Effects of exogenous GA_3 on germination of Orychophragmus violaceus seeds under NaCl stress

O.violaceus seeds were treated respectively with 0,100,200,300 and 500 mg/L GA3 solutions,and then their germination vigor,germination rate,germination index,vitality index and α-amylase activity were determined respectively under various NaCl stresses(0,0.5%,1.0% and 2.0% NaCl concentrations).The results showed that under relatively low concentration NaCl stress,the GA3 treatments had an accelerating effect on the seed germination,making the seeds' germination vigor,germination rate,germination index,vitality index and α-amylase activity significantly improve,and the treatment with 200 mg/L GA3 had the best effect.But the GA3 treatments had not an obvious effect on the seed germination under relatively high concentration NaCl stress.