Comparative Effects of Nanosized and Bulk Titanium Dioxide Concentrations on Medicinal Plant Salvia officinalis L.

Aims: The goal of the study was to evaluate concentrations of nanosized TiO2 at 0, 5, 20, 40, 60 and 80 mg L-1 with same concentrations of bulk TiO2 on sage (Salvia officinalis L.) seed germination and early growth stage.
Study Design: Experiment was performed in a completely randomized design with four replications.
Place and Duration of Study: The study was performed in a laboratory condition for 21 days at the College of Agriculture, Ferdowsi University of Mashhad, Iran.
Methodology: The treatments in the experiment were five concentrations (5, 20, 40, 60 and 80 mg L-1) of bulk and five concentrations (5, 20, 40, 60 and 80 mg L-1) of nanosized TiO2 and an untreated control. The experiment was done in a germinator with an average temperature of 25 ±1ºC. The size of TiO2 bulk and nanoparticles were determined through Scanning Tunneling Microscope (STM). Analysis of variance was performed between treatments samples. The data were subjected to analysis of variance using SAS software. Significant levels of difference for all measured traits were calculated and means were compared by the LSD test at 5% level.
Results: After 21 days of seed incubation, germination percentage improved following exposure to 60 mg L-1 bulk and nanosized TiO2. Studied treatments had not significant effects on shoot, root and seedling elongation and biomass. Exposure of sage seeds to 60 mg L-1 bulk and nanosized TiO2 obtained the lowest mean germination time (8.42 and 8.7 days, respectively) but higher concentrations did not improve mean germination time. Exposure of sage seeds to 60 mg L-1 concentrations of bulk and nano TiO2 particles led to enhanced germination rate.
Conclusion: In general, there was a significant response by sage seed to nanosized TiO2 presenting the possibility of a new approach to overcome problems with seed germination in some plant species, especially medicinal plants.