Identification And Growth Promoting Effect Of Eight Bacterium Isolated From Plant Rhizosphere

Eight bacterium isolated from plant rhizosphere showed significant plant promotingeffect. The gram stain, spore stain, physiological and biochemical tests and pot plant pottests were conducted. The results of promoting effect and interaction between somebacterium provided conditions for the production of biofertilizer inoculant.All the strains tested were grow quickly and entered the exponential phase after 4hours and the stationary phase after 16 hours incubation.Morphological, physiological and biochemical tests were used. Gram stain andspore stain showed that all eight bacterium were G⁺, forming spore at aerobicenvironment, so that these bacteria should be classified to Bacillus. According to furtherphysiological and biochemical tests, B1 was identified as Bacillus coagulans, B3 asBacillus megaterium, B4 as Bacillus azotoformans, B5 as Bacillus as Bacilluslicheniformis, B7 as Bacillus pumulis, B8 as Bacillus firmus. But B2's taxonomic statuswas unknown.The IAA producing ability of these bacterium were determined and results weredifference for each bacterium. The maximal IAA concentration of B1 was as 11.5μg/ml,the maximal IAA concentration of B2 and B8 were more than 5.0μg/ml, the other's wereless than 5μg/ml, B4 was less than 1.0μg/ml. Except for double peaks from strain B2,the other strains only showed one peak.L₁₆(2)¹⁵ orthogonal array was used to design plant pot experiments and their growthpromoting effects of bacterium mixture were analyzed. The results demonstrated thatfactor of B1, B4, B5, B6 and interaction of B₄₅, B₁₅ showed significantly influence on dryweight of tomato at confidence level 95% (a=0.05).Among them the interaction of B₄₅,B₁₅ showed negative effect. Factor of B1, B7, B8 and interaction of B₄₅,B₁₅,B₃₈ showedsignificantly influence on dry weight of capsicum. The interactions of B₁₅ and B₃₈showed also negative effect.