Question

A stained epidermal peel of a leaf appeared pinkish red under the microscope. The stain used was safranin. The extra stain is removed from the slide by

• A. washing with calcium chloride solution
• B. washing with water.
• C. soaking with cotton wool.
• D. soaking with blotting paper.

Answer 1

The correct option is B

washing with water.

The correct option is B.

An explanation for the correct option:

• The objective of staining is to enhance the contrasts between the organisms and the backdrop so that they can be seen in a light microscope more easily.
• The safranin stain works by attaching with a high affinity to acidic proteoglycans in cartilage tissues, producing a reddish-orange complex, and then washing away the excess stain with water.

The explanation for the incorrect option:

Option A:

• The anhydrous salt is very hygroscopic, and moisture can be removed by passing air or other gases through a calcium chloride column. It is not used to remove the extra stain from the slide.

Option B:

• The extra stain is removed by water, not soaked with cotton wool.

Option D:

• The extra stain will be removed with blotting paper when using Iodine solution as a stain. Safranin stain is removed by water.

Therefore the slide is washed with water to remove the extra stain.