Scientists tested a treatment that causes guard cells to make stomata open less widely. Equal areas of treated and untreated leaves from crop plants were tested under the same conditions.
| Leaves | Mean width of stomatal opening in µm | Carbon dioxide uptake in mg per dm² per hour | Water vapour loss in g per dm² per hour |
|---|---|---|---|
| Untreated | 10.0 | 18.0 | 2.4 |
| Treated | 4.0 | 7.0 | 0.8 |
Explain one advantage and one disadvantage of applying the treatment to crop plants when water is in short supply. Use data from the table.
74 exam-style questions on AQA GCSE Biology 2.3 Plant tissues, organs and systems, covering 2.3.1 Plant tissues and 2.3.2 Plant organ system. Each one has a worked solution and a mark scheme showing where the marks go.