盐碱条件下微杆菌q2-5对大豆生长与生理特性的影响OA

Soil salinization has seriously threatened the virtuous cycle of ecological environment and the healthy development of agriculture and animal husbandry,and the use of soil microorganisms to improve saline-alkali land,promote crop growth,and alleviate the salt stress of plants have become an important development direction.In this study,the purpose of this study was to explore the alleviating influence of plant rhizosphere growth-promoting bacteria on soybean growth under saline-alkali conditions,and the microbacterium q2-5 isolated in the laboratory was selected for resistance analysis and growth-promoting characteristics,including antibiotic identification,salt tolerance identification,alkali tolerance identification and salinity tolerance identification.The analysis of growth-promoting characteristics included the ability to secrete IAA,the ability to solulate phosphorus,and the activity of nitrogenase.At the same time,the influence of inoculation q2-5 under saline-alkali conditions on soybean growth and physiological indexes were analyzed.The results of antibiotic resistance identification showed that strains q2-5 were resistant to erythromycin(ERY),neomycin sulfate(NEO),kanamycin(Km),spectinomycin(Spe)and gentamicin(Gm).The results of salt tolerance identification showed that strain q2-5 at a concentration of 700 mmol•L-1 TY solid medium was grown normally.The alkali tolerance identification results showed that strain q2-5 could grow normally on TY solid medium at pH10.1.The results of mixed saline-alkali identification showed that strain q2-5 could be mixed with a saline-alkali concentration of 50 mmol•L-1 was grown normally on TY solid medium.The results of growth-promoting characteristics analysis showed that the amount of IAA produced by strain q2-5 was 0.07 mmol•L-1,the amount of phosphorus dissolved was0.33 mg•L-1,nitrogenase activity was243.8 U•L-1.The results showed that the plant height,stem diameter,aboveground weight and underground part of soybean seedlings inoculated with q2-5 increased by 23.94％,4.97％,33.74％,50.23％,33.31％and 43.31％(Hefeng 50)compared with those without inoculation,and 17.63％,4.60％,31.15％,48.79％,30.87％,and 42.15％(Heinong 91),and the antioxidant enzyme activity,soluble protein content and proline content of soybean seedlings in roots and leaves were significantly increased,and the content of O-2 and malondialdehyde content were also significantly decreased.These results indicated that strain q2-5 could alleviate the damage caused by saline-alkali stress to soybean.In conclusion,microbacterium q2-5 effectively alleviates the physiological damage caused by saline-alkali stress in soybean by enhancing its antioxidant capacity and osmotic regulation ability,providing theoretical basis and application potential for improving soybean cultivation in saline-alkali land using microbial agents.