Isolation And Identification Of Phosphate-solubilizing Bacteria From Banana Rhizosphere Soil And Their Growth Promoting Effect Of Banana

Phosphate-solubilizing microorganisms or dissolved phosphorus means the Phosphate rock can be transform in soil which plants are difficult to be absorbed into that which can be absorbed by the mimicrobes. Now,nearly50%of the agricultural soil has the problems of phosphorus deficiency in the world.The phosphorus deficiency means the phosphorus deficiency of genetics instead of phosphorus deficiency of soil.(Yijun Kang etc.2006; Qingren wang,2004). Phosphorus deficiency seriously affect the growth of plants. Applying chemical phosphorus directly would alleviate the phenomenon of phosphorus deficiency of soil in a certain extent. However, it will cause some problems,such as the lower of absorptivity less than25%, the waste of resources, soil harden and acid and alkali. Therefore, the research of microbial phosphorus fertilizer is one of the popular project in current agricultural research projects. The article was based on the phosphate rock as the substrate, isolated from rhizosphere soil of banana, screening and identification of a batch of high-efficiency phosphate-solubilizing bacteria, and studied the ability of phosphate-solubilizing of representative strains, optimize the culture conditions and phosphate-solubilizing bacteria agent has the promoting effect on the growth of banana seedlings.1. Three strains of bacteria were screened out and identified which have the efficiently capable of dissolved phosphate rock. Banana rhizosphere measure the effective phosphorus content in fermented liquid to screened one or two times by transparent circle method and Mo-Sb colorimetric method to got the better phosphate-solubilizing microorganisms B3-5-6, M-3-01and T1-4-01strain. It can be judged that the strain B3-5-6was Bacillus aerophilus, M-3-01was Serratia nematodiphila,T1-4-01was Enterobacter asburiae by bacteria morphology observation, physiological and biochemical experiments and16s rDNA molecular biology identification. Among these three strains, M-3-01strain dissolved phosphate rock powder works best, the ability of phosphate-solubilizing was37.85mg/L, which was taken as a representative of the phosphate-solubilizing microorganisms for further study.2. Optimized the fermentation technology of M-3-01strains’ phosphate-solubilizing. Through the combination of single factor test and orthogonal test method, single factor experiment screened that the best carbon source was glucose, the nitrogen source was ammonium oxalate. Once more, determined four main factors include the carbon source, nitrogen source, the ground phosphate rock, and inorganic salt with L9(34) orthogonal test, to screened out the optimal cultivation formula, then by used the single factor experiment, to screened out the optimal formula of the initial of pH, rotational speed, the inoculation quantity etc. Ultimately determined the high-efficiency phosphate-solubilizing fermentation formula of strains of M-3-01. The final optimization result were:1/5g/L of glucose,1.5g/L of ammonium oxalate,2.5g/L of phosphate rock powder,1.92g/L of inorganic salt,2%of inoculation quantity,6.0of pH,150r/min and37℃. And its formula were verified experiment, which optimized the set of effective phosphorus content up to88.64mg/L, which was2.34times that of CK effective phosphorus content.3. The representative phosphate-solubilizing of M-3-01strain was made into bacterium agent. Compared with the ground phosphate rock and fertilizer,the bacterium agent maked the effect of banana seedlings, potted experiment study which found that combination of the strains of M-3-01bacterium agent and phosphate rock powder processing works best:the average of plant’s height, stem circumference, fresh weight, dry weight were controlled respectively1.26,1.16,1.38,1.47times; And lipid membrane peroxidation and membrane permeability osmoregulation substance content and effect were significantly higher than other several processing. In view of the banana plant rhizosphere soil physical and chemical factors were analyzed, the receiving of phosphate-solubilizing bacteria agent group of effective phosphorus content was significantly higher than that of CK, effective K and total nitrogen content was obviously lower than CK, the change of pH was relatively stable, closed to neutral.