UV-C IRRADIATION EFFECTS ON YOUNG TOMATO PLANTS: PRELIMINARY RESULTS

摘要

Ultraviolet-C radiation (UV-C = 100-280 nm) is strongly affected by ozone levels, so that the amount of this radiationreaching the Earth's surface is extremely low. In the future, UV-C radiation is expected to increase as the result ofstratospheric ozone depletion due to atmospheric pollution, with strong negative effects on economically important crops.To assess the effect of UV-C irradiation on young tomato plants (Lycopersicon esculentum Mill.; cv Cuore di bue), anexperiment was conducted in controlled conditions, using a black chamber equipped with an UV-C lamp. Tomato plantswere divided in four groups on the basis of UV-C irradiation time (10, 30, 60, and 120 min), and non-irradiated plants werekept as controls. Plant gas exchange, leaf color and morphologic traits were recorded before and after UV-C treatments. Thephotosynthetic apparatus was influenced by UV-C treatment, as shown by the strong increase in intracellular CO2,particularly evident in the 120 min treatment (338 μL L–1). This was due both to the stomatal and non-stomatal inhibition ofthe assimilation activity due to UV-C exposure. In 10 and 30-min treated plants, leaf color, measured immediately after theirradiation, did not statistically change, whereas the 60 and 120-min treatments were characterized by a deep senescencewith a general stem and leaf yellowing. The results demonstrate that high UV-C doses determined irreversible damages,both at physiological and morphological levels, that lead plants to death, whereas lower irradiations (up to 60 min) allowedplants to partially recovery their normal physiological status.