Pollen tubes show:

Options

A. Haptotropism
B. Chemotropism
C. Anemotropism
D. Heliotropism.

Answer

To answer the question "Pollen tubes show:", we need to analyze the options provided and understand the types of movements or tropisms that plants exhibit. Here’s a step-by-step solution:

### Step 1: Understand the Types of Tropisms
First, we need to define the types of tropisms mentioned in the options:
- **Haptotropism**: This refers to the movement of plant parts in response to touch stimuli. An example is the tendrils of climbing plants that wrap around supports when they come into contact with them.
- **Chemotropism**: This is the growth or movement of a plant part in response to a chemical stimulus. Pollen tubes grow towards the ovule, which releases chemical signals.
- **Anemotropism**: This refers to the movement of plant parts in response to wind direction.
- **Heliotropism**: This is the directional growth of a plant in response to sunlight.

### Step 2: Analyze Each Option
- **Haptotropism**: Incorrect, as pollen tubes do not respond to touch.
- **Chemotropism**: Correct, as pollen tubes grow towards the ovule in response to chemical signals.
- **Anemotropism**: Incorrect, as pollen tubes do not respond to wind.
- **Heliotropism**: Incorrect, as pollen tubes do not respond to sunlight.

### Step 3: Conclusion
Based on the definitions and analysis, the correct answer is that pollen tubes show **chemotropism**.

### Final Answer
Pollen tubes show **chemotropism**.

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