Length of petiole increases by the acitivity of
(a) Apical meristem
(b) Lateral meristem
(c) Intercalary meristem
(d) All the above

Options

A. Apical meristem
B. Lateral meristem
C. Intercalary meristem
D. All the above

Answer

To solve the question regarding which type of meristem is responsible for the increase in the length of the petiole, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Petiole**:
- The petiole is the stalk that attaches the leaf blade to the stem. It plays a crucial role in supporting the leaf and facilitating the transport of nutrients and water.

2. **Identifying Types of Meristems**:
- **Apical Meristem**: Located at the tips of roots and shoots, responsible for primary growth (lengthening of the plant).
- **Lateral Meristem**: Found in the vascular and cork cambium, responsible for secondary growth (thickening of the plant).
- **Intercalary Meristem**: Located between the nodes and internodes, specifically in monocots, and is responsible for the elongation of stems and petioles.

3. **Analyzing the Options**:
- **Option A (Apical Meristem)**: While it contributes to the overall length of the plant, it does not specifically target the petiole.
- **Option B (Lateral Meristem)**: This type is involved in thickening rather than lengthening.
- **Option C (Intercalary Meristem)**: This type is specifically responsible for the increase in length of the petiole as it is located at the base of the leaf blade and between nodes.
- **Option D (All the above)**: This cannot be correct since not all types of meristems contribute to the lengthening of the petiole.

4. **Conclusion**:
- Based on the analysis, the correct answer is **(c) Intercalary meristem**, as it is specifically responsible for the increase in length of the petiole.

### Final Answer:
(c) Intercalary meristem