Improved cell growth and total flavonoids of Saussurea medusa on solid culture medium supplemented with rare earth elements

Callus cultures of Saussurea medusa were cultivated on solid culture medium supplemented with either Ce³⁺, La³⁺, Nd³⁺ or a mixture of rare earth elements. Ce³⁺, 0.05 mM, gave the highest biomass (0.53 g dry wt per flask) and total flavonoids (27.5 mg per flask), which were, 70% and 100% higher than those without Ce³⁺ addition, respectively. Ce³⁺, 0.01–0.1 mM, or La³⁺, 0.05 mM, or the mixture of rare earth elements, 0.025–0.1 mM, can substitute for 6-benzyladenine, and 0.025 mM Ce³⁺ can partly substitute for naphthaleneacetic acid in promoting cell growth and biosynthesis of total flavonoids in S. medusa.