Nano-cuprous oxide enhances seed germination and seedling growth in Lycopersicum esculentum plants

This study was carried out to determine the influence of cuprous oxide nanoparticles (Cu2O NPs) biosynthesised from leaf extracts of Flacourtia montana on the tomato Lycioersicum esculentum seed germination, seedling growth and vigour index. Here we examined the promotory and phytotoxic effect of Cu2O NPs (0-160ppm) on tomato seeds resulted in dosage dependent response. The highest germination percentage (95%) was observed at 20ppm Cu2O NPs, however, above 20ppm Cu2O NPs, there is a reduction in the seed germination. The tomato seedlings showed increased root and shoot elongation up to 20ppm Cu2O NPs concentration, further increase in NPs concentration caused the negative effect on plants growth and development. The leaf pigments showed increasing trend in tomato plants after treatment with Cu2O NPs up to 20ppm as compared to control. Phytotoxicity of Cu2O NPs in tomato seedlings demonstrated by lower contents of chlorophyll a, b and carotenoid pigments. The study of effect on antioxidant enzymes showed increases in activity with increase in Cu2O NPs concentration for two enzymes, Super oxide dismutase (SOD) and Glutathione Peroxidase (GPX) out of five enzymes treated. High antioxidant activity of enzymes is followed by the increased lipid peroxidation and decrease in free radical scavenging activity by the DPPH. The activity of Catalase, Pheny Alanine Aminolyase and Poly Phenol Oxidase enzymes were found to increase up to 20ppm as compared to control and above this, all three enzymes showed decrease in activity. Uptake of Cu2O NPs nanoparticle by tomato seedlings was confirmed by atomic absorption spectroscopy. Key words: Nano-Cuprous Oxide, Flacourtia montana, Tomato, antioxidant enzymes, lipid peroxidation