HE Zhongjun, LIANG Shewang, DING Ying, LIU Yi, CHEN Zhongjian
The taproots of spring P.notoginseng, rhizosphere soils, geographical and metrological data were sampled from 44 producing regions to analyze the taproots by adopted isotope ratio mass spectrometry (IRMS) and inductively coupled plasma spectrometry (ICP-MS), obtain geographical and metrological data were derived from GIS for Traditional Chinese Medicine database and analyze soils by regular soil chemical analysis methods. There were 49 ecological factors of geographical and metrological data, soil physiochemical properties and fertilities, and taproot nutrient element contents. The relationships were investigated between 49 ecological factors and δ18O in P. notoginseng taproots by combined analytical methods which included correlation, stepwise regression, path analysis, and decision analysis. The results showed that 89.60% change of δ18O in P.notoginseng taproots were controlled by 16 ecological factors, which were latitude, humidity, annual average temperature, annual precipitation, average temperature in July, maximum temperature in July, minimum temperature in January, annual active accumulated temperature, soil total potassium, total phosphorous, available phosphorous, available Mo, taproot Fe, taproot P, taproot Zn, and slope degree. The highest and direct impact factor on δ18O in P.notoginseng taproots was average temperature in July, followed the order of maximum temperature in July minimum temperature in January, latitude, humidity, annual average temperature, annual precipitation, taproot Fe, soil total potassium, soil total phosphorous, annual active accumulated temperature, soil available phosphorous, taproot Zn, soil available Mo, and slope degree. Annual precipitation was the most main decisive factor, and average temperature in July was the most main limiting factor among the ecological factors. Furthermore, for average temperature in July, maximum temperature in July, minimum temperature in January, annual average temperature, latitude, humidity, and annual precipitation, their absolute value of decisive coefficients were much higher than other factors. The results indicated that δ18O in P.notoginseng taproots were mainly influenced by local ecological factors such as temperatures, latitude, humidity and annual precipitation, these 7 factors have obviously regional feature. Therefore, δ18O in P.notoginseng taproots also have obviously regional feature. This study provides theoretical evidence for δ18O in P.notoginseng taproots used as an important index for origin traceability on P. notoginseng taproots and related products.