In vitro pollen germination and pollen tube elongation can be induced by----- -

Options

A. boric acid
B. glucose
C. lactose
D. sucrose

Answer

To answer the question regarding what induces in vitro pollen germination and pollen tube elongation, we can break down the process step by step.

### Step-by-Step Solution:

1. **Understanding In Vitro Pollen Germination**:
- In vitro pollen germination refers to the germination of pollen grains outside of the plant, typically in a controlled laboratory environment. This allows researchers to study the germination process in detail.

2. **Factors Required for Pollen Germination**:
- Pollen germination requires specific nutrients and conditions to facilitate the growth of the pollen tube, which is essential for fertilization.

3. **Identifying Key Nutrients**:
- Among the nutrients that can be used in in vitro conditions, we have:
- **Boric Acid**: Often used as a nutrient to aid in pollen germination.
- **Glucose**: A simple sugar that serves as an energy source for metabolic processes.
- **Lactose**: Another sugar, but not typically used for pollen germination.
- **Sucrose**: A disaccharide that is commonly used in plant tissue culture and provides energy for pollen tube growth.

4. **Role of Sucrose**:
- Sucrose is particularly important because it not only provides energy but also supports the metabolic processes necessary for pollen tube elongation. This makes it a critical component in the medium used for in vitro pollen germination.

5. **Conclusion**:
- Based on the above analysis, the correct answer to the question is **Sucrose**, as it is the substance that effectively induces in vitro pollen germination and pollen tube elongation.

### Final Answer:
In vitro pollen germination and pollen tube elongation can be induced by **Sucrose**.

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