Plant growth is enhanced by microbiological agents. In order to develop environment friendly composite microbial agent that can also improve the salt and drought tolerance of plants, the orthogonal experiment and response surface methodology were used to screen nutrients and fermentation conditions of composite microbial agent, and pot experiment was conducted to validate the application effect of optimized and complex microbial agent. Compatibility test showed that G2 () and G5 () did not show any inhibitory effect on each other’s growth in nutrient agar, moreover, in both the growth promotion characteristics and the seed germination tests, G2+G5 showed a synergistic effect. The process optimization results showed that the optimal carbon and nitrogen sources for the medium nutrients was maltose and yeast extract, and the optimal carbon-nitrogen ratio was 5:1; the optimal fermentation conditions included initial pH at 5.17, inoculation amount of 2.28%, liquid volume of 105.96 mL(250 mL), and incubation temperature at 30.06℃. Pot experiment showed that application with composite microbial agent was able to increase antioxidant enzyme activities, ascorbat, proline content, and reduce reactive oxygen species accumulation and membrane peroxidation of seedlings under salt-drought stress. In conclusion, the composite G2+G5 agent possessed remarkable synergistic effect for improve plant tolerance to drought combined with salt stress, suggesting a noticeble practical potential in agricultural practice, and it can be used to develop newtype environment friendly microbial fertilizer.

中文翻译：

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一种有利于提高乌拉尔甘草耐旱、耐盐能力的复合微生物菌剂的研制

微生物制剂可促进植物生长。为了开发同时提高植物耐盐、耐旱能力的环境友好型复合微生物菌剂，采用正交试验和响应面法筛选复合微生物菌剂的养分和发酵条件，并进行盆栽试验验证应用。优化和复合微生物制剂的效果。相容性试验表明，G2()和G5()在营养琼脂中对彼此的生长没有表现出任何抑制作用，而且在促生长特性和种子萌发试验中，G2+G5均表现出协同作用。工艺优化结果表明，培养基营养物质的最佳碳氮源为麦芽糖和酵母抽提物，最佳碳氮比为5:1；最佳发酵条件为初始pH 5.17、接种量2.28%、液量105.96 mL（250 mL）、培养温度30.06℃。盆栽试验表明，施用复合微生物菌剂能够提高幼苗在盐旱胁迫下的抗氧化酶活性、抗坏血酸、脯氨酸含量，减少活性氧积累和膜过氧化。综上所述，G2+G5复合剂对提高植物对干旱和盐胁迫的耐受性具有显着的协同效应，在农业实践中具有显着的实用潜力，可用于开发新型环境友好型微生物肥料。