Particle size-dependent biomolecular footprints of interactive microplastics in maize

The world is dealing with the mismanaged plastic waste found even in the Arctic. The crisis is being tried to solve with the plastivor bugs or bio-plastics, and the marine pollution profiles become priority however, putative phytotoxicity on terrestrial farming have not received significant attention. Hence, morpho-physiological and molecular response in maize seedlings exposed to the most prevalent microplastic (MP) types (PP, PET, PVC, PS, PE) differing in their particle size (75-150 μm and 150-212 μm) and combinations (PP + PET + PVC + PS + PE mix) was analyzed here for a predictive holistic model. While POD1 regulating the oxidative defense showed a slight down-regulation, HSP1 abundance quantified in the 75-150 μm MP lead a significant up-regulation particularly for PET (2.2 fold) PVC (3.3 fold), and the MP mix (6.4 fold). Biochemical imbalance detected at lower sized (75-150 μm) MPs in particular at the MP mix, involved the cell membrane instability, lesser photosynthetic pigments and a conjectural restraint in the photosynthetic capacity along with the accumulated endogenous H₂O₂ proved that the bigger the particle size the better the cells restore the damage under MP-caused xenobiotic stress. The determination of the impacts of MP pollution in in-vitro agricultural models might guide the development of policies in this direction and help ensure agricultural security by predicting the possible pollution damage.