Describe4 marksStandard
The table below shows the mean stomatal aperture (width of the stomatal pore in micrometres) measured in leaves of a plant species over a 24-hour period under natural conditions.
| Time (hours) | Stomatal aperture (μm) |
|---|---|
| 0 (midnight) | 1.0 |
| 4 | 1.2 |
| 8 | 3.5 |
| 12 (noon) | 7.0 |
| 16 | 6.0 |
| 20 | 2.0 |
| 24 | 1.1 |
Describe the daily rhythm of stomatal aperture shown in the table. Explain the mechanism by which guard cells change turgor to open and close stomata, including the role of abscisic acid (ABA) during water stress.