Maximizing seedling and root tuber production in Polygonum multiflorum for use in ethnomedicine

There is need for a robust production mechanisms to meet the ever increasing demand for herbal medicine in the world today. In this study, we developed a standard protocol for the in vitro culture of Polygonum multiflorum to rapidly produce seedlings and promote the enlargement of its medicinal root tubers. Seeds were grown on Murashige and Skoog (MS) basal medium to obtain 1-week-old microseedlings. The ideal growth medium for these seedlings was determined by subculturing in different culture media. Maximal growth was observed on WPM, with a growth index of 160% after 5 weeks. Wood Plant Medium (WPM) supplemented with the kinetin and indole-3-acetic acid hormones yielded the highest average seedling shoot elongation, root initiation, and root elongation after 6 weeks. At 16 weeks after planting in the field, seedlings cultured in WPM + kinetin (1.0 mg/l) and IAA (1.0 mg/l) produced enlarged root tubers with an average dry weight of 31.10 g, as compared to 10.10 and 16.80 g for root tubers from plants propagated from P. multiflorum seed and stem cuttings, respectively. Fourier-transform infrared spectroscopy and hierarchical cluster analyses of the enlarged root tubers revealed that their chemical composition was the same as that of tubers sold on the market and from plants propagated through seeds and stem cuttings. Our findings provide a basis for large-scale in vitro propagation of P. multiflorum as a resource for traditional Chinese medicine.