Exposure of engineered nanomaterials to plants: Insights into the physiological and biochemical responses-A review

• There is lack of consistency in the responses of plants to NPs’ exposure.
• Plant responses depend on exposure conditions and NP characteristics.
• Most of reports focus on seed germination and plant growth.
• Mechanisms of interaction between plants and NPs are not well understood.
• Further studies at the transcriptomic and genetic levels are needed.

Recent investigations show that carbon-based and metal-based engineered nanomaterials (ENMs), components of consumer goods and agricultural products, have the potential to build up in sediments and biosolid-amended agricultural soils. In addition, reports indicate that both carbon-based and metal-based ENMs affect plants differently at the physiological, biochemical, nutritional, and genetic levels. The toxicity threshold is species-dependent and responses to ENMs are driven by a series of factors including the nanomaterial characteristics and environmental conditions. Effects on the growth, physiological and biochemical traits, production and food quality, among others, have been reported. However, a complete understanding of the dynamics of interactions between plants and ENMs is not clear enough yet. This review presents recent publications on the physiological and biochemical effects that commercial carbon-based and metal-based ENMs have in terrestrial plants. This document focuses on crop plants because of their relevance in human nutrition and health. We have summarized the mechanisms of interaction between plants and ENMs as well as identified gaps in knowledge for future investigations.