Name the cells that make the leaves curl in plants during water stress.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the specific type of cells in plants that cause leaves to curl during periods of water stress.

2. **Identifying the Cells**: The cells responsible for this curling action are known as **bulliform cells**.

3. **Function of Bulliform Cells**: Bulliform cells are specialized cells that help in the curling of leaves. This curling is a response to water stress, which occurs when the plant is losing water, primarily through a process called transpiration.

4. **Location of Bulliform Cells**: These cells are located in the **epidermal region** of the leaves, specifically in **monocotyledonous (monocot) plants**.

5. **Mechanism of Action**: When water is scarce, bulliform cells lose turgor pressure, leading to their collapse. This collapse causes the leaves to curl, reducing the surface area exposed to the sun and thus minimizing water loss through evaporation.

6. **Conclusion**: Therefore, the cells that make the leaves curl in plants during water stress are **bulliform cells**.

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