5株耐盐碱促生细菌的筛选鉴定及其对红小豆的促生作用

Screening and identification of five saline-alkali tolerant bacteria for growth promotion of red adzuki bean

摘要:

【背景】黑龙江省大庆市地处松嫩平原，土地盐碱化程度较重。盐碱土中含有大量的耐盐碱菌株，其中部分具有特殊的促生功能，可以作为有益促生菌促进植物生长，提高植物对盐碱的抗性。【目的】有效解决土地盐碱化问题，提高粮食作物产量。【方法】采集大庆地区的盐碱土壤为实验材料，在NaHCO3终浓度为50 mmol/L、pH 9.0的条件下对土壤中耐盐碱细菌进行分离，用功能性培养基进行促生功能细菌菌株的筛选，并对相应促生物质产量进行测定；挑选促生功能较全、促生效果较好的细菌菌株，采用形态学观察、生理生化法以及16S rRNA基因序列分析法进行菌种鉴定，以确定菌株的分类学地位；在pH 8.5、15 mmol/L NaHCO3胁迫条件下测试施用促生菌株对红小豆种子发芽率、根长、芽长及插条生根数和根长的影响，以验证促生效果。【结果】对筛选获得的细菌菌株进行鉴定，29号细菌为卓贝尔氏菌属(Zobellella sp.)，23、34、36和41号细菌属于盐单胞菌属(Halomonas sp.)。5株细菌均具有固氮、产植物激素吲哚乙酸(Indole-3-Acetic Acid，IAA)及ACC脱氨酶功能，34号和23号细菌具有最高植物激素IAA和ACC脱氨酶产量，分别达到了17.66 mg/L和0.31 U/mg。另外，23号细菌具有产铁载体能力，铁载体产量为3.19%；29和41号细菌具有溶有机磷功能，溶磷量分别为20.05 mg/L和34.61 mg/L。植物促生试验结果显示，在盐碱胁迫条件下，红小豆种子接菌后种子的发芽率和根长分别提高了41.67%和32.63%以上；红小豆插条接菌后，幼苗的根长和生根数与盐碱胁迫对照相比分别提升了129%和160%以上。【结论】这5株耐盐碱促生细菌能够缓解盐碱胁迫对红小豆生长的抑制作用，可以较好地促进其根系生长发育，可为研制耐盐碱促生菌肥提供优良菌种。

Abstract:

[Background] Daqing is located in Songnen plain, which land is heavily salinized. Saline-alkali soil contains a large number of saline-alkali-resistant strains, some of which have special functions of promoting growth and can be used as beneficial bacteria to promote plant growth and improve plant saline-alkali-resistance. [Objective] In order to solve the problem of land salinization effectively and increase the yield of grain crops. [Methods] The saline-alkali soil collected in Daqing area as an experiment material was used to separate the saline-alkali tolerant bacteria under pH 9.0, 50 mmol/L NaHCO3, the growth promoting function of the strain was screened by functional medium, and the yield of corresponding substance was measured accordingly. The strains with complete promoting function and better promoting effect was selected, using analyses of morphology, physiological biochemistry, 16S rRNA gene sequence to identify the strains, so as to determine their taxonomic status. The growth promoting strains were tested on physiological indicators such as germination rate, root length, bud length, rooting number and root length of seeds of red adzuki bean to verify the growth promoting effect under pH 8.5 and 15 mmol/L NaHCO3. [Results] The strain 29 was Zobellella, and the others were Halomonas. All the five strains had the functions of nitrogen fixation and produced indole-3-acetic acid (IAA) and ACC deaminase. The strain 34 and strain 23 had the highest yield of IAA and ACC deaminase, reaching 17.66 mg/L and 0.31 U/mg respectively. In addition, the strain 23 was capable of producing siderophore, which content was 3.19%. The strains 29 and 41 had the ability of organophosphorus-dissolving and the phosphorus solution capacity is 20.05 mg/L and 34.61 mg/L. The results of plant growth promotion test showed that the germination rate and root length of red adzuki bean seeds were increased respectively by 41.67% and 32.63% after the seeds were treated with inoculation under saline-alkali stress. After inoculation, the root length and root number of seedlings increased by 129% and 160%, respectively, compared with saline-alkali stress control. [Conclusion] The five saline-alkali tolerance and growth-promoting bacteria could alleviate the inhibition of saline-alkali stress on the growth of red adzuki bean and promote the growth of its root system. This provides an excellent strain for the development of saline-alkali tolerant and growth-promoting microbial fertilizer.