Biochemical, anatomical and molecular level changes in cucumber (Cucumis sativus) seedlings exposed to copper oxide nanoparticles

Abstract

AbstractThe effect of copper oxide nanoparticles (CuONPs) at the biochemical, anatomical and molecular level was investigated in cucumber (Cucumis sativus L.) seedlings. The seedlings were grown in semi-solid half strength Murashige and Skoog medium supplemented with 0, 50, 100, 200, 400 and 500 mg/L of CuONPs for fifteen days under controlled growth chamber conditions. The results showed that exposure to all concentrations of CuONPs resulted in significant reduction in shoot and root growth and biomass. A concentration-dependant increase in reactive oxygen species (ROS) generation, malondialdehyde production, lignin content and decline in mitochondrial membrane potential were observed. Cross-sections of stem showed anatomical changes, viz. an increase in xylogenesis in CuONPs exposed plants. Significant modulation in the expression of genes related to oxidative stress and lignin biosynthesis, i.e. catalase, ascorbate peroxidase, phenylalanine ammonia lyase, cinnamate 4-hydroxylase, anionic and cationic peroxidases were observed in shoots and roots as a result of CuONPs exposure. Taken together, exposure to CuONPs has resulted in excess ROS generation, lignification and growth suppression in Cucumis sativus seedlings.