Study of Physiological and Biochemical Changes of Iraninan Licorice (Glycyrrhiza Glabra) under Salinity Stress in Filed Condition

Licorice is a medicinal and aromatic plant that is taken into consideration for its valuable compounds such as glycyrrhizin. Salinity is a major environmental stress that affects the crops productivity. In the present study, the effect of salinity stress (using  irrigation treatment with different salt concentrations; 0, 150 and 300 mM) on fresh weight of root and total plant, concentration of pigments, total antioxidant, phenol content, ascorbate peroxide enzyme activity and glycyrrhizin content was investigated. The experiment was performed as a factorial under complete randomized block design with three replications in field assay in Agricultural Biotechnology Research Institute of Iran-Isfahan. This experiments showed that, the irrigation treatmentswith150 and 300 mM resulted in increased necrotic leaves, phenol and glycyrrhizin in licorice, i.e. the plants increased their phenolics and glycyrrhizin content, as a part of the mechanism to resist under stress. Increasing the activity of ascorbate peroxide enzyme in plants exposed to salinity stress, indicating the activation of antioxidative and protective systems, and reduction of oxidative damage in these plants. In salinity tolerant genotypes such as Ilam growth parameters, photosynthetic pigments and glycyrrhizin content were higher than sensitive genotypes. The present study has shown that introduction of tolerant genotypes in filed condition can reduce successfully the adverse effects of salinity stress. Therefore, the results of this research can be useful for cultivation of licorice in saline fields and breeding the tolerant genotypes.