Impact of GenX on Zea mays: Alterations in Morphology and Physiological Performance

Hexafluoropropylene oxide dimer acid (HFPO-DA or GenX) is a highly mobile perfluoroalkyl substance (PFAS) increasingly detected in the environment, yet its impact on major crops remains poorly understood. For this reason, hydroponically grown Zea mays was exposed to 10, 100, and 1000 μg L^-1 of GenX for 7 days to couple bioaccumulation and physiological performance. This compound accumulated in both roots and leaves, reaching 4.5 μg g^-1 DW at 1000 μg L^-1, thereby demonstrating its toxic potential. Low doses stimulated lateral root proliferation and root surface area, whereas the highest GenX level drastically reduced root diameter, biomass, and aerial growth. All treatments significantly affected photosystem quantum yields, electron transport rates, CO₂ assimilation, and transpiration while enhancing nonphotochemical energy dissipation mechanisms and modifying the abundance of photosynthesis-related proteins. This work provides the first integrative evidence that GenX simultaneously disrupts maize hydraulics and chloroplast energy metabolism, suggesting potential yield penalties in PFAS-contaminated agroecosystems.