Question

Safranin stains which of the following elements of the tissue?
A. Starch elements
B. Lignified elements
C. Protein elements
D. Hard bast

Answer 1

Hint:- When a dye is used to visualize a cell and if the color component of the dye remains in the positive ion, it is considered as a basic dye (e.g., methylene blue, crystal violet, safranin). But if the pigmented part is in the negatively charged ion it is considered as an acid dye (Examples: nigrosin, congo red).

Complete solution:
Safranin ( basic red 2) is a biological stain used in cytology and histology. Its molecular weight is 350.8 g/mol. They are weakly soluble in water which when added to the sample stained it red. In many staining procedures, Safranin is used as a counterstain, coloring cell nuclei red. In both Gram stains and endospore staining, this is the classical counterstain. It may also be used for the detection of mucin, cartilage, and mast cells. In Gram-negative bacterial cells that have been decolorized, binding to safranin dye will appear pink under the microscope. With the use of safranin staining Gram-negative bacteria can be easily differentiated from Gram-positive bacteria. In many studies, it has been shown that safranin stains highly lignified wood fibers to pink, whereas it stains red to the less lignified fibers. But regardless of if cellulose is involved or not, Safranin stains lignin.
Therefore the correct answer is option (B), Lignified elements.

Note:- We can make Grama Safranin stain by dissolving 2.5 g of safranin O into 100 ml of 95 percent ethanol to create a stock solution. A working solution is obtained by diluting five parts of water with one part of the stock solution.