تعیین آستانه تحمل به شوری باکتری‌های حل‌کننده فسفات جداسازی شده از مزارع برنج استان مازندران

Phosphorus (P) is important for plant growth but in the soil it reacts readily to form insoluble compounds, which are not readily available for a plant’s utilization. However, some soil bacteria may have the ability to solubilize insoluble P and increase P uptake by plants. Therefore, the objective of this study was to evaluate the phosphate solubilization activity of bacteria from the rhizosphere of rice paddy soil in Mazandaran province. Also, part of this study focused on modeling the effect of NaCl% on the growth of these isolates. Two of the most effective isolates from a total of 53 colonies were isolated for this experiment. Based on a sigmoidal trend and a three-parameter logistic model, the salt concentration required for 50% inhibition was 6.30 and 8.23% NaCl for M100 and M183 isolates, respectively. However, there were significant differences between isolates in terms of NaCl tolerance based on their confidence limits and regression analysis (P < 0.001). In conclusion, results of this study reveal that two mentioned isolates could not only solubilize the phosphorus but also tolerate the salt stress. Therefore, these isolates may be considered to be good candidates for biofertilizers production.