Characterizations of "drumstick-forming" on saponin contents of Notoginseng Radix et Rhizoma and their saccharide metabolism basis of vegetative organs of Panax notoginseng

"Drumstick-forming" of Panax notoginseng refers to the drumstick-like thickening of the top stem segments of the two- and three- year-old P. notoginseng. More than 400 years of practices have shown that the "drumstick-forming" reflects the saponin increase in Notoginseng Radix et Rhizoma, but the increase connotation and its saccharide metabolism basis of P. notoginseng vegetative organs remain unclear. In this study, spectrophotometry together with HPLC and ELISA indicated that the "drumstick-forming" characterized the extremely significant increases of the Rg1 and total saponin monomer (TSM) contents of the taproots, the total triterpenoid saponin (TTS) and TSM contents of the lateral roots, the TTS, R1 and TSM contents of the rhizomes, the soluble sugar contents (SSCs) of the leaves, taproots, lateral roots and rhizomes, the sucrose contents of the leaves, stems, taproots, lateral roots and rhizomes, and the specific activities of the Rubiscos and sucrose synthases (for synthesis) of the leaves and the sucrose synthases (for cleavage) (SS-cs) and starch phosphorylases (SPs) of the taproots, lateral roots and rhizomes, the significant increases of the lateral root Re contents, the non-significant increases of the rhizome Rd contents, the ratios of the SSC average of the taproots, lateral roots and rhizomes to that of the leaves and stems, and the averages of the specific activities of the SS-cs and SPs of the taproots, lateral roots and rhizomes, and the extremely significant decreases of the rhizome Rg1 contents, the stem SSCs, the starch contents of the stems, taproots, lateral roots and rhizomes of the two- and three- year-old P. notoginseng. Collectively, this study provides a better understanding of the "drumstick-forming"-responsive increase of the saponin contents in the Notoginseng Radix et Rhizoma and its saccharide-metabolizing basis, underlying the optimization of the breeding and cultivation measures of P. notoginseng via inducing the "drumstick-forming".