Polyamines are well known in environmental stress tolerance induction of plants. The present study was conducted to evaluate the interactive effects of salinity (0, 100 and 200 mM NaCl) and spermine (Spm) concentration (0, 0.5 and 1 mM solution) on physiological performance of susceptible (Sepahan) and tolerant (Neyshabour) wheat cultivars. Proline accumulation was more affected by salinity than Spm. Chlorophyll a and b content was totally improved by Spm application. Catalase and ascorbate peroxidase (APX) activity was generally increased by increasing salinity and Spm level. Highest APX activity was observed on 200 mM salinity and highest level of Spm concentration in both tolerant and susceptible cultivars. Superoxide dismutase activity was elevated with increasing salinity level and applied Spm concentration in both cultivars. Higher levels of Spm under salinity conditions showed higher activity of glutathione reductase (GR) compared with the treatment without Spm, but it reduced GR activity under normal condition. Spm application decreased sodium content in all salinity levels in both cultivars, but not with a similar trend. Higher concentration of applied Spm also enhanced potassium content. To sum up, Spm application alleviated hazardous effects of salinity stress mainly through antioxidative defense and this was more evident in tolerant cultivar.

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