Tissue infiltration of polyethylene, polypropylene, and polystyrene microplastics in Solanum tuberosum L. influences plant growth and yield

Abstract

This study was carried out to evaluate the interaction between terrestrial food crop plants and microplastics (MPs) with a focus on understanding their uptake, effects on growth, physiological, biochemical, and yield characteristics of two different cultivars of Solanum tuberosum L. i.e., Variety-1, Astrix (AL-4) and Variety-2, Harmes (WA-4). Polyethylene (PE), polystyrene (PS), and polypropylene (PP) spheres of size 5 μm were applied to the soil at concentrations of 0 %, 1 %, and 5 %. Morphological parameters, including seed germination rate, shoot and root lengths, leaf area, and fresh and dry biomass of plants, got reduced significantly with the increase in MP concentration. PS MPs caused the most negative impact, particularly at 5 %, leading to the greatest decline in growth and Na, Mg, Zn, Cu, Ni, and Mn nutrient content. The highest DPPH scavenging activity was observed in the 5 % PS MPs treatment with approximately a 45.34 % increase from the control, indicating its potential to enhance antioxidant activity in response to stress caused by PS MPs. Both reducing and non-reducing sugar contents and total proteins were also decreased significantly. Vitamin C content exhibited a significant increase in response to MPs, with the highest levels recorded under 5 % PS MPs treatments. This suggests an adaptive antioxidant response to mitigate oxidative damage induced by MPs. SEM analysis revealed tissue infiltration of MP particles in shoots, leaves, and tubers of both varieties. Among MPs, PS had the most detrimental effects, followed by PP and PE, with higher concentrations increasing the negative impact.