In root nodules of leguminous plants, the pigment leghaemoglobin that gives pink colour to the nodules, is present in the

Options

A. intercellular spaces
B. cytosol of bacteroids
C. inside the bacterial wall
D. outside the peribacterial space in the cytosol of nodule cells.

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question asks about the location of the pigment leghaemoglobin in the root nodules of leguminous plants. Leghaemoglobin is known for giving a pink color to these nodules.

2. **Identifying the Options**: The options provided are:
- A) Intercellular spaces
- B) Cytosol of bacteroids
- C) Inside the bacterial wall
- D) Outside the peribacterial space in the cytosol of nodule cells

3. **Analyzing Each Option**:
- **Option A**: Intercellular spaces - This is not the correct location for leghaemoglobin as it is not primarily found in the spaces between cells.
- **Option B**: Cytosol of bacteroids - While bacteroids are involved in nitrogen fixation, leghaemoglobin is not specifically located in their cytosol.
- **Option C**: Inside the bacterial wall - This option is also incorrect as leghaemoglobin is not contained within the bacterial wall.
- **Option D**: Outside the peribacterial space in the cytosol of nodule cells - This option correctly identifies the location of leghaemoglobin.

4. **Conclusion**: Based on the analysis, the correct answer is **Option D**: leghaemoglobin is present outside the peribacterial space in the cytosol of nodule cells.

5. **Explanation of Terms**: The term "peribacterial space" refers to the area between the inner and outer membranes of the bacteria within the nodule. The cytosol is the fluid component inside the cells where various cellular processes occur.

**Final Answer**: In root nodules of leguminous plants, the pigment leghaemoglobin that gives pink color to the nodules is present in **Option D**: outside the peribacterial space in the cytosol of nodule cells.

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