Effect of seed halopriming on germination and seedling physiological characteristics of wheat (Triticum aestivum) cultivars Niknijad and Qods under salt stress condition

Halopriming involves pre-sowing soaking of seeds in salt solutions, which enhances germination and seedling emergence uniformity under adverse environmental conditions. An experiment was conducted to evaluate the effects of halopriming on the germination, malondialdehyde concentration and some hormones contents of wheat seeds under salinity stress. The experimental design was three factors factorial arranged in a completely randomized design (CRD), with four replications. The first factor was salinity stress (0 and 100 mmol NaCl solution), the second factor was priming concentration (1, 2 and 3% concentration of KNO3) and third factor was two wheat cultivars including Niknijad (salt tolerance) and Qods (salt sensitive). Remarkable decreases were observed in seed germination, seedling lenght, α-amylase activity and GA3 content of both wheat cultivars, especially in Qods under salinity stress condition. Wheat seed piming with KNO3 increased seed germination, antioxidants enzymes activities, α-amylase activity, GA3 concentration and reduced lipid peroxidation and ABA compared with other priming treatments in both wheat cultivars. Under salinity condition maximum Niknejad seed germination was observed in seeds primed with 2% and 3% KNO3 solutions (87.1% and 87.9 % respectively) and maximum seed germination in Qods seedling obtained in seed treated with 3% KNO3 solutions (75%). All KNO3 seed priming treatments decreased ABA content in Niknejad seeling but Qods seed priming with 2% ans 3% KNO3 solutions decreased ABA content compared non-primed seeds (113 and 101 μg g-1 respectively). Seed priming improved cell membrane stability in both wheat cultivars and the lowest malondialdehyde concentration under salinity stress obtained from seeds primed with 2% ans 3% KNO3 solutions in both wheat cultivars. In conclusion, KNO3 seed priming appears to be an appropriate treatment to improve wheat emergence and overall seedling establishment under salinity conditions.