The movement of pollen tube is called
(a) Chemotropism
(b) Thermotaxis
(c) Thermonastic
(d) Hydrotropism

Options

A. Chemotropism
B. Thermotaxis
C. Thermonastic
D. Hydrotropism

Answer

To determine the correct answer to the question about the movement of the pollen tube, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the type of movement exhibited by the pollen tube as it grows towards the embryo sac.

2. **Analyze the Options**:
- **(a) Chemotropism**: This refers to the movement of an organism or a part of an organism in response to a chemical stimulus.
- **(b) Thermotaxis**: This refers to movement in response to temperature, either towards or away from heat.
- **(c) Thermonastic**: This refers to movements in response to temperature changes, typically not directional.
- **(d) Hydrotropism**: This refers to movement in response to water.

3. **Identify the Mechanism of Pollen Tube Movement**: The pollen tube grows towards the embryo sac due to chemical signals. This process is guided by chemical attractants, which is characteristic of chemotropism.

4. **Eliminate Incorrect Options**:
- **Thermotaxis** is not relevant since the pollen tube does not move in response to temperature.
- **Thermonastic** movements are not directional and do not apply to the pollen tube.
- **Hydrotropism** is related to water presence, which is not the primary factor for pollen tube movement towards the embryo sac.

5. **Conclude the Correct Answer**: Since the movement of the pollen tube is directed by chemical signals, the correct answer is **(a) Chemotropism**.

### Final Answer:
The movement of the pollen tube is called **(a) Chemotropism**.

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