Evaluating Copper-Induced Oxidative Stress in Germinating Wheat Seeds Using Laser Photoacoustic Spectroscopy and EPR Techniques

Copper is an essential micronutrient for plants, but excessive levels can induce toxicity and impair physiological functions. This study evaluates the toxic effects of copper sulfate (CuSO<sub>4</sub>) on the germination of common wheat (<i>Triticum aestivum</i>), with emphas...

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Bibliographic Details
Main Authors: Mioara Petrus, Cristina Popa, Ana-Maria Bratu, Alexandra Camelia Joita, Vasile Bercu
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Toxics
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Online Access:https://www.mdpi.com/2305-6304/13/7/604
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Summary:Copper is an essential micronutrient for plants, but excessive levels can induce toxicity and impair physiological functions. This study evaluates the toxic effects of copper sulfate (CuSO<sub>4</sub>) on the germination of common wheat (<i>Triticum aestivum</i>), with emphasis on the gas emission dynamics and oxidative stress biomarkers. Seeds were germinated in agar and exposed to CuSO<sub>4</sub> at concentrations of 1 µM, 100 µM, 1 mM, and 10 mM; distilled water served as the control. Ethylene and ammonia emissions were quantified using CO<sub>2</sub> laser photoacoustic spectroscopy, while electron paramagnetic resonance (EPR) spectroscopy was employed to detect free radicals and Cu<sup>2+</sup> complexes. Exposure to Cu concentrations ≥ 1 mM significantly inhibited germination and biomass accumulation. Enhanced ethylene and ammonia emissions, particularly at 10 mM, indicated stress-related metabolic responses. The EPR spectra confirmed the presence of semiquinone radicals and Cu<sup>2+</sup> complexes under higher Cu levels. These results demonstrate that photoacoustic and EPR techniques are effective tools for the early detection of metal-induced phytotoxicity and offer a non-invasive approach to environmental toxicity screening and plant stress assessment.
ISSN:2305-6304