Abstract

This study showed the effect of Cu stress on Tomato (Lycopersicon esculentum var. Castel rock) plants. Effects of foliar spraying of plants with ascorbic acid (AsA) (200 ppm) under Cu stress (10, 50 and 250 µM) on growth, yield parameters and some chemical constituents of tomato plants were evaluated. Results demonstrate that increasing Cu levels resulted in gradual significant reductions in growth, yield parameters, carbohydrates, proteins and auxin contents. On the other hand, Cu stress caused a significant increase in proline, phenols, anthocyanins and ABA contents. Treatment with 200 ppm ascorbic acid (AsA) as a foliar spray mitigated Cu stress by inducing antioxidant enzymes activities responsible for anti-oxidation, e.g., catalase, peroxidase and polyphenol oxidase in tomato leaves under different concentration of Cu by detoxification as well as improving all the above recorded parameters. Furthermore, treating the plants with Cu concentrations alone or in combination with AsA leads to variation in the banding pattern of proteins. The accumulated Cu in fruits increased with increasing concentrations of Cu and gradually decreased by using AsA. These results indicate that the adverse effects of Cu toxicity on tomato plant and its accumulation in fruits were partially alleviated by treating tomato plants with ascorbic acid.

Key words: Copper, Tomato, Phenols, Proline, Ascorbic acid, Abscisic acid