Data Views Total Plants: 3 CSV Excel PDF Total Activities: 1 Click on column headings to sort table by that column Plant Part All Rhizome Root Low PPM High PPM StdDev *Reference Rheum palmatum Root 8500.0 31400.0 * Rheum palmatum Rhizome 20.0 10000.0 * Rheum rhabarbarum Root -- -- * *Unless otherwise noted all references are to Duke, James A. 1992. Handbook of phytochemical constituents of GRAS herbs and other economic plants. Boca Raton, FL. CRC Press.