In vitro variability of cell clones of Thalictrum minus

Growth dynamics, the content of protoberberine alkaloids, their release int o cultural medium, and variability of these characteristics during subcultu ring of the original strain of Thalictrum minus cells and the derived clone s were investigated in callus and suspension cultures. Callus and suspensio n cultures were characterized by a prolonged growth cycle-10 weeks and 27 d ays, respectively. The content of protoberberine alkaloids, 50% of which we re represented by berberine, increased in parallel with cell growth and att ained 150-220 mg/l toward the end of the growing cycle. During the period o f active biosynthesis, cells retained up to 80% of the total alkaloids, whe reas in other periods, cells and cultural medium contained similar amounts of alkaloids. The clones differed in growth index and colors of callus and agar medium. After 8 months of culturing, the percentage of clones with gro wth index >10 increased from 43 to 90%, the percentage of clones that had l ight-colored callus increased from 37 to 70%, and 9% clones had deep yellow callus. During this period, the growth index could decrease, increase, or remain at the original level, depending on the clone. The selection process in cell lines proceeded for a long time. During subculturing, most of the clones increased their growth rate and decreased the level of protoberberin e alkaloids. Following the transfer of clones to suspension culture, in fou r clones out of 182, the alkaloid content in cultural liquid after 20 passa ges attained 260-360 mg/l, which was two times higher than in the control c ulture. These clones can be recommended as active producers of protoberberi ne alkaloids.