Influence of UV-B irradiation on the carotenoid content of Vitis vinifera tissues.

The carotenoid content was examined in leaf and berry tissues of grapevines (cv. Cabernet Sauvignon) grown either under ambient conditions or under a polyester film to reduce UV light by 98%. Total carotenoids in leaves were less in vines grown under the UV screen. Levels of beta-carotene decreased with berry development around veraison. This effect was more pronounced in vines grown under reduced UV light. The lutein content of berries appeared to remain relatively constant with berry development, but levels were decreased under the UV screen. These observations are important for the wine industry because of the biosynthetic link between carotenoids and wine flavour and aroma compounds.