UPTAKE AND TRANSPORT OF QUINOLIZIDINE ALKALOIDS IN CUSCUTA-REFLEXA PARASITIZING ON LUPINUS-ANGUSTIFOLIUS

During parasitism on Lupinus angustifolius the phanerogamic parasite C uscuta reflexa takes up quinolizidine alkaloids from L. angustifolius via haustoria that tap xylem and phloem vessels of the host. The alkal oid pattern of the haustorial region of C. reflexa as revealed by GLC as well as by GLC-MS closely resembles that of infested lupin stems. W ith increasing distance from the haustoria towards the apex of C. refl exa the complex alkaloid pattern of the host is significantly reduced. Whereas alkaloid esters such as 13-benzoyloxylupanine and 13-cinnamoy loxy-lupanine are prominent peaks in the alkaloid profiles of the host as well as of the haustorial region of the parasite they are not dete cted in the apex of C. reflexa but are replaced by their respective al cohol component 13-hydroxylupanine. This change of alkaloid profiles i s accompanied by a strong decline of alkaloid concentration which drop s from approximately 11 mg/g dry wt. in the haustorial region of C. re flexa to 0.2 mg/g dry wt. in the apex. Alkaloid analyses of xylem sap and phloem exudate from L. angustifolius suggest that uptake of host p lant alkaloids by C. reflexa is mainly via the phloem even though a co ntribution of xylem sap to the supply of alkaloids to the parasite can not be excluded.