Studies on the labelling of terpenoids in shoots and cells or protoplasts from Calendula officinalis leaves.

1. From the leaves of Calendula officinalis, homogeneous preparations of isolated cells and protoplasts have been obtained which effectively synthesized terpenoid compounds from [1-14C]acetate. 2. The quantitative determinations have shown that the level of sterols, beta-amyrin and oleanolic acid was similar in shoots, isolated cells and protoplasts but the level of polyprenols was the highest in shoots, lower in cells and the lowest in protoplasts. 3. The determination of the dynamics of labelling with radioactive acetate has shown that sterols are labelled at a similar rate in shoots, cells and protoplasts, whereas the labelling of beta-amyrin, oleanolic acid and polyprenols is delayed in cells and protoplasts as compared with shoots. The labelling of beta-amyrin and oleanolic acid reached eventually the level observed in the shoots, but the labelling of polyprenols at this time was twice as high in the cells and protoplasts as in the shoots.