The nucleolus of plasma cells is stained green with the methyl green-pyronin technique.

• A. True
• B. False
• C. It stains red
• D. It stains blue

Answer: (B)

In the methyl green-pyronin technique, DNA is stained green by methyl green and RNA is stained red by pyronin Y. The nucleolus is rich in ribosomal RNA due to active ribosomal synthesis, so it will stain red rather than green. Plasma cells, with their prominent nucleoli and high RNA content, should show a red nucleolus. Therefore the statement that the nucleolus stains green is not correct.