祁连山南麓中段不同海拔土壤微生物多样性研究

发布时间：2018-09-11 15:26

【摘要】：祁连山地区在生物多样性维持方面发挥着巨大的作用。近年来,由于人类行为与环境变化的影响,逐步增加了祁连山地区草原退化和荒漠化,生态脆弱性更加明显,对经济和社会的可持续发展造成重大影响。迄今为止,前人对祁连山地区的植被方面的研究较多,对土壤微生物方面的报道相对较少,并且对该地区微生物资源很少进行系统地调查研究。本研究选取了5个不同海拔、两个不同深度共10个土壤样品,通过平板计数、Biolog微量分析、高通量测序技术,结合土壤理化性质分析,对祁连山南麓中段的土壤微生物分布规律及多样性进行了研究,得出以下主要研究结果和结论:1、整个研究区域采样点土壤pH属于中性,最高为7.24,最低为6.81。电导率最高为89.6 mS/cm,最低为16.3 mS/cm,研究结果表明,每个样点pH和电导率都随着土壤深度的增加呈增大趋势。pH和电导率表示土壤的盐碱化程度,这就表明,土壤盐碱化程度深层高于表层。AP、AK、SOC、TN含量与海拔和土壤深度呈负相关,即海拔越高、采样深度越深,以上指标相应地越小,而以上指标都代表着土壤的肥力。所以,所有指标共同表明,随着海拔和土壤深度的增加,祁连山地区土壤趋于贫瘠化和盐碱化。2、对土壤微生物中细菌、放线菌、真菌三大类群微生物的研究发现,研究区域可培养细菌数量的变化范围为51×107~4.8×107 CFU/g,放线菌数量范围为5.59×106~4.19×106 CFU/g,真菌数量变化范围为5.98×105~1.92×105 CFU/g。祁连山地区可培养微生物数量特征为细菌放线菌真菌。其中,细菌的数量占绝大多数,可以决定微生物数量的分布。三大类可培养微生物的数量在不同采样深度的总体变化规律是相同的,海拔越高、采样深度越深三大类微生物的数量越小。3、研究区域土壤微生物的总体活性变化趋势为:24小时以内活性较低基本没有明显的变化,24小时以后随着培养时间的延长而逐步增大。0-10 cm层土壤微生物的多样性指数H变化的幅度不是很大,而多样性指数U随海拔的升高明显减小。经相关性分析发现0-10 cm层微生物多样性指数H与电导率呈显著正相关,多样性指数U与海拔及pH呈显著负相关,与SOC、脲酶含量呈显著正相关(10-20 cm层与其相似)。也就说明其土壤微生物的丰富度随海拔的变化不大,主要受电导率的影响,但是均匀度主要受海拔、pH、SOC和脲酶的影响,研究区域不同海拔微生物的丰富度变化不明显但均匀度变化较大。5个样点0-10 cm层的微生物利用的主要碳源都是酯类,氨基酸类次之,糖类最低(1号样点除外)。微生物对碳源的利用情况与环境因子的相关性分析发现微生物对六大类碳源的利用与pH呈显著负相关,与电导率、SOC、TN、脲酶等含量呈显著正相关。10-20 cm层的微生物利用的主要碳源也是酯类,氨基酸类次之,糖类最低。4、MiSeq宏基因组测序:Chao/Ace指数、Shannon指数、Simpson指数以及OTU聚类分析共同表明,在不同的海拔高度和土壤深度的样品中,研究区域微生物的物种丰富度和均匀度差异都较显著,随着海拔高度的增加表现为先增大后降低的趋势,而且上层土壤高于深层土壤。10个样品中优势菌群都是变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、疣微菌门(Verrucomicrobia)和酸杆菌门(Acidobacteria)。不同土壤深度四类优势菌群的数量差异显著。酸杆菌门的数量都是深层多于表层,相反地变形菌门的数量都是表层高于深层,放线菌门和疣微菌门的数量与土壤深度的变化没有明显的规律。对理化因子与微生物数量的相关性分析发现,10个样点微生物的数量与有机质、SOC、TN、脲酶、蔗糖酶、过氧化氢酶等有显著的相关性。本研究较为系统地阐明了祁连山南麓中段地区土壤微生物的群落结构特征及其影响因素。揭示了该区域内不同海拔、不同深度土壤微生物的多样性。为祁连山地区生态保护与修复提供科学支撑,并为应用微生物技术在祁连山地区进行环境治理提供科学依据和种质资源。
[Abstract]:The Qilian Mountains play an important role in maintaining biodiversity. In recent years, due to the influence of human behavior and environmental change, the grassland degradation and desertification in the Qilian Mountains have been gradually increased. The ecological fragility is more obvious, which has a great impact on the sustainable development of economy and society. In this study, 10 soil samples were selected from 5 different altitudes and 2 different depths, and the soil physical and chemical properties were combined by plate counting, Biolog microanalysis, high-throughput sequencing technology. The distribution and diversity of soil microorganisms in the middle part of the southern foot of the Qilian Mountains were studied by qualitative analysis. The main results and conclusions were as follows: 1. Soil pH in the whole study area was neutral, the highest was 7.24, the lowest was 6.81. The highest conductivity was 89.6 mS/cm, the lowest was 16.3 mS/cm. The results showed that pH and electricity of each sampling point were neutral. PH and conductivity indicate that the salinization degree of soil is higher in the deep layer than in the surface layer. AP, AK, SOC and TN contents are negatively correlated with the altitude and soil depth, that is, the higher the altitude, the deeper the sampling depth, the smaller the above indicators correspondingly, and the above indicators represent the soil. Soil fertility. Therefore, all indicators show that with the increase of altitude and soil depth, the soil in Qilian Mountains tends to be barren and saline-alkaline. 