Effect of vine nitrogen status on grape and wine quality: Terroir study in the Vaud vineyard (Switzerland)

Atmospheric carbon dioxide (CO2) concentration has continuously increased since pre-industrial times from 280 ppm in 1750, and is predicted to exceed 700 ppm by the end of 21st century. For most of C3 plant species elevated CO2 (eCO2) improve photosynthetic apparatus results in an increased plant biomass production. To investigate the effects of eCO2 on morphological leaf characteristics the two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, grown in the Geisenheim VineyardFACE (Free Air Carbon dioxide Enrichment) system were used. The FACE site is located at Geisenheim University (49° 59′ N, 7° 57′ E, 94 m above sea level), Germany and was implemented in 2014 comparing future atmospheric CO2-concentrations (eCO2, predicted for the mid-21st century) with current ambient CO2-conditions (aCO2). Experiments were conducted under rain-fed conditions for two consecutive years (2015 and 2016). Six leaves per repetition of the CO2 treatment were sampled in the field and immediately fixed in a FAA solution (ethanol, H2O, formaldehyde and glacial acetic acid). After 24 h leaf samples were transferred and stored in an ethanol solution. Subsequently, leaf tissue was dehydrated using ethanol series and embedded in paraffin. By using a rotary microtomesections of 5 µm were prepared and fixed on microscopic slides. Subsequent the samples were stained using consecutive staining and washing solutions. Afterwards pictures of the leaf cross-sections were taken using a light microscope and consecutive measurements were conducted with an open source image software. Differences found in leaf cross-sections of the two CO2 treatments were detected for the palisade parenchyma. Leaf thickness, upper and lower epidermis and spongy parenchyma remained less affected under eCO2 conditions. The observed results within grapevine leaf tissues can provide first insights to seasonal adaptation strategies of grapevines under future elevated CO2 concentrations.

The traditional pruning system in Piedmont (North-West Italy) is the Guyot system; it requires trained personnel, difficult to find, and it does not permit the mechanization of winter pruning, thus it is very expensive. An alternative technique that could allow the reduction of the vineyard management costs could be the spur-pruning which is simpler to perform and fully mechanized.

to maintain viticulture under global warming conditions, it is important to carefully select the appropriate genotypes for each vine-growing region and develop cultivars that are drought resistant. this ability is highly dependent on hydraulic traits, which are dynamic and vary according to the vine’s developmental stage and climatic conditions. this framework steadily enhances our understanding of the differences in drought resistance among vitis genotypes. however, there is still a need to comprehensively grasp the intra-specific variability, particularly between oenological and table grape cultivars.

Heatwaves, defined as three or more consecutive days above average historical maximum temperatures, are having a significant impact on agricultural crop yields and quality, especially in arid or semi-arid regions with reduced water availability during the growing season.

Aims: Viticulture practices linked with soil management, as cover crops and deficit irrigation, can help to regulate the vineyard behavior reducing in most cases plant vigor and modifying plant water and nutrient status, and as a consequence, grape yield and quality. Also, these practices can modify the soil biological activity mostly related to microbiome diversity and functionality.