Accumulation of trace elements within Vitis vinifera L. varieties cultivated in Biscay (Basque Country) for txakoli production: a two-year case study

Abstract

Environmental contextTxakoli wine is unique to the Basque Country, and is characterised by its high acidity and minerality. Trace element profiles were obtained over a two-year period for the roots, leaves and fruits of three grape varieties intended for txakoli production. These data on the growth- and variety-specific trace-element profiles could guide the choice of grape for the production of txakoli with particular elemental characteristics. AbstractThe accumulation of 20 elements in two autochthonous and one authorised txakoli grapevines (Vitis vinifera L.) commonly used in regional and European viticulture was investigated here over a two-year period, in order to understand how these elements are taken up, transported and stored, and to compare the results among the three grapevine varieties. Samples of the three grapevines were collected at four phenological growth stages (leaf development, flowering, fruit formation and ripening of berries). The concentrations of 20 essential, non-essential and toxic elements were measured by using ICP-MS. Most of the toxic elements were immobilised in the roots (P < 0.001, Al, As, Pb, Ti, V, Tl, Cr and Cd), which thus acted as a detoxification barrier against aboveground contamination. The main pool of essential elements was in the leaves (P < 0.001, Mg, Ca, Mn and Cu), which accumulate and transport micronutrients to other organs for the plants growth and development. The concentrations of non-essential and toxic elements in grape berries were low, especially at the time of harvesting (P < 0.05, richer in Fe, Na, Mg and K), which is important for food quality and safe wine production (Cd and Pb were far below the threshold established by the European Commission 1886/2006). Riesling presented more effective mechanisms to accumulate Mn, Co, K and Fe (P < 0.05) in leaves and berries at the time of harvesting than those of autochthonous varieties, which corroborates the common origin of the latter. Understanding these growth- and variety-specific mechanisms is important for choosing the right grape for the production of a txakoli with specific elemental characteristics.