| China is the country with the widest distribution of saline-alkali soil,and improving saline-alkali soil can increase the available land area,which is of great significance for increasing agricultural production and income in China.Straw is a renewable resource that can be utilized and has significant effects in improving saline-alkali grasslands.After decomposition,it increases the content of carbon and nitrogen in the soil,which has the effect of increasing yield and fertilizer;The role of bioengineering bacteria in saline-alkali land improvement is constantly strengthening,such as the ability of phosphate solubilizing bacteria to produce acid,which has attracted attention from researchers.In order to study the interaction between microorganisms and plants to improve the effectiveness of saline alkali soil improvement,this experiment isolated saline alkali resistant strains from saline alkali soil samples,prepared bacterial agents,and applied them back to the saline alkali soil with added straw for potted experiments on Leymus chinensis.The main results of this experiment are as follows:1.Gradient dilution was conducted on saline-alkali soil collected from Zhenlai County,Baicheng City,Jilin Province,and applied to NBRIP medium,cellulase producing medium,and improved LB solid medium for screening of phosphorus solubilization,cellulose solubilization,and salt alkali resistance.Then,16 S r DNA strain identification was conducted to obtain two saline-alkali resistant functional strains,one with phosphorus solubilization ability and the highest phosphorus solubilization amount of 74.85 μ G/m L,is a strain of Priestia aryabhattai,named JL-5,registered with Gen Bank and numbered OQ443070.1;The other strain has the ability to hydrolyze cellulose,with the highest cellulase activity of 2.2 U/m L.It is Staphylococcus pseudoxylosus,named XW-4,registered with Gen Bank and numbered OQ443074.1.2.The transcriptome sequencing of JL-5 showed that there were 1304 differentially expressed genes(DEGs)produced by JL-5 under saline-alkali stress,1066 of which were up-regulated and 238 of which were down regulated.As the degree of salinization deepens,the lactate and proline content of JL-5 increases,and the activity of glutamine synthase(GS)significantly increases.Microscopic examination reveals that a large number of cells are in an asymmetric separation period.3.Using Leymus chinensis as the test material,the growth and soil nutrients of Leymus chinensis after treatment with sterile solution,single bacterial solution,and composite bacterial solution were studied.The results showed that when the ratio of JL-5: XW-4 in the composite bacterial solution was 2:1 and the amount of straw added was 5 g,the germination rate of Leymus chinensis was the highest;The growth status of aboveground and underground parts of Leymus chinensis grown for 14 days treated with composite bacterial solution was better than that of other treatment groups;The accumulation of malondialdehyde(MDA)in the whole plant of Leymus chinensis was significantly reduced,the activities of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD)and the content of proline(Pro)were significantly increased,and the content of available N,P,K and organic matter in the soil was also better than other treatment groups.4.Using saline-alkali soil cultured with compound bacterial solution for 14 days as the experimental group and saline-alkali soil cultured with 14 days as the control,using 16 S r RNA amplicon technology and based on GO and Meta Cyc database analysis,it was found that the compound bacterial solution increased the diversity and richness of multiple genera in the soil,including Rubrobe,Arthrobacter,and Bacillus;Soil microbial metabolic pathways: degradation of 4-hydroxyphenylacetate,production of acetate,biosynthesis of phosphowallic acid,biosynthesis of L-aspartic acid and L-asparagine,with significant enrichment. |
PDF Full Text Request