Research Article: Multi-walled Сarbon Nanotubes Penetrate into Plant Cells and Affect the Growth of Onobrychis arenaria Seedlings

Date Published: , 2011

Publisher: A.I. Gordeyev

Author(s): E.A. Smirnova, A.A. Gusev, O.N. Zaitseva, E.M. Lazareva, G.E. Onishchenko, E.V. Kuznetsova, A.G. Tkachev, A.V. Feofanov, M.P. Kirpichnikov.

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Abstract

Engineered nanoparticles (ENPs) are now being used in many sectors of industry; however, the impact of ENPs on the environment still requires further study, since their use, recycling, and accidental spill can result in the accumulation of nanoparticles in the atmosphere, soil, and water. Plants are an integral part of ecosystems; hence their interaction with ENPs is inevitable. It is important to understand the consequences of this interaction and assess its potential effects. The present research is focused on studying the effects of the industrial material Taunit, containing multi-walled carbon nanotubes (MWNTs), on plants, and testing of its ability to penetrate into plant cells and tissues. Taunit has been found to stimulate the growth of roots and stems and cause an increase in peroxidase activity inOnobrychis arenariaseedlings. Peroxidase activity increases with decreasing concentration of Taunit from 1,000 to 100 mg/l. MWNTs from Taunit were detected in the cells and tissues of seedling roots and leaves, implying the ability of MWNTs to penetrate into roots and accumulate there, as well as their ability to be transported into seedling leaves. Thus, the changes in the physiological parameters of plants are associated not only with MWNT adsorption on the root surface, as previously believed, but also with their penetration, uptake and accumulation in the plant cells and tissues.

Partial Text

The great benefits of using nanomaterials in modern technologies are no longer questioned. However, the potential negative effects associated with the propagation and accumulation of nanomaterial components, such as nano-particles and nanofibers in the environment, require further study [1, 2]. Plants are the major components of ecosystems; subsequently, significant attention should be paid to the effects of various technogenical materials upon them [3–5]. Carbon nanomaterials (CNM), such as fullerenes, multi-walled carbon nanotubes (MWNTs), and single-walled carbon nanotubes (CWNTs), are a matter of special interest, as their industrial production is rapidly developing. Since nanotubes have a fibrillar form, they are compared with asbestos [6]. In light of such an analogy, potential adverse effects on living organisms can be anticipated [7]. Preliminary studies have provided evidence that MWNTs and SWNTs are pathogenic to animals [8], yet they have different effects on plants. MWNTs were shown to considerably increase the growth rate of tomato seedlings [9], have no effect on the growth parameters of wheat [10], and inhibit the growth of rice seedlings [11]. SWNTs have been shown to suppress the growth of tomato roots, but stimulate the root growth of onion and cucumber [12]. In contrast, MWNTs have a toxic effect on Arabidopsis cultured cells. [13]. High adsorption of MWNT/SWNT on the roots of seedlings was observed in all the experiments conducted. However, the penetration, uptake and accumulation of MWNTs/SWNTs in plant cells and tissues are not well documented . Furthermore, the mechanism of the development of the physiological changes caused by the exposure of plants to nanotubes also remains unclear. The present work was aimed at studying the effect of the industrial nanomaterial Taunit, containing MWNTs, on O. arenaria seedlings, and the ability of MWNTs to penetrate and accumulate in plant cells and tissues.

Object of the study

Effect of Taunit on the morphometric and biochemical characteristics of

We demonstrated that MWNTs penetrate cell walls, accumulate in the cells and tissues, and most likely are transported via a plant’s vascular system from roots to stems and the leaves of O. arenaria seedlings. We argue that the stimulation of O. arenaria roots and stems growth and the increase in peroxidase activity were induced by the oxidative stress which develops due to the accumulation of MWNTs in plant cells and tissues.

 

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