Photos of the group of the main Cost action meetings

Annex

Effect of anthocyanin absence on white berry grape (Vitis vinifera L.)

In grapevines, white berried cultivars are characterized by the absence of anthocyanins, which are the main pigments in V. vinifera fruits. These varieties produce berries with a yellowish color. The pigments responsible of this hue are still not well defined. In this paper, spectrophotometric analyzes were carried out using non-invasive methods (reflectance spectra) and destructive quantifications (chlorophyll and carotenoid quantifications) to describe the variation in color of three white grape varieties during ripening. A decrease in chlorophylls and carotenoids was found. Changes in the proportion of blue (450-500 nm) and red (630\u2011700 nm) absorption bands were underlined. The contribution of melanin-like pigments (oxidation products) is also discussed. In general, our results indicate that the yellow color of white cultivars is not related to the activation of specific biosynthetic pathways. It is most likely due to a series of catabolic processes (and to their relative intensity), which become visible and that are possibly stimulated by the anthocyanin absence

Chlorophyll and carotenoid quantifications in white grape (Vitis vinifera L.) skins by reflectance spectroscopy

In white grapes, chlorophylls and carotenoids play important roles in berry color and environmental interactions (e.g. radiative stresses). In this paper, easy, fast and low cost non-invasive reflectance methods have been tested and developed. Previously published indexes showed good performances for chlorophyll quantifications. However, in this work, new formulas able to discriminate chlorophylls a and b were also proposed. The wavelengths of major interest for the absorption detection were identified. Formulas based on the Gaussians half heights were proposed. In general, chlorophyll quantifications were obtained directly from reflectance spectra, while carotenoid absorption bands did not allow good reflectance correlations. However, the chlorophyll/carotenoid ratio (due to the pigments physiological linked roles) could be used to estimate carotenoid content. Their proportion changes during berry development, thus the index coefficients should be adapted in relation to the BBCH phenological phase. The obtained indexes demonstrated good correlations with the destructive quantifications. These methods could support further researches concerning cultivar classification and physiological studies

Optical Properties of Berry Epicuticular Waxes in Four Georgian Grape Cultivars (Vitis vinifera L.)

The epidermis of plant shoot organs is generally covered by epicuticular waxes. The role of this layer isrelated mainly to the protection of the inner tissues from biotic and abiotic stresses. In this study, attentionis focused on the optical properties of the berry epicuticular waxes of the grapevine (Vitis vinifera L.) atfruit ripening. The reflectance of the berry surface was measured before and after chloroform treatmentsin four Georgian grape cultivars grown in northern Italy. Epicarp optical properties were underlinedat different wavelengths (341 to 1025 nm) for each cultivar. The results show that the berry waxes haveseveral optical properties; it is possible that their main eco-physiological effect is to provide specificprotection against different types of radiation. Besides the physiological aspects, the results are interestingalso from a technical point of view in the field of interpretation of reflectance measurements carried out bynon-invasive instruments

Effect of anthocyanin absence on white berry grape (Vitis vinifera L.)

In grapevines, white berried cultivars are characterized by the absence of anthocyanins, which are the main pigments in V. vinifera fruits. These varieties produce berries with a yellowish color. The pigments responsible of this hue are still not well defined. In this paper, spectrophotometric analyzes were carried out using non-invasive methods (reflectance spectra) and destructive quantifications (chlorophyll and carotenoid quantifications) to describe the variation in color of three white grape varieties during ripening. A decrease in chlorophylls and carotenoids was found. Changes in the proportion of blue (450-500 nm) and red (630‑700 nm) absorption bands were underlined. The contribution of melanin-like pigments (oxidation products) is also discussed. In general, our results indicate that the yellow color of white cultivars is not related to the activation of specific biosynthetic pathways. It is most likely due to a series of catabolic processes (and to their relative intensity), which become visible and that are possibly stimulated by the anthocyanin absence

Proposal for the wild grapevine (Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi) conservation in the European countries

Annex

Potassium partitioning between leaves and clusters: Role of rootstock

Different scion/rootstock combinations in grapevine (Vitis vinifera/Vitis spp.) were tested for nutritional properties and juice composition. Chardonnay and Cabernet Sauvignon each grafted on 22 rootstock varieties (10 new crosses and 12 already used in viticulture) were grown in outdoor pots containing very poor nutritional substrate. Crop load had a strong effect on juice composition and potassium nutrition. Results indicate that under our experimental conditions rootstock can have an effect on potassium partitioning between leaves and cluster 9 out of 22 rootstocks that we tried were able to improve leaf potassium content without inducing a significant increase in juice potassium conten

Preliminary study of Armenian grapevines phenolic contents

Research Not