Effects of Two-Dimensional Nanoparticles on Seed Production of Tobacco and Maize

Two-dimensional nanomaterials (2D-nm) are increasingly proposed for environmental and agricultural applications, including crop protection, nutrient delivery, and sustainable farming practices. However, their potential ecological implications, particularly at the reproductive level of plants, remain poorly understood. This study investigated the effects of four 2D-nm - graphene oxide (GO), hexagonal boron nitride (h-BN), molybdenum disulfide (MoS₂), and mica (MI) - on seed production in two model crop species, tobacco (Nicotiana tabacum L.) and maize (Zea mays L.).

Plants were exposed to aqueous dispersions of 2D-nm at environmentally relevant concentrations (25, 50, and 100 µg mL⁻¹) through controlled spray applications. Tobacco was evaluated in both pot (2022) and open-field (2023) experiments, while maize was assessed under controlled conditions. Endpoints included total seed production, thousand-seed weight, seed germination, early root development, and elemental composition of seeds, determined using ICP-OES and CHN analyses.

In tobacco, seed production was unaffected in the pot experiment but significantly reduced under field conditions at the highest exposure level, particularly following GO and MI treatments, with GO causing up to a 44% decrease compared to the control. In maize, seed yield was less sensitive to 2D-nm exposure, showing no significant reductions, although material-specific effects on seed weight and germination parameters were observed. Across both species, limited changes in seed elemental composition were detected.

These findings highlight that 2D nanomaterials can exert species- and material-dependent effects on plant reproductive performance, especially under realistic field conditions. The study underscores the importance of incorporating reproductive endpoints into environmental risk assessments to support the safe and sustainable application of nanotechnology in agroecosystems.

This work was supported by the Italian Ministry of University and Research through the PRIN2020 funding program (project name: “2D-NANO MAD PLANTS: Effects of 2D-nanomaterials on seed plants reproduction”; CUP: G53C22000050001; project code: 2020KRY7RB).