Effect of Phosphate Solubilizing Rhizobium Strains on Alfalfa Seedlings Growth Under Nitrogen Free and Phosphorus Deficient Conditions

Effect of phosphate solubilizing Rhizobium spp. on growth, nodulation, phosphorus (P) uptake and nitrogen (N) uptake of Medicago sativa seedlings (cv. Golden Empress) were investigated in sand culture experimentation under available P deficient and N free conditions. Results indicated that the growth, nodulation, biomass and phosphorus accumulation of alfalfa seedlings were promoted after inoculation with P-solubilizing Rhizobium meliloti LW107 and sainfoin Rhizobium sp. RSW96. Biomasses of seedlings inoculated with Rhizobium meliloti LW107 were 85.94% and 36.78% times higher than none-inoculated control (CK1) and treatment inoculated with control strain Sinorhizobium meliloti 12531. Nodule's diameters and nitrogenase activity were 57.3% and 95.81% times higher in seedlings treated with R. meliloti LW107 compared with seedlings inoculated with Sinorhizobium meliloti 12531, respectively. In the case of both Rhizobium strains treatments, P uptake was 19.86% and 10.27% times higher than none-inoculated control and seedlings inoculated with S. meliloti 12531, respectively. Leaf number and leaf surface area of seedlings were significantly higher under rhizobia strains treatments than that in none inoculated control or inoculated with Sinorhizobium meliloti 12531 strain.