Views: 30 Author: Site Editor Publish Time: 2020-07-30 Origin: Site
Smear materials include single-celled organisms, small algae, blood, bacterial culture, loose tissues of animals and plants, testis, anthers, etc.
Attention should be paid when smearing:
(1) The slide must be clean.
(2) The slide should be flat.
(3) The coating must be uniform. The smear is dropped to the right of the middle of the glass slide, and spread evenly with a scalpel blade or toothpicks.
(4) The coating should be thin. Use another slide as a pusher, and gently push it from right to left along the surface of the slide where the smear solution is dripped (the angle between the two slides should be 30°-45°) to make a thin layer evenly.
(5) Fixed. For fixation, use chemical fixative or dry method (bacteria) fixation.
(6) Dyeing. Use methylene blue for bacteria, Wright's stain for blood, and sometimes iodine. The dyeing solution should cover the entire painted surface.
(7) Flushing. Soak dry with absorbent paper or bake dry.
(8) Cover the film. For long-term storage, use Canadian gum to seal the slides.
Loading materials include: tiny organisms such as Chlamydomonas, Spirogyra, amoeba, nematodes; Hydra, leaf epidermis of plants; insect wings, feet, mouthparts, human oral epithelial cells, etc.
Attention should be paid to the production of mounting method:
(1) When holding the slide glass, it should be kept flat or placed on a platform. The amount of water should be appropriate when dripping, so that it is just covered by the cover glass.
(2) The material should be unfolded with dissecting needles or tweezers without overlapping and flattened on the same plane.
(3) When placing the cover glass, slowly cover the water droplets from one side to prevent bubbles from appearing.
(4) When staining, drop a drop of staining solution on one side of the cover glass, and suck it from the other side with absorbent paper to make the specimen under the cover glass evenly colored. After coloring, use the same method to drop a drop of water to suck out the staining solution and observe under a microscope.
Due to different requirements, a blade can be used for freehand sectioning, or the tissue block can be embedded in paraffin or collodion or frozen at low temperature, and sectioned with a microtome. Cut into 5-10 micron slices for observation by optical microscope. Ultra-thin sections cut with epoxy resin or methacrylic acid embedded tissue blocks, the thickness of which is 20-50 nanometers, and is exclusively for observation under an electron microscope. The sections of root tips and stems used in general teaching are generally called paraffin sections.