Cadmium-resistant bacteria inoculation enhances growth and cadmium phytoextraction efficiency of Celosia argentea L. in contaminated agricultural soil

Abstract

This paper highlights the influence of cadmium (Cd)-resistant bacterial strains on enhancing Cd phytoextraction in Celosia argentea L., an ornamental plant with phytoremediation potential. Micrococcus sp. and Paenarthrobacter sp. were inoculated into highly Cd-contaminated agricultural soil cultivated with C. argentea. The results demonstrated that both bacterial strains significantly promoted plant growth and increased chlorophyll a, chlorophyll b, and carotenoid contents. Micrococcus sp. was more effective in stimulating growth and photosynthetic pigment accumulation than Paenarthrobacter sp. However, reductions in growth and photosynthetic pigment levels were observed after two months, which may be attributed to high levels of Cd accumulation in plant tissues. Bacterial inoculation also enhanced total antioxidant capacity, suggesting improved tolerance to Cd-induced oxidative stress. Cd accumulation was higher in shoots than in roots and increased over time, indicating a strong phytoextraction potential. Bacterial inoculation enhanced Cd accumulation in both shoot and root tissues, with the most pronounced effects observed after two months of cultivation. Moreover, the application of Cd-resistant bacteria significantly enhanced key phytoremediation indices, including root uptake, shoot uptake, bioaccumulation factor and translocation factor. In conclusion, Cd-resistant bacteria enhanced plant growth and Cd uptake in C. argentea, highlighting their potential for application in the remediation of Cd-contaminated soils.