Unveiling the impact of cerium oxide nanoparticles on bio-macromolecules, antioxidants and bacoside-A of Bacopa monnieri (L.) Pennell

CeO2 nanoparticles commercially utilised in petroleum, pharma and agriculture industry. Their release and deposition in agri-environment may affect the plant growth yield. Their accumulation in plant poses threat to consumers and human as well. In this study, the effect of CeO2 NPs (0; 2; 4 µg mL−1) on plant stress markers, antioxidant defence system, bio-macromolecule composition and bacoside-A of Bacopa monnieri has been studied. ICP-MS and SEM EDAX data confirmed the uptake and buildup of cerium in different tissues of B. monnieri. Ce accumulation in stomata caused structural distortion in stomatal morphology. The concentration dependent accumulation of cerium accompanied upregulation of oxidative stress markers (MDA, H2O2). The alterations in bio-macromolecules also depended on exposure concentrations of CeO2 NPs. Further, increased levels of cellular and enzymatic antioxidants have been observed at both experimental concentrations of CeO2 NPs as compared to control. The stimulated antioxidants served as a plant defence response against CeO2 NPs induced abiotic stress. A maximum increment of 53.3 % in Bacoside-A yield has also been observed at 4 µg mL−1 CeO2 NPs. The ability B. monnieri to internalize CeO2 NPs may serve as a candidate species for phytoremediation of CeO2 NPs contaminated agri-environments. Further CeO2 NPs, elevated phytotoxic risk raises concerns about their regulated use and disposal in agri-environment.