VineyardFACE: Investigation of a moderate (+20 %) increase of ambient CO₂ concentration on berry ripening dynamics and fruit composition of Cabernet-Sauvignon

Abstract

Climate change and rising atmospheric carbon dioxide concentration are a concern for agriculture, including viticulture. Studies on elevated carbon dioxide have already been conducted on grapevines, mainly taking place in greenhouses using potted plants or using field-grown vines under instant and higher CO2 enrichment, i.e., > 650 ppm. The VineyardFACE, located at Hochschule Geisenheim University, is an open field Free Air CO2 Enrichment (FACE) experimental set-up designed to study the effects of elevated carbon dioxide using adapted, field-grown vines (Vitis vinifera L. cv. Cabernet-Sauvignon). As the carbon dioxide fumigation started in 2014, the long-term effects of elevated carbon dioxide treatment can be investigated on berry ripening parameters and fruit metabolic composition.The present study investigates the effect on fruit composition under a moderate increase (+20 %; eCO2) of carbon dioxide concentration, as predicted for 2050 on Cabernet-Sauvignon. Berry growth, ripening dynamics and composition were determined and primary (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins) were analysed. Compared to previous results of the early adaptive phase of the vines (Wohlfahrt et al., 2020), our results show little effects of eCO2 treatment on primary metabolites composition in berries. However, total anthocyanins concentration in berry skin was lower for eCO2 treatment in the hot and dry season of 2020, although the ratio between anthocyanins derivatives did not differ.