`C_(4)` plants can tolerate saline conditions due to

Options

A. Occurrence of organic acids
B. Absence of photorespiration
C. Presence of PEP synthetase enzyme
D. Presence of PEP carboxylase enzyme

Answer

### Step-by-Step Solution:

1. **Understanding C4 Plants**: C4 plants utilize a specific pathway for photosynthesis known as the C4 pathway or Hatch-Slack pathway. This pathway allows them to efficiently fix carbon dioxide (CO2) even in conditions where CO2 is limited.

2. **Photosynthesis Process**: In C4 plants, the initial fixation of CO2 occurs in the mesophyll cells. This is different from C3 plants, where the fixation occurs in the same cells where the Calvin cycle occurs.

3. **Role of Enzymes**: The enzyme responsible for the initial fixation of CO2 in C4 plants is called PEP carboxylase. This enzyme catalyzes the reaction where phosphoenolpyruvate (PEP) combines with CO2 to form oxaloacetic acid (OAA), which is an organic acid.

4. **Formation of Organic Acids**: The formation of organic acids, particularly OAA, is crucial for the C4 pathway. These organic acids play a significant role in the plant's metabolism and adaptation to various environmental conditions.

5. **Tolerating Saline Conditions**: C4 plants can tolerate saline conditions primarily due to the presence of these organic acids. The organic acids help in osmoregulation, allowing the plant to maintain cellular functions and integrity in the presence of salt.

6. **Conclusion**: Therefore, the ability of C4 plants to tolerate saline conditions is due to the occurrence of organic acids formed during the photosynthetic process.

### Final Answer:
C4 plants can tolerate saline conditions due to the occurrence of organic acids.

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