Environmental and biological factors influence flavonoid and saponin contents in Ziziphi Spinosae Semen in the taihang mountains

Abstract

Geographic variation is vital for regulating secondary metabolite synthesis in medicinal plants. In this study, the influence of ecological and biological factors on the accumulation of major medicinal ingredients in Ziziphus jujuba var. spinosa (Z. jujuba) seeds, commonly known as Ziziphi spinosae semen (ZSS), across 38 natural populations in the Taihang Mountains of China, was investigated. Among the four medicinal ingredients (spinosin, 6‴-feruloyl spinosin, jujuboside A, and jujuboside B), jujuboside B exhibited the greatest variation across regions. The combined effects of environmental and biological factors explained 47.60 % of the chemical variation in ZSS, with climatic and soil factors contributing more substantially than biological traits. Jujuboside B, indicating high environmental and biological sensitivity, was significantly negatively correlated with the growing season effective accumulated temperature, precipitation, long-term average annual temperature, soil clay content, soil nitrogen (SN), total organic carbon (TOC), leaf nitrogen content, and fresh fruit edible ratio (P < 0.05). Jujuboside B was positively correlated with longitude, latitude, soil total phosphorus (TP), and the nutlet rate (P < 0.05). Jujuboside A was significantly negatively correlated with the relief degree of the land surface (RDLS), SN, and leaf water content (LW) (P < 0.05). The spinosin content was negatively correlated with SN, TOC, fruit rate, and LW (P < 0.05), whereas 6‴-feruloyl spinosin was negatively associated with the soil electrical conductivity and LW (P < 0.05). This study revealed that climate factors are crucial for regulating the accumulation of medicinal ingredients in ZSS. Furthermore, lower soil nutrients (such as low TOC, SN, and high sand contents) promoted the accumulation of active constituents. This study deepens our understanding of the ecological mechanisms underlying the variation in ZSS chemical composition and provides a scientific foundation for its ecological cultivation and quality improvement.