Анотация: Salinity effects were evaluated on seed germination and seedling growth of six bread wheat cultivars (Triticum aestivum L) including Hirmand, Chamran, Hamoon, Bolani, Sorkhtokhm and Kavir. The seeds were grown in pots and subjected to six levels of electr
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џLog_Str_IDical conductivity (Ec) 0, 2.5, 5, 7.5, 10 and 12.5 ds/m. The measured factors consisted of water uptake, germination percentage, shoot and root dry weight, shoot and root lengths and Na+ and K+ uptake amounts by seeds. The experimental design was randomized complete block design used as factorial arrangement of treatments (cultivars and NaCl levels) with three replicates. Water uptake by seeds showed to have a direct relationship with increases in NaCl levels. The highest water uptake level was recorded in Hamoon and Kavir cultivars. By increasing NaCl concentration, seed germination delayed and decreased in all cultivars. The lowest germination percentage took place in Chamran and Bolani cultivars and the highest germination in Kavir and Hamoon cultivars. The largest shoot length was observed in the controls of Sorkhtokhm and Bolani cultivars. The largest root length obtained in Hamoon, Hirmand, Chamran cultivars and the lowest in Kavir cultivar. Increasing NaCl concentrations adversely affected shoot dry weight in each cultivar; shoot dry weight fluctuated by varying NaCl concentrations. The lowest value found in Chamran cultivar. Differences in root dry weight were not significant in different cultivars; the highest root dry weight was found in Chamran and Hamoon cultivars. The root to shoot dry weight ratio changed in different NaCl levels. High NaCl levels caused a remarkable increase in the root to shoot dry weight ratio. The highest ratio was obtained in Hamoon cultivar and the lowest ratio in Sorkhtokhm and Kavir cultivars. Seedling dry matter decreased by increasing salinity. Salinity increased the accumulation of Na+ and decreased the K+ content in roots and shoots. The Na+ content of germinated seeds gradually increased, while the K+ level diminished. Hamoon, Sorkhtokhm and Bolani cultivars appeared to be more tolerant to salt stress than the others. It was concluded that the delay in germination was mainly due to higher Na+ accumulation in the seeds rather than osmotic stress in wheat cultivars