Individual and Combined Effects of CaCl2 and UV-C on the Biosynthesis of Resveratrols in Grape Leaves and Berry Skins

The individual and combined effects of calcium chloride (CaCl2) and ultraviolet C (UV–C) light on the synthesis of resveratrol in grape leaves and berry skins were investigated. Results showed that all treatments could increase leaf resveratrol contents at least about 5 times, but the combination treatment was the most efficient. Moreover, compared with UV–C treatment, the combination treatment delayed the decline of resveratrol contents. The expression levels of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), coumaroyl-CoA ligase (4CL), and stilbene synthase (STS) and 3-O-β-glycosyltransferases, which are related to the synthesis of resveratrol, increased in response to these treatments, paralleling the change in resveratrol content. All treatments also induced the biosynthesis of resveratrol in berry skins at room temperature. The berries of these treatments held at room temperature for 1 day were further stored under low temperature (−1 ± 0.5 °C, RH 95%) for 27 days, and the results s...