lab exam - The purpose of the Kohler illumination to focus...

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The purpose of the Kohler illumination to focus and center the light in the plane of the specimen. Raise the condenser to its uppermost position. Open the condenser diaphragm and close the field diaphragm. Using the condenser-focusing knob, adjust the condenser until the image of the field diaphragm is sharp or has a slightly blue margin. With the field diaphragm centering knobs, center the light in the field. Open the field diaphragm until the light is centered. The lens are parfocal. TS (or XS) - transverse or cross section LS- longitudinal section RLS- radial longitudinal section TLS- tangential longitudinal section CRT- a prepared slide with cross, radial, and tangential sections. A. Toluidine blue Method A: 1) Immerse sections in toluidine blue solutions for 15-30 secs. 2) Rinse sections in water. 3) Transfer sections to drop of water on microscope slide and add a cover slip. Method B: 1) Add a small drop of toluidine blue to drop of water on a microscope. 2) Add sections to the drop on the slide and then add a coverslip. Results: A good metachromatic stain. Lignified walls and tannin-containing structures tend to stain blue-green or green. Cell walls of nonlignified parenchyma, collenchyma, sieve-tube members, and companion cells tend to stain pinkish-purple to red. Phlorogluconol- HCl is more reliable.
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B) Phlorogluconol- HCl 1) Immerse sections in phlorogluconol solution on a microscope slide. After several mins add a cover slip and view. 2) This stain contains 20% HCl and is corrosive. Be careful not to get the phlorogluconol solutions on a microscope parts. Results: Lignin stains red or red-orange. IKI- immerses sections in drop IKI solution on a microscope slide and add a cover slip. Results: Starch stains blue-black to brown to orange, depending on the type of starch present. Nuclei may stain a pale golden color and cell walls may appear light yellow. Sudan IV: Immerse sections in drop of Sudan IV solution on microscope slide and quickly add a cover slip. If the stain begins to evaporate, add more Sudan IV to the edge of the cover slip. After a few mins, rinse with water and observe. Results: Cutin, suberin, and waxy and oily substances stain red to orange-red. Aniline blue- A) Use one drop of stain to 10 drops of water. Immerse sections in aniline blue solution for 5 mins. Gently rinse with water. Transfer sections to drop of water on microscope slide and add a cover slip. Results: Sieve-plate and sieve-area callose stain blue. Two types of plastids that may not be as familiar are the chromoplasts and amyloplasts. Plastids- plastids are derived from the proplastids of meristematic cells.
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lab exam - The purpose of the Kohler illumination to focus...

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