Abstract: Resveratrol（Res）and piceid（PD）synthesis in leaves，berry skin，and seeds in‘Beifeng’and‘Beiquan’grapes in response to UV-C irradiation were studied. In addition，the dynamic changes of Res and PD content in berry skin and seeds with the extension of storage time at room temperature under dark conditions were investigated. The results showed trans-resveratrol（trans-Res）synthesis in various organs in response to UV-C irradiation was different. The optimal dosage of UV-C irradiation for leaves was 1.8 kJ · m-2，while for berry skin it ranged from 1.8 to 5.4 kJ · m-2，and Res synthesis in leaves was more sensitive than that in fruits in response to UV-C irradiation. Trans-Res content in grape seeds was not significantly changed when grape berries，excised seeds，and dissected seeds were directly irradiated with 3.6 kJ · m-2 UV-C. Trans-Res content in UV-C treated grape berry skin and leaves increased rapidly andthen decreased sharply with the extension of storage time at room temperature in the dark. Trans-PD and cis-PD content in UV-C treated grape berry skin and leaves increased rapidly during the first 12–48 h storage，and then maintained a relatively stable level. There was no difference in trans-Res content between the UV-C treated grape seeds and the control grape seeds.

Key words: grape, resveratrol, piceid, UV-C irradiation