【作者】 苗文莉；

【导师】 黄进勇； 唐保宏；

【作者基本信息】 郑州大学 ， 生态学， 2011， 硕士

【摘要】 内生真菌广泛分布于植物的各个组织和器官中,与宿主植物长期共处,两者之间形成了一种复杂、特殊的关系,它们能够通过自身的代谢产物,或借助于信号传导等作用影响宿主的生长发育、系统演化过程及生态的适应性等方面。因此系统地研究植物内生真菌的多样性及其与宿主的相互关系,具有重要的意义。小麦是我国第二大粮食作物,研究内生真菌与小麦之间的相互关系,对于增强内生真菌对宿主小麦的有益作用,控制潜在的有害内生真菌,促进小麦生产具有重要的意义。本文优化了小麦各部位内生真菌的分离纯化条件,研究了小麦各时期各部位内生真菌的种类和分布的多样性；并通过与小麦根际真菌多样性进行比较分析以及小麦幼苗内生真菌的分离,探究内生真菌对宿主小麦的入侵机制；研究了不同土壤条件对小麦内生真菌的影响,并对内生真菌对宿主小麦生长的影响进行了初步研究。1.选择了次氯酸钠结合75%酒精进行表面消毒的方法,对小麦不同器官的表面消毒时间进行了优化。通过分离培养基的筛选,确定了PDA培养基作为小麦内生真菌分离培养基。2.研究发现小麦不同部位内生真菌多样性存在较大差异,小麦根的内生真菌分离率最高,为25.60%,叶部和茎部分别为16.37%,11.92%。小麦各个部位的内生真菌分离率随小麦植株的生长呈现上升的趋势,成熟阶段达到最高。在越冬期间,各部位内生真菌分离率出现不同程度的降低,表明小麦内生真菌的数量受到低温的影响。3.共鉴定出小麦内生真菌11个属,分离频率较高的真菌有Alternaria、Penicillium、Bipolaris、Fusarium、Rhizopus和Trichoderma等属,其中,Alternaria、Penicillium、Rhizopus和Fusarium在小麦的各生育期均可分离得到。Alternaria、Bipolaris、Fusarium是潜在致病菌；在小麦苗期的根中分离到了Acremonium sp.,该属菌是禾本科植物的共生性内生真菌。4.通过与根际真菌的比较,发现小麦内生真菌在分类单位上与小麦根际真菌主要类群有一定联系,但存在较大差异,表明内生真菌可能具有其他来源。进一步对小麦种子萌发过程内生真菌的分离和分析表明,内生真菌可以通过种子萌发进行传播,也可以通过植株体表侵入到宿主体内。初步研究了若干小麦内生真菌菌株对小麦苗期生长的影响,暂未发现明显的作用,有必要做进一步的研究,探索内生真菌与宿主小麦的关系。通过该研究,我们系统地了解了对小麦各个时期各个部位内生真菌的多样性,初步了解了小麦内生真菌的来源和分布,而且对内生真菌影响小麦生长方面也进行了初步研究,为小麦内生真菌多样性及其与宿主关系的进一步研究奠定了基础,为小麦内生真菌应用于农业生产提供了理论依据。更多还原

【Abstract】 Endophytic fungi are widely distributed in plant tissues and organs, and have formed a kind of complex and special relationship after long-term coexistence with the host. They can affect the growth and development, the evolution process and ecological adaptability of the host. So it is significant to study the diversity of endophytic fungi and their relationship with the host systematically. Wheat is the second-largest food crop in China. Study on the wheat-endophyte interaction has a very important significance for the utilization of beneficial endophytes, the control of the potential harmful endophytes, and therefore, the improvement of wheat production.Isolation methods of endophytic fungi in the organs of wheat were firstly optimized in this research. Diversity and distribution of endophytic fungi in each organ and growth period of wheat were studied, which was compared with the diversity of wheat rhizospherical fungi. Endophytic fungi in seedling wheat cultivated under aseptic condition were isolated to reveal the infection pathway. The diversity of wheat endophytic fungi in wheat cultivated under different soil conditions was explored. The influence of endophytic fungi to the growth of wheat was preliminarily studied.1.3% NaClO and 75% alcohol were used as the disinfectants in combination. The disinfecting time of each organ was optimized. PDA medium was selected for the isolation of the endophytic fungi in wheat.2. It was found that endophytic fungi in each organ of wheat were different. Isolated rate of endophytic fungi in roots was the highest, which was 25.60%, and that of leaves and stems were 16.37% and 11.92% respectively. Isolating rates in the roots, stems and leaves of wheat rose with the maturation of the wheat. But in the Over-wintering stage, the rates of each part fell in different extent, which indicated that the quantity of endophytic fungi could be influenced by low temperature.3. Eleven genera of endophytic fungi of wheat were isolated and identified. Alternaria, Penicillium, Bipolaris, Fusarium, Rhizopus and Trichoderma were the advantage fungi. And Alternaria, Penicillium, Rhizopus and Fusarium could be isolated in each growth period of Wheat. Alternaria, Bipolaris and Fusarium are potential pathogenic fungi. A fungus of Acremonium sp. was isolated in wheat root of seedling stage, which was found symbiotic with gramineous grasses.4. Comparison with rhizospherical fungi revealed certain relationship between endophytic and soil fungi, but the difference was also obvious, which indicated that other sources existed for the endophytic fungi in the wheat plants. Further analysis of endophytic fungi in wheat seedlings cultivated under aseptic condition indicated that endophytic fungi could infect through the seeds when the seeds germinated, or through the surface of the roots, stems or leaves.The relationship of the endophytic fungi isolated and the host wheat was studied preliminarily. No significant influence on the growth of the host was found. It is necessary to make further study of the relationship of the endophytic fungi and the host.Diversity of endophytic fungi in each organ and each growth period of wheat was studied systematically. Source and distribution of endophytic fungi in wheat were revealed. And the influence of endophytic fungi to the growth of wheat was studied preliminarily. These conclusions set the foundation for the further study on endophytic fungi of wheat and their relationship with the host, and provided theoretical basis for the application of endophytic fungi in agriculture.更多还原