Study Of The Wild Rice Rhizosphere’s Microorganisms On Cultivated Rice Tolerance’s Under Drought Stress

Drought has caused several major famines and has a significant and devastating impact on rice production in rainfed regions of Asia in particular.Studies have found that wild crops can still survive and grow in harsh environments.In recent years,studies have shown that rhizosphere microorganisms of wild species can be made into biological preparations under harsh conditions.The use of these biological preparations can improve plants tolerance to drought stress and growth promotion.Therefore,it is reasonable to assume that the rhizosphere microbiota of wild rice contributes to the growth and survival of host plants under drought conditions.In this paper,the rhizosphere microorganisms and endophytic microorganisms of Dongxiang wild rice were isolated and screened under drought stress,and use the screened strains to carry out the pot experiment of cultivated rice under drought stress.The production of extracellular polysaccharide（EPS）and indole acetic acid（IAA）are important indicators of bacterial drought resistance and plant growth promotion,respectively,and with this as an indicator,at PEG 6000 concentrations of 30.3%（-1 MPa）and 43.8%（-2MPa）,3 strains with research potential were screened out.The strains were named as P1,N1g and N2.Through physiological,biochemical and molecular biological identification,P1 was Enterobacter kobei,N1g was Bacillus toyonensis,and N2 was Enterobacter asburiae.In addition,these strains have also been found to have certain potential in promoting plant growth,such as having ACC deaminase activity,dissolving phosphate（P）and potassium（K）,producing ammonia（NH₄⁺）,producing siderophores and hydrocyanic acid（HCN）etc.Taking Dong Dao 4 rice as the research material,the plants were inoculated with the combination of N1g and N2 strains by foliar spraying;and the P1 strain was inoculated individually in another experiment to evaluate its effect on drought resistance and growth promotion of rice.The results showed that compared with the control,the morphological,physiological and biochemical indexes of the plants were significantly improved,which were reflected in the length of the shoots,fresh and dry weight of the shoots and roots,relative content of leaf,leaf area index,photosynthetic pigments,antioxidant defense,and a significant reduction in MDA content.In both experiments,no significant differences are shown for some of the indicators evaluated between the treatments with the inoculation of these strains P1（-）L and N1g+N2 under drought conditions and the control treatment of healthy plants CK（+）,as in the relative water content of the leaf,with an increase of 297.8%for P1 compared to the non-inoculated group CK（-）WL.And significant increases are also observed compared to healthy plants CK（+）,such is the case of the fresh weight of the root of the rice plants inoculated with N1g+N2 with an increase of 42.9%;and the dry weight that increased by 34.1%.The fresh weight of healthy plants inoculated with P1,P1（+）L,significantly exceeded the control treatment of healthy plants CK（+）with an increase of 21.8%,evidencing its promoting effect on plant growth.Due to the efficiency of the foliar inoculation of these strains in combination and individually,in drought tolerance and growth promotion of rice,wild rice rhizospheric and endophytes microorganisms represent a promising source of research for plant development under drought conditions.Concluding that the treatments with the combination of strains N1g+N2,and P1 individually,had a good effect for growth promotion under drought conditions in rice cultivation.