eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2024-07-01 21 2 779 788 10.13005/bbra/3264 51014 article Rajnandini Srivastava 1 R. C. Mishra 1 Department of Botany Mahakaushal University, Bhopal M. P, India. This study investigates the impact of Copper Oxide (CuO) nanoparticles on Dunaliella sp., assessing relative growth rate (RGR), growth rate coefficient (K), and physiological parameters. Increasing CuO nanoparticle concentrations led to a decline in RGR, reflecting negative growth effects, but the lowest concentration (25µl) exhibited the highest RGR and K values. Pigment estimation revealed decreasing chlorophyll a, chlorophyll b, and carotenoid concentrations, indicating disrupted photosynthetic activity. Protein concentration decreased with increasing CuO nanoparticle treatment, signalling interference with synthesis and metabolic processes. Conversely, glutathione superoxide transferases and lipid peroxidase concentrations increased, suggesting activated defence mechanisms against nanoparticle-induced oxidative stress. These findings enhance our understanding of CuO nanoparticles' adverse effects on Dunaliella sppp., emphasizing the need for further research to ensure the safe application of nanoparticles in aquatic environments. The study underscores the importance of sustainable nanoparticle use and its implications for aquatic organisms. https://www.biotech-asia.org/vol21no2/impact-of-cuo-nanoparticles-on-dunaliella-spp-bdug10113-growth-photosynthesis-and-cellular-processes/ Aquatic organisms; Copper Oxide NP; Dunaliella; Growth inhibition; Nanoparticles; Toxicity