特基拉芽孢杆菌Bt-RS对盐胁迫环境下香蕉幼苗生长的影响

Effect of Bacillus tequilensis Bt-RS on the Growth of Banana Seedling under Salt Stress

土壤盐渍化是世界性生态环境问题,是阻碍作物生长并致使农业生产损失的潜在非生物胁迫因子之一。利用植物根际促生菌促进植物生长,提高植物耐盐性,缓解植物所受的非生物胁迫被视为1种新兴有效可行方法。本研究以实验室前期于南海岛礁根际土壤中分离到的1株特基拉芽孢杆菌(Bacillus tequilensis)Bt-RS为研究对象,利用功能培养基对其耐盐特性和耐盐促生性状进行定性定量分析,并进一步通过土壤盆栽实验评价该菌株在盐胁迫环境下对香蕉幼苗生长的影响。研究结果显示:Bt-RS菌株能够在NaCl含量为0~10%的条件下生长,能耐受多种类型盐分,具有产1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylate,ACC)脱氨酶能力;在1%~5%的NaCl浓度下能够分泌植物生长素吲哚-3-乙酸(indole-3-acetic acid,IAA),最大产量值为6.4mg/L。盆栽实验结果显示:在正常条件下,接种菌株Bt-RS的香蕉幼苗相比未接种菌株其株高、叶面积、地上部分鲜重、地下部分鲜重、地上部分干重、地下部分干重分别提高40.30%、93.00%、102.38%、81.08%、65.82%、50.50%;在200mmol/L盐胁迫环境下,接种菌株Bt-RS的香蕉幼苗与对照组相比在株高、叶面积、地上部分鲜重、地下部分鲜重、地上部分干重、地下部分干重方面分别提高20.55%、65.01%、98.14%、144.93%、87.85%、54.01%;在正常条件与盐胁迫下接种菌株均能显著提高香蕉幼苗的株高、叶面积以及生物量(P<0.05),盐胁迫环境下的实验组与正常条件下的对照组相比在株高和叶面积上均无显著差异,因此通过施用菌株Bt-RS能够有效缓解NaCl对香蕉幼苗的胁迫,促进香蕉幼苗的生长。综上结果表明,特基拉芽孢杆菌Bt-RS具有较强的耐盐性以及产IAA和ACC能力,能够促进香蕉幼苗生长并在盐胁迫环境下显著提高植物耐盐性,可为开发与利用盐渍土提供菌株资源。

Soil salinization is an ecological environment issue globally and is one of the major abiotic stress factors that cause crop loss worldwide as well as hindering crop productivity.Halotolerant plant growth-promoting rhizobacteria(PGPR)having potential to promote crop growth and increase salt tolerance in crops can be employed to counter this issue in a more effective and eco-friendly way.The recent study aimed to assess the salinity tolerance and growth-promoting capacity of Bacillus tequilenis Bt-RS isolated from the rhizosphere soil of islands in the South China Sea,for assessment,the corresponding media were used for qualitative and quantitative analysis.A pot trail was also conducted to further evaluated its bacterial consortium to promote banana seedlings growth under salinity stress.The results showed that strain Bt-RS could grow well under the condition of 0-10%NaCl content with various types of salts.The strain Bt-RS also possessed 1-aminocyclopropane-1-carboxylic acid(ACC)deaminase activity along with indole acetic acid(IAA,up to 6.4 mg/L under the condition of 1%-5%NaCl).Base on the pot experiment,the banana seedlings that were inoculated with Bt-RS displayed a significant increase in height,leaf area,fresh weight of above ground and underground,as well as dry weight of above ground and underground(40.30%,93.00%,102.38%,81.08%,65.82%and 50.50%,respectively)compared to the control group under normal conditions;The 200 mmol/L NaCl-stress treatment significantly increased the growth of banana seedlings in height,leaf area,fresh and dry weight of both above ground and underground by 20.55%,65.01%,98.14%,144.93%,87.85%and 54.01%respectively,when compared with the control group.The plant height,leaf area and biomass of banana seedlings were significantly increased in both nor-mal conditions and salt stress environment(P<0.05).There was no difference in plant height and leaf area between the experimental group under salt stress environment and the control group under normal conditions,indicating that apply-ing Bt-RS can alleviated the adverse effects of NaCl stress and enhanced banana seedlings growth attributes.In conclu-sion,the strain B.tequilensis Bt-RS exhibits high salt tolerance and possess the ability to produce IAA and ACC deaminase,making it a valuable strain for improving banana seedling growth and salt tolerance,and also providing re-sources of strain for developing and utilizing in saline soil.