Lime-assisted cultivation of Erigeron breviscapus: enhancing plant biomass production and scutellarin content in cadmium-contaminated soil.

Purpose: Developing a practical strategy for both remediating and utilizing Cd-contaminated soils is important, particularly in areas with limited soil resources. Here, Erigeron breviscapus, a plant material used for extracting scutellarin, was selected for a pot experiment to evaluate utilization and remediation potential of heavily Cd-contaminated soil. Methods: We established five treatments, comprising a no-Cd added control (CK) and 0.01% Cd addition with four amounts of lime (0, 5, 15 and 20 g·kg⁻¹ for CdL0, CdL5, CdL15 and CdL20, respectively). Systematic analysis of E. breviscapus physiological and biochemical characteristics, Cd-accumulation capacity, and active ingredients content were performed to thoroughly assess the application effectiveness and ecological restoration potential of lime in managing heavily Cd-contaminated soils. Results: Compared with CdL0, lime application (CdL5, CdL15 and CdL20) reduced soil available Cd and plant shoot-Cd concentrations by 19.2–29.4% and 29.3–36.3%, respectively, due to decreased bioconcentration factor. Soil-Cd concentrations after harvesting E. breviscapus was decreased by 11.8–31.7% with lime application compared with that before cultivation. In the CdL0 treatment, biomass and scutellarin content of E. breviscapus decreased compared to those of the CK. However, plant biomass and scutellarin content increased with CdL15 and CdL20 compared to CdL0. Structural equation modeling indicated that lime application reduced plant Cd uptake via regulating soil-Cd speciation, thereby alleviating damage caused by Cd to photosynthesis, antioxidant system, and Mg acquisition, ultimately increasing biomass and scutellarin content of E. breviscapus. Conclusions: In summary, growing E. breviscapus after lime application is a feasible method for remediating and utilizing heavily Cd-contaminated soil. [ABSTRACT FROM AUTHOR]