عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Understanding of physiological responses of salt tolerance might be lead to identify main salt tolerance mechanisms and essential approaches for improving grain yield stability, and also to select salt tolerant wheat cultivars. Thus, the effects of salinity were investigated on grain yield and some of the characteristics related to salt tolerance. Six wheat cultivars (Roshan, Kavir, Karchia, Gaspard, Shiraz and Qods) differing in salt tolerance at three salinity levels (0, 100 and 200 mM NaCl) were used in a pot experiment, using a factorial experiment based on a randomized complete block design with three replications. Salt stress caused to decrease grain yield, biomass production, chlorophyll content, and catalase activity, while it caused to increase the activity of peroxidase, ascorbate peroxidase and glutathione reductase and malondialdehyde (MDA) content. Cultivars showed different responses to salt stress. Cultivars Roshan, Kavir and Karchia showed lower yield losses. With increasing salinity treatment levels, MDA content and antioxidant activity increased except for catalase. Cultivars Roshan and Kavir were showed the highest antioxidant enzyme activity, but the lowest MDA content. Cultivars Qods and Shiraz were showed lowest antioxidant enzyme activity, but the highest MDA content in flag leaf blade. In salt tolerant cultivars, a higher antioxidant enzyme activity was accompanied with lower MDA content, resulting higher capacity to eliminate active oxygen species and yield stability. Correlations coefficient analysis exhibited increasing of antioxidant enzyme activity in salt stress condition with no considerable effect on grain yield, while chlorophyll and MDA content illustrated negative correlation with grain yield and so a main role in yield.