Growth of pollen tube is

Options

A. Apical
B. Basal
C. Intercalary
D. Diffused.

Answer

**Step-by-Step Solution:**

1. **Understanding Pollen Tube Growth**: The growth of a pollen tube occurs after the pollen grain germinates on the stigma of a flower. This is the first step in the fertilization process in flowering plants.

2. **Germination of Pollen Grain**: When a pollen grain lands on a compatible stigma, it absorbs moisture and nutrients, leading to germination. This process involves the formation of a pollen tube that will grow towards the ovule.

3. **Growth Direction**: The pollen tube grows through a structure known as the germ pore. The growth of the pollen tube is not random; it is directed and occurs in a specific manner.

4. **Chemotropic Growth**: The pollen tube exhibits chemotropic growth, which means it grows in response to chemical stimuli. In this case, the sugary fluid present in the style and stigma acts as a chemical attractant that guides the growth of the pollen tube.

5. **Type of Growth**: The growth of the pollen tube is apical, meaning it grows from the tip (apex) rather than from the base or in a diffuse manner. This is because the growth occurs at the apex of the pollen tube, allowing it to penetrate through the tissues of the stigma and style effectively.

6. **Exclusion of Other Growth Types**:
- **Basal Growth**: This type of growth would mean that the growth occurs from the base of the pollen tube, which is not the case here.
- **Intercalary Growth**: This type of growth occurs in regions of the plant that have intercalary meristems, which are not present in pollen tubes.
- **Diffused Growth**: This would imply that growth occurs uniformly throughout the structure, which is also not how pollen tubes grow.

7. **Conclusion**: Based on the above points, the correct answer to the question "Growth of pollen tube is" is **apical**.

**Final Answer**: The growth of the pollen tube is apical.

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