丛枝菌根真菌对宿根高粱修复铯污染的调节效应

发布时间：2018-06-20 18:25

本文选题：丛枝菌根真菌 + 铯　；参考：《西南科技大学》2015年硕士论文

【摘要】：目前,核素铯对土壤造成的污染日益严重,植物提取技术是最常用的生物修复技术,但修复植物的生物量往往成为制约提取效率的因素。经研究发现丛枝菌根真菌(Arbuscular Mycorrhiza l fungi,AMF)是一类能够与80%以上陆生植物根系形成互利共生体的内生菌根真菌,能够与宿主植物根系形成庞大的菌丝网,增强植物对土壤中矿质元素的吸收,提高对重金属和核素的耐受性。本研究以盆栽宿根高粱(Sorghum halpense.L)为植物修复材料,进行铯污染和接种菌根处理,分析不同处理对宿根高粱根际土壤酶活性、矿质元素的吸收效率、生长状况、As A-GSH循环系统以及铯富集能力的影响,探讨AMF在植物修复核素铯污染土壤领域的应用前景,为今后利用AMF-植物共生体复垦铯污染土壤提供理论参考。本研究的主要内容和结果如下:1铯胁迫下宿根高粱菌根侵染率及依赖性研究铯胁迫下宿根高粱接种5种不同AMF(G lomus geosporum,G.m o ss e ae,G.d i ap ha n um,G.v e r s if o rm e,G.et u n i cat um)后菌根侵染率均显著高于对照,以接种G.diaphanum最为显著,达到了63.38%。同时,菌根依赖性也均显著高于对照,以接种G.versiform e最为显著,达到了156.32%,其它处理菌根依赖性顺序为:G.m osseaeG.et u n i cat umG.g e os p or umG.d ia ph a num,说明宿根高粱是菌根依赖性植物。2 AMF对宿根高粱根际土壤肥力、土壤酶及生物量的影响铯胁迫下宿根高粱接种AMF后促进了根际土壤酸性磷酸酶、蔗糖酶和过氧化氢酶的活性,分别以接种G.diaphanum,G.m osseae和G.et unicat um处理最显著,分别是对照的7.5 8,2.26和1.12倍。相反,接种AMF后显著抑制了根际土壤脲酶的活性,其中对接种G.ge o sp o rum处理抑制作用最显著,其酶活性为对照的8 4.2 1%。另一方面,宿根高粱接种AMF后增强了对土壤中铵态氮、有效磷、有机质的吸收,且生长量得到了提高,其中叶干重、茎干重和根长分别以接种G.diaphanum,G.v ersif orme和G.etunicat um增幅最显著,分别为43.93%,74.28%和92.60%,接种G.m osseae显著增强了地下部干重、株高和茎粗,分别是未接种的2.02,1.65和1.33倍。宿根高粱根长、株高与根际土壤酶的回归分析表明,根长与土壤酶的相关性大于株高。说明接种amf后能增强宿根高粱根际土壤酶的活性,促进植物根部对土壤中矿质元素的吸收,进而增加寄主植物的生物量。3amf对铯胁迫下宿根高粱asa-gsh循环的影响铯胁迫下接种amf提高了宿根高粱根系和叶片抗坏血酸(ascorbicacid,asa)和还原型谷胱甘肽(glutathione,gsh)含量,降低了脱氢抗坏血酸(dehydroascorbateacid,dha)和氧化型谷胱甘肽(oxidasedglutathione,gssg)含量,提高了asa/dha和gsh/gssg比值。同时,铯胁迫下接种5种不同amf增强了宿根高粱asa-gsh循环的抗氧化酶活性,其中接种g.mosseae处理后显著提高了根系中过氧化物酶(ascorbateperoxidase,apx)、脱氢抗坏血酸酶(dehydroascorbatereductase,dhar)和谷胱甘肽还原酶(glutathionereductase,gr)酶活性,分别相当于对照的2.34,3.50和3.78倍,而接种g.versiforme处理显著提高了单脱氢抗坏血酸还原酶(monodehydroascorbatereductase,mdhar)活性;另外,接种g.geosporum处理显著增加了叶片mdhar和gr酶活性,而接种g.versiforme和g.mosseae处理对apx和dhar酶活性影响最显著。由此可以说明,铯胁迫下宿根高粱接种amf处理增强了根系和叶片抗氧化酶活性,促进了抗氧化物质asa和gsh的再生,进而增强铯胁迫能力。菌根侵染率与宿根高粱根部和叶子部asa-gsh循环的相关性分析表明,菌根侵染率与抗氧化物质asa和gsh,抗氧化酶apx、mdhar、dhar和gr及氧化还原态比值asa/dha、gsh/gssg呈正相关,与gssg、dha呈负相关;说明接种amf增强了铯胁迫下宿根高粱的抗氧化能力,提高了对铯抗胁迫能力。4amf对宿根高粱修复核素铯的评价接种amf后增强了宿根高粱对核素铯的富集能力,显著增加了地上部和地下部铯含量,叶子较根系是主要的富集器官,促进了地上部对铯的富集,降低了土壤中铯残留量,同时地上部和地下部铯富集系数均高于未接种,分别以接种g.versiforme和g.mosseae富集系数最大,分别为10.41和2.3,接种g.diaphanum转运系数最大为5.03。相关性分析结果表明,菌根侵染率与地上部和地下部铯含量呈正相关,与土壤中铯残留量呈负相关,地上部和地下部铯富集系数与根际过氧化氢酶、蔗糖酶和酸性磷酸酶呈正相关,说明接种AMF后增强了铯胁迫下宿根高粱根际土壤酶活性,促进了宿根高粱对土壤中铯的吸收、迁移和转运。而地上部和地下部铯富集系数与脲酶呈负相关,相关系数分别为-0.97*,-0.98*,说明接种丛枝菌根真菌后铯对脲酶的抑制作用可能大于丛枝菌根对根际脲酶的促进作用,从而脲酶可作为衡量土壤中核素铯污染的一个生理指标。
[Abstract]:At present, the pollution caused by nuclide cesium is becoming more and more serious. Plant extraction is the most commonly used bioremediation technology, but the biomass of plants is often a factor restricting the efficiency of extraction. It is found that the Arbuscular Mycorrhiza l fungi (AMF) is a kind of mutual benefit to the root system of more than 80% terrestrial plants. The endophytic mycorrhizal fungi of the symbiont can form a large mycelial net with the root of the host plant, enhance the absorption of the mineral elements in the soil and improve the tolerance to the heavy metals and nuclides. In this study, the potted perennial root sorghum (Sorghum halpense.L) was used as a phytoremediation