Abstract
BACKGROUND: Antimony (Sb) and lead (Pb) toxicities are serious threats to crop productivity, living organisms, and ecosystem sustainability. Thus, it is essential to find ways to reduce their entry into the environment to ensure safe and sustainable food production. Recently, biochar (BC) and signaling molecules have shown appreciable results in mitigating Sb and Pb toxicity. Thus, an attempt was made to explore the role of BC and gamma-aminobutyric acid (GABA) in mitigating Sb + Pb toxicity by applying the following treatments; control, Sb stress (600 mg kg(- 1)) + Pb stress (600 mg kg(- 1)), Sb + Pb + BC (2.5%), Sb + Pb + GABA (1 mM) and Sb + Pb + BC (2.5%) + GABA (1 mM). RESULTS: Antimony and Pb significantly decreased the growth and productivity by increasing hydrogen peroxide (H(2)O(2)), malondialdehyde (MDA), electrolyte leakage (EL), Sb + Pb accumulation in plant organs, and decreasing photosynthetic pigments, leaf water contents, and nutrient availability. However, co-applied BC + GABA enhanced rice yield by increasing chlorophyll synthesis (42-53%), leaf water contents (23%), antioxidant performance, nutrients uptake, and decreasing H(2)O(2) (61%), EL (90%), MDA (64%), soil Sb (155%), and Pb (127%) availability. CONCLUSION: Therefore, combining BC with GABA can mitigate the antimony and lead toxicity by increasing antioxidant activities, osmolyte synthesis, and decreasing their availability. The synergistic application of BC, and GABA presents an effective strategy to enhance sustainable rice production in multi-metal contaminated soils.