Sugarcane show high efficiency of `CO_(2)` fixation because of

Options

A. Calvin cycle
B. hatch and Slack cycle
C. TCA cycle
D. Greater sunlight

Answer

**Step-by-Step Solution:**

1. **Identify the Plant Type**: Sugarcane is classified as a C4 plant. C4 plants are specifically adapted to thrive in dry tropical regions.

2. **Understand C4 Photosynthesis**: C4 plants, including sugarcane, utilize a unique photosynthetic pathway known as the Hatch-Slack pathway, which enhances their efficiency in fixing carbon dioxide (CO2).

3. **Hatch-Slack Pathway**: This pathway is also referred to as the C4 pathway. Its primary function is to fix CO2 effectively.

4. **Primary CO2 Acceptor**: In the Hatch-Slack pathway, the primary CO2 acceptor is a three-carbon molecule called phosphoenolpyruvate (PEP), which is present in the mesophyll cells of the plant.

5. **Role of Enzyme**: The enzyme that catalyzes the fixation of CO2 in this pathway is called PEP carboxylase (PEP case). Notably, mesophyll cells in C4 plants lack the enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco).

6. **Formation of 4-Carbon Compounds**: When CO2 is fixed, it combines with PEP to form oxaloacetic acid (OAA), a four-carbon compound. This OAA is then converted into either malic acid or aspartic acid.

7. **Transport to Bundle Sheath Cells**: The malic acid (or aspartic acid) is transported from the mesophyll cells to the bundle sheath cells.

8. **Decarboxylation in Bundle Sheath Cells**: In the bundle sheath cells, the C4 acids (like malic acid) are broken down to release CO2 and a three-carbon compound. This step is crucial as it allows for the efficient use of CO2 in the Calvin cycle.

9. **Conclusion**: Therefore, sugarcane shows high efficiency of CO2 fixation primarily due to the Hatch-Slack pathway, which allows it to effectively utilize CO2 in a way that is adapted to its environment.

**Final Answer**: Sugarcane shows high efficiency of CO2 fixation because of the Hatch-Slack pathway.

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