Screening And Algicidal Characteristics Of Aquatic Plant Endophyte

At present, the eutrophication caused by serious eutrophication phenomenon resulting inwater environment pollution, and explore the effective method to control algae bloom isparticularly urgent. Physical,chemical methods of traditional algae removal has its limitations,cost of manpower, treatment of algae may cause water pollution. Using microorganism has greatpotential and application prospect in theaspects of governance bloom. Aquatic plant internalwidely exist a lot ofendophytic bacteria, and the use of endophytes as biocontrol agents is aresearch hotspot in recent years. This paper adopts from ChangchunUniversity of Blue Lake thegrowth of aquatic plants, the separation ofseveral plant endophyte and cultivate the plant surface,disinfectionreagent by comparing selected on the effect of long after disinfection ofthe plantstested different disinfection, selected the best disinfectiontime, ensure that the disinfection plantsurface completely, can beisolated and cultured endophytic bacteria from inside the plant, andsuccessfully isolated with algicidal bacterium algicidal effect, the concrete research contents areas follows:（1）To determine the aquatic plant tissue surface disinfection time:75%,0.2%,5%sodiumhypochlorite disinfectant mercuric chloride reagentthrough test for single aquatic plants weresurface sterilized and the results of the analysis were determined three kinds ofdisinfectionreagent of aquatic plants on the disinfection time.（2）Isolated from the plant internal four strains of endophytic bacteria (E1,E2, E3, E4) andits algicidal experiment screened a strain with algalbacterial E1soluble algicidal effect. The E2,E3E4endophytic bacteria,endophytic fungi.（3）Separation and purification of algicidal bacteria E1and its colony characteristics andGram staining were observed under the microscope:the colony characteristics: colony was milkywhite, round, shiny, neat edge, the smaller colonies. Results of Gram staining grampositivebacteria, the rod like shape.（4）In beef extract peptone medium under the condition of25℃afterconstanttemperature incubator shaker cultures, draw the growth curveby OD600measurements.（5）The growth status of different pH conditions: find the algicidal bacteriagrow best inneutral and alkaline conditions. The suitable pH value range of6-9, and the pH value of5and10when the bacteria growing weaker,pH value of3and11basic not long.（6）Algae lysing different light conditions: algae liquid will access the algicidal bacteria metabolites placed light, light dark cycle, under the three conditions, found the best darkconditions algicidal effect, followed by light cycle, then the light.（7）Metabolic products of different algicidal effect added: add different number ofalgicidal bacteria metabolites to Microcystis aeruginosa liquid,the algae lysing effect andproportional to the amount of added.（8）As a nutrient source for growth on different carbon sources: the bacteriahave theability of organic nitrogen to good use, does not have the capacity to use inorganic nitrogen.（9）After heat treatment the algicidal bacteria metabolites and withoutmetabolic productsprocessing on Microcystis algae lysing effect: two ways to deal with the algae removal rate isnot much difference,indicating that the algicidal bacteria with thermal stability.