Which of the following statements is incorrect about photosynthesis ?

Options

A. Increases in incident light beyond a point increases formation of chlorophyll and thus increase in photosynthesis .
B. At high light intensities , both `C_3 and C_4` plants show increase in the rates of photosynthesis.
C. `C_3` plants respond to higher `CO_2` concentration by showing increased rates of photosynthesis leading to higher productivity has been used for some greenhouse crops such as tomatoes and bell pepper.
D. Tropical plant have a higher temperature optimum than the plants adapted to temperature climates.

Answer

To determine which statement about photosynthesis is incorrect, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose, using carbon dioxide and water. It primarily occurs in the chloroplasts of plant cells.

2. **Analyzing the First Statement**:
- The first statement claims: "Increase in incident light beyond the point increases formation of chlorophyll and thus increases in photosynthesis."
- This statement is incorrect because while light is essential for photosynthesis, excessive light can lead to photoinhibition, which can cause damage to chlorophyll and reduce the rate of photosynthesis. Therefore, an increase in light intensity beyond a certain point does not lead to increased chlorophyll formation or photosynthesis.

3. **Analyzing the Second Statement**:
- The second statement states: "At high light intensities, C3 and C4 plants increase in the rates of photosynthesis."
- This statement is correct. C3 and C4 plants can utilize high light intensities effectively, leading to increased rates of photosynthesis.

4. **Analyzing the Third Statement**:
- The third statement mentions: "C3 plants respond to higher CO2 concentration by showing increased rates of photosynthesis leading to higher productivity, has been used for some greenhouse crops such as tomatoes and black pepper."
- This statement is also correct. C3 plants do benefit from higher CO2 levels, which can enhance their photosynthetic rates.

5. **Analyzing the Fourth Statement**:
- The fourth statement asserts: "Tropical plants have a higher temperature optimum than the plants adapted to temperate climates."
- This statement is correct as tropical plants are adapted to higher temperatures compared to those in temperate climates.

6. **Conclusion**:
- After analyzing all statements, the first statement is the only incorrect one regarding photosynthesis.

### Final Answer:
The incorrect statement about photosynthesis is: **"Increase in incident light beyond the point increases formation of chlorophyll and thus increases in photosynthesis."**

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