Gibberlic Acid and Salicylic Acid Effects on Seed Germination and Seedlings Growth of Wheat (Triticum aestivum L.) Under Salt Stress Condition

Seedlings establishment at early growth stages of crop plants is severely affected by soil salinity. Therefore, high germination rate and vigorous early growth under salty soils is preferred. In this study germination and seedling growth of a wheat (Triticum aestivum L.) cultivar was assessed using three replicates of 50 seeds in a factorial laid out in two separate experiments as Completely Randomized Design (CRD) testing combinations of three levels of salinity (0, 50, 100 and 200 mMol NaCl) and four levels of salicylic acid (0, 1.5, 3 and 4.5 m gr Lit) in the first experiment and the same salinity levels with three levels of gibberellic acid (0, 0.5 and 1 m Mol) in the second experiment. SA increased germination percentage and germination rate to 3 m gr Lit, but applying more decrease it. However, GA decreased germination percentage and germination rate to about 38 and 41% in 1 m Mol than control, respectively. Germination percentage and germination rate was significantly increased by SA and GA under salinity conditions compared to non treatment of SA and GA. Priming with 1.5 m gr Lit SA showed maximum radicle and hypocotyl length and higher amount decreased both traits. Priming with SA could not improve radicle length and radicle dry weight in all salinity levels. However, treated seeds with SA produced the higher hypocotyl length in all salinity levels than untreated seeds. GA decreased radicle length, while increased hypocotyl length relatively. Application of GA enhanced radicle and hypocotyl length in all salinity levels compared to untreated seeds with treatment. Dry weight of hypocotyl was decreased due to salinity stress but seedlings raised from seeds primed with SA improved dry weight of seedlings as compared to non treatment of SA under non salinity and salinity conditions. Application of GA decreased both radicle and hypocotyls dry weight. GA decreased seedling fresh and dry weight to about 20 and 35% in 1 m Mol than control.