Nanoplastics in Agroecosystem and Phytotoxicity

Microplastics (MPs) and nanoplastics (NPs) have gained attention in the discussions of scientists, regulators, and the public, as MPs/NPs cause serious problems in various ecosystems. Numerous researchers have focused on the detection, occurrence, characterization, and toxicology of MPs/NPs in marine ecosystems, but the terrestrial and agroecosystem have largely been overlooked despite the fact that annual plastic release into soil is much higher than that into the ocean. To date, most of the scientific literature describe both these particles simultaneously under the term micro(nano)plastics to describe their ecotoxicology. We argue that the environmental fate and behavior of NPs are significantly different from those of MPs; therefore, they should be evaluated independently. It is expected that within agroecosystems, NPs can influence soil geochemistry and biophysical properties, and interfere with the soil and rhizosphere biota that have an indirect effect on plant performance and growth. Furthermore, NPs may act as a transport vector for other potential environmental pollutants, which compounded their toxicity to soil and plant systems. Primary research indicates that NPs might be able to cross biological barriers and cause phytotoxicity in plant cells by triggering oxidative stress, cytogenotoxicity, and epigenetic regulations. Enormous research gaps exist on molecular mechanism(s) of the phyotoxicity of NPs and research on these aspects must thus be intensified to gain a better understanding of the impact of these emerging pollutants on agricultural systems and crop plants. This chapter provides new insights on the potential effects of NPs on the agroecosystem and summarizes the genetic and epigenetic pathways underpinning plant responses to NPs along with further study directions in this emerging field.