水稻土鐵還原細(xì)菌豐度及群落結(jié)構(gòu)對(duì)淹水時(shí)間的響應(yīng)
發(fā)布時(shí)間：2018-08-15 16:04
【摘要】：Fe(Ⅲ)是厭氧土壤中最豐富的電子受體,鐵的氧化和還原過程對(duì)碳、氮元素循環(huán),微量營(yíng)養(yǎng)元素的移動(dòng),尤其是有機(jī)和無(wú)機(jī)污染物的降解、轉(zhuǎn)化與固定過程有著強(qiáng)烈的影響。水稻土是非常復(fù)雜又典型的生態(tài)系統(tǒng),分析水稻土鐵還原細(xì)菌豐度和群落結(jié)構(gòu)對(duì)淹水培養(yǎng)過程的響應(yīng),對(duì)深入探討其鐵還原、營(yíng)養(yǎng)元素轉(zhuǎn)換、抑制甲烷生成及生物修復(fù)過程具有重要意義。本文采用Real-time PCR、PCR-DGGE以及文庫(kù)構(gòu)建手段,分析了淹水非種植水稻土中細(xì)菌及其地桿菌、梭菌、芽孢桿菌、假單胞菌和厭氧粘細(xì)菌等典型鐵還原菌的豐度和群落結(jié)構(gòu)對(duì)淹水時(shí)間的響應(yīng)特征及其與Fe(Ⅲ)還原變化的關(guān)系,為進(jìn)一步明確微生物在異化鐵還原及其他生態(tài)過程中的作用提供理論依據(jù)。獲得了以下主要結(jié)果:(1)供試水稻土在淹水培養(yǎng)過程中,Fe(Ⅱ)含量在前期(1 h-10 d)迅速增加,而之后趨于穩(wěn)定;最大還原潛勢(shì)為5.929 mg/g,最大反應(yīng)速率為0.989 mg/(g.d),最大反應(yīng)速率對(duì)應(yīng)的時(shí)間(TVmax)為2.853 d。(2)淹水水稻土中細(xì)菌的豐度在1 d時(shí)最大,并在40 d到達(dá)第二個(gè)峰值,淹水過程改變了細(xì)菌的豐度。基于16S rDNA的DGGE圖譜分析顯示淹水過程中細(xì)菌的群落結(jié)構(gòu)發(fā)生了演替性變化:r策略生存的細(xì)菌僅存在于淹水初期;k策略生存的細(xì)菌存在于淹水后期;r和k-策略共生存的細(xì)菌存在于整個(gè)淹水過程中,淹水后期k-策略的細(xì)菌占據(jù)優(yōu)勢(shì)。淹水培養(yǎng)過程中優(yōu)勢(shì)種群多樣性指數(shù)大體呈現(xiàn)先上升后減小的趨勢(shì)。PCA分析將淹水處理過程分成幾類不同的生境,反映出中、后期細(xì)菌群落結(jié)構(gòu)較為穩(wěn)定;測(cè)序結(jié)果表明,32個(gè)優(yōu)勢(shì)條帶所代表的細(xì)菌分別屬于厚壁菌門、綠彎菌門、擬桿菌門、變形菌門和酸桿菌門,且與來(lái)自不同地域的水稻土、其他類型土壤、活性污泥以及湖泊沉積物等生態(tài)系統(tǒng)的細(xì)菌關(guān)系密切。(3)對(duì)5種典型鐵還原細(xì)菌的豐度分析表明,整個(gè)淹水過程中,芽孢桿菌豐度最高,占絕對(duì)優(yōu)勢(shì),假單胞菌豐度最低。在淹水初期,梭菌和芽孢桿菌豐度都快速上升并在1 d達(dá)到最大值,而地桿菌、假單胞菌和厭氧粘細(xì)菌在1 d時(shí)豐度最小,之后呈現(xiàn)上升趨勢(shì),分別在40 d、30 d和60 d達(dá)到最大。由此推測(cè)芽孢桿菌對(duì)鐵還原過程的貢獻(xiàn)最大,假單胞菌的最小。淹水初期,芽孢桿菌和梭菌的貢獻(xiàn)較大,而后期對(duì)鐵還原過程貢獻(xiàn)大的是地桿菌、厭氧粘細(xì)菌和假單胞菌。(4)對(duì)5種典型鐵還原細(xì)菌的群落結(jié)構(gòu)分析表明,淹水過程中群落結(jié)構(gòu)發(fā)生了演替性變化。多樣性分析表明,淹水過程中不同細(xì)菌的Shannon指數(shù)H'變化明顯,其中芽孢桿菌的變化最大,從1 h的1.674,到40 d達(dá)到最大,為4.129。根據(jù)淹水時(shí)間的PCA分析顯示,總體上講,與細(xì)菌的結(jié)果類似,5種鐵還原菌也被分成不同的生境,且培養(yǎng)后期均形成了獨(dú)立的生境,也表明淹水后期群落結(jié)構(gòu)變化趨于穩(wěn)定。(5)基于DGGE優(yōu)勢(shì)條帶和克隆文庫(kù)序列的系統(tǒng)發(fā)育分析表明,供試土壤中5種鐵還原菌的生態(tài)分布廣泛,且能與多種具有污染物降解和重金屬還原等的微生物聚在一起。(6)CCA分析顯示,淹水過程中水稻土的Fe(Ⅱ)濃度、pH值、5種鐵還原菌的豐度和香農(nóng)指數(shù)對(duì)生境相似度都有貢獻(xiàn)。綜上所述,細(xì)菌及其5種鐵還原細(xì)菌的豐度和群落結(jié)構(gòu)對(duì)淹水時(shí)間產(chǎn)生了各自的響應(yīng);鐵還原菌對(duì)水稻土的鐵還原過程作出了貢獻(xiàn),推測(cè)芽孢桿菌對(duì)整個(gè)淹水過程的鐵還原貢獻(xiàn)最大,淹水后期地桿菌和厭氧粘細(xì)菌也作出了重要貢獻(xiàn)。
[Abstract]:Fe(III) is the most abundant electron acceptor in anaerobic soils. The oxidation and reduction of iron have a strong influence on the cycling of carbon and nitrogen, the movement of micronutrients, especially the degradation, transformation and fixation of organic and inorganic pollutants. Paddy soils are very complex and typical ecosystems. The abundance of iron-reducing bacteria in paddy soils is analyzed. The response of the community structure to the submerged culture process is of great significance to the further study of iron reduction, nutrient transformation, inhibition of methane production and bioremediation. In this paper, Real-time PCR, PCR-DGGE and library construction methods were used to analyze the bacteria and their geobacteria, Clostridium, Bacillus and Pseudomonas in the submerged non-cultivated paddy soil. The characteristics of abundance and community structure of typical iron-reducing bacteria such as bacteria and anaerobic myxobacteria in response to flooding time and their relationship with Fe(III) reduction provide theoretical basis for further clarifying the role of microorganisms in dissimilated iron reduction and other ecological processes. The content of Fe (II) increased rapidly in the early stage (1 h-10 d) and then stabilized; the maximum reduction potential was 5.929 mg/g, the maximum reaction rate was 0.989 mg/(g.d), and the corresponding time of the maximum reaction rate (TVmax) was 2.853 D. (2) The abundance of bacteria in flooded paddy soil reached the second peak at 1 D and reached the second peak at 40 D. The process of flooding changed