Slides, Microscope, Acid-washed,

Alternatively, the air-dried slide may be transferred to a solution of quinacrine mustard dihydrochloride (50 ju.g/ml in Macllvaine s buffer — 6.5 ml 0.2 M Na2HP04, 43.6 ml 0.1 M citric acid and H20 to 100 ml pH 7.0). After 20 min the slides are washed three times with Macllvaine s buffer and sealed wet for visualisation with a fluorescence microscope. 

The procedure for this test consists basically of three sequential treatments of the lignified tissue with 1% potassium permanganate, 3% hydrochloric acid (Note 1), and concentrated ammonium hydroxide. A small amount of wood meal or wood slices is placed on a watchglass or microscope slide and immersed in a 1% potassium permanganate solution for 5 min at room temperature. The solution is discarded and the sample is washed twice with water and then treated with a 3% hydrochloric acid solution until the color turns from black or dark brown to light brown. If necessary, additional hydrochloric acid may be added to facilitate discharge of the dark color. The hydrochloric acid solution is discarded, and the sample is washed twice with water. On subsequent treatment with concentrated ammonium hydroxide, a red-purple color develops for hardwoods and some tannins, and a brown color for softwoods. 

The crude carotenoid is to be chromatographed on a 12-cm column of acid-washed alumina (Merck), prepared with petroleum ether (37-53°C) as solvent. Run out excess solvent, or remove it from the top of the chromatography column with a suction tube, dissolve the crude carotenoid in afew milliliters of toluene, and then transfer the solution onto the chromatographic column with a Pasteur pipette. Elute the column with petroleum ether, discard the initial colorless eluate, and collect all yellow or orange eluates together in a 50-mL Erlenmeyer flask. Place a drop of solution on a microscope slide and evaporate the rest to dryness (rotary evaporator or aspirator tube). Examination of the material spotted on the slide may reveal crystallinity. Then put a drop of concentrated sulfuric acid beside the spot and mix with a stirring rod. Compare the color of your test with that of a test on the other carotenoid. 

Preparation of microchromatoplates. Microscope slides must first be cleaned by wiping, washing with a detergent, then water and then alcohol. Do not touch the clean surfaces as this will prevent satisfactory coating. Place a mixture of 50 g silica gel G (a mixture of silicic acid and plaster of... 

Clean microscope slides Place slides into chromium trioxide solution in 80% (w/v) sulfuric acid (Merck, Rahway, NJ) for at least 3 h at room temperature. Wash slides in mnning water for 5 min, rinse them thoroughly in distilled water, and air-dry. Place slides in 100% ethanol, remove, and dry with a tissue immediately pnor to use (see Note 3). 

Arabidopsis thaliana seedlings were grown using a 1 x 10-4 M Rhodamine-6G aqueous solution on a filter paper of glass fiber. For the preparation of microscopic specimens, Arabidopsis thaliana roots were crushed between two glass slides after soaking in 1M HC1 in a hot-water bath for 10 min, and washed with 45% acetic add and 3 1 methanol/acetic acid. The preparation was sealed in nujol mull with a cover slip. 

Immediately prior to use mix an equal volume of silver amplification solution A with solution B and add 500 pL to the slide. At this point the slide may be covered with a glass cover slip and the silver deposition monitored under the microscope (although light exposure hastens silver deposition). Stop the reaction by washing in water followed by 1% acetic acid for 2 min. 

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