THE METABOLISM OF SCOPOLETIN BY HEALTHY AND VIRUS INFECTED POTATO TUBERS

After extraction of the chlorophyll, rolled leaves of potato plants infected with the leaf roll virus fluoresced a brilliant blue color in ultraviolet light. This blue fluorescence was not observed in leaves of healthy potato plants or plants infected with mild mosaic, rugose mosaic, or spindle tuber viruses. Neither was it found in unrolled leaves of leaf roll diseased plants. The blue fluorescent substance in rolled leaves had the same fluorescent and solubility properties as scopoletin.Scopoletin was metabolized by healthy and diseased potato tubers with the production of an unstable blue intermediary that turned bright yellow on standing. This reaction was accelerated by hydrogen peroxide and inhibited by heating the tissue to 65 °C., by cyanide, azide, hydroxylamine, and hydrogen sulphide. Healthy tubers were found to metabolize scopoletin more rapidly than leaf roll infected tubers.