Resveratrol production potential was determined in the leaves and berries of Vitis ficifolia Bunge var. lobata (Ebizuru) and V. ficifolia Bunge var. ganebu (Ryuukyuuganebu), wild grapes native to Japan. Ultraviolet-C (UV-C) irradiation was used to stimulate resveratrol production. Resveratrol levels in the nonirradiated leaf discs were 3.6 times higher in Ryuukyuuganebu than in Ebizuru, and levels in the Ryuukyuuganebu leaf discs were 4.4 times higher than Ebizru after UV-C irradiation. Resveratrol levels in the nonirradiated berries differed little between the varieties. The resveratrol level in immature berries of both varieties increased significantly 24 hr after 15 min of UV-C irradiation. However, the resveratrol production stimulated by UV-C had a different pattern. Resveratrol production in Ebizuru declined during berry development and maturation, whereas that of Ryuukyuuganebu declined until veraison before it increased to almost the same level as that found during the most immature stage at harvest. Increased resveratrol in the mature berries of Ryuukyuuganebu was also detected 48 hr after UV-C irradiation. UV-C irradiation had no effect on the piceid level of either variety. Ryuukyuuganebu is a wild grape with a distinctive resveratrol production pattern, especially in the berry.
- ©2013 by the American Society for Enology and Viticulture