A researcher has developed two stains for use with seed plants. One stains sporophyte tissue blue, the other stains gametophyte tissue red. If the researcher exposes pollen grains to both stains, and then rinses away the excess stain, what should occur?
a) The pollen grains will be pure red.
b) The pollen grains will be pure blue.
c) The pollen grains will have red interiors and blue exteriors.
d) The pollen grains will have blue interiors and red exteriors.

Options

A. The pollen grains will be pure red.
B. The pollen grains will be pure blue.
C. The pollen grains will have red interiors and blue exteriors.
D. The pollen grains will have blue interiors and red exteriors.

Answer

To solve the question regarding the staining of pollen grains, we need to understand the structure of pollen grains and the effects of the stains on them.

### Step-by-Step Solution:

1. **Understanding Pollen Grain Structure**:
- Pollen grains consist of two main parts: the outer layer called the exine and the inner layer called the intine.
- The exine is derived from the sporophyte generation, while the intine and the cells inside (such as the generative cell) are derived from the gametophyte generation.

2. **Identifying the Stains**:
- The researcher has developed two stains:
- One stains sporophyte tissue blue.
- The other stains gametophyte tissue red.

3. **Applying the Stains**:
- When pollen grains are exposed to both stains, the exine (sporophyte-derived) will absorb the blue stain, and the intine and the generative cell (gametophyte-derived) will absorb the red stain.

4. **Rinsing Away Excess Stain**:
- After rinsing, the pollen grains will retain the blue color on the outside (exine) and the red color on the inside (intine and generative cell).

5. **Conclusion**:
- Therefore, the pollen grains will have blue exteriors (from the sporophyte tissue) and red interiors (from the gametophyte tissue).

### Final Answer:
The correct answer is **c) The pollen grains will have red interiors and blue exteriors.**