耐鉛鋅菌群的鑒定及其去除鉛鋅特性研究
發(fā)布時間：2018-10-31 14:10
【摘要】：長期生活在重金屬污染環(huán)境的微生物部分已具備耐受重金屬的能力,從環(huán)境中將其分離馴化,是目前獲得高效微生物修復(fù)資源的有效途徑。通常,單一的微生物易受環(huán)境影響,難以廣泛應(yīng)用。而經(jīng)過長期適應(yīng)的多種微生物構(gòu)成的協(xié)同菌群具有一定的穩(wěn)定性,同時兼具一定系統(tǒng)功能性,在強(qiáng)化植物修復(fù)方面頗具潛力。本文以鉛鋅尾礦區(qū)有機(jī)菌肥處理組與對照組獲得的可培養(yǎng)根際菌群為研究對象,通過正交試驗對比其去除鉛鋅的能力及特性的差異,優(yōu)化培養(yǎng)條件以獲得高效的耐性菌群。通過營養(yǎng)液-沙培試驗分析耐性菌群對鉛鋅脅迫下蓖麻種子萌發(fā)、幼苗生長及重金屬積累的影響機(jī)制,結(jié)合高通量測序技術(shù)對耐性菌群的結(jié)構(gòu)及多樣性進(jìn)行分析鑒定。主要研究結(jié)論如下:1)在鉛鋅復(fù)合脅迫下,有機(jī)菌肥處理組與對照組獲得的可培養(yǎng)根際菌群去除鉛的差異大,去除鋅的差異不顯著。菌群LJ(加有機(jī)菌肥)的鉛、鋅去除率較菌群LJO(未加有機(jī)菌肥)有不同程度的增加,最大增量可達(dá)40.2%、12.7%。鉛鋅濃度、培養(yǎng)基類型等因素對菌群LJ的鉛、鋅去除率有一定影響,其中培養(yǎng)基類型的影響最大。綜合而言,菌群LJ去除鉛鋅的最佳培養(yǎng)條件為:鉛鋅濃度50mg/L、接菌量1.0mL、培養(yǎng)時間6 d、牛肉膏蛋白胨培養(yǎng)基。2)優(yōu)化培養(yǎng)條件獲得的兩組耐性菌群對蓖麻初期的生長發(fā)育產(chǎn)生了不同的影響。在種子萌發(fā)階段,接種牛肉膏菌群(細(xì)菌)對發(fā)芽有一定促進(jìn)作用,馬丁氏菌群(真菌)則呈現(xiàn)抑制作用。在幼苗生長發(fā)育階段,牛肉膏菌群有利于植物株高的伸長,馬丁氏菌群則更益于幼苗根系的發(fā)育。蓖麻幼苗對鋅的積累及轉(zhuǎn)運能力均強(qiáng)于鉛,重金屬主要積累在根部。兩組菌群對植物根系吸收鋅的抑制作用較明顯,對鉛的吸收影響較小。在較高鉛鋅濃度(100 mg/L)脅迫下,接種兩組菌群更有利于植物對鉛鋅的向上轉(zhuǎn)移。3)蓖麻根際的耐性細(xì)菌類群豐富,優(yōu)勢細(xì)菌門為變形菌門,優(yōu)勢細(xì)菌綱為藍(lán)細(xì)菌綱、芽孢桿菌綱,優(yōu)勢細(xì)菌屬為劍菌屬、貪銅菌屬。100 mg/L鉛鋅脅迫下,耐性細(xì)菌群落的豐富度有所降低,優(yōu)勢菌的相對豐度也有下降趨勢,但不改變其優(yōu)勢地位,少數(shù)類群出現(xiàn)了相對豐度增加的現(xiàn)象�？傮w上,耐性細(xì)菌群落具有一定的穩(wěn)定性。由于測序深度不夠,所檢測的真菌類群十分單一。子囊菌門(Ascomycota)、糞殼菌綱(Sordariomycetes)、鐮刀菌屬(Fusarium)是群落在門、綱、屬分類水平上的優(yōu)勢菌,占據(jù)了真菌總量的99.9%。100 mg/L鉛鋅脅迫對鐮刀菌屬的相對豐度有顯著的降低作用,對曲霉屬則有極顯著的提高。
[Abstract]:The microbes living in the polluted environment of heavy metals for a long time already have the ability to tolerate heavy metals. It is an effective way to obtain efficient microbial remediation resources by separating and domesticating them from the environment. Usually, a single microorganism is easily affected by the environment and is difficult to be widely used. The synergistic microflora which has been adapted for a long time has a certain stability and a certain system function. It has great potential in strengthening the phytoremediation. In this paper, the culturable rhizosphere flora obtained from the organic bacterial fertilizer treatment group and the control group in the lead-zinc tail mining area was studied. The differences in the ability and characteristics of removing lead and zinc were compared by orthogonal experiment, and the culture conditions were optimized to obtain the efficient tolerant flora. The effects of tolerant microflora on seed germination, seedling growth and heavy metal accumulation of castor under lead and zinc stress were analyzed by nutrient liquid-sand culture test. The structure and diversity of tolerant flora were analyzed and identified by high-throughput sequencing technique. The main conclusions are as follows: 1) under the combined stress of lead and zinc, the differences of lead removal and zinc removal between the organic fertilizer treatment group and the control group were great. The removal rate of lead and zinc in LJ was higher than that in LJO, and the maximum increment was 40.2%. The concentration of lead and zinc and the type of culture medium had a certain influence on the removal rate of lead and zinc of LJ, and the type of culture medium had the most influence on the removal rate of lead and zinc. Generally speaking, the optimum culture conditions for removal of lead and zinc by LJ were as follows: lead and zinc concentration 50 mg / L, inoculation amount 1.0 mL, culture time 6 days. Beef extract peptone medium. 2) the two groups of resistant bacteria obtained by optimizing the culture conditions had different effects on the growth and development of castor. At the stage of seed germination, inoculation of beef paste bacteria (bacteria) promoted germination to some extent, while Martin's group (fungi) showed inhibitory effect. In the stage of seedling growth and development, the plant height elongation was facilitated by the beef extract flora, while the Martin's group was more beneficial to the development of the seedling root system. The accumulation and transport of zinc in castor seedlings were stronger than that of lead, and heavy metals mainly accumulated in roots. The inhibition of zinc uptake by the two groups was more obvious than that of lead absorption. Under the stress of high concentration of lead and zinc (100 mg/L), inoculation of the two groups of bacteria was more favorable to the upward transfer of lead and zinc. 3) the dominant bacteria phylum was Proteus and the dominant class was cyanobacterium in the rhizosphere of castor. Under lead and zinc stress of 100 mg/L, the abundance of tolerant bacteria community decreased, and the relative abundance of dominant bacteria decreased, but it did not change its dominant position. A few groups appeared the phenomenon of relative abundance increase. Generally speaking, the tolerant bacterial community has certain stability. Because the sequencing depth is not enough, the detected fungi group is very single. (Sordariomycetes), is the dominant species in the taxonomic level of phylum, class and taxonomy of Fusarium (Sordariomycetes),. The relative abundance of Fusarium decreased significantly under lead and zinc stress of 99.9. 