Oxidative Stress in Wheat Caused by Ampicillin and Amoxicillin and Their Mixture Applied to the Soil

Ampicillin (AMP) and amoxicillin (AMX) are widely used penicillin antibiotics. After administration to humans and animals, they are largely excreted in unchanged or metabolized forms, leading to their release into wastewater. In surface waters, their concentrations usually reach the ng∙L−1 range and rarely exceed µg∙L−1, although in India AMX levels above mg∙L−1 were detected in hospital effluents. The limited efficiency of wastewater treatment plants allows these compounds to enter aquatic and terrestrial environments, where they affect various organisms. The aim of this study was to assess the effects of AMP, AMX, and their mixture on wheat, one of the most extensively cultivated cereals. Determinations were carried out using standardized methodologies. The results showed that antibiotics induce oxidative stress in plants, with symptoms observed only at concentrations of 1000 mg∙kg−1 of soil DW. At this level, changes included altered antioxidant enzyme activity (APX, SOD, POD, and CAT), increased proline and H2O2 content, and reduced MDA levels. By contrast, antibiotics had minimal influence on glutathione and ascorbate and caused only slight changes in photosynthetic pigments and chlorophyll fluorescence.