芦苇-AMF共生系统对阿特拉津胁迫的响应及其降解作用研究

发布时间：2018-04-05 10:00

  本文选题：阿特拉津　切入点：摩西球囊霉　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：阿特拉津是一种国内外农业上常用的除草剂,虽然具有很低的毒性,但是由于长时间的大面积使用、加之自身结构稳定不易降解从而导致在环境中残留时间长,而且是一种环境荷尔蒙和潜在致癌物质,目前已经对我国的环境生态安全造成了相当大的威胁。丛枝菌根真菌(Abscular Mycorrhizal Fungi,AMF)是一种很常见的菌根真菌,其菌丝可以通过侵入宿主植物的细胞组织内部,与之根部形成共生体系。目前,利用丛枝菌根真菌-植物构建的复合体系对污染物进行联合修复的方法由于具有应用成本低、修复效率高、对环境友好且安全不产生二次污染等优势,已经逐渐成为了生态修复领域一项极其具有发展前景的技术。本文采用水培盆栽方法进行实验,以湿地植物芦苇作为供试植物,以农药阿特拉津作为研究对象,在播种前向基质中接种摩西球囊霉(Glomus mosseae,GM),以不接菌处理作为空白对照,研究共生体系对湿地中阿特拉津的修复作用。实验结果表明:经过25d的施药周期后,实验基质中施加的阿特拉津绝大部分被降解,且降解速率随时间变化呈现先快后慢的趋势。不同浓度的阿特拉津降解速率也有所不同,在药物浓度为0.1mg/L时,其降解速率是最高的。接种AM真菌使得植物对阿特拉津的降解效果更好,各浓度培养液中阿特拉津的平均降解率较不接菌处理高约13.83%。在播种前,通过向培养基质中人工施加AM菌剂,在环境适宜的条件下,AM菌剂对芦苇根部的侵染率可以达到17.67%,菌根依赖性指数达到342%。接种AM真菌植株的株高较未接菌处理高出27.88%、根长高出45.50%、地上地下两部分生物量分别比未接菌处理高192%和221%。且接种AM真菌后,能够使得芦苇的光合作用加强、叶片中叶绿素含量也有明显提高。在阿特拉津胁迫下,菌根的存在可以对芦苇产生很好的保护作用,扩大了芦苇对阿特拉津胁迫的承受阈值(≤1mg/L),并且在有效阈值内能够显著提高植物的抗逆能力,植物根部过氧化物酶活性均有明显提高、丙二醛含量降低。接种AMF还能有效提高基质中的土壤脲酶的活力。芦苇植株对阿特拉津的富集能力较低,初始添加的药品主要通过取代、分解、氧化等化学反应途径被降解。施加AM菌剂后,阿特拉津的代谢途径较空白对照组在过程中有所不同,但两组处理均会最终生成主要的降解产物——三聚氰胺酸二酰胺(C3N5OH5),很有可能是降解过程中的反应类型不同或反应速率不同从而导致了最终降解率的差别。芦苇与AM真菌构成共生体系后,使得植物的各项生长生理指标、抗逆能力和对阿特拉津的降解能力都有了很大的提高,因此,利用微生物-植物共生体系对污染物进行联合修复的技术具有很高的实用性,应用前景是十分可观的。
[Abstract]:Atrazine is a herbicide commonly used in agriculture at home and abroad. Although it has low toxicity, it has been used for a long time on a large scale, and its structure is stable and difficult to degrade, resulting in a long residual time in the environment.Moreover, it is a kind of environmental hormone and potential carcinogen, which has posed a great threat to the ecological security of our country.Arbuscular mycorrhizal fungi (Amycorrhizal mycorrhizal fungi) are common mycorrhizal fungi. Their hyphae can form a symbiotic system by invading the cells of the host plant and forming a symbiotic system with the root of arbuscular mycorrhizal fungi.At present, the composite system constructed by arbuscular mycorrhizal mycorrhizal fungi and plants has the advantages of low application cost, high remediation efficiency, environmental friendliness and no secondary pollution.It has gradually become an extremely promising technology in the field of ecological restoration.In this paper, a pot culture experiment was carried out. The wetland plant Reed was used as the experimental plant, the pesticide atrazine was used as the research object, the GMN of Glomus mosseaeae was inoculated into the substrate before seeding, and the non-inoculated treatment was used as the blank control.To study the effect of symbiotic system on atrazine in wetland.The results showed that after 25 days of application, most of the atrazine applied in the experimental substrate were degraded, and the degradation rate showed a tendency of first faster then slower with time.The degradation rate of atrazine at different concentrations was different, and the degradation rate of atrazine was the highest when the drug concentration was 0.1mg/L.The average degradation rate of atrazine was 13.83% higher than that of non-inoculated AM fungi.Before sowing, the infection rate of AM on the root of Reed could reach 17.67, and the mycorrhizal dependence index reached 342.The infection rate of AM bacteria on Reed root was 17.67 by artificial application of AM bacteria to the culture substrate under the suitable environment.The plant height of AM plant inoculated with AM fungi was 27.88 higher than that of uninoculated treatment, and the root length was 45.50% higher than that of uninoculated treatment. The biomass of the above ground and underground parts was 19.2% and 221% higher than that of the uninoculated treatment, respectively.After inoculation with AM fungi, the photosynthesis of Reed was strengthened, and the chlorophyll content in leaves was also increased.Under atrazine stress, the existence of mycorrhizal mycorrhiza could protect Reed from stress, which increased the tolerance threshold (鈮，

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