DISTRIBUTION, BIOSYNTHESIS AND TURNOVER OF PYRROLIZIDINE ALKALOIDS INCYNOGLOSSUM-OFFICINALE

The facultative biennial Cynoglossum officinale contains the N-oxides of the following pyrrolizidine alkaloids (PAs): trachelanthamine, viri diflorine, 7-angeloylheliotridine, rinderine, echinatine, 3'-acetylech inatine and heliosupine. The inflorescences contain the highest levels of PAs. At the vegetative rosette stage, the youngest leaves have hig her PA levels than the older leaves. Both isolated roots and isolated shoots of rosette plants were able to produce PAs from C-14-labelled p utrescine. PA production patterns differed between roots and shoots. I n intact plants, there was no significant turnover of PAs within 32 da ys. Within the shoot, PAs were reallocated from the ageing leaves into the newly formed, youngest leaves. Shoot to root transport of PAs was observed, which indicated that PAs are transported via the phloem.