The application of increasing NaCl concentra-tions significantly decreased EO yields (Fig. 2). The negative effectof salt stress on oil yield was also reported for other mint species (El-keltawi and Croteau, 1987; Tabatabaie and Nazari, 2007; Azizet al., 2008). This decline in oil yield under salt stress has been attributed in part to the inhibition of the supply of cytokinin from roots to shoots and subsequent alteration of the ratio between leaf cytokinin and abscisic acid (El-keltawi and Croteau, 1987). As shown in Table 2, twenty-eight compounds were identified,accounting for 99.2% of the total EO from control plants. The EO was primarily made up of oxygenated monoterpenes and the con-trol contained pulegone as the main component (62.1%), followed by menthone (12.9%) and isomenthone (11.3%). It is of note that salt stress did not reduce the relative abundance of oxygenated monoterpenes in general. However, salt stress did affect the con-tent of pulegone and, most markedly, menthone. The application