TULIPALINE AND TULIPOSIDE IN CULTURED EXPLANTS OF TULIP BULB SCALES

We developed a method for rapid and reliable determination of tulipali ne A (alpha-methylene-gamma-butyrolactone) and tuliposide A. In this p rocess we identified two isomers of the tuliposide A which are spontan eously interconverted into each other. In bulb scales of tulip (Tulipa gesneriana) cv. Apeldoorn, relatively large amounts of free tulipalin e A were found to be present in the scale tissue and a small amount of tuliposide A. In young developing shoots, the situation was reversed: tuliposide is the main component but the concentration is much lower. During the tissue culture period (10 weeks) an increase was found of both tulipaline A and tuliposide A. In bulb scale explants this tempor ary increase amounted to ca. 1300% in non-regenerating and ca. 550% in regenerating explants, when compared to the start level. It was follo wed by a decrease of ca. 700% in non-regenerating and ca. 250% in rege nerating explants, when compared to the peak level. The higher increas e in non-regenerating bulbs suggests a role for tulipaline A in the re sponse of bulb scales to incubation in vitro. (C) 1998 Elsevier Scienc e Ltd. All rights reserved.