The effect of TiO2 bulk and nanoparticles on indicators of Echinacea purpurea germination under drought stress

The present study with the purpose to evaluate the effect of bulk and nanosized TiO2 on indicators ofPurple Coneflower germination under drought stress was conducted. The experiment was arranged as factorial based on completely randomized design with three replications was performed in medicinal plants laboratory at the University of Torbat Heydarieh. In this experiment first factor was all concentration of TiO2 bulk 0, 10, 50, 100 and 150 mg/L and nanosized TiO2 concentrations 0, 10, 50, 100 and 150 mg/L and second factors was drought stress from PEG6000 in levels of 0, -3, -6 and -9 bar. The Results showed that application of TiO2 on Coneflower seeds under drought stress had significant effects on root, shoot and seedling length and weight, vigor index I and II and mean germination time. Drought stress did not have negative effect on germination percentage, mean day germination (MDG) and vigor index I and II on Echinacea purpurea until -3 bar stress. The 150 mg/L concentration of TiO2 bulk particles improved shoot, root and seedling length three times more than control. In confronting with drought stress, the 10 mg/L concentration of TiO2 nanoparticles treatment had the least performance in most of the examined indicators and 100 mg/L of bulk and nanoparticles application improved most germination indicators of coneflower.