The leaves of Mimosa pudica (sensitive plant) droop down on touch because

Options

A. The plant has nervous system
B. The leaves are very tender
C. The leaves are injured
D. The turgor pressure of the leaf base changes

Answer

**Step-by-Step Solution:**

1. **Identify the Plant**: The plant in question is Mimosa pudica, commonly known as the sensitive plant or touch-me-not plant. This plant is known for its rapid response to touch.

2. **Understand the Response Mechanism**: When the leaves of Mimosa pudica are touched, they exhibit a drooping behavior. This is a response to a stimulus (in this case, touch).

3. **Analyze the Cellular Changes**: The drooping occurs due to changes in the cells at the base of the leaf, specifically in the petiole (the stalk that attaches the leaf to the stem).

4. **Water Loss in Cells**: Upon receiving the touch stimulus, the cells in the petiole lose water (H2O). This loss of water leads to a decrease in turgor pressure within those cells.

5. **Effect of Turgor Pressure**: Turgor pressure is the pressure of the cell contents against the cell wall. When the cells lose water and become flaccid (soft and limp), the turgor pressure decreases, causing the leaves to droop down.

6. **Conclusion**: The correct explanation for why the leaves of Mimosa pudica droop down upon touch is that the turgor pressure at the base of the leaf changes due to the loss of water from the cells.

**Final Answer**: The leaves of Mimosa pudica droop down on touch because the turgor pressure of the leaf base changes due to the loss of water from the cells.

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