Effects of Plant Growth Promoting Rhizobacteria Microbial Inoculants on the Growth, Rhizosphere Soil Properties, and Bacterial Community of Pinus sylvestris var. mongolica Annual Seedlings

Abstract [Objective] Determine the ability of three plant growth promoting rhizobacteria (PGPR) strains (Pseudomonas Mandelli A36, Serratia plymuthica A13 and Pseudomonas koreensis A20) to promote plant growth, evaluate the effect of inoculation with PGPR strains on seedling biomass, root structure, nutrient index, and enzyme activity, and assess the effect of PGPR inoculation on soil nutrient index, enzyme activity, and the soil microecological environment.[Method] The ability of the three PGPR strains to secrete indole-3-acetic acid (IAA), dissolve inorganic phosphorus, and produce siderophore and hydrolase was determined by the medium color change method, pot experiment to determine the effects of three PGPR strains on plant biomass, physicochemical properties, soil physicochemical properties and microbial diversity. [Result] The three PGPR strains had the ability to secrete IAA, solubilize inorganic phosphorus, and produce siderophore, the results of the pot experiment showed that inoculation with PGPR strain had a significant effect on plant biomass, root index, nutrient index and enzyme activity, as well as soil nutrient index, enzyme activity and bacterial diversity. [Conclusion] This study provides basic data references for PGPR strains to improve the soil microecological environment and promote the growth and development of Pinus sylvestris var. Mongolica seedlings.