TISSUE PRINTING FOR PEROXIDASES ASSOCIATED WITH LIGNIFICATION

Peroxidases with syringaldazine oxidase activity have been claimed to be specifically involved in lignification. The use of syringaldazine a s a substrate presents problems of color diffusion and fading. We repo rt a method for timing color development of syringaldazine peroxidase reactions in tissue prints, and conditions under which diffusion is mi nimized. The best time interval in which the tissue print and backgrou nd gave significant contrast was determined using ELISA plates in whic h impressions of the tissue could be made, mimicking reactions on a me mbrane. This technique permitted simultaneous reading of a large numbe r of samples and blanks, rendering enough data points for statistical analysis. Optimum development time for syringaldazine peroxidase react ions was between 10 and 20 min. Color diffusion and smearing of syring aldazine peroxidase reactions in tissue prints were minimized when pri nts were covered with a strip of membrane before adding the substrate mixture.