Effect of Multi-Walled Carbon Nanotubes on the Growth and Expression of Stress Resistance Genes in Birch

Recent studies have shown that nanomaterials, including carbon nanotubes, are associated with a wide range of effects on living organisms, from stimulation to toxic effects. Plants are an important object of such research, which is associated with the potential use of carbon nanomaterials in agriculture and environmental protection. At the same time, the specific mechanisms of formation of plant resistance to the effects of carbon nanotubes remain not fully understood, especially in woody plants. Therefore, we studied the effect of aqueous colloids of multi-walled carbon nanotubes (MWCNTs) with an outer diameter of 10–30 nm and a length of about 2 μm at a concentration of 1, 10, 50, and 100 mg/L on morphometric parameters and the level of expression of stress resistance genes in Betula pubescens Ehrh. and B. pendula Roth. plants in greenhouse conditions. The results showed an increase in the length and diameter of the shoot in the studied plants. The dry biomass of the leaf increased by 30%, the stem by 42%, and the root by 49% when using MWCNTs at a concentration of 10 mg/L. The expression of the stress resistance genes DREB2 and PR-10 significantly increased under the influence of 1 mg/L MWCNTs on plants of both species. At the same time, the use of 100 mg/L nanoparticles led to a decrease in the studied parameters in Betula pendula, which may be associated with the negative effect of MWCNTs in high concentrations. The revealed positive effects of low concentrations of MWCNTs on morphometric parameters and stimulation of stress resistance genes by nanotubes open up prospects for their use in woody plant biotechnology.