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 mm and 150 -212 mm) and combinations (PP thorn PET thorn PVC thorn PS thorn 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 mmMP 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 mm) 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. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study analyzed the morpho-physiological and molecular responses of maize seedlings exposed to different types and sizes of microplastics, revealing the detrimental effects on cell membrane stability, photosynthetic pigments, and photosynthetic capacity. Larger particles of microplastics were found to result in better cell restoration under microplastics-induced stress.