Major limiting factor for photosythesis in `C_(3)` plants is

Options

A. `CO_(2)`
B. Temperature
C. Light
D. Water

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants convert light energy into chemical energy, using carbon dioxide and water, and releasing oxygen as a byproduct.

2. **Identifying Factors Affecting Photosynthesis**: Several factors can limit the rate of photosynthesis in plants, including light intensity, carbon dioxide concentration, temperature, and water availability.

3. **Focusing on C3 Plants**: C3 plants are a type of plant that uses the C3 carbon fixation pathway. They are the most common type of plants and include species like wheat, rice, and soybeans.

4. **Determining the Major Limiting Factor**: Among the factors affecting photosynthesis, carbon dioxide concentration is identified as the major limiting factor for C3 plants. This is because the atmospheric concentration of carbon dioxide is relatively low (approximately 0.03 to 0.04%).

5. **Impact of Carbon Dioxide Concentration**: An increase in carbon dioxide concentration up to a certain point (around 0.05%) can enhance the rate of photosynthesis. However, beyond this concentration, the rate may decrease due to potential harmful effects of excessive carbon dioxide.

6. **Comparing C3 and C4 Plants**: C4 plants have a different mechanism for carbon fixation and can saturate at lower concentrations of carbon dioxide (around 360 micromoles per liter), while C3 plants require higher concentrations (above 450 micromoles per liter) for saturation.

7. **Conclusion**: Therefore, the major limiting factor for photosynthesis in C3 plants is carbon dioxide concentration.

**Final Answer**: The major limiting factor for photosynthesis in C3 plants is carbon dioxide.

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