A transverse section of stem is stained first with safranin and then with fast green following the ususal schedule of double staining for the preparation of a permanent slide. What would be colour of the stained xylemand phloem?

Options

A. Red and green
B. green and red
C. orange and yellow
D. purple and orange.

Answer

To determine the colors of the stained xylem and phloem in a transverse section of a stem that has been stained first with safranin and then with fast green, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Staining Process**:
- The transverse section of the stem is stained first with safranin and then with fast green. These are two different dyes used in the double staining technique.

2. **Identifying the Dyes**:
- **Safranin**: This dye is known for staining nuclei and appears as a brilliant red color. It is commonly used to highlight cellular structures.
- **Fast Green**: This dye is primarily used to stain cellulose and cytoplasm, giving a bright green color.

3. **Staining Sequence**:
- When the section is stained with safranin first, the nuclei of the cells will take up the red color.
- After that, when fast green is applied, it will stain the cellulose and cytoplasm, which will appear green.

4. **Determining the Colors of Xylem and Phloem**:
- **Xylem**: The xylem typically contains lignin, which does not take up the safranin dye, so it will remain unstained or may appear in the color of the fast green, which is green.
- **Phloem**: The phloem contains living cells that have nuclei, which will be stained red by safranin. The cytoplasm of the phloem cells will be stained green by fast green.

5. **Final Color Identification**:
- Therefore, in the stained section:
- The **xylem** will appear **green**.
- The **phloem** will appear **red** due to the presence of nuclei stained by safranin.

### Conclusion:
- The color of the stained xylem will be **green**, and the color of the stained phloem will be **red**.