where it begins to bend
Explain a positive geotropism
1 Auxins in the root are on the lower side and grow towards the direction of gravity
2 In the root an extra auxin inhibits growth meaning cells on top elongate faster and the root beings down
