Effects Of Two Plant Growth Promoting Rhizobacteria On Drought Resistance And Uranium Bioaccumulation Abilities By Macleaya Cordata

The mining of uranium is often accompanied by the production of a large amount of tailings and wastes,causing pollution to the ecology.Moreover,the uranium in the environment can enter the food chain through the biosphere and eventually pose a threat to human health.Phytoremediation is increasingly used in the restoration of contaminated soil for its low cost,environmental protection and other characteristics.However,the effect of phytoremediation often depends on the growth status of the plant itself.For example,drought,salinity,heavy metal nuclides and many other abiotic stress can directly or indirectly affect the normal growth and development of the plant,and ultimately lead to unsatisfactory results in phytoremediation.Plant growth promoting rhizobacteria and their secretions can promote the growth of plants in the reverse environment and increase the bioavailability of metals in soil.So,this study was aimed at uranium-contaminated soils in arid regions to explore the application of plant growth promoting rhizobacteria in phytoremediation,and the enhancement on drought resistance anduranium bioaccumulation abilities of Macleaya cordata inoculated with Plant growth promoting rhizobacteria.Therefore,Macleaya cordata,which has a good enrichment effect on uranium,and Pseudomonas fluorescens,Pseudomonas chlororaphis subsp.aurantiaca,which have a growth-promoting effect on plants,were used as research objects in this study.A series of pot experiments were conducted to investigate the effect on drought resistance and uranium bioaccumulation abilities of Macleaya cordata inoculated with Pant growth promoting rhizobacteria.The objectives of this study were(1)to explore the resistance of Pseudomonas fluorescens and Pseudomonas chlororaphis subsp.aurantiaca to drought stress and uranium stress;(2)to Evaluate the effect of growth promoting rhizobacteria on drought resistance and uranium enrichment of Macleaya cordata form the changes in some factors of it after inoculated with Pseudomonas fluorescens,Pseudomonas chlororaphis subsp.aurantiaca and both of them;(3)to determine the optimal combination of Macleaya cordata and plant growth promoting rhizobacteria to repair the uranium-contaminated soils under drought conditions Through the above experiments.The main results of this study were(1)both two strains all have certain drought resistance,and Pseudomonas fluorescens has better drought resistance than Pseudomonas chlororaphis subsp.aurantiaca.Both strains can grow well at a concentration of 5% and 10% PEG-6000,However,Pseudomonas chlororaphis subsp.aurantiaca cannot grow at a concentration of 15% of PEG-6000,whereas Pseudomonas fluorescens can.(2)we found that these two plant growth promoting rhizobacteria can to a degree promote drought resistance and uranium bioaccumulation abilities by comparing the biomass,proline,relative water content,and uranium bioaccumulation of Macleaya cordata between inoculated and uninoculated plant growth-promoting rhizobacteria;(3)we found that the symbiotic system formed by Macleaya cordata and Pseudomonas fluorescens can do better in improving the drought resistance and uranium bioaccumulation abilities of Macleaya cordata.