Describe5 marksChallenge
The table below shows the mean stomatal aperture (width in µm) of leaves of a plant species measured every two hours over a 24-hour period. The plant was kept under a natural light-dark cycle (light from 06:00 to 18:00).
| Time (hours) | Stomatal aperture (µm) |
|---|---|
| 00:00 | 0.5 |
| 02:00 | 0.4 |
| 04:00 | 0.3 |
| 06:00 | 0.8 |
| 08:00 | 3.2 |
| 10:00 | 5.1 |
| 12:00 | 5.5 |
| 14:00 | 5.2 |
| 16:00 | 4.8 |
| 18:00 | 3.0 |
| 20:00 | 1.0 |
| 22:00 | 0.6 |
Describe the daily rhythm of stomatal aperture shown in the table, and describe the cellular mechanism that causes these changes in aperture. Your answer should include how the rhythm balances the plant's need for CO₂ uptake with the risk of water loss.