Evaluation of Response of Growth and Physiological Factors of Barberry (Berberis vulgaris L.) Inoculated With Plant Growth-Promoting Rhizobacteria to Salinity of Irrigation Water

Introduction Barberry is one of the important agricultural products of Iran and has an important role in the economy of farmers, especially in South Khorasan province. Salinity as abiotic stress can cause an ionic or osmotic imbalance in plant cells. Salt stress also restricts plant growth and development by affecting water reducing availability and affecting plant production. Despite the relatively high tolerance of barberry to environmental stresses, increasing soil salinity and irrigation water in barberry growing areas, the growth, and yield of this agricultural product have decreased. The use of plant growth-promoting rhizobacteria (PGPR) is a new method that has been shown to increase the tolerance of various plants to salinity stress. Materials and Methods Due to the lack of information about the effect of salinity on the growth and establishment of barberry off-shoot and the role of beneficial soil bacteria in increasing the tolerance of this plant to salinity stress, this study aimed to investigate the role of bacteria on growth, physiological and biochemical properties and uptake of nutrients by barberry off-shoot at different levels of irrigation water salinity. For this purpose, a factorial study was conducted in a randomized complete block design with 3 replications. Experimental factors included plant growth-stimulating bacteria at three levels (control (Without inoculation) and inoculation with Pseudomonas sp. P1 and Pseudomonas sp. P2) and salinity of irrigation water at three levels (control, 6 and 12 dS/m from sodium chloride source). The bacteria used in this study were able to produce indole acetic acid, siderophore, ACC deaminase enzyme, and dissolve insoluble phosphate (tricalcium phosphate) in vitro. For inoculation, inoculum containing each bacterium with a population of 108 cells/ml was prepared in the Nutrient Broth medium and added to the root medium. The plants were irrigated with non-saline water for one month and then with saline water for two months based on experimental treatments. Finally, leaf sampling was performed and various characteristics such as leaf dry weight, chlorophyll, proline, total sugar, RWC and phosphorus, potassium, sodium, and chloride concentrations were measured. Analysis of variance of traits was performed using SAS software and the means were compared using the LSD method with a probability level of P≤0.05. Results and Discussion The results showed that the salinity of irrigation water reduced leaf