Increase of P and Cd bioavailability in the rhizosphere by endophytes promoted phytoremediation efficiency of Phytolacca acinosa

• Published in: Journal of hazardous materials 2022-06, Vol.431, p.128546-128546, Article 128546
• Main Authors: Liu, Chenjing, Lin, Hai, Dong, Yingbo, Li, Bing
• Format: Article
• Language: English
• Subjects: Bioavailability; Biodegradation, Environmental; Biological Availability; Cadmium - analysis; Endophytes; Heavy metal contamination; Metals, Heavy - analysis; Phosphatase activity; Phytolacca; Plant growth promoting endophytes; Plant Roots - chemistry; Rhizosphere; Rhizosphere microecology; Soil; Soil Pollutants - analysis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.128546

The information about the spatial distribution of bioavailable phosphorus (P) and heavy metal (HM) in the rhizosphere could aid in the precise phytoremediation regulation. In this study, a rhizobox system was adapted to study soil-root interactions and used to access the endophyte inoculation variation on bioavailable P and cadmium (Cd) spatial distribution during phytoremediation of Cd contaminated soils. Results showed that endophyte PE31 Bacillus cereus inoculation enhanced Cd uptake of P. acinosa by 52.70% and 46.73% in low and high Cd contaminated soils, increasing the phytoremediation hotspot area from 45.78% and 15.29% to 60.97% and 21.80%, respectively. Available P and Cd significantly diminished because root activities depleted large amounts of bioavailable P and Cd concentrations. However, PE31 increased bioavailable P and Cd concentration in the rhizosphere soil. The bioavailable P enhancement in the rhizosphere was positively correlated to plant growth and Cd accumulation. Overall, endophyte inoculation compensated the diminution of bioavailable P and Cd in the rhizosphere to improve plant biomass and HM absorption, and thus promote phytoremediation efficiency. This study helped to better understand bioavailable P and Cd spatial distribution under endophyte inoculation, which could provide effective management strategies for the precise regulation of phytoremediation. [Display omitted] •Depletion zones of bioavailable Cd and P developed around the root.•Endophyte inoculation compensated the loss of bioavailable Cd and P in rhizosphere.•B.cereus promoted phytoremediation by improving Cd and P bioavailability.•The enhancement of bioavailable P promotes Cd accumulation.