2. The study of bacteria, actinomycetes and fungi in soil microorganisms found that the number of culturable bacteria in the study area ranged from 51 *107 to 4.8 *107 CFU/g, actinomycetes. The number of culturable microorganisms in Qilian Mountains ranged from 5.59 *106 to 4.19 *106 CFU/g, and the number of fungi ranged from 5.98 *105 to 1.92 *105 CFU/g. The quantity of culturable microorganisms in Qilian Mountains was characterized by bacterial actinomycetes. The overall change law is the same, the higher the altitude, the deeper the sampling depth, the smaller the number of three types of microorganisms. 3. The overall change trend of soil microbial activity in the study area is as follows: the activity of soil microorganisms within 24 hours is low, basically no significant change, 24 hours later with the extension of cultivation time and gradually increase the number of soil microorganisms. The correlation analysis showed that the microbial diversity index H in 0-10 cm layer was positively correlated with electrical conductivity, and the diversity index U was negatively correlated with altitude and pH, and positively correlated with SOC and urease content (similar to 10-20 cm layer). The results showed that the richness of soil microorganisms changed little with altitude and was mainly affected by electrical conductivity, but the uniformity was mainly affected by altitude, pH, SOC and urease. The richness of microorganisms at different altitudes in the study area did not change significantly but the uniformity changed greatly. The main carbon sources used by microorganisms in 0-10 cm layers of 5 plots were esters and ammonia. Microbial utilization of the six carbon sources was negatively correlated with pH, and positively correlated with conductivity, SOC, TN, urease, etc. The main carbon sources used by microorganisms in the 10-20 cm layer were esters and amino acids. MiSeq macrogenome sequencing: Chao/Ace index, Shannon index, Simpson index and OTU cluster analysis showed that there were significant differences in species richness and evenness of microorganisms in the study area at different altitudes and soil depths. The dominant bacteria in 10 samples were Proteobacteria, Actinobacteria, Verrucomicrobia and Acidobacteria. The number of dominant bacteria in different soil depths was significantly different. On the contrary, the number of Proteus in the surface layer was higher than that in the deep layer, and the number of actinomycetes and verrucous microflora had no obvious relationship with soil depth. This study systematically elucidated the characteristics of soil microbial community structure and its influencing factors in the middle part of the southern foot of the Qilian Mountains, revealed the diversity of soil microorganisms at different altitudes and depths in the region, provided scientific support for ecological protection and restoration in the Qilian Mountains, and provided scientific support for the application of microbial technology in the Qilian Mountains. The area provides scientific basis and germplasm resources for environmental control.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154.3

【共引文献】