The organic acid concentration in CAM plants

Options

A. Decreases during day
B. Increases at night
C. Both (1) and (2)
D. Remains same always

Answer

**Step-by-Step Solution:**

1. **Understanding CAM Plants:**
- CAM stands for Crassulacean Acid Metabolism. These plants are adapted to arid (dry) conditions, which is crucial for their survival in environments where water is scarce.

2. **Stomata Behavior:**
- In most plants, stomata (the small openings on leaves) open during the day for gas exchange and close at night. However, CAM plants have adapted to open their stomata at night to minimize water loss.

3. **Carbon Dioxide Fixation:**
- During the night, when the stomata are open, carbon dioxide (CO2) enters the plant. This CO2 is then fixed into a 4-carbon compound called oxaloacetate, which is subsequently converted into malic acid (malate).

4. **Organic Acid Concentration at Night:**
- As a result of the CO2 fixation during the night, the concentration of organic acids (like malate) increases. This is because the stomata are open, allowing for gas exchange and the formation of these acids.

5. **Organic Acid Concentration During the Day:**
- During the day, the stomata of CAM plants remain closed to prevent water loss. Consequently, no new CO2 enters the plant, leading to a decrease in the concentration of organic acids as they are utilized in the process of photosynthesis.

6. **Conclusion:**
- Therefore, the concentration of organic acids in CAM plants:
- Increases at night (when stomata are open).
- Decreases during the day (when stomata are closed).
- The correct answer is that the organic acid concentration in CAM plants decreases during the day and increases at night.

**Final Answer:**
The organic acid concentration in CAM plants decreases during the day and increases at night.

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