The element which prevents bursting of the pollen tube and helps in pollen germination is

Options

A. K
B. B
C. Fe
D. `H_(2)O`

Answer

To solve the question regarding which element prevents the bursting of the pollen tube and aids in pollen germination, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Elements in Pollen Germination**:
- Pollen germination is a critical process in plant reproduction, where the pollen tube grows towards the ovule. Certain elements play specific roles in this process.

2. **Evaluate the Given Options**:
- The options provided are:
- A. Potassium
- B. Boron
- C. Ferrous (Iron)
- D. Water

3. **Analyze Each Option**:
- **A. Potassium**:
- Potassium is primarily involved in the regulation of stomatal opening and closing and does not directly influence pollen tube growth or germination. Therefore, this option is incorrect.

- **B. Boron**:
- Boron is a micronutrient essential for various plant processes. It is crucial for pollen germination as it helps in the formation of the pollen tube and cell differentiation. It also plays a role in carbohydrate transport and the synthesis of proteins and nucleic acids. Thus, this option is likely correct.

- **C. Ferrous (Iron)**:
- Iron is important for chlorophyll synthesis and enzyme functions but is not directly involved in pollen germination. Therefore, this option is incorrect.

- **D. Water**:
- While water is essential for plant growth and maintaining turgidity, it does not specifically prevent the bursting of the pollen tube. Thus, this option is also incorrect.

4. **Conclusion**:
- After evaluating all the options, the element that prevents bursting of the pollen tube and assists in pollen germination is **Boron**.

### Final Answer:
The correct answer is **B. Boron**.