Mass propagation of microtubers from suspension cultures of Pinellia ternata cells and quality analysis of the regenerated tubers

We established optimal conditions for the mass production of microtubers from suspension cultures of Pinellia ternata cells including the relative effects of regulators of plant growth, carbon sources, nitrogen sources, pH and inoculation amount on the growth of suspended cells and the induction of microtubers. Histological analysis was used to investigate the morphogenesis of microtubers and the quality of the microtuber-propagated tubers was evaluated. The results showed that the optimal culture conditions for inducing P. ternata microtubers from suspension culture included MS medium containing 1.5 mg·L⁻¹ of 6-BA, 1.5 mg·L⁻¹ of NAA, 10 g·L⁻¹ of sucrose and 0.2 g·L⁻¹ CH at pH 5.8; the best initial inoculation amount was determined to be 20 g·L⁻¹. After 60 days of culture under these conditions, the maximum yield of P. ternata cells was 7.54 g; furthermore, the embryonic callus generated microtubers via organogenesis at a frequency of 88.5%. The microtubers were planted directly into soil to permit growth, the seedling rate was approximately 50%. Microtuber-propagated tubers were of better quality, with a succinic acid content similar to that of field-cultivated tubers, but with the content of trigonelline and adenosine that were superior to those of cultivated tubers. Collectively, these data indicate that microtubers can be efficiently produced from suspension cultures and that microtuber-propagated tubers can be used for commercial use and field production in the P. ternata industry.