盐爪爪根部微生物分布特征及盐浓度对碳源代谢分析的影响

Microbial distribution characteristics around the roots of Kalidium foliatum and the effect of salt concentrations on microbial metabolism analysis

摘要:

【背景】耐盐植物盐爪爪广泛分布于盐碱荒漠区域，其根际存在明显的盐离子富集，形成“盐岛效应”，研究此过程中微生物如何演替和适应，对揭示盐爪爪根际微生物的分布及其耐盐特性、“盐岛”的形成具有重要科学意义。【目的】揭示盐爪爪根际、根区及其周围环境土壤中微生物分布特征，确定不同盐浓度处理对根际微生物Biolog Eco微平板碳源代谢多样性的影响。【方法】采用Biolog Eco微平板技术，对采自新疆和硕地区的盐爪爪根际、根区和环境土壤微生物碳源利用情况进行分析，并采用不同浓度NaCl溶液对盐爪爪根际土壤样品进行稀释加样，评估盐浓度对根际微生物活性及多样性分析的影响。【结果】样品微生物代谢活性总体呈现根际>根区>环境的趋势；随着与根部距离的增加，样品中利用氨基酸、胺类碳源微生物所占比例明显降低，而利用吐温和肝糖等多聚化合物类碳源微生物所占比例明显增加；多样性分析表明，随着与根部距离的增加，Shannon指数(H)随之降低且存在明显差异。不同浓度NaCl溶液对采用Biolog Eco微平板技术分析盐爪爪根际微生物的代谢活性和代谢多样性有着明显的影响，其中采用5% NaCl溶液作为稀释加样液的根际微生物活性最高。【结论】盐爪爪根部微生物组成和分布有着明显的演变规律，且采用Biolog Eco微平板技术分析微生物代谢多样性时需进行培养条件的优化。

Abstract:

[Background] Kalidium foliatum are typical salt-tolerant plants widely distributed in saline-alkali desert areas. Salt accumulation constructed a salt island in the rhizosphere. There was rare investigation about how the microorganism succeed and adapted in the salt accumulation process. However, it was important to reveal the salt tolerance of Kalidium foliatum and formation of the salt island. [Objective] We analyzed the distribution characteristics of microorganism in soils of the rhizosphere, the root zone and the environment, and determined the effect of different salt concentration treatments on metabolic diversity of rhizosphere bacteria using Biolog Eco microplate. [Methods] Soils of the rhizosphere, the root zone and the environmental were sampled from Heshuo County, Xinjiang. The Biolog Eco microplate technique was used to analyze the utilization of microbial carbon sources. The rhizosphere soil samples were diluted by different NaCl concentrations, and then the dilution was taken to add into Biolog Eco microplates. The effect of the salt concentration on rhizosphere microbial activity and diversity was analyzed. [Results] Microbial metabolic activity of the samples showed a trend of the rhizosphere > the root zone > the environment. With the increase of distance from the root, the proportion of microorganisms using amino acids and amines as carbon sources decreased significantly, while the proportion of microorganisms using polymeric compound carbon sources increased significantly such as Tween, Glycogen and so on. Analysis of diversity showed that the Shannon index (H) decreased with significant difference. The significant effect of dilution solutions in different NaCl concentrations was observed on the metabolic activity and distribution of microbial community. And microbial activity of the rhizosphere was the highest at 5% NaCl solution as dilution solution. [Conclusion] The composition and distribution of microorganisms around the roots of Kalidium foliatum showed obvious evolution regularity. And it is necessary to optimize the cultivation condition using Biolog Eco microplate.