In this thesis, we present an efficacious way of tracking nanoparticle movement in plant tissue through the use of fluorescence lifetime imaging (FLIM) and spectroscopy as well as a review of nanoparticle uptake in plants and the proposed mechanisms governing them. Given the increasing number of nanomaterials in agriculture and society as a whole, proper imaging tools and proactive measures must be taken to track nanoparticle movement in plant tissues and create infrastructure and products to keep things sustainable and safe. Herein we report a ZnO comparable nanoparticle— a CdS:Mn/ZnS/ N-acetyl cysteine (NAC) quantum dot— which boasts longer lifetimes and suitable fluorescent properties above ZnO to properly delineate from plant tissue fluorescence of chlorophyll and cinnamic acids. In addition to FLIM mapping, quantum dot localization in plant vascular tissue was clearly seen and confirmed via characteristic emission spectra and time correlated single photon counting decay curves (TCSPC). Most quantum dots were seen to reside in the xylem. Plant age and structure was seen to affect uptake. QD size likely restricted extensive translocation. Inhibitive effects of QDs were likely water and mechanical stress. We surmise that travel of the cadmium quantum dots up the leaf and branch plant tissues is likely most governed by diffusion as the quantum dots bound to the cell structures create a diffusion gradient which aids travel up the leaf.
Master of Science (M.S.)
College of Graduate Studies
Nanoscience Technology Center
Length of Campus-only Access
Masters Thesis (Campus-only Access)
Washington, Torus, "Fluorescence Lifetime Imaging and Spectroscopy Aided Tracking of ZnO and CdS:Mn/ZnS/ N-acetyl cysteine (NAC) Quantum Dots in Citrus Plants" (2017). Electronic Theses and Dissertations. 5637.