Synergistic effect of cerium oxide nanoparticles and vermicompost on hemp productivity under lead contaminated soils

Industrial hemp has an excellent tolerance for lead (Pb) and accumulation capacity. Further improving the Pb tolerance in industrial hemp is of great interest for its future application in phytoremediation. Present study was performed to evaluate the various Pb contaminated soils (normal soil; Pb spiked soil using Pb(NO 3 ) 2 and Pb polluted mine soil) with the Pb level 1300 mg kg −1 and various treatments of the vermicompost (VC) and cerium oxide nanoparticles (CeO 2 NPs), (T 0 = no VC and CeO 2 -NPs; T 1 = CeO₂ NPs (30 mg L −1 ); T 2 = VC (5 % w/w of soil); and T 3 = T 1 + T 2 on the Pb accumulation and hemp productivity. The findings indicated that Pb stress (artificially spiked and natural contamination) led to significant reduction in the growth, biomass, and physiological traits of hemp. The Pb polluted mine soil exhibits more harmful impacts in comparison to artificially Pb spiked soil. The sole application of CeO 2 -NPs leads to less pronounced enhancements in growth and development parameters at rapid growth and harvesting stage in comparison with soil applied VC treatment under the treated and untreated Pb-stressed plants. Combined application of CeO 2 -NPs and VC effectively reduced the malondialdehyde contents (41.34 %), increased the soluble protein (62.35 %) and soluble sugar (29.97 %) as compared to control group. Moreover, the co-active effect of VC and CeO 2 -NPs also had the prospects of reducing Pb accumulation in difference tissues by enhancing physiological resiliency in hemp. Particularly, combined use of VC and CeO 2 -NPs counteracted the adverse effect of Pb stress by boosting growth, biomass, enzymatic antioxidants, and osmoprotectants through limiting the Pb accumulation. Use of organic amendments (VC) and metallic oxide NPs (CeO 2 -NPs) holds promising tool for mitigating the Pb stress, offering a practical and viable approach for hemp production. • Hemp productivity is adversely affected by Pb contamination. • Pb enriched mine soils boosted enzymatic leaf antioxidant in hemp. • Metallic NPs and organic amendments have ability to mitigate the Pb stress. • Vermicompost proved best for alleviating the Pb toxicity compared to CeO 2 -NPs. • Combined application of CeO 2 -NPs + VC is viable approach to mitigate Pb stress.