Today’s, engineered nanoparticles are more frequently found in medical and consumer products as well as in agricultural applications. This study intended to indicate the effects of nano-sized titanium dioxide (TiO2) particles (10-15 nm) on biomass accumulation and elicitation of two main tropane alkaloids namely atropine and hyoscine in Hyoscyamus niger during flowering stage. The crystal properties of TiO2 nanoparticles were examined by X-ray diffraction (XRD), which showed that used TiO2 nanoparticles were all present in the anatase form. A transmission electron microscopy (TEM) image of the TiO2 particles is also provided. Plants were foliar sprayed with different concentrations (0, 20, 40 and 80 mg l-1) of nano TiO2 and its bulk during flowering stage. Alkaloids were identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis. Results showed that the highest alkaloids content values, atropine: 0.286 g kg-1 and hyoscine: 0.126 g kg-1, were achieved in plants treated with nano TiO2 at 80 and 20 mg l-1, respectively. The maximum and minimum plant biomass and total alkaloid yields were obtained in plants exposed to nano TiO2 at 40 mg l-1 and control, respectively. Our results suggest that nano TiO2 particles in appropriate level (40 mg l-1) may act as an abiotic elicitor for growth responses and tropane alkaloids biosynthesis in H. niger plants.
