The current research is aimed at investigating the micropropagation process of GF677 (peach and almond hybrid) rootstock using multi-wall carbon nanotubes (MWCNTs). For shoot proliferation, single-node explants were cultured on Woody Plant Medium (WPM) medium, containing 6-benzyladenine (BA; 0, 1, 2.5 and 5 mg L-1) and MWCNTs (0 and 10 mg L-1); then shoot number, shoot elongation, leaf area index, fresh and dry weight and dry mass were evaluated. Moreover, toxicity of MWCNTs was studied by measuring the chlorophyll content and the electrolyte leakage of grown buds. Results indicated positive effects of MWCNTs on shoot number and shoot elongation, and increased weight and leaf area. When compared to the control, the proliferation rate was found to be significantly higher for explants cultured on the medium containing MWCNTs together with low concentration of BA. Investigations on grown bud tissues by transmission electron microscopy (TEM) imaging confirmed the penetration of MWCNTs into the tissues. MWCNTs were found in bud and stem tissues and affected proliferation and growth rates. It seems that MWCNTs are able to create water pores in cell wall supporting water uptake. Furthermore, there were no significant differences between control and MWCNTs treated explants concerning the chlorophyll content and the electrolyte leakage, which could explain the non-toxic effect of MWCNTs.
