Plants show light saturation effect at _______ of full sunlight

Options

A. 0.1
B. 0.5
C. 0.7
D. 1

Answer

**Step-by-Step Solution:**

1. **Understanding Light Saturation Effect**: The light saturation effect refers to the point at which an increase in light intensity no longer results in an increase in the rate of photosynthesis. This is because the photosynthetic machinery of the plant has reached its maximum capacity to utilize light energy.

2. **Factors Affecting Photosynthesis**: Several factors influence the rate of photosynthesis, including light intensity, carbon dioxide concentration, temperature, and the availability of water. Among these, light intensity is crucial as it directly affects the energy available for photosynthesis.

3. **Photosynthesis in C3 and C4 Plants**: Different types of plants have different light saturation points. For C3 plants, the light saturation point is typically around 60-70% of full sunlight. In contrast, C4 plants can achieve light saturation at much higher light intensities, around 200% of full sunlight.

4. **Conclusion**: Based on the information provided, the light saturation effect for plants occurs at approximately 10% of full sunlight for the initial carbon fixation process. However, for maximum photosynthesis rates, C3 plants reach saturation at 60-70% of full sunlight, while C4 plants can utilize up to 200% of full sunlight.

**Final Answer**: Plants show light saturation effect at **60-70%** of full sunlight for C3 plants and **200%** for C4 plants, but for initial carbon fixation, it can be considered as **10%** of full sunlight.

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