Copper cause oxidative damage in plant cells, and plant extracts are the sources of free radical scavengers. We tested the hypothesis that whether Corchorus olitorius (jute) and Urtica pilulifera (Roman nettle) seed extract treatments of germinated seeds affect copper induced oxidative and genotoxic damage or antioxidant response in tomato. Seedlings were exposed to toxic copper concentration (30 ppm) for 7 days. In one experimental group (treatment 1), extract (100 μg mL-1) was added to media. In the other group (treatment 2), tomato seeds were pre-soaked by the extract (100 μg mL-1) prior to germination and copper application. Malondialdehyde and endogenous H2O2 levels in the groups treated with extract and copper were significantly lower than that of the untreated groups. Pre-soaking seeds with the nettle extract solution significantly enhanced catalase activity under unstressed condition. Jute treatment also enhanced catalase activity under copper stress. Ascorbate peroxidase activity remained at unstressed level in copper treated groups. Extract treatments significantly decreased copper induced DNA damage in root nuclei. Jute seed extract contained salicylic acid and quercetin which can be correlated with the evoked effects. We demonstrated protective effect of plant extract treatments against copper stress of tomato seedlings prior to germination or during seedling development.
Keywords: Copper stress; Roman nettle; Solanum lycopersicum; genotoxic damage; jute.