Due to its geological origin and the intense agro-industrial activity, regions whose vocation is the agri-food production present a high level of contamination by heavy metals as the arsenic that induces toxicity in the crops of economic importance as in the case of barley (Hordeum vulgare L.). The evaluation of the response of different cultivars and genotypes in the first phenological stages is indispensable to generate technical information regard the tolerance to arsenic and the same time theoretical knowledge about how this metal is absorbed. The aim of this study was to evaluate the physiological response of barley seedlings to arsenic V (AsV) toxicity and deduce how this metal could be absorbed by the plants. Seedlings of the cultivars Alina and Esperanza were evaluated under the concentrations of 100, 200, 500 and 700 mg L^-1. Besides, models for the proteins PHT1 and HvHMA1 were performed by homology with affinity assays for AsV. The seedlings of Alina presented higher degree of tolerance to the toxicity whereby potentially the productive plots of this cultivar Alina could tolerate higher concentrations of this heavy metal. Also, the AsV could be transported by its competence with the endogenous ions as Mg²⁺ and PO4^3-.