Inorganic nutrition of callus tissues of tagetes species the effects on morphogenesis and accumulation of thiophenes and other non polar secondary metabolites
Journal of Plant Physiology 125(1-2): 69-78
ISSN/ISBN: 0176-1617 DOI: 10.1016/s0176-1617(86)80244-9
The formation and morphology of callus were studied on leaf explants of Tagetes patula and Tagetes minuta, inserted into three different solid media with the inorganic composition of media used for soilless culture of intact pants, or into MS-medium. Callus formation responded differently to the type of medium and plant species. On all "plant media" callus formation occurred in only one of the two species. Which species died and which species proliferated depended on the type of medium. Growth of calli was curtailed on plant culture media as compared with MS-medium. However, transfer of secondary calli from plant culture media to fresh MS-medium restored a high rate of growth. Calli of T. patula had a higher level of non-polar metabolites and thiophenes (natural biocides from Tagetes plants) than calli of T. minuta. In T. patula calli the content of non-polar metabolites increased from primary to secondary cells and was highest when MS medium was used. In contrast, T. minuta calli showed a decrease in non-polar metabolite content upon subculturing and this content was lowest on MS medium. These trends of the content of non-polar secondary metabolites paralleled the trends in morphological differentiation that were observed when calli were cultured continuously on MS-medium (Ketel, Physiol. Plant. 66 , 392) and confirm the positive correlation between morphological and biochemical differentiation. It is concluded that the inorganic composition of the medium affected secondary metabolism only to a quantitative extent and that a correct inorganic composition of the medium together with the choice of the most suitable species are essential in the production of desired secondary metabolites in vitro.