RT Journal Article SR Electronic T1 Effects of Leaf Position on Blade and Petiole Mineral Nutrient Concentration of Tempranillo Grapevine (Vitis vinifera L.) JF American Journal of Enology and Viticulture JO Am. J. Enol. Vitic. FD American Society for Enology and Viticulture SP 544 OP 550 DO 10.5344/ajev.2010.09091 VO 61 IS 4 A1 Izaskun Romero A1 Enrique García-Escudero A1 Ignacio Martín YR 2010 UL http://www.ajevonline.org/content/61/4/544.abstract AB Concentrations of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and B were monitored throughout the season in leaf blades and petioles sampled at three different positions on the shoot of Tempranillo (Vitis vinifera L.) grapevines. Petioles had higher concentrations of K, Mg, and Zn, whereas N, P, Ca, and micronutrients other than Zn were more abundant in leaf blades. Seasonal trends were identified for macronutrients, with decreasing patterns for N, P, and K, while Ca and Mg increased through the season. Minor differences in nutrient concentration were observed in leaf blades and petioles opposite basal and distal clusters. These results provide guidelines for the sampling of representative tissues for nutritional diagnosis of Tempranillo after veraison. However, differences among leaves opposite basal clusters and those placed four nodes beyond the second cluster suggest that these younger leaves are not useful for nutritional diagnosis using reference concentrations obtained for basal leaves.