Effects of elevated ozone on physiological, biochemical and morphological characteristics of eggplant

Air pollutants are emitted from various anthropogenic sources into the atmosphere. Especially, ozone (O₃) has become a critical problem since the average O₃ concentration is increasing every year by about 0.5–2% across the world. O₃ in the air affects plant growth because it mainly passes through the stomata of leaves into plants. This experiment was designed to identify the physiological, morphological, and biochemical responses of plants to O₃. For the purposes of this study, eggplant (Solanum melongena L.), which is one of the most well-known crops produced in the world, was used. Eggplants were continuously subjected to 110 nmol mol⁻¹ for 25 days using the phytotron. Following O₃ treatment, the growth and biomass of the eggplant were reduced, and the photosynthetic rates were lower than those of the controls. In contrast, water use efficiency increased progressively on the leaves of the eggplant. Initial visible injures were observed at 15 days after O₃ treatment. Stomatal density was reduced in response to the O₃ treatment. With regard to biochemical responses, malondialdehyde content and relative ion leakage were higher than those of the control. Superoxide and hydrogen peroxide accumulation was observed on the leaf surface after 25 days of O₃ treatment. These observations indicate that treatment with 110 nmol mol⁻¹ O₃ had negative effects on the physiological, morphological, and biochemical activities of eggplant. Further studies investigating the damage caused by exposure to different concentrations of O₃ and for different periods of time are required.