Response to Engineered Nanomaterials in Arabidopsis thaliana, a Model Plant

Engineered nanomaterials of various chemical, physical and morphological characteristics are released into the environment because of their diverse applications. Plants being ubiquitous are the first sink for such released materials as they can easily uptake, transport, accumulate and transform materials in the nano/micrometre range. As a model plant, Arabidopsis thaliana has several advantages over other plants, which can be used to delineate the cellular or molecular interactions. Investigations based on Arabidopsis exposure indicate that the nanoparticles tend to induce changes in growth pattern with obvious growth promotion at lower concentrations while significant inhibition at higher concentrations. Even though growth promotion has been recorded in case of treatments with metallic nanoparticles including gold, silver, titanium for many plant species the actual mechanism of action is unclear. Prominent physiological features supporting growth include significant increases in water content, chlorophyll, and total protein contents at lower concentrations, which revert upon treatment with higher concentrations. The size, shape and surface characteristic and concentration of different nanoparticles were found influencing the interaction and outcome within a metal type. Changes in certain physiological, biochemical parameters and gene expression patterns in Arabidopsis signify the operation of stress perception and response pathways in case of inhibitory effects. While the adverse effects vary in the extent of genotoxicity and alteration in the gene expression patterns related to cell division, photosynthesis and other physiological phenotypes, the oxidative stress pathways are common over types of the metal or non-metal nanoparticles examined.