Explain6 marksChallenge
A student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea. The rate was measured as oxygen production (arbitrary units per minute) in a 20-minute period. Sodium hydrogencarbonate (NaHCO₃) was added to the water to provide different concentrations of carbon dioxide. The experiment was carried out at two different light intensities: 200 µmol m⁻² s⁻¹ (low light) and 800 µmol m⁻² s⁻¹ (high light). All other factors were kept constant. The results are shown in the table below.
| CO₂ concentration (% in water) | Rate at low light (arbitrary units) | Rate at high light (arbitrary units) |
|---|---|---|
| 0.04 | 2 | 3 |
| 0.08 | 6 | 9 |
| 0.12 | 10 | 14 |
| 0.16 | 10 | 18 |
| 0.20 | 10 | 20 |
Explain the results shown in the table, including the concept of limiting factors.