狐尾藻内生细菌的锰耐受性能及强化植物修复潜力研究

发布时间：2018-05-07 02:36

本文选题：狐尾藻 + 内生菌　；参考：《广西大学》2017年硕士论文

【摘要】：植物-微生物联合修复是利用基质-植物-微生物组成的复合体系来共同降解或清除污染物的一种污染控制技术。这种技术的关键一是寻找超富集植物,二是寻找可与超富集植物共生并对其环境修复能力具有促进作用的微生物。内生菌从宿主植物中分离得出,对宿主植物具有促进其生长甚至增强其对污染物富集能力的作用。本研究从野生及温室培养的轮叶狐尾藻中分离内生菌,通过在含锰培养基培养,筛选出在锰离子浓度800 mg/L的胁迫下,对锰具有抗性和特异性的内生菌株并对其种属进行鉴别,考察抗锰内生菌在锰及其它重金属胁迫下的耐受性、生长曲线和相关生理生化特性以及对宿主植物生长生理的影响,在此基础上推测内生菌对促进植物生长、植物累积锰和抗锰毒害可能的作用机制。为了解以上耐锰内生菌在非均相固体基质中与多金属的相互作用,还探讨接种内生菌对矿渣和河流底泥中金属形态变化的作用效果。研究结果表明:(1)生长环境对植物体内生细菌影响显著。温室培养会导致狐尾藻茎叶部内生菌多样性的损失。从野生狐尾藻样本中分离获得78株内生菌,而从温室培养样本中只获得27株,其中大部分为细菌。(2)从轮叶狐尾藻分离出的内生菌中,有12个菌株能耐受800mg/L锰离子胁迫,其中来自野生狐尾藻的三个菌株YJ01、YJ31和YY07在高达1000 mg/L锰离子浓度胁迫下仍对锰有良好的抗性。温室培养狐尾藻内生菌中,XY09对锰的耐受能力最好,XJ02对低浓度锰离子有“Hormesis”效应。低浓度的锌和锰离子对YJ31和YY07的生长或适应能力具有毒性刺激效应。重金属对上述菌株毒害强弱顺序均表现为:CdCuZnMn。(3)初步鉴定五株内生菌YJ01、YJ31、YY07、XJ02和XY09分别属于:芽孢杆菌属、不动杆菌属、假苍白杆菌属、泛菌属和假单胞菌属。其中,泛菌属XJ02为新发现的一种具有耐锰特性的内生菌种类。(4)内生菌定殖狐尾藻水培实验表明,五株内生菌均表现至少有一种植物促生潜能,狐尾藻根、茎、叶的鲜重和干重、株长和锰吸收量较对照组增加,甚至提高了极高锰浓度胁迫下的存活率;接种内生菌还能有效缓解锰对植物的胁迫毒性效应,表现在接菌处理对狐尾藻抗氧化系统有积极影响,叶片丙二醛含量也明显低于对照。(5)五株抗锰菌对矿渣和底泥中金属形态有明显的影响。其中,五株内生菌均能提高锌的生物有效性,YY07和XY09提高锰的生物有效性,YY07、XJ02和XY09提高镉的生物有效性,而YJ31降低锰的生物有效性。综上可知,从狐尾藻分离筛选出的部分内生菌对锰胁迫具有良好的抗性和耐受能力,同时,还具有促进宿主植物的生长和富集锰的潜力,接种上述内生菌对矿渣和底泥中重金属生物有效性产生一定影响。本研究为基质-水生植物-内生菌联合修复技术发展提供了理论依据和新的微生物种源,但基质-水生植物-内生菌之间的协同机制与调控手段尚有待深入研究。
[Abstract]:Phytoremediation is a pollution control technique which uses a composite system composed of matrix plant and microorganism to degrade or remove pollutants. The key of this technique is to search for super-enriched plants and to find microbes that can co-exist with super-enriched plants and promote their environmental remediation ability. Endophytic bacteria isolated from host plants can promote the growth of host plants and even enhance their ability to enrich pollutants. In this study, endophytic bacteria were isolated from the wild and greenhouse cultured algae, and the endophytic strains with resistance and specificity to manganese were selected and identified under the stress of manganese ion concentration of 800 mg/L on the medium containing manganese. The tolerance, growth curve and related physiological and biochemical characteristics of manganese resistant endophytic bacteria under mn and other heavy metal stress were investigated, and the effects of endophytes on the growth of host plants were also studied, based on which it was inferred that endophytic bacteria could promote plant growth. The possible mechanism of plant accumulation and resistance to manganese toxicity. In order to understand the interaction of manganese resistant endophytic bacteria with polymetallic in heterogeneous solid matrix, the effect of inoculating endophytic bacteria on the changes of metal morphology in slag and river sediment was also discussed. The results showed that the growth environment had a significant effect on the growth of bacteria in plants. Greenhouse culture will result in loss of endophytic diversity in stem and leaf. 78 strains of endophytic bacteria were isolated from the samples of C. vulgaris, but only 27 strains were isolated from greenhouse culture samples, most of which were bacteria. (2) among the endophytic bacteria isolated from C. auriculata, 12 strains were able to withstand 800mg/L mn ~ (2 +) stress. Among them, three strains YJ01PYJ31 and YY07 were still resistant to manganese under mn ~ (2 +) concentration of up to 1000 mg/L. The tolerance ability of XY09 to manganese in endophytic bacteria cultured in greenhouse was the best. XJ02 had "Hormesis" effect on low concentration manganese ions. Low concentrations of zinc and manganese ions have toxic stimulative effects on the growth or adaptability of YJ31 and YY07. The order of toxicity of heavy metals to the above strains was: 1: CdCuZnMn.K3) five endophytic bacteria, YJ01, YJ31, YY07, XJ02 and XY09, belong to the genus Bacillus, Acinetobacter, Pseudopallidus, Panum and Pseudomonas, respectively, which belong to the genus Bacillus, Acinetobacter, Pseudomonas and Pseudomonas respectively. Among them, XJ02 is a newly discovered endophytic species with manganese tolerance. 4) the hydroponic experiment showed that all five endophytes have at least one plant growth potential, and the fresh weight and dry weight of root, stem and leaf of P. vulgaris. Plant length and manganese uptake increased compared with the control group, and even increased the survival rate under very high mn concentration stress. Inoculation of endophytic bacteria also effectively alleviated the toxicity of manganese to plants, which was shown by the positive effect of inoculation treatment on the antioxidant system of P. vulgaris. The content of malondialdehyde in leaves was also significantly lower than that in control group. (5) Manganese resistant bacteria had a significant effect on metal morphology in slag and sediment. Among them, five endophytic bacteria could increase the bioavailability of zinc (YY07 and XY09) and the bioavailability of manganese (YY07, XJ02 and XY09), but YJ31 could decrease the bioavailability of mn. It can be concluded that some endophytic bacteria isolated from Sargassum vulgaris have good resistance and tolerance to manganese stress, and also have the potential to promote the growth and enrichment of manganese in host plants. Inoculation of endophytic bacteria affected the bioavailability of heavy metals in slag and sediment. This study provides a theoretical basis and new microbial provenance for the development of the combined remediation technology of matrix aquatic plant-endophyte but the synergistic mechanism and regulatory means between matrix and aquatic plant-endophyte need to be further studied.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X17;X505

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