In Australian Acacia, petiole is modified into leaf like sickle shaped structure known as

Options

A. Phyllode
B. Phylloclade
C. Cladode
D. Hypsophyll

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the modification of the petiole in Australian Acacia, specifically what this modified structure is called.

2. **Identifying the Structure**: In Australian Acacia, the petiole (the stalk that attaches the leaf blade to the stem) is modified into a structure that resembles a leaf. This structure is known for its sickle shape.

3. **Function of the Modified Structure**: The modified petiole, which takes on the leaf-like appearance, plays a crucial role in photosynthesis. This is significant because the original leaf lamina may fall off quickly, leaving the petiole to perform the photosynthetic function.

4. **Naming the Structure**: The modified petiole in Australian Acacia is called a "phyllode." Phyllodes are typically flattened and leaf-like, allowing them to carry out photosynthesis effectively.

5. **Additional Characteristics**: Phyllodes usually develop vertically and possess stomata, which are small openings that allow for gas exchange. This enables not only photosynthesis but also transpiration, which is the process of water movement through a plant.

6. **Comparison with Other Terms**: It is important to differentiate phyllodes from other terms:
- **Phylloclade**: A modified branch that resembles a leaf.
- **Cladode**: A stem that is flattened and functions like a leaf.
- **Hypsophyll**: A bract or bractiol associated with flowers.

7. **Conclusion**: Based on the understanding of the modifications and their functions, the correct answer to the question is that the modified petiole in Australian Acacia is called a "phyllode."

**Final Answer**: Phyllode

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