| Tobacco black shank and bacterial wilt are the most serious diseases on tobacco production,especially in many years of continuous cropping tobacco fields.Owing to these two pathogenic diseases mainly exist in pathological soil,it is difficult to control once them break out.Currently people usual use soil fumigation and agents irrigating to control the diseases,but a number of soil treatment not only pollute the soil and environment but also result in holding short-acting and the recurrenting of these disease.Using beneficial microorganisms in soil to control soil-born disease can avoid these problems.In this study,the tested strains with obviously resistance against the tobacco black shank and bacterial wilt were isolated from soil obtained throughout tobacco.Firstly,we selected 6 strains with a higher antimicrobial activity through analyzing the antagonistic activity of these tested strains and measures their promoting effect on tobacco seedlings.The optimization of the culture condition and the analyzation of the effects of different additives on the antagonistic activity provided a basis on the further development of complex microbial inoculants.The main researching results were as follow:1.The restrain impact of biocontrol bacteria to Ralstonia solanacearum and Phytophthora Parasitica.Five good effective strain was gained through confront culture of the strain of our laboratory for R.solanacearum and P.Parasitica.The five strains belong to Peanibacillus sp.,H1-2?B1?H7-3-1 belong to Peanibacillus polymyxa.2.Bio-control Trichoderma strains to tobacco black shank disease heavy parasitic effectsMycopara sitism of Trichoderma atroviride on P.Parasitica M5(T.atroviride)and P.Parasitica were co-cultured and result showed that mycelium of M5 gradually invaded the P.Parasitica colony.After 13 days black shank pathogen mycelium is completely covered by T.atroviride strains.3.Promoting biocontrol strains indoor Efficiency AnalysisA pot experiment,the effects of various strains of tobacco seedling growth,including growth-promoting influence on Seedling H1-2 best,its aboveground and underground fresh weight were increased up 81.18%,218.94%,Each other strains on the growth of tobacco seedlings also have obvious role in promoting4.Interaction between the strain analysisOf 5 strains with PGPR bacteria strain T.atroviride M5 interaction analysis,found the antagonism between bacterial strains and the M5 have not antagonism role.The results show that composite strain of tobacco seedlings growth-promoting effect of the best,and its above-ground and underground fresh weight was 23.34 g,7.46 g,respectively,compared with control increased 41.54%,63.96%.Tobacco black shank and the efficacy was 49.05%.5.The anti-germ germ stub ferments the condition of excellent turn.In composite materials for the B1 strain of bacterial strains fermentation medium carbon,nitrogen and inorganic salts were optimized to get the most appropriate screening bacterial strains were grown in medium composition and ratio: 0.5% calcium carbonate,0.3% corn flour,0.3% soybean meal.It further optimize the culture conditions,found that the most suitable conditions for the growth of the bacterial strain inoculation 3%,p H value of 7.0 to 7.5,bottling volume 60ml(250ml Erlenmeyer flask),the temperature is 30,incubation time 48 hours.6.The lively influence of different additives on Antagonistic BacteriaThe humic acid,maltodextrin,sodium alginate,etc.Fifteen different additives were added to a certain amount of broth,found humic acid,maltodextrin,CMC-Na,sodium alginate four substances can improve the fermentation broth of Bacillus survival.By orthogonal design and test the storage stability of liquid protective agents have been studied,initially determine the best protection formulation of 0.8% humic acid,0.4% maltodextrin,2% CMC-Na,1.5% sodium alginate. |
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