Researchers attached two narrow strips to opposite sides of the growing region of each young plant organ.
The researchers measured the mean cell length on each side at the start and after 12 hours.
| Plant organ | Side and treatment | Mean cell length at start in µm | Mean cell length after 12 hours in µm |
|---|---|---|---|
| shoot | left, auxin-releasing strip | 200 | 300 |
| shoot | right, control strip | 200 | 240 |
| root | left, auxin-releasing strip | 200 | 220 |
| root | right, control strip | 200 | 280 |
Calculate how many times as great the percentage increase in mean cell length was on the right side of the root as on the left side.
Explain what the results show about the effect of additional auxin on cell elongation in shoots and roots.
The strips remained attached to the intact shoot and root.
Predict how the shoot and the root curved after 12 hours. Explain both predictions.
105 exam-style questions on Edexcel GCSE Biology 6.3 Plant hormones, covering 6.3.1 Plant hormones and tropisms and 6.3.2 Commercial uses of plant hormones. Each one has a worked solution and a mark scheme showing where the marks go.