ИСТИНА

Engineered nanodaimonds (NDs) are a class of novel carbon based nanoparticles with unique mechanical, optical, thermal and surface properties that are currently being used in a wide range of scientific and commercial applications. NDs are incorporated into different consumer and industrial products, such as modern polymer compositions, electronics, abrasive tools, greases and lubricants. Their unique surface composition and size-dependent physicochemical properties improve the product’s characteristics; however, by ending up in the environment, these same ND’s properties may be the cause of a potential hazard for living organisms. The aim of our study was to examine toxicity of NDs towards plants using a standard environmental approach called Allium test that allows to reveal cytotoxicity and genotoxicity. Sets of common onion Allium cepa L. were germinated in distilled water containing NDs («Sinta», Republic of Belarus) of 5 nm in diameter in the concentrations 0.5 or 1.0 g/L for 5 days in the dark. After that period of time, root length was measured followed by microscopic analysis of microslides prepared form the root tip cells. The results have shown that low concentration of NDs stimulated root growth, while higher concentration inhibited it. In the presence of 0.5 g/L NDs the roots grew by one-third over the control sample’s roots (distilled water); whereas under the dose 1.0 g/L root’s length reduced considerably. The microscopical analysis determined disturbances in the mitotic cycle in the root cells of onions exposed to both studied concentrations. In cells treated with 0.5 g/L NDs the number of cells in prophase increased substantially. On the contrary, at concentration 1.0 g/L not only did the number of cells in prophase rise, but also severe chromosomal alterations were discovered. Therefore, our results have demonstrated genotoxicity of NDs on plants for the first time. Acknowledgment NDs were kindly provided by Dr. G. A. Badun (Department of Chemistry, Lomonosov MSU)