Pollination of pollen grains in Pinus takes place at

Options

A. One celled
B. Two celled
C. Three celled
D. Four celled.

Answer

**Step-by-Step Solution:**

1. **Understanding Pollination in Pinus**:
- Pollination in Pinus involves the transfer of pollen grains from the male cones to the female cones, primarily facilitated by wind.

2. **Structure of Pollen Grains**:
- Pollen grains in Pinus are produced in male cones, which contain microsporophylls where microspores develop.

3. **Development of Pollen Grains**:
- The pollen grains develop into a four-celled structure. This structure consists of:
- Two prothallial cells
- One generative cell
- One tube cell

4. **Pollination Stage**:
- The question specifically asks at what stage pollination occurs. In Pinus, this occurs when the pollen grains are at the four-celled stage.

5. **Conclusion**:
- Therefore, the correct answer to the question "Pollination of pollen grains in Pinus takes place at" is **four-celled stage**.

**Final Answer**: Pollination of pollen grains in Pinus takes place at the **four-celled stage**.

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