fine. The abundance of bacteria. The DGGE analysis based on 16S rDNA showed that the community structure of bacteria changed successively in the course of flooding: the bacteria survived by strategy r only existed in the early stage of flooding; the bacteria survived by strategy K existed in the late stage of flooding; the bacteria survived by strategy R and strategy K existed in the whole process of flooding, and the bacteria occupied by strategy K in the late stage of flooding. According to the dominance, the diversity index of dominant species increased first and then decreased in the process of submerged culture. PCA analysis classified the process of submerged water treatment into several different habitats, reflecting that the structure of bacterial community was relatively stable in the middle and later stages. Bacteroides, Proteus and Acidobacteriaceae are closely related to bacteria from paddy soils, other types of soils, activated sludge and lake sediments. (3) Abundance analysis of five typical iron-reducing bacteria showed that Bacillus was the most abundant and predominant bacteria in the whole flooding process, and Pseudomonas was abundant. At the beginning of flooding, the abundance of Clostridium and Bacillus increased rapidly and reached the maximum value in 1 day, while the abundance of Enterobacter, Pseudomonas and Anaerobic Myxobacteria was the smallest in 1 day, and then showed an upward trend, reaching the maximum at 40, 30 and 60 days respectively. (4) The community structure analysis of five typical iron-reducing bacteria showed that the community structure changed during the flooding process. Diversity analysis showed that different bacteria contributed greatly to the iron reduction process. The change of Shannon index H'was obvious, and the change of Bacillus spp. was the greatest from 1.674 h to 4.129 D. According to the PCA analysis of flooding time, five kinds of iron-reducing bacteria were divided into different habitats, and formed independent habitats in the later period of culture, which also indicated that the community in the later period of flooding was similar to that of bacteria. (5) Phylogenetic analysis based on DGGE dominant bands and clone library sequences showed that five iron-reducing bacteria were widely distributed in the soil and could be aggregated with many microorganisms with pollutant degradation and heavy metal reduction. (6) CCA analysis showed that Fe (II) concentration and pH value of paddy soil during flooding. In summary, the abundance and community structure of bacteria and their five iron-reducing bacteria responded to the flooding time respectively; iron-reducing bacteria contributed to the iron reduction process of paddy soil, and Bacillus spp. contributed the most to the iron reduction of the whole flooding process. In the late stage of flooding, the bacteria and anaerobic bacteria also made important contributions.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S154.36
本文編號(hào)：2184707
[Abstract]:Fe(III) is the most abundant electron acceptor in anaerobic soils. The oxidation and reduction of iron have a strong influence on the cycling of carbon and nitrogen, the movement of micronutrients, especially the degradation, transformation and fixation of organic and inorganic pollutants. Paddy soils are very complex and typical ecosystems. The abundance of iron-reducing bacteria in paddy soils is analyzed. The response of the community structure to the submerged culture process is of great significance to the further study of iron reduction, nutrient transformation, inhibition of methane production and bioremediation. In this paper, Real-time PCR, PCR-DGGE and library construction methods were used to analyze the bacteria and their geobacteria, Clostridium, Bacillus and Pseudomonas in the submerged