Early developmental responses of plants exposed to metals and oxides nanomaterials

Abstract

Over the last decade or so, one question about engineered nanomaterials (ENMs) has been constantly asked: Are nanomaterials inherently toxic? It is because characteristics such as “nano” scale size, surface charge, surface plasmon resonance, greater surface area, and propensity to ligand with (in)organic and/or polymeric molecules set ENMs physicochemically apart from their bulk/parent analogs. Related to unique properties, which enable greater functionality in a wide range of consumer applications, is the uncertainty about whether unique risk is posed to the environment, health, and safety (EHS) as ENMs are anthropogenically released into the environment. Recognized as the major sinks, soil, water, and air contamination of ENMs, including their leachable or modified by-products, is inevitable. Understanding of potential impacts on terrestrial plant species has remained unclear as anomalies in morphological, anatomical, and physiological endpoints, which have potential for impairing later development in life, are not routinely screened for, however. In this chapter, we report valuable information synthesized via thorough literature review of the current understanding of potential implications of ENM release and exposure to plants via soil, water, and atmospheric deposition. In particular, we report potential fate, biouptake, site of translocation/associated mechanisms, in vivo transformation, and toxicity (germination rate, growth and development, anatomical and physiological anomalies, and yield) of metal-based ENMs. Additionally, potential mechanisms and factors influencing ENMs’ toxicity are explained. Such information is critical to direct future research aimed at uncovering better understanding of nanotoxicology in plants, and to determine whether risk to public health exists from exposure to ENMs through the dietary route.