Rose plants with different severities of black spot were grown for four weeks. The table shows the mean percentage of leaves that dropped and the mean increase in root dry mass.
| Mean percentage of leaves that dropped (%) | Mean increase in root dry mass (g) |
|---|---|
| 0 | 2.8 |
| 20 | 2.4 |
| 40 | 2.0 |
| 60 | 1.6 |
Use the data and your knowledge of photosynthesis to explain the effect of black spot on root growth. Predict the mean increase in root dry mass if 80% of the leaves dropped.
133 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.