Plant Anatomy - 2013

Chapter 1. TECHNIQUES FOR PREPARING MICROSCOPE SLIDES

There are temporary mounts, which are discarded after observation, and permanent mounts, which can be preserved indefinitely.

Preparing Microscope slides requires tools, auxiliary Materials, and Reagents, as well as obtaining a series of sections from plant specimens and mounting them in a mounting medium.

You will need Glass slides and coverslips, a sharp razor or razor blades, a dissecting needle, a scalpel, forceps, a soft cloth for cleaning glass, and filter paper.

1.1. Sectioning

When studying cylindrical Organs in detail, sections are made in three planes: transverse (cross-section), longitudinal radial, and longitudinal tangential.

Leaves can be sectioned in two ways: perpendicular to the blade (transverse sections) and parallel to the blade (surface sections).

Sections are made using a razor or blade by following these steps:

- Hold the specimen firmly between the thumb and index finger of your left hand, keeping your thumb 5-10 mm below the level of the cut;

- Trim The surface of the specimen flat using a scalpel or sharp knife;

- Holding the specimen in a strictly vertical position, hold the razor horizontally between the thumb and index finger of your right hand; drawing the blade diagonally toward you in one smooth, swift motion, cut a thin section. Avoid short, choppy strokes, which result in uneven sections. It is recommended to keep both the blade and the specimen constantly moistened with Water;

- Cut several sections at once;

- Transfer the sections from the blade to a drop of mounting medium on a glass slide using a dissecting needle;

- Examine the sections under a microscope at low magnification (LM) to select the best ones;

- Stain the sections with various Dyes to create contrast between the biological structures of The Cell Tissues.

For thin, delicate organs (such as leaves or young roots) as well as tiny specimens (like seeds) that are difficult to hold by hand, sections are made by embedding the plant material in the pith of elderberry, cork, or a small piece of potato or carrot tuber approximately 1 cm in diameter.

To do this, cut a piece of elderberry pith in half with a sharp knife or scalpel, place and clamp the specimen between the two pieces, level the surface, and slice through both the pith and the specimen together using a razor blade.

Place the sections or other specimens to be examined onto a glass slide in a drop of mounting medium and cover with a coverslip. Hold the coverslip by its edges with two fingers, bring its lower edge down at an acute angle to the edge of the liquid drop, and then gently lower it while supporting it with a needle. Excess

liquid spilling beyond the edges of the coverslip should be removed with filter paper, while any shortage can be remedied by adding an extra drop at the interface of the coverslip and slide.

If air bubbles become trapped under the coverslip, it is best to lift it slightly with a needle and lower it again.

The top of the coverslip must remain completely dry and fit snugly against the microscope slide.

Certain conditions must be met when preparing slides. Both slides and coverslips must be clean and dry. To prevent contamination from grease, avoid touching the surface of the coverslip with your fingers; instead, hold it with forceps by the middle of the edge, or by its edges using your thumb and index finger. Handle with extreme care, as the glass is very thin and breaks easily.

Fig. 2. Sectioning technique

Fig. 4. Microscope operation technique