A researcher investigated substance P, which is produced by young leaves and moves to a growing bud.
The researcher measured the effect of substance P on cells from different parts of the plant.
| Cells tested | Mean increase in cell length without substance P / µm | Mean increase in cell length with substance P / µm |
|---|---|---|
| growing bud | 45 | 180 |
| mature leaf | 5 | 5 |
Explain why the researcher concluded that substance P is a plant hormone. Use the information in the question.
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.