A researcher grew young roots through transparent gel. A narrow beam illuminated one side of each root tip for 12 hours. The other side was screened from the light.
The table shows the mean results.
| Side of root | Relative auxin concentration (arbitrary units) | Increase in length of growth zone in 12 hours (mm) |
|---|---|---|
| Illuminated side | 3.2 | 1.5 |
| Screened side | 7.8 | 0.8 |
Explain, using the data and your knowledge of auxin, how the roots would respond to the light.
87 exam-style questions on AQA GCSE Biology 5.4 Plant hormones, covering 5.4.1 Control and coordination and 5.4.2 Use of plant hormones (HT only). Each one has a worked solution and a mark scheme showing where the marks go.