a.[2]
Commercial growers use plant hormones to manipulate crop development. What are two commercial uses of gibberellins? Tick (✓\checkmark✓) two boxes.
- To stimulate root growth on cuttings
- To trigger seed germination out of season
- To promote the ripening of stored bananas
- To increase the size of seedless grapes
- To act as selective herbicides on broad-leaved weeds
b.[2]
Students investigated how directional light affects the growth of mustard seedlings. Figure 1 shows the experimental setup.
Describe two improvements the students should make to their investigation.
c.[1]
Figure 2 shows a seedling stem (shoot) bending towards a light source in response to light.
Suggest how the students could accurately measure the length of the curved shoot in Figure 2.
d.[3]
Explain how the unequal distribution of auxin causes the shoot in Figure 2 to bend towards the light. Refer to Side C (shaded side) and Side D (light side) in your answer.