At the whole plant level, water scarcity induces complex changes in C and N metabolism resulting from modifications in the availability of nutrients (Foyer et al., 1998; Imsande and Touraine,1994). In addition to the discussed changes in carbon assimilation, water stress may restrain nitrate acquisition by the roots,as well as restrict the ability of plants to assimilate and reduce nitrogen (Yousfi et al., 2012; Kocheva et al., 2007).