Geochemical-isotopic and fluorimetric analyses for the characterization of two red chicory varieties in sandy coastal soil of the Ferrara province (Italy)

The concept of Terroir, developed with respect to grape and wine, can be generalized to define the inseparable link between an agri-food product and its territory of origin as a determining element for its economic valorisation. While the terroir certainly impacts on physiological and compositional aspects of a crop, an important influence is due to the species diversification in cultivars. Therefore, both environment/soil and cultivar participate in defining the geographical authenticity of crops. Geochemical-isotopic techniques are a powerful tool to authenticate a crop with respect to its geographical origin. The integration of multi-elemental analyses with the determination of isotopes such as carbon (δ13C) and nitrogen (δ15N) can allow a detailed mapping of the geographical origin of agricultural products. The stable isotopes of light elements present in crops offer a unique form of ‘isotopic signature’ that reflects the geochemical conditions of the soil together with the metabolic specificity of the plants (photosynthesis, N assimilation). This is crucial not only to authenticate the plant provenance, but also to support protected designations of origin (PDOs) and geographical indications (PGIs), strengthening the consumer’s confidence in the authenticity and quality of products. In this first report, we have combined geochemical-isotopic and chlorophyll fluorimetric analyses of two red chicory (“radicchio rosso”, cv. Chioggia and cv. Treviso) cultivars typical of the Emilian coastal environment, but not yet recognized as PGI, different from analogous crops in Veneto Region. An effort in this respect is motivated by the special geochemistry of sandy coastal soils, which tend to be dry and exposed to salinisation phenomena. Soil was thoroughly characterized based on its chemical-physical properties, including XRF analysis of major elements. A detailed analysis of elements in soil and plants was performed by ICP-MS-QQQ down to ultra-trace elements, and EA-IRMS analysis was done for the evaluation of C and N isotopic ratios. Plant phenotyping, based on chlorophyl fluorescence indexes, was performed to highlight the physiological specificities of the two cultivars, to put in relation with the stable isotope profile of light atoms. The comparative results of the geochemical composition of the plant organs evidenced a cultivar-specific fractionation of some elements: cv. Chioggia had higher element absorption capacity than cv. Treviso, and both cultivars share an attitude to concentrate P, Cu and Mo. Upon translocation of elements from roots to leaves, especially the rare earth elements showed the specificity of the two cultivars, which can be differentiated based on the concentration of lanthanides as compared to the soil. A better use of mineral nutrients could be supported by higher photosynthetic performance in cv. Treviso than cv. Chioggia. This research, to be further implemented, can constitute a useful database for the reconstruction of the geochemical-isotope profile for the geographical traceability of “radicchio rosso” and the possible further promotion of this crop in Ferrara province. This research was allowed by PhD fellowship granted by EUROPEAN SOCIAL FUND P L U S - The ESF+ 2021-2027 Programme of the Regione Emilia Romagna