100 mg/L and increased significantly on Aspergillus.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X172;X753
[Abstract]:The microbes living in the polluted environment of heavy metals for a long time already have the ability to tolerate heavy metals. It is an effective way to obtain efficient microbial remediation resources by separating and domesticating them from the environment. Usually, a single microorganism is easily affected by the environment and is difficult to be widely used. The synergistic microflora which has been adapted for a long time has a certain stability and a certain system function. It has great potential in strengthening the phytoremediation. In this paper, the culturable rhizosphere flora obtained from the organic bacterial fertilizer treatment group and the control group in the lead-zinc tail mining area was studied. The differences in the ability and characteristics of removing lead and zinc were compared by orthogonal experiment, and the culture conditions were optimized to obtain the efficient tolerant flora. The effects of tolerant microflora on seed germination, seedling growth and heavy metal accumulation of castor under lead and zinc stress were analyzed by nutrient liquid-sand culture test. The structure and diversity of tolerant flora were analyzed and identified by high-throughput sequencing technique. The main conclusions are as follows: 1) under the combined stress of lead and zinc, the differences of lead removal and zinc removal between the organic fertilizer treatment group and the control group were great. The removal rate of lead and zinc in LJ was higher than that in LJO, and the maximum increment was 40.2%. The concentration of lead and zinc and the type of culture medium had a certain influence on the removal rate of lead and zinc of LJ, and the type of culture medium had the most influence on the removal rate of lead and zinc. Generally speaking, the optimum culture conditions for removal of lead and zinc by LJ were as follows: lead and zinc concentration 50 mg / L, inoculation amount 1.0 mL, culture time 6 days. Beef extract peptone medium. 2) the two groups of resistant bacteria obtained by optimizing the culture conditions had different effects on the growth and development of castor. At the stage of seed germination, inoculation of beef paste bacteria (bacteria) promoted germination to some extent, while Martin's group (fungi) showed inhibitory effect. In the stage of seedling growth and development, the plant height elongation was facilitated by the beef extract flora, while the Martin's group was more beneficial to the development of the seedling root system. The accumulation and transport of zinc in castor seedlings were stronger than that of lead, and heavy metals mainly accumulated in roots. The inhibition of zinc uptake by the two groups was more obvious than that of lead absorption. Under the stress of high concentration of lead and zinc (100 mg/L), inoculation of the two groups of bacteria was more favorable to the upward transfer of lead and zinc. 3) the dominant bacteria phylum was Proteus and the dominant class was cyanobacterium in the rhizosphere of castor. Under lead and zinc stress of 100 mg/L, the abundance of tolerant bacteria community decreased, and the relative abundance of dominant bacteria decreased, but it did not change its dominant position. A few groups appeared the phenomenon of relative abundance increase. Generally speaking, the tolerant bacterial community has certain stability. Because the sequencing depth is not enough, the detected fungi group is very single. (Sordariomycetes), is the dominant species in the taxonomic level of phylum, class and taxonomy of Fusarium (Sordariomycetes),. The relative abundance of Fusarium decreased significantly under lead and zinc stress of 99.9. 100 mg/L and increased significantly on Aspergillus.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X172;X753
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