The effect of salt-tolerant Pseudomonas fluorescens bacteria on the characteristics of germination and seedling growth indices of two sesame cultivars under salt stress

In this research, morphological and biochemical traits of 10 isolates of Pseudomonas fluorescens bacteria, salt tolerance and the effect of bacteria on germination and seedling growth indicators of sesame cultivars under salt stress were conducted. All isolates were Gram-negative and had positive motility and fluorescent properties. Among the bacteria, P2, P3 and P9 isolates were more capable of solubilizing inorganic phosphorus. The ability to produce siderophore was higher in some isolates and the isolates P1, P2, P3, P8, and P10 showed the highest in vitro salt-tolerance. A factorial experiment including two sesame cultivars, 4 salinity levels and inoculation with 3 isolates was done in the form of a completely randomized design in three replications. Based on the results, the effect of bacteria, salinity, variety and their interaction on the percentage and rate of germination, germination indices, allometric coefficient and seedling length and weight index were significant. Under salt stress, the germination and growth of seedlings significantly decreased but, the pretreatment of sesame seeds with salt-tolerant isolates increased the characteristics related to germination and growth indices of sesame cultivars. The highest effect on all parameters including germination rate belonged to P9. Therefore, P9 isolate can be used to increase the tolerance of sesame to salinity stress.