Factors influencing cultivated ginseng (Panax ginseng C. A. Meyer) bioactive compounds

Abstract

We aimed to investigate the effects of genome, age, and soil factors on cultivated Panax ginseng C. A. Meyer (CPG) compounds under identical climate and agronomic practices. Eight populations of CPG from different years and rhizosphere soils were collected from garden and cropland in the city of Ji'an, China. Inter-simple sequence repeat (ISSR) primers were used to detect genetic diversity and identity, and soil microbial community diversity. Soil enzyme activities and nutrients were also measured. The contents of total ginsenosides (TG), Rg1, Re, Rf, Rd, and ginsenoside extractions of CPG were analyzed by spectrophotometry and HPLC. The relative importance of each factor was analyzed by mathematical methods such as correlation analysis, stepwise line regression, and path analysis. Regression equations of similarity values of HPLC fingerprint (SVHF), richness index of HPLC fingerprint (RIHF) and the TG, Rg1, Re, Rf, and Rd contents with their respective significant correlation factors were obtained. For SVHF, the relative importance is age>microbial community diversity>genetic diversity. For RIHF, the relative importance is age>genetic diversity> microbial community diversity. For TG, Rg1, and Rf contents, the relative importance is age>microbial community diversity. Ginseng age and genetic identity influenced Rd content, and age was more important. Total phosphorus was the only directly negative effect on Re. According to regression equations and path analysis, increasing age and decreasing Shannon (H') could improve the TG, Rg1, and Rf contents, with little effect on SVHF. Adding age, genetic diversity, and decreasing Shannon (H') increased RIHF. Adding age and genetic identity could also improve Rd content. Appropriate decreases in total phosphorus might increase Re content. These findings are significant for CPG scientific cultivation methods, through which CPG bioactive ingredients could be finely controlled via regulation of genotypes and cultural conditions.