Combined effects of allantoin glycyrrhetinic acid-biochar on soil functionality and mitigating aluminium toxicity in tobacco

This study comprehensively examines the impacts of integrating allantoin glycyrrhetinic acid and biochar individually or in conjunction at different rates in aluminium-polluted soil. Their impact was analysed on soil properties, seed germination, root systems and phenotypic attributes, morphology, plant biomass and RWC (relative water content), photosynthetic pigments, NBT and DAB (Nitroblue Tetrazolium, 3,3′-Diaminobenzidine) staining, oxidative stress, metabolite content, and antioxidants activities in tobacco cultivated in Al-polluted soil in Yunnan, China. Findings indicated that AGA and biochar in combined use enhanced plant-soil productivity. Biochar and AGA in combination yielded an increase in soil health and reduced aluminium content. AGA and biochar in combined use caused more significant improvements in plant morphology and chlorophyll levels (89 %) than the use of AGA or biochar alone. The proline level and enzymatic activity were both elevated in the AGA-biochar combination. Malondialdehyde level decreased by 48.11 %, as well as peroxidase and catalase activities increased by 201.06 % and 200.08 %, respectively. Total metabolites identified in tobacco seedlings treated with AGA-biochar under metal stress improved by 49.92 % compared to the control group. Their treatment exhibited significant promise in enhancing tobacco growth and development in contaminated soil. • Biochar and allantoin glycyrrhetinic acid enhanced the morphology, pigmentation, and antioxidant characteristics of tobacco. • Biochar combined with allantoin glycyrrhetinic acid significantly diminished aluminum uptake in soil. • The integrated treatment reduced aluminum uptake and improved metabolite in leaves. • Efficiency of the biochar was boosted by applying allantoin glycyrrhetinic acid. • The combination was more efficient in enhancing the soil-plant system.