Jerky lateral leaflet movements of Desmodium gyrans are

Options

A. Negative geotropic movements
B. Positive geotropic movements
C. Hydrotropic movements
D. None of the above.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the jerky lateral leaflet movements of Desmodium gyrans, also known as the telegraph plant. We need to identify the type of movement these leaflets exhibit.

2. **Identifying the Plant's Characteristics**: Desmodium gyrans is famous for its rapid and jerky movements of its leaflets. These movements occur in response to various stimuli, such as touch, light, warmth, or vibrations.

3. **Analyzing the Options**: The options provided are:
- A) Negative geotropic movements
- B) Positive geotropic movements
- C) Hydrotropic movements
- D) None of the above

4. **Understanding Geotropic Movements**: Geotropic movements refer to the growth of plant parts in response to gravity. Positive geotropic movements occur when roots grow downwards (towards gravity), while negative geotropic movements occur when stems grow upwards (away from gravity).

5. **Understanding Hydrotropic Movements**: Hydrotropic movements are responses to water. Plants may grow towards moisture, but this does not apply to the jerky movements of Desmodium gyrans.

6. **Identifying the Correct Movement Type**: The jerky movements of the leaflets of Desmodium gyrans are not related to gravity (geotropism) or water (hydrotropism). Instead, they are a response to external stimuli like touch and light, which is a form of hegemotropism.

7. **Conclusion**: Since the movements do not fit into any of the categories provided (geotropic or hydrotropic), the correct answer is "none of the above."

**Final Answer**: The jerky lateral leaflet movements of Desmodium gyrans are **none of the above**.

---