الفهرس 
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Abstract
The pattern of phosphate solubilization by Pseudomonas fluorescence, Bacillus megaterium, Serratia marcescens and Bacillus subtilis as bacterial phosphate solubilizers (PSB) were assessed in NBRIP broth medium for their capacity to solubilize inorganic P in the form of rock phosphate (RP) (hydroxyapatite structure, [Ca5(PO4)3(OH)]. The main objective of this study is to evaluate the synergistic influence of rock phosphate application (0 and 31 P2O5 kg/fedd.), BPS strains (Pseudomonas fluorescence, Bacillus megaterium, Serratia marcescens and Bacillus subtilis) and arbuscular mycorrhizal fungi (AMF) on soil available P content, pH values, wheat (Triticum aestivum L. Gemeza 9) growth, yield components and nutrient uptake. The amount of P solubilized from rock phosphate by the tested PSB ranged from 0.22 to 80.8 mg P l-1 and the pH values of the cultures were reduced from initial value of 7.3 to values varied between 4.04 and 6.62. The amount of P solubilized of RP reached 80.8, 14 days after an inoculation with Bacillus subtilis and the pH values of the medium were reduced from initial value of 7.3 to value 4.95. The PSB and AMF inoculations resulted in a significant increase in soil P content compared with the non-inoculated soil, and this increase was much higher after 69 days comparing with those after 130 days. Alkaline phosphatase activity was significantly increased by inoculating the soil with AMF and PSB comparing with both the non-inoculated and the individually inoculated soil. Wheat grain, straw, biological yields and grain/straw ratio were significantly increased with the application of rock phosphate to the PSB and AMF inoculated soil compared with the untreated soil by rock phosphate, AMF and PSB non-inoculated soil. Phosphate solubilizing bacterial strains Pseudomonas fluorescence, Bacillus megaterium and Serratia marcescens were more effective in increasing the concentration and uptake of N, P and K of wheat shoot as compared with Bacillus subtilis in soil amended with rock phosphate and inoculated with AMF.