| Rhodopseudomonas palustris is a kind of photosynthetic bacteria widely used in sewage treatment,agricultural planting,animal husbandry and aquaculture.The aim of this experiment is to use low-cost,high-density culture method to obtain high yield of photosynthetic bacteria products.During the experiment,it was found that Rhodopyomonas palustris had control effect on some diseases of winter jujube,so the control effect of plant diseases was tested.In the natural culture conditions to optimize the medium formula,the factors affecting the growth of bacteria in the culture conditions were explored.The results showed that N,P,C and other basic elements had great influence on the growth of Rhodopseudomonas palustris.The highest bacterial density could be obtained in C sodium acetate supplemental concentration groups of 10and 20g/L.In the N source types exploring experiment,the experimental results show that Rhodopseudomonas palustris can metabolism of organic nitrogen,nitrate nitrogen,ammonium nitrogen,such as a variety of nitrogen source,inorganic nitrogen composite compound without models of N source strongest ability to promote the growth of the bacteria,ammonium dihydrogen phosphate,sodium nitrate,potassium nitrate,urea addition can significantly promote the growth of bacteria.In the p-source type exploration experiment,the addition of compound fertilizer and ammonium dihydrogen phosphate can significantly promote bacterial growth,and compound fertilizer has a better promotion effect in the later stage of the experiment,but the promotion effect of NH4H2PO4 group is more obvious and rapid in the early stage.After further optimization experiment of N and P concentration,it was found that although potassium dihydrogen phosphate,compound fertilizer 1（N:P:K=28:6:6）and compound fertilizer 2（N:P:K=15:15:15）.Both had good promoting effect on bacterial growth,and the promoting effect was proportional to the addition concentration.However,the final bacterial density of compound fertilizer group 2 was higher,and the maximum cell density of potassium dihydrogen phosphate group was the fastest.Since this experiment is to provide a theoretical basis for large-scale production,the best sodium acetate concentration of C source is 10g/L,and the best N and P source is compound fertilizer 2（N:P:K=15:15:15）,and the best concentration is 0.5g/L,considering the promotion effect and production cost comprehensively.It was found that temperature had the greatest influence on bacterial growth,and bacteria could grow normally in the range of 400-7000lux of light intensity.p H also had a certain influence on bacterial growth,and the weakly alkaline environment（p H range7.5-8）was more conducive to bacterial growth.In the experiment of plant disease control,the disease parts collected from jujube trees,cherry trees,young tomato plants and strawberry plants were studied.The main diseases were jujube rust and jujube anthracnose;Powdery mildew and brown rot on strawberry plants;Root rot on cherry,leaf mold and late blight of tomato seedlings.the results showed that the fermentation broth,supernatant after centrifugation,bacterial weight suspension after centrifugation and inactivated fermentation broth all had significant inhibitory effect on the pathogen of jujube rust,root rot,brown rot and leaf mildew.Fermentation liquid,supernatant after centrifugation and bacterial suspension after centrifugation all had good inhibitory effect on the pathogen of anthracnose,powdery mildew and late blight.And different processing of Rhodopseudomonas palustris liquid of different disease pathogens inhibition effect is different,the fermentation liquid of jujube anthracnose pathogen inhibition effect is better,supernatant of jujube rust pathogens inhibition effect is better than that of fermentation liquid,after centrifugal weight suspended bacteria anthrax bacteria liquid of jujube,jujube rust and powdery mildew pathogen has good inhibition effect,The bacteria solution still had a good inhibitory effect on the pathogen of jujube rust. |
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