Steps to Prepare a Temporary Slide of a Sectioned Root or Stem.
Steps to Prepare a Temporary Slide of a Sectioned Root or Stem.
A temporary slide is a microscope slide prepared with wet ingredients such as blood, pond water and distilled water.
Preparing a temporary slide allows the observer to view any microscopic organisms present in the slide while they are still alive.
The organisms will move in the liquid while you view them through the viewfinder of the microscope.
-
BIOLOGY PRACTICAL ON ONION BULB AND RHIZOME OF GINGER.
-
BIOLOGY PRACTICAL ON OIL PALM FRUIT AND MANGO FRUIT AS SPECIMENS.
-
BIOLOGY PRACTICAL ON AN ORANGE AND A TOMATO FRUIT.
It is also referred to as a wet-mount slide because the water soon dries up.
They are also used for any sort of specimen that needs to be kept moist.
A plant tissue can be mounted in;
- Water (Water makes cells turgid. It also prevents drying out of the slide
- Glycerine (Prevents dehydration or drying out of the specimen/slide and prevents air bubbles)
- A stain. (Stains make tissues and structures easily distinguishable from others.)
STAINS USED IN PLANT ANATOMY
- Stains are dyes which, when applied to plant specimens, colour certain structures, thereby making them easily identified.
- Staining is the addition of stains to transparent specimens in order to distinguish between different structures.
Examples are;
- Eosin stain, cellulose red, and cytoplasm pink.
- Haematoxylin and methylene blue stain the nucleus blue
- Iodine solution stains starch blue black
- Phloroglucinol; HCI stains colours lignified cell wall of sclerenchyma and xylem cells red. Hence, when used to stain the root, the central vascular cylinder of xylem will stain red. When used to stain dicot stems, peripheral parts, including walls of sclerenchyma and xylem cells, stain red
- Aniline hydrochloride, Aniline chloride or Aniline sulphate stains the above structures yellow
Materials Needed for preparing a temporary slide;
- Razor blade
- Brush
- Mounted needle/large pin
- Two Petri dishes / watch glasses
- Dropper: (used to add stain)
- Slide
- Cover slip
- Staining solution (phloroglucinol – HCI stain, aniline sulphate, iodine solution, etc.)
- 30% glycerol solution/Glycerine
- Blotting paper or filter paper
- Compound light microscope
- Wash the bottle with distilled water
NSMQ 2022 BIOLOGY PAST QUESTIONS AND ANSWERS.
PROCEDURE
- Cut several thin transverse sections of the root or stem into a petri dish or a watch glass containing water
- Select the thinnest section as the specimen
- Put into a second petri dish containing water
- Stain the thin section of the root or stem with a suitable stain such as aniline chloride/eosin/phloroglucinol
- Take a clean and transparent glass slide.
- Drop water or Glycerine on the slide
- Use a brush to transfer a thin slide.
Cover with a clean cover slip as follows:
- First at an angle of 45°
- Then lower gently and carefully to avoid air bubbles
- Use filter paper or blotting paper to remove any excess water on the slide.
- Place the slide on the stage of the microscope
- Observe with low power
Precautions
- Cut sections must not be obliquely cut
- Cut sections must be thin
- The cover slip must be lowered gently to avoid trapped air bubbles
- The microscope slide and cover slip must be clean
- And the cover slip must be well-positioned over the section
- Use a brush to transfer the section.
Importance of the cover slip
- To prevent wetting the objective lens
- To prevent the evaporation of water
- To make the specimen flat
Steps taken to change from low-power magnification to a higher viewing magnification
- The revolving nose piece is turned.
- And this moves the low-power objective piece away from the centre of the stage
- And brings the high-power objective piece to the centre of the stage;
- Then the fine adjustment knob is turned slowly while looking into the eyepiece;
- To obtain a sharp image;
- Till the detail of the specimen is focused/seen on the slide;
- The course focusing knob should not be used.