material for cesium pollution and inoculation of mycorrhizal treatment, and the different treatments were analyzed. The effects of the enzyme activity of perennial sorghum rhizosphere soil, the absorption efficiency of mineral elements, the growth status, the As A-GSH cycle system and the accumulation of cesium were discussed, and the application prospect of AMF in the field of phytoremediation of nuclide contaminated soil was discussed, and the theoretical reference for the future reclamation of caesium contaminated soil soil with AMF- plant symbionts was provided. The infection rate and dependence of the root sorghum mycorrhiza under 1 caesium stress were studied under the stress of 5 different AMF (G lomus geosporum, G.m o SS e AE, G.d I AP). The root dependence was also significantly higher than that of the control, with the most significant inoculation of G.versiform e, reaching 156.32%. The other treatment of mycorrhizal dependence was G.m osseaeG.et U N I cat umG.g e OS P. After inoculation of AMF under cesium stress, the activity of acid phosphatase, invertase and catalase in rhizosphere soil was promoted by inoculating G.diaphanum, G.m osseae and G.et Unicat um, respectively, 7.5 8,2.26 and 1.12 times of control respectively. On the contrary, the activity of rhizosphere soil urease was inhibited significantly after inoculation of AMF, and G.g was inoculated for G.g. The inhibition effect of e o SP o rum was the most significant, and its enzyme activity was 84.2 1%. on the other hand. After inoculation with AMF, the root sorghum was inoculated with AMF and enhanced the absorption of ammonium nitrogen, effective phosphorus and organic matter in the soil, and the growth was improved. The leaf dry weight, stem weight and root length were respectively increased by inoculation of G.diaphanum, G.v ersif Orme and G.etunicat. Significantly, 43.93%, 74.28% and 92.60% respectively, inoculated G.m osseae significantly enhanced the dry weight of the underground, the plant height and the stem diameter, respectively, the uninoculated 2.02,1.65 and 1.33 times. The root length of the sorghum root was long, the plant height and the rhizosphere soil enzyme showed that the correlation between root length and soil enzyme was greater than that of plant height. It indicated that the root soil of perennial root sorghum could be enhanced after inoculation of AMF. The activity of soil enzyme promotes the absorption of mineral elements in soil roots, and then increases the biomass of host plants.3amf on the AsA-GSH cycle of perennial sorghum under cesium stress. The inoculation of AMF under cesium stress increases the content of ascorbicacid, ASA and glutathione, GSH in the roots of sorghum and leaves of perennial root sorghum and leaves and reduced glutathione (GSH). The content of dehydroascorbic acid (dehydroascorbateacid, DHA) and oxidized glutathione (oxidasedglutathione, GSSG) increased the ratio of asa/dha to gsh/gssg. At the same time, inoculation of 5 different AMF under cesium stress enhanced the antioxidant enzyme activity of the perennial root sorghum AsA-GSH cycle, which significantly