Auxins and Apical dominance 5.5.4

Question 1

Where are auxins produced?

Answer 1

At the growing tip at the apex

Question 2

What do auxins do?

Answer 2

They cause the stem to grow upwards and also stop lateral buds from growing. This is known as apical dominance

Question 3

Why is it best for plants to grow towards the light?

Answer 3

Ensures the plant has more energy for photosynthesis

Question 4

What is a benefit of apical dominance

Answer 4

Sideways growth is not so useful to a plant, so ensures plant growth is preferably upwards

Question 5

What happens if the growing tip at the apex is removed?

Answer 5

Apical dominance no longer occurs as the source of auxins has been removed

Question 6

What happens to the lateral buds that grow eventually?

Answer 6

They curl up to the light, resulting in growth in an upwards direction

Question 7

How is apical dominance shown experimentally?

Answer 7

The apical bud of the first test plant is removed
This allows lateral bud growth
A second (genetically identical) test plant is decapitated but this time the cut plant is immediately replaced with an agar block containing auxin
This restores the inhibition of lateral bud growth and no lateral buds grow