Date of Graduation

Spring 2017

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Alexander Wait

Abstract

Engineered nanoparticles (ENPs) are increasingly being used in commercial products, and may accumulate in soils when the products are disposed. I examined the effects of two common ENPs, carbon nanotubes (CNTs) and silver quantum dots (Ag-QDs), on plant gas exchange. To do this, I grew Arabidopsis thaliana in soil (n=36) for 6 weeks and added a CNT suspension at increasing concentrations (10, 30, 90, 150, 190, 250 μg/ ml) each week. I also grew A. thaliana in petri dishes (n=83) containing Murashige and Skoog (MS) medium, with a concentration of 4μg/ ml Ag-QDs or 4μg/ml CNTs. I measured carbon assimilation rates, stomata conductance, and transpiration rates, using a LI-6400XT Portable Photosynthesis System. I found that gas exchange in soil-grown A. thaliana was unaffected by CNTs. There were no effects on rates of photosynthesis, transpiration or stomata conductance. There was also no apparent effect on light or carbon fixation reactions. I found that gas exchange in petri dish-grown A. thaliana was negatively affected by Ag-QDs, and marginally affected by CNTs. There was a reduction in photosynthesis rates, but no apparent effects on stomatal conductance and transpiration rates in A. thalian grown with either Ag-QDs or CNTs. The negative effects of the ENPs were directly related to light and Calvin cycle reactions. My research illustrates a model system for examining ENP effects on plants, and demonstrated that if Ag-QDs are disposed of in soils, they can negatively affect plant growth.

Keywords

Arabidopsis thaliana, carbon nanotubes, quantum dots, gas exchange, physiology

Subject Categories

Biology

Copyright

© Maryam Ibrahim Subaylaa

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