Abstract: An effective cytochemical technique for the simultaneous demonstration of lipids, polysaccharides and protein bodies in the same section from the tissue embedded in Epon 812 is described. Thick sections of peanut cotyledon are used for a typical sample according to the following procelures. Firstly, PAS reaction: (1) Oxidize sections in 0.5% periodic acid in 0.3% nitric acid for 10 min, (2) Wash in running water for 1–2 min and then pass through distilled water, (3) Stain in Schiff's reagent for 30 min, (4) Wash in sodium metabisulfite 3 times, 2 min for each time, (5) Wash in running water for 5 min and then pass through distilled water. Secondly, Sudan black B staining: (1) Rinse section in 70% ethanol for 1-2 min, (2) Stain in fresh 1% Sudan black B in 70% ethanol for 30–60 min at 40–60℃, (3)Rinse in 70% ethanol for 1 min and then in distilled water. Thirdly, Coomassie brilliant blue R staining: (1) Rinse sections in 7% acetic acid for 1–2 min, (2) Stain in I% Coomassie brilliant blue R in 7% acetic acid for 20 min at 60℃, (3) Differentiate in 0.1% acetic acid for I min, (4) Rinse in lunning water for 5 min and then pass through distilled water, (5) Dry at room temperature or in oven, 40℃. The dry sections mount in glycerin-gelatin. After the above three step staining, the three main compounds of the cell can be stained simultaneously. Starch grains and cellulose cell wall take cherry red colour, lipids appear in black, protein bodies are blue. The sealed slides can be kept permanently.

Key words: Cytochemistry, Polysaccharides, Protein bodies, Lipids, Thick resin section