Outline4 marksStandard
A study investigated stomatal aperture in leaves of a drought-sensitive plant species. The table shows the mean stomatal aperture (µm) at different times of day for plants grown under well-watered conditions and plants subjected to water stress (no water for 5 days).
| Time of day | Well-watered (µm) | Water-stressed (µm) |
|---|---|---|
| 06:00 | 2.5 | 1.2 |
| 12:00 | 5.8 | 0.8 |
| 18:00 | 4.1 | 0.6 |
Using your knowledge of the mechanism of stomatal closure, outline how water stress leads to the reduction in stomatal aperture seen in the data.