Date of Award

2022-08-01

Degree Name

Doctor of Philosophy

Department

Chemistry

Advisor(s)

Jorge L. Gardea-Torresdey

Abstract

The use of nanotechnology in agriculture has attained high interest to enhance crop production due to their unique properties. Moreover, metal oxide nanomaterials can potentially supplement nutrients, enhance plant growth, and crop production. When investigating fruits' nutritional quality, carbohydrates and phytonutrients (bioactive compounds) play important roles. Therefore, it is important to understand how nanomaterials will affect the quality of tomato fruits. In this dissertation, various metal oxides were synthesized and applied to Candyland Red tomato seedlings to assess the plant growth and tomato production. In the first investigation, Candyland Red tomatoes (Solanum lycopersicum) were exposed to synthesized pristine CuO and functionalized CuO nanomaterials via soil application at two concentrations 50 and 500 mg/kg and grown to full maturity (120 days). Additionally, purchased CuO and CuSO4 were used for comparison purposes. After harvesting, physiological parameters, micronutrient/macronutrient profiles, carbohydrates, and bioactive compounds were investigated. This investigation showed that CuO treatments altered the total soluble proteins (TSP) in the root tissues and caused a micronutrient (Cu and Fe) redistribution throughout all plant tissues. Moreover, it was determined that both the purchased CuO and functionalized CuO caused a decrease in fruit starch content. This study demonstrated how functionalization on NPs can induce different biochemical responses in plants. In the second investigation, Candyland Red tomatoes were foliarly exposed to magnetite (Fe3O4), hybrid ferrites (MnFe2O4, ZnFe2O4, and Zn0.5Mn0.5Fe2O4), hausmannite (Mn3O4), and ZnO NMs at 250 mg/L and grown for a total of 135 days. During plant growth, the tomato fruits were harvested as they ripened. It was found that the sugar content in the fruit was enhanced by Mn3O4 and ZnO treatments by 118 and 111 %, respectively. Additionally, the phytonutrients of the tomato fruits were investigated at different storage times (0 and 15 days). MnFe2O4, ZnFe2O4, and Zn0.5Mn0.5Fe2O4 caused an initial decrease in lycopene content at 0 stored days, but after 15-day storage, the treatments and the control were statistically the same. Moreover, the β-carotene in the fruit was decreased by Mn3O4 and ZnO at both 0 and 15 days stored. The total phenolic compounds decreased upon storage; however, ZnFe2O4, Zn0.5Mn0.5Fe2O4, and ZnO mitigated the reduction and improved the phenols, compared to the control. Overall, this dissertation investigation assesses both the potential applications and implications of various metal oxide NMs on tomato fruit quality and underlines the need for caution using nanoscale treatments for crop growth.

Language

en

Provenance

Recieved from ProQuest

File Size

101 p.

File Format

application/pdf

Rights Holder

Jesus Manuel Cantu

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