Biostimulation and toxicity: The magnitude of the impact of nanomaterials in microorganisms and plants

Background: Biostimulation and toxicity constitute the continuous response spectrum of a biological organism against physicochemical or biological factors. Among the environmental agents capable of inducing biostimulation or toxicity are nanomaterials. On the < 100 nm scale, nanomaterials impose both physical effects resulting from the core's and corona's surface properties, and chemical effects related to the core's composition and the corona's functional groups. Aim of Review: The purpose of this review is to describe the impact of nanomaterials on microorganisms and plants, considering two of the most studied physical and chemical properties: size and concentration. Key Scientific Concepts of Review: Using a graphical analysis, the presence of a continuous biostimulation-toxicity spectrum is shown considering different biological responses. In microorganisms, the results showed high susceptibility to nanomaterials. Simultaneously, in plants, a hormetic response was found related to nanomaterials concentration and, in a few cases, a positive response in the smaller nanomaterials when these were applied at a higher level. With the above, it is concluded that: (1) microorganisms are more susceptible to nanomaterials than plants, (2) practically all nanomaterials seem to induce responses from biostimulation to toxicity in plants, and (3) the kind of response observed will depend in a complex way on the nanomaterials physical and chemical characteristics, of the biological species with which they interact, and of the form and route of application and on the nature of the medium - soil, soil pore water, and biological surfaces- where the interaction occurs. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of Cairo University.

Automated summary

This study focuses on the impact of nanomaterials on microorganisms and plants, specifically examining the effects of size and concentration. Microorganisms were found to be highly susceptible to nanomaterials, while plants showed a hormetic response tied to nanomaterial concentration. The complex responses observed in both microorganisms and plants underscore the importance of considering the physical and chemical characteristics of nanomaterials, as well as the specific biological species involved and the environmental conditions in which they interact.