Petiole of Australian Acacia helps in

Options

A. respiration
B. photosynthesis
C. transpiration
D. secretion

Answer

### Step-by-Step Solution:

1. **Understanding the Petiole**: The petiole is the stalk that attaches the leaf blade to the stem. In the case of Australian Acacia, the petiole is modified to serve a specific function.

2. **Identifying the Plant Type**: Australian Acacia is classified as a xerophyte, which means it is adapted to survive in dry environments. Xerophytes have special adaptations to minimize water loss.

3. **Adaptations of Australian Acacia**: To reduce water loss, Australian Acacia has adapted by reducing the size of its leaves or transforming them into spiny or scale-like structures. This adaptation helps the plant conserve water.

4. **Role of Chlorophyll**: In typical plants, chlorophyll in the leaves is essential for photosynthesis, the process by which plants make their food. However, since the leaves are reduced or modified in Australian Acacia, there is a lack of chlorophyll in the traditional sense.

5. **Modification of Petiole**: To compensate for the absence of leaves, the petiole of the Australian Acacia is modified into structures known as phyllodes. These phyllodes are green and contain chlorophyll.

6. **Function of Phyllodes**: The green phyllodes take over the role of the leaves by performing photosynthesis. This allows the plant to produce food despite the absence of traditional leaves.

7. **Conclusion**: Therefore, the petiole of Australian Acacia helps in photosynthesis by being modified into green phyllodes that contain chlorophyll.

### Final Answer:
The petiole of Australian Acacia helps in **photosynthesis**.

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