Lignin Staining
Materials Required
- Potato
- Double edged razor blade
- Dropper
- Brush
- Glass slide and coverslip
- Needle
- Phloroglucinol stain
- Petri dish
- Watch glass
- Stem of a plant.
Preparation of Phloroglucinol-HCl Stain
There are various procedures to make up the staining solution but commonly it is prepared as a saturated solution of phloroglucinol in 20% hydrochloric acid. The hydrochloric acid used is about 2 N. Please be sure to handle the solution with care. Wear gloves. Prepare this solution in the fume hood. First dissolve phloroglucinol (about 2.0 g) in 80 ml of 20% ethanol solution and then add 20 ml of concentrated HCl (12 N) to it.
Procedure
- Take a potato and cut it into a block. Make a slit in the middle of the potato block using a razor blade.
- Place the stem of the plant in the middle of the slit.
- Cut thin sections of the potato block along with the stem into a petri dish containing water.
- Transfer the only the cut sections of the stem using a brush into a petri dish containing water.
- Add two or three drops of phloroglucinol stain to a watch glass using a dropper.
- Transfer the potato sections using a brush into the watch glass containing the stain.
- Take a clean glass slide and add two drops of water onto the slide. Transfer the sections onto the slide using a wet brush.
- Place a cover slip onto the slide with the help of a needle or forceps.
- Remove the solution from the edges of the cover slip using a blotting paper and observe under the microscope.
Difference Encountered in a Real Laboratory
In an actual laboratory setting, there are certain important steps that are not necessarily applicable in a virtual lab:
- Before starting the experiment sterile the laminar air flow chamber using spirit.
- Ensure that while placing the cover slip over the section.
- Avoid the presence of air bubbles in between the cover slip and section.
- Always disinfect your work area when you are finished.