A grower has two unlabelled fertilisers, P and Q. One fertiliser contains magnesium ions and the other contains nitrate ions.
The grower applies the same volume of each fertiliser to separate groups of yellow-leaved strawberry plants. All other conditions are kept the same.
| Fertiliser applied | Leaf colour before fertiliser was applied | Leaf colour three weeks later |
|---|---|---|
| P | Yellow | Green |
| Q | Yellow | Yellow |
Explain which fertiliser contains magnesium ions.
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.