Origin of Cardenolides in Rhizomes and Roots of Convallaria majalis L. Biogenesis in situ or Transport from Leaves?

After administration of sodium fl —14C]acetate to rhizome or root cuttings of Convallaria maja­ lis L. two of the main cardiac glycosides were isolated and examined for incorporated radioactivity. With a detection limit of 0.0003% of incorporated label it can be assumed, that the subterranean organs o f C. majalis are not capable of cardenolide biogenesis de novo. Interconversions on the cardenolide level do not take place, too, as was proved by application o f [U —14C]convallatoxol and examination of convallatoxin, the main m etabolite in leaves. Therefore the cardenolide content of the subterranean parts of C. majalis (0.2% ) must have its origin in the leaves, from where the cardiac glycosides are translocated to rhizomes and roots, which only fulfil a storage function in this respect.