Impact nano- and micro- form of CdO on barley growth and oxidative stress response

The objective was investigated the effects of CdO and nano-CdO as potential toxic pollutants on growth and redox response of barley. CdO and nano-CdO have been found to cause significant phytotoxicity in barley seedlings, with nano-CdO increasing plant tissue cadmium accumulation. This accumulation is linked to growth retardation and oxidative stress. Low molecular weight antioxidants like restored glutathione and ascorbate have been found to increase the activity of glutathione peroxidase (GPX), glutathione-S-transferase (GSTs), and ascorbate peroxidase (APX) in green tissues. Catalase (CAT) activity increased from 50 % with 100 mg/l CdO to 70 % with 1000 mg/l and nano-CdO. The observed disturbance in redox balance signals the upregulation of corresponding genes. Antioxidant enzyme isoform gene transcripts increased for SODB, CAT2, and APX. Cadmium buildup in root cells causes oxidative stress, leading to upregulation of SOD, CAT, GR, and GSTs isoform genes as well as protein carbonylation, sulfhydryl group degradation, and MDA accumulation. CdO and nanoCdO have similar phytotoxic effects, but bioavailability affects biochemical and molecular responses.