A Study On The Colonization And Promoting Plant Growth Of Tomato Endophytic Bacillus In Xining Area

Collecting healthy tomato plants in different regions of Xining,24 strains of bacteria were obtained by using dilution-plate method,and 20 strains are endophytic bacteria after inoculating them into plants.The strain TG-1,TG-2 and S-2 were screened for their stable Antagonist toward Staphylococcus aureus and Escherichia coli.The three strains were identified as Bacillus firmus, Bacillus subtilis, Bacillus polymyxa by observing their morphological characters on the NA culture medium and biochemics characters.One–factor experiments showed the best pH, temperature, inoculm concentration, rorate speed, liquid volume of three strains. And their growth curve roughly same.stagnate growth phase is 0 to 12 h, 12 to 22 h is logarithm growth phase, stable phase is 22 to 48 h and after 48 h,strains start to decline.The ultimate bioasis will be achieved when the pH 6.7,the temperature at 28℃, the inoculm concentration is 1%, rorate speed is 150r/min,liquid volume is 50ml/200ml for strain TG-1 and S-2.The optimized condition for strain TG-2 ,when the temperature at 30℃, pH 7.3, the inoculm concentration 1%, rorate speed 150r/min, liquid volume 50ml/250ml bioasis will be achieved the most.The culture medium recipe was optimized by the one factor experiment and orthogonal test. Optimal medium recipe of strain TG-1: cornmeal 20g, bran 1.5g, K₂HPO₄ 0.6g, yeast cream 1.5g, water 1000ml. Optimal medium recipe of strain TG-2: cornmeal 20g, peptone 2g , K₂HPO₄ 0.2g, MgSO₄ 0.2g, yeast cream 1.5g, water 1000ml. Optimal medium recipe of strain S-2:brown sugar 20g,beef extrat 1.5g,K₂HPO₄ and MgSO₄ 0.6g,yeast cream 1.5g ,water 1000ml.The mutaanted by antagonism against the streptomycin suifate and the rifampicin, the results showed that the strain TG-1 and TG-2 by different inoculation methods were able to live and move in the different breed tomato plants except nebulization. The best methods are irrigating roots and seed dipping.The strain TG-1 and TG-2 also can live and move in the other plants, such as cabbage and pepper.the growth and decline rule is from raise to drop.So the two strains have no selectivity to tomato breeds, and they have widely host plants.The different treatments (fermented liquor,10 times dilution,100 times dilution,1000 times dilution)of strain TG-1 and TG-2 to treat the seeds and young plants of tomato,the test showed that the fermented liquor have inhibiting effect for seed germination ,dry weight,the length of root and stem,emergence rate,fresh weight of tomato ,on the contray,the dilution have some degree promoting effect.These different treatments (fermented dilution,supernatant,precilitum) of strain TG-1 and TG-2 also have some promoting effect for the tomato yong plants .For strain TG-1,the best treatment is precilitum,but for strain TG-2, the best way is supernatant treat.These three ways(irrigation root,seed dipping ,injection) all showed certain promoting effect for the height,fresh weight and dry weight of tomato plants and other plants. They not only can raise weight per ftuit and yield per fruit of tomato.but also can improve the quality of tomato, for example, to improve the content of sugar, the content of lycopene and acidity in tomatos.so these two strains can applicatein agricultural production extensively. The research on the promote mechanisms showed that the strain TG-1 and TG-2 can live and move in the plants.The cell weight colonization in the plants correlated with grows role.Promoting effect not only the function of supernatant or precilitum, but the rusults of these two substances.By increasing the content of chlorophyll in the plant,improving the plants photosynthesis and transpiration rate,thereby romoting plant photosynthesis to promote its growth.Reducing the malondialdehyde level to protect membrane and promote plant growth; Increaseiing the intensity of the root to promote the growth of root.These were proposed to be the key mechanisms of strain TG-1 and TG-2 on promoting growth.