Enhancement the physiological and biochemical efficiency of cumin seeds (Cuminum cyminum L.) with different longevity under salt stress

Priming is one of techniques to improve the physiological and biochemical efficiency that can enhance seed germination under stressful conditions such as salinity. Therefore, for seeds produced in the years of 2012, 2013 and 2014, three separate experiments were conducted based on completely randomized design with two factors of seed priming and salinity stress. first factor was priming treatments in 4 levels involving priming in Ascorbic acid 200 mg. l-1 at 20°C for 24h; in NaH2Po4 1% at 20°C for 24h; in NaH2Po4 1% at 4°C for 24h; for 2012 and 2013 seeds and priming in GA3 100 mg. l-1 at20°C for 12h, in GA3 100 mg. l-1 at 20°C for 24h, in GA3 200 mg. l-1 at 20°C for 24h for of 2014 seeds, non-primed seeds of each three years used as priming control. The second factor was salinity stress imposed by sodium chloride (NaCl) at four osmotic potentials of 0, -3, -6 and -9 bar. The results showed that with increasing stress levels, seed germination characteristics, soluble protein content and antioxidant enzyme activities of CAT, POX and APX decreased in all seeds produced in different years, but priming treatments in all levels effectively improved them. In 2012 and 2013 seeds, priming with NaH2Po4 1%-20°C-24h and in 2014 seeds, GA3100 mg. l-1-20°C-24h had greater germination indices and antioxidant activities. The overall results of this study showing that priming increase germination of cumin under salinity by improving seed quality and anioxidant enzymes activity.