Correlating physiological parameters with biomarkers for UV-B stress indicators in leaves of grapevine cultivars Pinot noir and Riesling created by Katharina Schoedl, Rainer Schuhmacher, Astrid Forneck

The robustness of seven physiological parameters together with two potential biomarkers for ultraviolet (UV)-B stress assessment was tested in greenhouse assays on the Vitis vinifera L. cultivars Pinot noir and Riesling. Effects of year, UV-B treatment, cultivar and clone were studied in four individual experiments. Grapevine plants were exposed to three dosed UV-B stress treatments (−UV-B: no UV-B radiation; +UV-B: daily dose of 4856·3 J/m2 UV-BBE; ++UV-B: daily dose of 7025·3 J/m2 UV-BBE) to detect changes of chlorophyll fluorescence and gas exchange parameters. Significant correlations between the leaf polyphenols quercetin-3-O-glucoside and kaempferol-3-O-glucoside with the maximum fluorescence (Fm), the variable fluorescence (Fv) and the maximum quantum yield for photosystem (PS) II (Fv/Fm) were found, which confirmed the biomarkers’ relevance, additionally validated by cultivar- and year-independency.