Sorghum and sugarcane plants show saturation at about

Options

A. 50% of full sunlight
B. 10% of full sunlight
C. 360 ppm of `CO_2`
D. 500 ppm of `CO_2`

Answer

To solve the question regarding the saturation point of sorghum and sugarcane plants, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Type of Plants**:
- Sorghum and sugarcane are both classified as C4 plants. This is important because C4 plants have a different mechanism for photosynthesis compared to C3 plants.

2. **Understand the Concept of Saturation**:
- Saturation in this context refers to the point at which an increase in carbon dioxide (CO2) concentration no longer leads to an increase in the rate of photosynthesis.

3. **Know the CO2 Concentration Levels**:
- The question provides several options regarding CO2 concentration levels:
- 50% of full sunlight
- 10% of full sunlight
- 360 ppm of CO2
- 450 ppm of CO2

4. **Relate CO2 Concentration to Plant Types**:
- C4 plants, such as sorghum and sugarcane, typically show saturation at lower CO2 concentrations compared to C3 plants.
- C3 plants show a response to increased CO2 concentrations beyond 450 ppm.

5. **Determine the Correct Answer**:
- Based on the information that C4 plants show saturation at around 360 ppm of CO2, we can conclude that the correct answer to the question is **360 ppm of CO2**.

### Final Answer:
Sorghum and sugarcane plants show saturation at about **360 ppm of CO2**.

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