Panax notoginseng is a famous Chinese traditional medicinal. However, soil cadmium pollution seriously affected the yield and quality of notoginseng. This study systematically investigated the effects of soil Cd stress at different concentrations on the growth of one-year-old notoginseng. The results indicate that Cd exhibits a typical low-dose stimulation and high-dose inhibition effect on the development of notoginseng. At low concentrations (1 mg/kg), Cd promotes the growth of plants, including increased biomass (∼40 % of root dry weight) and higher saponin contents (∼30 % of total saponins). At high concentrations, Cd inhibits the overall growth and metabolism of notoginseng. Meanwhile, the impact of Cd on the rhizospheric micro-environment shows dose dependency. In a low Cd stress environment, the total and unique microbial populations increase, including Rhizobiaceae, Streptomycetaceae, and Mesorhizobium. Conversely, under strong Cd stress, the richness and diversity of the rhizospheric microbial community decrease, while the abundance of cadmium-tolerant species increases, such as Deinococcus and Rhodanobacter.

Panax notoginseng is a prominent traditional Chinese medicinal herb, yet its yield and quality are significantly constrained by continuous cropping obstacles, primarily stemming from soil-related issues. This study analyzed soils subjected to various degrees of continuous P. notoginseng cultivation, soils without P. notoginseng planting, and natural forest floor soil without P. notoginseng planting. The objective was to investigate variations in soil microbial communities, physicochemical properties, and enzyme activities across different cropping conditions. Macro-genome sequencing was employed to reveal microbial shifts and key factors influencing rhizosphere microbial communities. Notably, the natural forest floor soil exhibited the highest levels of soil organic matter, soil organic carbon, total nitrogen, and available potassium. Furthermore, continuous cropping soils showed the highest levels of pH, available phosphorus, electrical conductivity, and total potassium. The activities of catalase, urease, acid phosphatase, sucrase, and soil FDA hydrolase decreased significantly after continuous cropping, but increased again after five years of fallowing. Microbial analysis revealed that Bacteroidetes, Firmicutes, and Chloroflexi dominated the soils without P. notoginseng planting, whereas Proteobacteria, Actinobacteria, and Acidobacteria were the predominant phyla in continuous cropping and natural forest floor soils. Continuous cropping led to an increase in Acidobacteria, Gemmatimonadetes, and Chloroflexi, while fallowing reduced Actinobacteria. Gemmatimonades was almost exclusively present in the continuous cropping soils. Overall, continuous P. notoginseng planting altered the soil nutrients and microbial composition. Key factors influencing microbial communities included pH, nitrate nitrogen, available phosphorus, available potassium, and electrical conductivity. The study suggests that attention should be paid to scientific and rational fertilization practices to mitigate the effects of continuous cropping. Additionally, a fallow period of more than five years is recommended. The proper application of probiotic fertilizers is also advised. Finally, cultivating P. notoginseng under forest conditions is recommended as a viable method.

Background: Cadmium (Cd) contamination poses a major threat to Panax notoginseng (Burk.) F.H. Chen cultivation, yet the dose-dependent thresholds separating adaptive responses from toxicity remain poorly understood, particularly at the level of rhizosphere microbial processes. Methods: A 75-day pot experiment was conducted using eight soil Cd concentrations (0–100 mg kg ^–1 ). Plant growth traits and antioxidant enzyme activities (SOD, POD, CAT) were measured. Rhizosphere microbial communities were characterized in terms of alpha and beta diversity, co-occurrence network structure, and predicted functional potential using PICRUSt2 and FAPROTAX. Results: Moderate Cd exposure (∼30 mg kg ^–1 ) enhanced plant growth and antioxidant enzyme activities, whereas high Cd ( ≥ 80 mg kg ^–1 ) caused physiological inhibition, consistent with a hormetic response. Microbial alpha diversity also peaked under moderate Cd but declined sharply at high Cd levels. Beta diversity differentiation was primarily driven by shifts in relative abundance rather than taxonomic turnover. Severe Cd stress reduced co-occurrence network connectivity and increased negative correlations, although several persistent core taxa (e.g., Granulicella ) were maintained. Functional predictions indicated substantial functional redundancy, with key nutrient-cycling pathways largely retained despite pronounced network simplification.