Assessment of tropospheric ozone phytotoxic effects on the grapevine (Vitis vinifera L.): A review

The grapevine (Vitis vinifera L.) is a crop with great cultural, economic and ecological relevance for Mediterranean environments besides being the fruit crop with largest acreage and economic value at the global scale. Its exposure to high levels of tropospheric ozone (O-3) can result in phytotoxic effects and thus it is important to comprehensively re-evaluate these effects as well as related processes. A review of the validity and limitations of the standards used for the protection of vegetation in relation to ambient O-3, the state-of-the-art knowledge on O-3 phytotoxic effects on the grapevine and the available means to assess its impact are presented and discussed. It is concluded that wide regions in the world, mainly between latitudes 30 degrees and 50 degrees N, where the grapevine has been traditionally cultivated, are exposed to O-3 concentrations that can affect both the yield and quality of the grape. Recently reported studies for global cultivars such as Cabernet Sauvignon or Merlot, along publicly available maps on O-3 standards to protect vegetation at the European and global scale, indicate potential yield reductions in the range of 20-31% and the quality of the grape can also be affected by reductions of total polyphenols in the range of 15-23% for these areas. Although a tendency to reduce ambient O-3 levels has been registered since 2000 in the western European Mediterranean basin, the flux of O-3 into the grapevine leaves could still exceed critical levels with phenological advancement driven by the increase of temperatures or interaction between O-3 and other climatic variables such as drought or high summer light intensities. Higher O-3 exposures are reported in western United States of America and eastern China, with this last region maintaining an increasing tendency in summer ambient O-3 levels. It is still necessary to adopt common experimental and monitoring protocols to establish grapevine-specific O-3 relationships and critical levels, as there is not yet a coherent and shared database for detailed risk assessment for this crop.

Automated summary

Grapes, as a significant crop with great economic and cultural value globally, may suffer from reduced yield and quality due to exposure to high levels of tropospheric ozone, especially in Mediterranean environments. There is a lack of comprehensive risk assessment database and shared experimental protocols to establish grapevine-specific O-3 relationships and critical levels.