Biochar counteracts the negative effects of microplastics on physiological and biochemical characteristics and leaf metabolism in Zea mays L.

The influence of microplastics (MPs) on plant development has attracted increased attention; however, whether biochar (BC) impacts the toxicological impacts of MPs on plants remains unclear. Exogenously added MPs and mulched 10-year soils were selected to study the possible combined effects of BC and various MPs on maize development to fill this knowledge gap. Maize leaves subjected to various MP treatments showed significant levels of antioxidant enzyme activities, and adding BC counteracts this negative effect. Compared with PET and PLA treatments, CAT activity increased by 137.5 % and 47.6 % in PET+BC and PLA+BC treatments, respectively. The metabolomics analysis showed that adding BC upregulated lipid-related metabolites and amino acid metabolism and enhanced plant growth and response to adversity. The addition of BC to MP-contaminated soil restored bacterial community diversity, which was beneficial in improving the stability of MP-contaminated soil. In the PET and PLA treatment groups, the relative abundance of Proteobacteria increased by 12.9 % and 44.1 %, respectively, through the addition of biochar. Biological pathway studies suggested that BC may help plants resist energy deficits induced by MP-induced stress by increasing glucose metabolism in root systems. This research study establishes a conceptual framework allowing for a more thorough assessment of the impacts of MPs and BC on agricultural productivity. SYNOPSIS: This work initially revealed that biochar may offset the harmful impacts of microplastics on plants through multiple dimensions.