Date of Award

2018-01-01

Degree Name

Master of Science

Department

Chemistry

Advisor(s)

Jorge L. Gardea-Torresdey

Abstract

The effects of Cu-based nanoparticles (NPs) in bok choy (Brassica rapa subsp. chinensis) are unknown. In this study, Rosie and Green, two varieties of bok choy, with different anthocyanin content, were cultivated for 70 days in soil amended with copper oxide nanoparticles (nano CuO), bulk copper oxide (bulk CuO) and copper chloride (CuCl2) at 75, 150, 300 and 600 mg Cu/kg soil. Cu and essential elements in tissues, and relative chlorophyll content, were determined. In both varieties, nano CuO treatments caused significantly more Cu uptake in roots and shoots, compared with bulk CuO and ion CuCl2 (p ≤ 0.05). Additionally, under the same concentration treatments, Cu uptake in Rosie was higher than in Green. At all concentration the copper compounds reduced the biomass of both Rosie and Green bok choy. At 150 mg/kg, nano CuO reduced K by 45% in Rosie leaves, while at 600 mg/kg reduced it by 41% in Green root, with respect to each control (p ≤ 0.05). Fe accumulation in roots was significantly reduced in the range of 18-50% in both Rosie and Green plants, compared with control (p ≤ 0.05). Similarly, root P was also significantly decreased up to 70% with Cu-based compounds (p ≤ 0.05), with respect to control. Total sugar, starch and protein content were not significantly altered by any of the treatments, except for bulk CuO at 150, 300, and 600 mg/kg, which increased total sugar in Rosie leaves by 56.87%, 51.89% and 49.46%, respectively, compared with control ( p ≤ 0.05). Rosie bok choy, with significantly higher anthocyanin content, accumulated more Cu in both root and leaf and the growth of plants was inhibited more than Green bok choy significantly (p ≤ 0.05). Results showed that nano CuO was more toxic to bok choy plants than bulk CuO, especially at higher concentrations (300 and 600 mg/kg).

Language

en

Provenance

Received from ProQuest

File Size

94 pages

File Format

application/pdf

Rights Holder

Chaoyi Deng

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Included in

Chemistry Commons

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