In majority of dicot plant, the guard cells are

Options

A. Dumb-bell shaped
B. Bean shaped
C. Rounded
D. Polygonal

Answer

**Step-by-Step Solution:**

1. **Understanding Guard Cells**: Guard cells are specialized cells that surround the stomatal pores on the leaves of plants. Their primary function is to regulate the opening and closing of these pores, which allows for gas exchange (such as oxygen and carbon dioxide) and transpiration.

2. **Identifying Plant Groups**: Plants are classified into two main groups based on the number of cotyledons in their seeds: monocots (one cotyledon) and dicots (two cotyledons). This classification helps in understanding various characteristics of the plants, including the structure of guard cells.

3. **Shape of Guard Cells in Dicot Plants**: In the majority of dicot plants, guard cells are typically bean-shaped. This shape is crucial for their function, as it allows them to change shape effectively to open and close the stomatal pores.

4. **Comparison with Monocots**: In contrast, guard cells in monocot plants are usually dumbbell-shaped. This difference in shape is a key characteristic that distinguishes the two groups of plants.

5. **Mechanism of Action**: The shape of the guard cells, along with the arrangement of microfibrils, allows them to expand and contract. When the guard cells take in water, they swell and become turgid, causing the stomatal pore to open. Conversely, when they lose water, they shrink, leading to the closure of the pore.

6. **Conclusion**: Therefore, the correct answer to the question is that in the majority of dicot plants, the guard cells are bean-shaped.

**Final Answer**: In majority of dicot plants, the guard cells are bean-shaped.

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