Trace element contents in leaves. Soil/leaf ratios
For primary production through photosynthesis, in addition to water and carbon dioxide, plants require some inorganic mineral nutrients that are taken up through the root system. In this process elements are transferred from soil to plant and the leaf mineral composition should reflect the complex interaction between Vitis vinifera and the local soil composition, since it is one of main factors that limits plant productivity and quality. The Biological Absorption Coefficient (BAC) is the bioaccumulation of a given element and this is the ratio between the leaf/soil concentrations (Kabatha-Pendias 2003). The BAC values are listed in Table 4.
The modified Kabata-Pendias BAC classification (2001) was used here to classify the major elements accumulated in the vine leaf. The elements Ca, K, Mg and S had high BAC values (greater than 1), whereas Sr and Zn had medium BAC values (between 0.4 and 0.7) and Ba, Pb, Cu had low values (between 0.4 and 0.10). Finally, V and Cr had very low values (<0.1). The BAC value obtained for Sr in this study is similar to those reported in the scientific literature (Kabata-Pendias and Sadurski 2004). If we compare the results obtained in other studies carried out in Castilla-La Mancha (AmorĂ³s et al. 2012b; Bravo et al. 2017) it can be observed that the values for Sr and Zn are higher (0.56 vs. 0.28 and 0.7 vs. 0.37, respectively); the values for Ba, V, Cr and Cu are lower (0.14 vs. 0.26; 0.06 vs. 0.16; 0.07 vs. 0.17 and 0.19 vs 1.86, respectively); while the value of Pb is similar (0.12 vs. 0.15).