Polyethylene microplastic: impacts on ryegrass seed germination and seedling development

Microplastic pollution has emerged as a critical global environmental concern, particularly within agricultural ecosystems where its impact on forage production is highly significant. This study used a hydroponic system to investigate the potential effect of polyethylene (PE) microplastics at different concentrations (20, 50, 100, 200, 500, and 1000 mg/L) and particle sizes (200 nm, 25 μm, and 200 μm) on the growth of perennial ryegrass (Lolium perenne L.), with no added PE microplastics (0 mg/L) as a control. Our findings indicate that PE microplastics, especially those with a particle size of 200 nm, significantly inhibit ryegrass seed germination. The presence of microplastics disrupts normal water uptake in ryegrass and suppresses biomass accumulation, with the inhibitory effects intensifying as microplastic concentrations increase. Overall, ryegrass seed germination and seedling growth are adversely affected by microplastic exposure levels, with the extent of impact closely associated with both the quantity and size of the microplastics present.