STIMULATION OF DIMERIC ALKALOID PRODUCTION BY NEAR-ULTRAVIOLET LIGHT IN MULTIPLE SHOOT CULTURES OF CATHARANTHUS-ROSEUS

Under irradiation with near-ultraviolet light with a peak at 370 nm, the levels of leurosine and vinblastine in multiple shoot cultures of Catharanthus roseus increased and vindoline and catharanthine, in vivo precursors for dimeric alkaloid synthesis, decreased. The effects of the near-ultraviolet light on the dimeric and monomeric alkaloids levels were more remarkable in the leaves than in shoots or the whole multiple shoot cultures. Furthermore, dimeric alkaloid production was strongly stimulated by near-ultraviolet light in cultures where high levels of vindoline and catharanthine were previously accumulated or produced simultaneously with dimers.