increased the peroxides in the root system after the inoculation of g.mosseae. Enzyme (ascorbateperoxidase, APX), dehydrogenase ascorbase (dehydroascorbatereductase, DHAR) and glutathione reductase (glutathionereductase, GR) enzyme activities are equivalent to the control of 2.34,3.50 and 3.78 times, respectively, while g.versiforme treatment significantly improves the activity of mono dehydrogenate ascorbate reductase (monodehydroascorbatereductase, MDHAR). In addition, inoculation with g.geosporum significantly increased the activity of MDHAR and GR enzymes in leaves, while g.versiforme and g.mosseae treatments had the most significant effects on the activity of APX and DHAR enzymes. Thus, it was suggested that the inoculation of perennial root sorghum with AMF under cesium stress enhanced the antioxidant enzyme activity of roots and leaves, and promoted the regeneration of ASA and GSH of antioxidants. The correlation analysis between mycorrhizal infection rate and AsA-GSH cycle of root and leaf of perennial root showed that the infection rate of mycorrhiza was positively correlated with antioxidant enzyme ASA and GSH, antioxidant enzyme APX, MDHAR, DHAR and GR and the ratio of redox state asa/dha, gsh/gssg, and GSSG and DHA, indicating that inoculation AMF enhanced the cesium stress. The antioxidant capacity of perennial sorghum increased the ability of.4amf to repair the nuclide in sorghum with the ability to resist the cesium resistance. After AMF, the enrichment ability of perennial sorghum on nuclide was enhanced, and cesium content in the upper and underground parts of the sorghum was enhanced, and the leaf root was the main concentrator Officer, which promoted the enrichment of cesium in the upper part of the ground and reduced the soil. The concentration coefficient of cesium in the soil was higher than that of uninoculated, and the enrichment coefficient of g.versiforme and g.mosseae was the largest, respectively, 10.41 and 2.3 respectively. The maximum 5.03. correlation analysis showed that the infection rate of mycorrhiza was positively correlated with the content of cesium in the upper and underground parts. Cesium residues in the soil were negatively correlated, and the cesium enrichment coefficient in the upper and underground parts was positively correlated with the rhizosphere catalase, sucrase and acid phosphatase, indicating that after AMF, it enhanced the enzyme activity in the rhizosphere soil of the perennial sorghum under the stress of cesium and promoted the absorption, migration and transport of cesium in the soil, and the cesium in the upper and underground parts was rich. The coefficient of collection was negatively correlated with urease, and the correlation coefficient was -0.97*, -0.98*, indicating that the inhibition of cesium to urease after inoculation of arbuscular mycorrhizal fungi may be greater than that of arbuscular mycorrhizal urease, thus urease can be used as a physiological index to measure the pollution of nuclide caesium in soil.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S514;X53

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