Mahurin Honors College Capstone Experience/Thesis Projects



Document Type



In recent years titanium dioxide nanoparticles (TiO2NPs) have been ingredients in everything from paints to cosmetics, and even in some kinds of food. This growth in use has resulted in a substantial increase in the amount of titanium released into the environment, which could have detrimental effects on nearby plant and animal life. Currently, the number of studies conducted on the effects of TiO2NPs is quite small, especially when it comes to edible crops. Because of this lack of research data, this study has been designed to assess the effect of TiO2 NPs exposure on growth and physiology of Medicago truncatula. This plant was chosen because each species has a unique reaction to nanoparticles, and it also an important feed crop for the cattle industry. The plants were grown in Turface MVP® soil that had been treated with 250, 500, 1000, and 2000 parts per million of TiO2NPs for two weeks and then examined for changes in biomass, metal ion concentrations, and gene expression related to antioxidant and photosynthesis. The results varied between the different experiments, but in general the dry weight showed a decrease in mass from the control to the treated soils. The metal nutrients estimation, which recorded a spike in titanium content in the 500 and 1000 PPM samples, showed a correlation between the titanium and important building blocks such as phosphorus, and a majority of the genes tested showed a spike in shoot expression at 250 PPM relative to control mark followed by a decline with the other samples. Altogether, it appears that TiO2 NPs adversely affect the growth of Medicago at high concentration exposure.

Advisor(s) or Committee Chair

Dr. Shivendra Sahi


Biology | Environmental Health | Genetics | Plant Biology