IDENTIFICATION AND ASSAY OF PYRETHRINS IN CHRYSANTHEMUM-CINERARIEFOLIUM CALLI

Callus from four clones of Chrysanthemum cinerariaefolium have been in vestigated for pyrethrins biosynthesis. Calli from disc-flowers, bud-f lowers, stems and leaves of clone HY D were cultivated. Best growth wa s obtained by initiating the culture on Murashige and Skoog medium con taining 3% sucrose, 1% agar, 4 ppm beta-naphtoxy acetic acid (ANA) and 0.4 ppm 6- benzyl aminopurine (BAP) for 28 d, then transfering explan ts on 1/2, MS medium containing the same nutriments. Pyrethrins were f ound in all callus but higher amounts were found in callus from disc-f lowers. Synthesis was optimal 4 weeks after the 6th passage culture Le . at the beginning of the stationnary phase. Disc-flowers calli from t wo high-producers clones (HY C and HY D) and two low-producers clones (SY A and SY B) were also cultivated. Pyrethrin amounts found in callu s cells showed a direct relationship between parental done synthesis a bility and callus cell production, Selection of high-producers clones is thus essential for optimisation of pyrethrin synthesis.