Where do bacteroids occur in a legume plant?

Options

A. Leaves
B. Root nodules
C. Stem
D. Flower

Answer

**Step-by-Step Solution:**

1. **Understanding Bacteroids**: Bacteroids are specialized forms of nitrogen-fixing bacteria that are found in certain plants, particularly legumes. They play a crucial role in converting atmospheric nitrogen into a form that plants can use.

2. **Identifying the Location**: In legume plants, bacteroids are specifically located in the root nodules. These nodules are small outgrowths that form on the roots of the legume plants.

3. **Function of Bacteroids**: The primary function of these bacteroids is nitrogen fixation. They convert atmospheric nitrogen (N₂) into ammonia (NH₃), which is a usable form of nitrogen for the plant.

4. **Symbiotic Relationship**: Bacteroids, such as those from the genus Rhizobium, establish a symbiotic relationship with legume plants. This means that both the bacteria and the plant benefit from this association.

5. **Examples of Legumes**: Common examples of legume plants that contain these root nodules with bacteroids include sweet clover, sweet pea, garden pea, and beans.

6. **Conclusion**: Therefore, the correct answer to the question is that bacteroids occur in the root nodules of legume plants.

**Final Answer**: Bacteroids occur in the root nodules of a legume plant.

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