Effect of D-mannitol and Gibberellic Acid on Physiological Parameters, Early Seedling Growth Characteristics, and Some of the Most Important Chemical Components of Barberry (Berberis vulgaris L.)

Background: One of the important medicinal plants and agricultural products in Asia, particularly in Iran, is barberry, and both salinity and drought can cause osmotic or ionic imbalance in plant cells. In order to study the impacts of D-Mannitol and gibberellic acid on seed germination, physiological parameters, early seedling growth characteristics, and some of the most important chemical ingredients of barberry, one experiment is designed. Methods: The experimental design was Completely Randomized Design (CRD) with three replicates, and drought stress was done by D-mannitol at various stress levels, namely, 0 MPa, 40 MPa, and 80 MPa, and the reaction of studied cultivar was assessed on the basis of experimental characteristics associated to germination and seedling growth, and Gibberellic acid treatments were 0 mgL-1, 300 mgL-1, 600 mgL-1, and 900 mgL-1. Results: The effects of D-mannitol were significant in germination percentage, germination rate, seedling vigor index, chlorophyll a, total chlorophyll, leaf dry weight and total sugar. Experimental treatments such as germination percentage, germination rate, and total chlorophyll were also influenced by the application of gibberellic acid. The interaction between D-mannitol and gibberellic acid had significant effect on peroxidase activity. The highest germination percentage, germination rate, seedling vigor index, catalase activity, peroxide activity, and Chlorophyll a were obtained for 0 MPa application of D-Mannitol, followed by usage of 40 MPa, and 80 Mpa, respectively. The maximum total chlorophyll, relative water content, and leaf dry weight were also related to control treatment (0 MPa D-Mannitol), while the higher values of proline content, carotenoids and total sugar were obtained for 80 MPa application of D-Mannitol. The maximum values of germination rate, germination percentage, seedling vigor index, peroxidase activity, and chlorophyll a were related to control treatment (0 mgL-1 gibberellic acid), and the highest CAT activity was related to the application of 300 mgL-1 gibberellic acid. The highest total chlorophyll content and relative water content were related to 0 mgL-1 gibberellic acid, while the maximum praline content and leaf dry weight were obtained for the application of 600 mgL-1 and 0 mgL-1 gibberellic acid. There was not any significant difference in carotenoids between gibberellic acid treatments, while the application of 900 mgL-1 gibberellic acid obtained the highest value of total sugar of barberry. Conclusion: Conclusively, on the basis of the results, the application of 80 MPa D-Mannitol and 600 mgL-1 could be recommended as they can increase the absorption of nutrients and water.