Effect of pre- treatment with plant hormones on germination characteristics of flax (Linum usitatissimum L.) in drought stress condition

In order to evaluate the effect of plant hormones on germination indices of flax (Linum usitatissimum) in drought stress condition, a factorial experiment in a completely randomized design (CRD) with three replicates was conducted in laboratory of Seed Science and Technology, College of Agriculture, Shahed University in 2016. The factors were pre-treatment with gibberellin (500 mg.l) and acid abscisic (5 mM) and drought stress in six levels (-3,-6, -9, - 12, -15 bar). Results of analysis of variance showed that the effect of pre-treatment with plant hormones on root length, shoot length, seedling length and average time of germination was significant at 1 percent probability level. Also, the effect of drought stress on root length, seedling length and average time of germination was significant at 1 percent probability level, and on germination percentage and vigor of weight seedling at level 5 percent probability. The interaction effect of plant hormones and drought stress on all traits was significant at 1 percent probability level. Also, the highest weight index of seedling vigor related to the control and no drought stress (287514) and the lowest one was related to the control and -15 bar drought stress (155). The lowest MGT (2.82 day) was obtained in control treatment and no drought stress. In general, the results showed that pre-treatment with GA were not significant to high germination indices of seed flax, but ABA lead to reduce growth of flax. Therefore, in order to achieve optimum germination percentage under drought stress conditions it is better to use higher concentrations of GA.