Revealing the bioavailability and phytotoxicity of different particle size microplastics on diethyl phthalate (DEP) in rye (Secale cereale L.)

• Published in: Journal of hazardous materials Vol. 480; p. 135979
• Main Authors: Hu, Jinke, Bao, Guozhang, Pan, Xinyu, Wang, Huixin, Xing, Ningning
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 28.09.2024
• Subjects: Adsorption; Diethyl phthalate; Microplastics; Molecular docking; Oxidative stress; Transcriptomics; Oxidative stress; Microplastics; Adsorption; Transcriptomics; Molecular docking; Diethyl phthalate
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.135979

Understanding how widely distributed microplastics (MPs) and diethyl phthalate (DEP) interact with crops remains limited, despite their significant implications for human exposure. We used physiology, transcriptomics, adsorption kinetics, and computational chemistry to assess rye’s molecular response to two sizes of MPs (200 nm and 5 µm) and DEP, both individually and in combination. Findings systematically highlight potential ecological risks from MPs and DEP, with ecotoxicity ranking as follows: CK (Control Check) < LMPs < SMPs < DEP < LMPs+DEP < SMPs+DEP. Fluorescence and scanning electron microscopy revealed SMP’s translocation ability in rye and its potential to disrupt leaf cells. DEP increased the electronegativity on MPs, which enhanced their uptake by rye. DEP adsorption by MPs in hydroponics reduced DEP bioavailability in rye (18.17–46.91 %). Molecular docking studies showed DEP interacted with chlorophyll, superoxide dismutase, and glutathione S-transferases proteins’ active sites. Transcriptomic analysis identified significant up-regulation of genes linked to mitogen-activated protein kinase signaling, phytohormones, and antioxidant systems in rye exposed to MPs and DEP, correlating with physiological changes. These findings deepen the understanding of how MPs can accumulate and translocate within rye, and their adsorption to DEP raises crop safety issues of greater environmental risk. [Display omitted] •The combination of MPs and DEP inhibits root activity and photosynthesis.•SMPs are more toxic than LMPs and can be absorbed and transported within rye plants.•Both SMPs and LMPs reduced the bioavailability of DEP in rye.•DEP enhanced the uptake of SMPs into rye tissues, leading to greater health risks.