Effect of osmotic potentials caused by polyethylene glycol and sodium chloride on growth and biochemical characteristics of Salicornia sinus-persica Akhani spec. nov.Akhani seeds

Germination and seedling establishment are sensitive and important stages in the life cycle of plants that are affected by abiotic stresses, especially drought and salinity stresses. This study was conducted to investigate the effects of osmotic potential (due to sodium chloride and polyethylene glycol) on germination and biochemical indices of Salicornia sinus-persica Akhani spec. nov.Akhani seeds in 2020 in the Agriculture Laboratory of Yasouj University of Agriculture in a completely randomized design with three replications of 50 seeds. A separate experiment was performed in which the first experiment consisted of 13 levels of osmotic potential (zero, -0.3, -0.6, -0.9, -1.2, -1.5, -1.8, -1.2, -2.4, -2.7, -3, -3.3 and -3.6 MPa) which were made of polyethylene glycol and the second experiment included 13 salinity stress levels with osmosis similar to the first experiment (zero, 62, 122, 187, 249, 311, 368, 435, 498, 560, 622, 684 and 746  mM) were used to make sodium chloride. The results showed that the trend of salicornia seed germination indices in salinity and drought stresses had a constant trend up to the level of about -1.2 (249 mM) and -0.6 MPa, respectively, and then with a decrease in the osmotic potential of germination percentage, root and stem length, root and shoot dry weight and seedling vigor length and weight index showed a decreasing trend so that the slope of this decreasing trend was higher in drought stress compared with salinity stress. From osmotic potential of 1.2 MPa onwards, in salinity thirst, seed biochemical parameters such as proline content, malondialdehyde content and sodium element increased whereas potassium element decreased and in drought stress, proline and malondialdehyde content showed an increasing trend. In general, Salicornia seeds were more sensitive to drought stress than salinity stress.