Movement of sunflower peduncle from east to west towards the direction of sun is

Options

A. photonasty
B. phototropism
C. nyctinasty
D. seismonasty

Answer

To answer the question regarding the movement of the sunflower peduncle from east to west towards the direction of the sun, we will analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the Movement**: The sunflower peduncle moves from east to west following the sun's path. This behavior is known as a directional response to light.

**Hint**: Consider how plants respond to light and what terms are used to describe these movements.

2. **Evaluating Option 1: Phototropism**: Phototropism is the growth of a plant in response to light direction. In this case, the sunflower is growing towards the light source (the sun), which fits the definition of phototropism.

**Hint**: Think about how plants orient themselves in relation to sunlight for optimal growth.

3. **Evaluating Option 2: Nastic Movement**: Nastic movements (like phototropism) are non-directional responses to stimuli. Phototropism is directional, while nastic movements (like nyctinasty) do not involve growth towards the stimulus.

**Hint**: Distinguish between directional and non-directional movements in plants.

4. **Evaluating Option 3: Nyctinasty**: Nyctinasty refers to movements that occur in response to the daily cycle of light and dark, such as the closing of flowers at night. This does not apply to the sunflower's movement towards the sun.

**Hint**: Recall the definitions of movements that occur due to daily light changes.

5. **Evaluating Option 4: Thigmonasty**: Thigmonasty (or Cismonasti) refers to movements in response to touch or vibration, which is not relevant to the sunflower's response to sunlight.

**Hint**: Consider how plants react to physical stimuli versus light stimuli.

### Conclusion:
The correct answer to the question about the movement of the sunflower peduncle from east to west towards the direction of the sun is **Phototropism**.

### Final Answer:
**Phototropism**