Question

Which stain do you use to observe onion root cells?
A. Safranin
B. Acetocarmine
C. Iodine
D. Methylene blue

Answer 1

Hint: Staining is done to enhance contrast in the microscopic image. Different stains and dyes are used for staining specific cells which allows in easy viewing of the highlighted structures.

Complete Answer:
To solve this question, we must know about different types of stains used.
The stains and dyes mainly add colour to the specific cells. This colouring aids in better viewing and identification of cells.

The different kinds of stains used are:
1. Safranine- It is a cationic dye which is used in histology and cytology. It helps in identification of tissues and cells.
2. Acetocarmine- It is a dye obtained from insects. It is a nuclear stain and gives colour to chromosomes.
3. Iodine- It is used as an indicator for starch. It is mainly used in plant cells.
4. Methylene blue- It is used to stain animal cells like cheek cells. It makes the nucleus more highlighted. It is also used to stain blood cells.
According to the question, the stain used in onion root cells is acetocarmine as it stains the nucleus and helps in viewing different stages of mitosis.

The correct answer is (B).

Additional information- Hematoxylin and eosin are commonly used to stain tissue samples. Hematoxylin stain nuclei blue and eosin stains cytoplasm pink.

Note: Acetocarmine gives red colour to the chromosomes. The slide is prepared by staining a thin section of root tip by adding 2 drops of acetocarmine and smashing it with a clear cover slip.