Abstract: To clarify the influence of cultivation duration on heavy metal accumulation in soil-Paeonia lactiflora systems and Paeonia lactiflora quality, we collected a total of 91 paired soil and P. lactiflora samples in Bozhou City, Anhui Province, China, and measured the concentrations of eight heavy metals: copper (Cu), chromium (Cr), lead (Pb), nickel (Ni), zinc (Zn), manganese (Mn), iron (Fe), and mercury (Hg). The bioconcentration factor (BCF) was utilized to characterize heavy metal accumulation patterns in the soil-Paeonia lactiflora system across different planting durations. Additionally, a Generalized Additive Model (GAM) was applied to identify factors influencing paeoniflorin content. Results showed that soil concentrations of Pb, Cu, Cr, Ni, and Mn exceeded local background values, indicating varying degrees of accumulation. With the increases of planting years, soil heavy metal content was decreasing, while it showed an opposite pattern in Paeonia lactiflora. Paeoniflorin content was significantly affected by planting duration (P<0.05), with 5-year-old Paeonia lactiflora exhibiting significantly higher levels than 3-year-old Paeonia lactiflora. There were differences in the factors affecting the content of paeoniflorin under different planting years. Soil pH was the main factor affecting the paeoniflorin content in 3-year-old Paeonia lactiflora, while available phosphorus was the main factor affecting the paeoniflorin content in 4- and 5-year-old Paeonia lactiflora. We conclude that beyond heavy metal effects on paeoniflorin, it is necessary to pay attention to regulating the soil physicochemical properties in the early establishment stage of Paeonia lactiflora, and to focus on soil nutrient inputs in the later stage. These findings provide a scientific basis for improving cultivation practices and quality control of Paeonia lactiflora.

Key words: soil-Paeonia lactiflora system, heavy metal, paeoniflorin, cultivation age, GAM model