The increase in grape berry ripening rates associated to climate change is a growing concern for wine makers as it rises the alcohol content of the wine. The present work studied the combined effects of elevated CO 2, temperature and UV-B radiation on leaf physiology and berry ripening rates. Three doses of UV-B: 0, 5.98, 9.66 kJ m -2 d -1, and two CO 2-temperature regimes: ambient CO 2-24/14°C (day/night) (current situation) and 700 ppm CO 2-28/18°C (climate change) were imposed to grapevine fruit-bearing cuttings from fruit set to maturity under greenhouse-controlled conditions. Photosynthetic performance was always higher under climate change conditions. High levels of UV-B radiation down regulated carbon fixation rates. A transient recovery took place at veraison, through the accumulation of flavonols and the increase of antioxidant enzyme activities. Interacting effects between UV-B and CO 2-temperature regimes were observed for the lipid peroxidation, which suggests that UV-B may contribute to palliate the signs of oxidative damage induced under elevated CO 2-temperature. Photosynthetic and ripening rates were correlated. Thereby, the hastening effect of climate change conditions on ripening, associated to higher rates of carbon fixation, was attenuated by UV-B radiation.
