Effect of Salt Stress On Respiration of Various Wheat Lines/Cultivars At Early Growth Stages.

Germination and seedling emergence are critical stages in plant growth cycle due to their effect on crop stand and eventual crop yield. In the present investigation, the effects of increasing applications of NaCl on germination, seedlings establishment at early growth stages, and respiration were studied in 20 wheat lines/cultivars. Seeds were germinated and grown in black covers using distilled water as control. NaCl was applied at concentrations of 8 and 16 dS/m for 48 hours. Experimental design was factorial using completely randomized design with 3 replications. Seedling respiration was expressed as the difference between initial seed weight and seedling dry weight after 48 hours. Significant differences were found among lines/cultivars in terms of plumule and radicles length under salt stress conditions. Salt stress inhibited plumule growth and length more than radicles. Chamran, Yavarous, 83-3, Taro3, Cross Boullani, Cross Aadl, and Dabira cultivars showed higher tolerance to NaCl treatment during the germination and showed the highest germination percentages. Maximum and minimum respiration rates were obtained in Falat and D81-17, respectively. Differences among lines/cultivars in terms of respiration rate indicated that genetic variations exist among wheat lines/cultivars. It was also found that seedling respiration decreased as salinity level increased. These results suggest that at early growth stages, lines/cultivars with higher respiration rate have accelerated seedling growth. It was concluded that the seedling respiration rate might be used as a useful criterion in selection of wheat tolerant lines/cultivars to salt stress.