In vitro influences of TiO₂ nanoparticles on barley (Hordeum vulgare L.) tissue culture.

In the last decades, extensive research on the effects of nano-TiO₂ on plant systems and different microorganisms has confirmed its photocatalytic and antimicrobial activity. However, there is no report on its application in plant cell and tissue culture as well as its role in eliminating contaminating microorganisms in tissue culture. In this work, barley mature embryos were cultured in Murashige and Skoog medium with four concentrations (0, 10, 30, 60 μg/ml) of TiO₂ suspension in four repetitions. Quantitative and qualitative characteristics of calli were analyzed after each subculture. Data analysis for calli number in the first culture and callus size in all three cultures showed that the effect of treatment was significant at p > 0.95. As a result, quantitative features such as callus color, shape, embryogenesis, etc. were completely similar in both control and TiO₂ nanoparticle treatments; there is no doubt that TiO₂ nanoparticles could dramatically increase callugenesis and the size of calli. As well, TiO₂ nanoparticles are effective bactericides with an aseptic effect, causing no negative change in the quality of the callus. It is necessary to do more complementary works to identify mechanisms involved for the increased calli size and embryogenesis of explants in darkness.