PHYTOECDYSTEROIDS IN KOCHIA-SCOPARIA (BURNING BUSH)

Seed and plants of Kochia scoparia have been analyzed for phytoecdysteroids by high-performance liquid chromatography coupled to ecdysteroid-specific radioimmunoassay (RIA) or bioassay. Relatively low levels of RIA-positive material are found in seed and throughout the plant. Evidence is presented that the major phytoecdysteroids present in seed are 20-hydroxyecdysone and polypodine B (5 beta,20-dihydroxyecdysone), but significant amounts of other, as yet unidentified, phytoecdysteroids also occur. Extracts of whole plants contain a similar mix of phytoecdysteroids, but also contain a large amount of an apolar conjugate of ecdysone which is not present in seed. Concentrations of RIA-positive material vary throughout the plant, with higher concentrations being present in the root and leaves. Results are discussed in relation to the phytoecdysteroid distribution in other members of the Chenopodiaceae and with regard to the relationships between K. scoparia and its insect predators/pollinators.