Abstract
Rice (Oryza sativa L.), a major staple food for billions of people, was assessed for its phytotoxicity of copper oxide nanoparticle (CuO NPs, size < 50 nm). Under hydroponic condition, seven days of exposure to 62.5, 125, and 250 mg/L CuO NPs significantly suppressed the growth rate of rice seedlings compared to both the control and the treatment of supernatant from 250 mg/L CuO NP suspensions. In addition, physiological indexes associated with antioxidants, including membrane damage and antioxidant enzyme activity, were also detected. Treatment with 250 mg/L CuO NPs significantly increased malondialdehyde (MDA) content and electrical conductivity of rice shoots by 83.4% and 67.0%, respectively. The activity of both catalase and superoxide dismutase decreased in rice leaves treated with CuO NPs at the concentration of 250 mg/L, while the activity of the superoxide dismutase significantly increased by 1.66 times in rice roots exposed to 125 mg/L CuO NPs. The chlorophyll, including chlorophyll a and chlorophyll b, and carotenoid content in rice leaves decreased with CuO NP exposure. Finally, to explain potential molecular mechanisms of chlorophyll variations, the expression of four related genes, namely, Magnesium chelatase D subunit, Chlorophyll synthase, Magnesium-protoporphyrin IX methyltransferase, and Chlorophyllide a oxygenase, were quantified by qRT-PCR. Overall, CuO NPs, especially at 250 mg/L concentration, could affect the growth and development of rice seedlings, probably through oxidative damage and disturbance of chlorophyll and carotenoid synthesis.
Highlights
Engineered nanoparticles (ENPs) are particles with sizes ranging from 1 to 100 nm [1]
The aims of this study were to (i) investigate the phenotypic changes caused by short-time exposure of CuO NPs to rice seedlings at early stage under hydroponic culture; (ii) examine the changes of physiological factors, e.g., oxidative damage and impaired photosynthesis, caused by CuO NPs in seedlings; and (iii) evaluate the potential mechanisms of the decreased chlorophyll in rice leaves exposed to CuO NPs at the molecular level
The statistical results showed that 62.5, 125, and 250 mg/L CuO NPs reduced the weight of rice roots by 31.1%, 67.2%, and 73.5%, respectively, compared to the control (p < 0.05) (Figure 1B)
Summary
Engineered nanoparticles (ENPs) are particles with sizes ranging from 1 to 100 nm [1]. Due to their particular properties, they have been utilized for various purposes, such as in biomedicine, agriculture, and industries [2,3]. The extensive utilization of ENPs has resulted in their inevitable and irreversible release into the environment [4]. With ENPs expected to become more widely used, their effect on the environment and organisms has been an increasing cause of concern [5,6,7,8]. Frequent assessment of the phytotoxicity of ENPs is considered to be of pivotal significance in environmental protection [9,10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Environmental Research and Public Health
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
