Effects of varieties on root morphological characteristics of Panax notoginseng（Burk.） F. H. Chen and its relationship with quality

【Objective】This study aimed to analyze the differences of root morphological indexes and saponin content of different varieties of Panax notoginseng（Burk.） F. H. Chen， and to explore the relationship between root morphological characteristics and biomass， saponin content， as well as saponin accumulation. The results of this study could provide a theoretical basis for breeding high-quality P. notoginseng varieties based on root morphological characteristics. 【Method】 Four P. notoginseng varieties，Miaoxiang P. notoginseng No. 1（M1），Miaoxiang No. 7（M7），Miaoxiang No. 8 （M8），and Wenyuan Ziqi No. 1（Z1），were chosen and the two-year-old P. notoginseng plants of these varieties were collected. The root morphological indexes were determined by root scanner，and the contents of saponins in the taproot were analyzed through high performance liquid chromatography （HPLC）. The aboveground and underground biomass of P. notoginseng were also determined. The correlation of root morphological indexes with biomass， root/shoot ratio， saponin content and accumulation of P. notoginseng was analyzed. 【Result】The aboveground and underground biomass and root/shoot ratio of different varieties of P. notoginseng were different. The aboveground fresh weight of Z1 was the highest，while M1 had the highest value of underground fresh weight and dry weight，with the root/shoot ratio being highest the in M8. The root morphological indexes of different varieties of P. notoginseng were also different. The total root length，total root tips and forks of M7，M8，and Z1 were significantly higher than those of M1（P<0.05，the same below），while the total root surface area of M7 and Z1 were significantly larger than that of M1. As for the saponins content and accumulation in the taproots of different P. notoginseng varieties， the content of notoginsenoside R₁，ginsenoside （Rg₁， Rb₁ and Rd），and total saponins in the taproots of Z1 were the highest，whereas the accumulation amounts of monomeric saponins and total saponins in the taproot of M1 were the highest. The results of correlation analysis showed that root morphological indexes such as total root surface area，root mean diameter and total root volume were positively correlated with the aboveground and underground biomass and saponin accumulation of P. notoginseng. The root surface area and root volume of coarse roots （diameter>2 mm） exhibited stronger correlations with the aboveground and underground biomass， as well as saponin accumulation， compared to that of fine roots （diameter ≤2 mm）. 【Conclusion】There are some differences in root morphological characteristics， biomass， saponin content and accumulation of different P. notoginseng varieties， and the total root surface area， root mean diameter and total root volume are closely related to the biomass and accumulation of saponins， indicating that good root morphology is important for the growth and quality formation of P. notoginseng.