[en] The aim of this research was to determine the effects on growth variables and leaf mineral concentration of tomato plants watered with nutrient solutions containing amino acids. Two separate experiments were then carried out to achieve this goal. In the first experiment, plants were watered with seven different nutrient solutions consisting of half-strength Hoagland solution supplemented with single (Alanine, Serine, Phenylalanine, Tyrosine) or combined (Ala + Ser; Phe + Tyr) amino acids, each at 0.2 mM of concentration. The control nutrient solution did not have any amino acids added. Relative to the control, growth variables were not affected by the presence of amino acids. In general, the mixture of Ala + Ser increased the leaf Ca2+ concentration, and the aliphatic amino acid treatments favoured an increase in leaf K+, Fe, Cu, and Mn concentrations. In addition, amino acids with hydroxyl groups in their structure, Ser and Tyr, increased Mg2+ concentration. In the second experiment, the nutrient solutions were supplemented with 0.05 mM of the same amino acids (T1). Control plants were irrigated with amino acid-free nutrient solution (T0). The concentration of Ca2+, K+, Mg2+, Fe, Cu, and Mn in the leaf also increased due the amino acids treatment. Chlorophyll contents in the leaves and amino acids compositions in the xylem sap and leaf water relation were also determined. In conclusion, the data reported in the two experiments point out that the application of amino acids to the nutrient solution has a beneficial effect on the leaf mineral status and on the chlorophyll concentration of the leaves.

[es] En este trabajo se estudiaron los efectos sobre el crecimiento y la concentraci&oacute;n mineral de hojas de plantas de tomate cultivadas con soluciones nutritivas con distinta composici&oacute;n en amino&aacute;cidos. Para ello se plantearon dos experimentos. En el primero las plantas se regaron con siete soluciones nutritivas 1/2 Hoagland que difer&iacute;an en la composici&oacute;n de los amino&aacute;cidos, todos ellos a una concentraci&oacute;n total de 0,2 mM (Ala, Ser, Fen y Tir aplicados de forma individual, dos con la combinaci&oacute;n Ala+Ser y Fen+Tir, un control sin amino&aacute;cidos). Las variables de crecimiento no mostraron diferencias entre los tratamientos; sin embargo, se observaron cambios en las concentraciones de nutrientes aunque los efectos dependieron de los amino&aacute;cidos utilizados. La mezcla de Ala + Ser aument&oacute; la concentraci&oacute;n de Ca2+, mientras que los tratamientos de amino&aacute;cidos alif&aacute;ticos favorecieron un aumento de K+, Fe, Cu y Mn, y aquellos con grupos hidroxilo (Ser y Tyr) aumentaron el Mg2+. En el segundo experimento las plantas se regaron con disoluci&oacute;n 1/2 Hoagland (T0) o con disoluci&oacute;n 1/2 Hoagland m&aacute;s una mezcla de los 4 amino&aacute;cidos (0,05 mM) ensayados (T1). En este experimento tambi&eacute;n aument&oacute; la concentraci&oacute;n de Ca2+, K+, Mg2+, Fe, Cu, y Mn en las hojas. Asimismo se determinaron la concentraci&oacute;n de clorofilas en las hojas, relaciones h&iacute;dricas y la composici&oacute;n de amino&aacute;cidos del xilema. En conclusi&oacute;n, los datos obtenidos en los dos experimentos indican que la aplicaci&oacute;n de amino&aacute;cidos a la soluci&oacute;n nutritiva podr&iacute;a mejorar el estado nutricional de las plantas y la concentraci&oacute;n de clorofilas en las hojas.