瓜类植物内生真菌的物种多样性和促生活性初步研究

发布时间：2018-02-28 18:55

  本文关键词： 黄瓜 瓜类植物 内生真菌 物种多样性 促生作用　出处：《中国农业科学院》2015年硕士论文　论文类型：学位论文

【摘要】：内生真菌能够存活在世界上几乎所有植物的组织中。大量内生真菌生活于瓜类植物中,其中有些能促进植物生长。对植物有益的真菌被称为植物促生真菌(PGPF),它们能以不同类型的机制促进植物生长、保护寄主植物免遭环境胁迫。植物促生内生真菌的促生机制与根际促生真菌的机制相似,但内生真菌能进一步地寄生于植物组织内,相比于附着在根际的促生真菌更能为寄主提供高效而直接的保护。因此,内生真菌在各种环境条件下促进植物生长方面很可能优于类似的非内生真菌。本研究比较了由两种分离培养方法揭示的内生真菌多样性,探讨了内生真菌对黄瓜生长的促进作用。本研究中,三种无病症的常见葫芦科植物黄瓜、丝瓜和南瓜采集自北京延庆和大兴两地,用稀释培养法和组织分离法分别从植株的上部茎、下部茎和根三个部位共分离到68株内生真菌。基于形态特征和rDNA ITS序列比对进行鉴定,这些菌株中,镰刀菌属Fusarium是最常分离到的属。其他属有木霉属Trichoderma,青霉属Penicillium,肉座菌属Hypocrea,伏革菌属Corticium,曲霉属Aspergillus,炭疽菌属Colletotrichum,枝孢属Cladosporium,裂褶菌属Schizophyllum,穗枝霉属Clonostachys,链格孢属Alternaria和丛赤壳属Nectria。所分离到的内生真菌菌株中,有30株只分离自组织分离法,28株只分离自稀释培养法,其余10株则在两种方法中都分离到。通过所分离到的内生真菌数量来评价物种丰富度,依据得到的物种丰富度对两种分离方法进行了比较。共有43株选择的内生真菌用于本研究,它们均由本实验室的其它同学分离自瓜类植物并保存在中国农业微生物菌种保存管理中心(ACCC)。为探索利用内生真菌促进黄瓜生长的方法,盆栽试验在温室中进行,采用孢子悬液接种和培养物接种两种方式接种。结果表明,采用两种接种方式接种内生真菌的植物都比对照组的植物生长有显著增加。通过比较发现,培养物接种的方法能更好地促进黄瓜生长。在用培养物接种的处理中,接种菌株3F8、Jcl44和F87的生物量增加的最高,与对照相比它们分别使生物量增加了90.45%、89.79%和82.18%。超氧化物歧化酶(SOD)活性分析显示其变化趋势与对应的生物量相同,表明接种内生真菌有益于寄主植物生长。各处理的植株中酶活最高的几个菌株依次为4F8(1533.87±336.55 unit/ml)、3F59(873.79±147.62 unit/ml)和Jcl44(737.58±98.49 unit/ml),对照组的酶活为254.69±62.67 unit/ml。在17个植物促生内生真菌菌株的发酵液里都发现了与植物生长素相关的吲哚类化合物:吲哚乙酸(IAA),吲哚乙醛(IAAld)和吲哚乙醇(IEt)。用MS培养基代替PDA所做试验的结果暗示,内生真菌的提取物可能代替植物生长素作为生长调节剂促进黄瓜植株的生长。因此,本试验中使用的部分内生真菌菌株也许可以用作黄瓜植株的生长促进剂。
[Abstract]:Endophytic fungi can survive in almost every plant tissue in the world. A large number of endophytic fungi live in melons. Some of them promote plant growth. Fungi that are beneficial to plants are called plant-promoting fungi, PGPF, and they promote plant growth through different types of mechanisms. The promotion mechanism of plant endophytic fungi is similar to that of rhizosphere fungi, but endophytic fungi can further parasitize in plant tissues. They provide more efficient and direct protection to the host than to the rhizospheric growth promoting fungi. Endophytic fungi may be superior to similar non-endophytic fungi in promoting plant growth under various environmental conditions. This study compared the diversity of endophytic fungi revealed by two methods of isolation and culture. The effects of endophytic fungi on the growth of cucumber were studied. In this study, three common cucurbitaceae plants, luffa and pumpkin, were collected from Yanqing and Daxing, Beijing. 68 strains of endophytic fungi were isolated from the upper stem, lower stem and root of the plant by dilution culture method and tissue separation method respectively. Other genera include Trichoderma, Penicillium, Hypocrea, Corticium, Aspergillus, Colletotrichum, Cladosporium, Schizophyllum, Clonostachys, Alternaria and Nectria. Of the endophytic fungi isolated, 30 strains were isolated by self-tissue isolation method and 28 strains by self-dilution culture method. The other 10 strains were isolated in both methods. The species richness was evaluated by the number of endophytic fungi isolated. A total of 43 selected endophytic fungi were used in this study. All of them were isolated from other students in our laboratory and preserved in ACCCC.In order to explore the method of using endophytic fungi to promote cucumber growth, pot experiment was carried out in greenhouse. Spore suspension inoculation and culture inoculation were used to inoculate endophytic fungi. The results showed that the growth of plants inoculated with endophytic fungi was significantly higher than that of the control group. The method of culture inoculation could promote cucumber growth better. The biomass of inoculated strains 3F8 Jcl44 and F87 increased the highest in the treatment of inoculation with culture. Compared with the control, they increased the biomass by 90.45% and 82.18%, respectively. The analysis of the activity of superoxide dismutase (SOD) showed that the change trend was the same as that of the corresponding biomass. The results showed that inoculation of endophytic fungi was beneficial to the growth of host plants. The highest enzyme activity of the plants treated was 4F833.87 卤336.55 unit-r.ml) and Jcl44(737.58 卤98.49unitr.ml. respectively. The enzyme activity of the control group was 254.69 卤62.67 unit / ml. In the fermentation broth of 17 strains of endophytic fungi, the enzyme activity of the control group was 254.69 卤62.67 unit.ml. in the fermentation broth of 17 strains of endophytic fungi, the enzyme activity of the control group was 254.69 卤62.67 unit / ml. Indole compounds related to plant growth hormone, such as indoleacetic acid, indoleacetaldehyde (IAAld) and indoleethanol (IET), were found. The results of the experiment using MS medium instead of PDA suggested that, The extracts of endophytic fungi may be used as growth regulators instead of plant growth regulators. Therefore, some of the endophytic fungi strains used in this experiment may be used as growth promoters for cucumber plants.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S182
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本文编号：1548535