non-cultivated paddy soil. The characteristics of abundance and community structure of typical iron-reducing bacteria such as bacteria and anaerobic myxobacteria in response to flooding time and their relationship with Fe(III) reduction provide theoretical basis for further clarifying the role of microorganisms in dissimilated iron reduction and other ecological processes. The content of Fe (II) increased rapidly in the early stage (1 h-10 d) and then stabilized; the maximum reduction potential was 5.929 mg/g, the maximum reaction rate was 0.989 mg/(g.d), and the corresponding time of the maximum reaction rate (TVmax) was 2.853 D. (2) The abundance of bacteria in flooded paddy soil reached the second peak at 1 D and reached the second peak at 40 D. The process of flooding changed fine. The abundance of bacteria. The DGGE analysis based on 16S rDNA showed that the community structure of bacteria changed successively in the course of flooding: the bacteria survived by strategy r only existed in the early stage of flooding; the bacteria survived by strategy K existed in the late stage of flooding; the bacteria survived by strategy R and strategy K existed in the whole process of flooding, and the bacteria occupied by strategy K in the late stage of flooding. According to the dominance, the diversity index of dominant species increased first and then decreased in the process of submerged culture. PCA analysis classified the process of submerged water treatment into several different habitats, reflecting that the structure of bacterial community was relatively stable in the middle and later stages. Bacteroides, Proteus and Acidobacteriaceae are closely related to bacteria from paddy soils, other types of soils, activated sludge and lake sediments. (3) Abundance analysis of five typical iron-reducing bacteria showed that Bacillus was the most abundant and predominant bacteria in the whole flooding process, and Pseudomonas was abundant. At the beginning of flooding, the abundance of Clostridium and Bacillus increased rapidly and reached the maximum value in 1 day, while the abundance of Enterobacter, Pseudomonas and Anaerobic Myxobacteria was the smallest in 1 day, and then showed an upward trend, reaching the maximum at 40, 30 and 60 days respectively. (4) The community structure analysis of five typical iron-reducing bacteria showed that the community structure changed during the flooding process. Diversity analysis showed that different bacteria contributed greatly to the iron reduction process. The change of Shannon index H'was obvious, and the change of Bacillus spp. was the greatest from 1.674 h to 4.129 D. According to the PCA analysis of flooding time, five kinds of iron-reducing bacteria were divided into different habitats, and formed independent habitats in the later period of culture, which also indicated that the community in the later period of flooding was similar to that of bacteria. (5) Phylogenetic analysis based on DGGE dominant bands and clone library sequences showed that five iron-reducing bacteria were widely distributed in the soil and could be aggregated with many microorganisms with pollutant degradation and heavy metal reduction. (6) CCA analysis showed that Fe (II) concentration and pH value of paddy soil during flooding. In summary, the abundance and community structure of bacteria and their five iron-reducing bacteria responded to the flooding time respectively; iron-reducing bacteria contributed to the iron reduction process of paddy soil, and Bacillus spp. contributed the most to the iron reduction of the whole flooding process. In the late stage of flooding, the bacteria and anaerobic bacteria also made important contributions.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S154.36
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