Light condition Mean number of open stomata per field Dark 3 Dim light 18 Bright light 41 A science club tested how light affects stomata in floating water-...
Question 1 Report
| Light condition | Mean number of open stomata per field |
|---|---|
| Dark | 3 |
| Dim light | 18 |
| Bright light | 41 |
A science club tested how light affects stomata in floating water-lily leaves. Table 1 gives the mean number of open stomata seen in three microscope fields. Each field had the same area. Open stomata allow carbon dioxide to enter leaf cells for photosynthesis, but they also allow water vapour to leave.
| Light condition | Mean number of open stomata per field |
|---|---|
| Dark | 3 |
| Dim light | 18 |
| Bright light | 41 |
(a) Identify the light condition with the greatest number of open stomata. [1]
(b) Describe the relationship between light level and the mean number of open stomata. [1]
(c) Explain one advantage of opening stomata in bright light. [2]
Answer Details
(a) Bright light [1] (b) As light level increases, the mean number of open stomata increases [1] (c) More carbon dioxide diffuses into the leaf [1]; this can increase the rate of photosynthesis / glucose production [1]
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