【作者】 张宏昌；

【导师】 康振生；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2007， 硕士

【摘要】 小麦条锈病是中国以及世界上其它国家小麦生产上最重要的病害之一。培育和利用抗病品种是防治小麦条锈病最经济、有效的措施之一。进行小麦抗锈性机制的研究,是选育抗病品种和合理利用寄主抗病性的前提和基础。本文采用荧光显微镜、微分干涉显微镜和电子显微镜技术,系统研究了小麦新抗源一粒葡抗小麦条锈病的组织学和超微结构特征,为评估抗原材料抗病特点和应用潜力提供科学依据。结果如下:(1)在组织学水平,表现为菌丝生长受抑,菌落发育延迟或败育,吸器母细胞和吸器数目明显减少;同时,侵染点的寄主细胞表现出不同程度的过敏性坏死症状。(2)电镜观察发现,在一粒葡和感病品种中,条锈菌均可由芽管顶端直接进入或通过形成附着胞进入小麦气孔。其后,在一粒葡上,病菌胞间菌丝、吸器母细胞、吸器在细胞和亚细胞水平均发生了一系列异常变化,其中原生质电子致密度逐渐加深,液泡增多变大,逐渐消解原生质;胞间菌丝、吸器母细胞细胞壁不规则增厚;胞间菌丝线粒体肿胀数目增多,逐渐解体;吸器母细胞细胞质逐渐空泡化后丧失其生理功能。吸器外质膜皱褶;吸器外间质加宽并有丝状或颗粒状物质形成,吸器体壁逐渐消解出现孔洞,吸器体最终畸形坏死;同时,寄主细胞产生一系列显著的结构防卫反应:形成胞壁沉积物、乳突、吸器鞘等结构,以及发生坏死,阻碍及抑制病菌的发育及扩展。(3)结果表明:一粒葡对条锈菌的侵染,相对于感病品种,在组织学和超微结构上表现出明显的抗锈性特征。(4)发现条锈菌,可入侵一粒葡叶片表皮细胞形成吸器,而吸器结构异常,表明抗锈性同样可在表皮细胞得以表达。更多还原

【Abstract】 Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat production in China and many other countries worldwide. It is the most economical and effective method to breed and utilize the wheat resistant cultivar for controlling the disease. The research on resistant mechanism to rust fungi is the basis of breeding resistant cultivar selectively and utilizing host rsistace in reason. In this paper, the histology and ultrastructure of resistant mechanism of a new wheat material-Yilipu to Puccinia striiformis were examined by means of fluorescent microscopy,differential interference contrast microscopy,and electron microscopy. It provided scientific basis for avaluating resistant features and application potential of wheat material. The mainly results were as follows:(1) The main histological manifestation of the pathogen development in the Yilipu wheat included inhibition of hyphal growth, delay of hyphal branching and colony formation, decrease of formation of haustorial mother cells and haustoria, at the same time, occurrence of host cell necrosis in different degrees.(2) The observation by scanning electron microscopy demonstrated that the pathogen can enter pore of stomatal by developed appressorium or apical of germ tube both in Yilipu and susceptible wheat cultivar. Later, a series of abnormal changes occurred in intercellular hyphae, haustorial mother cells and haustoria during pathogen development in the Yilipu. The cytoplasm became more electron-dense and vacuoles increased in number and in size which digested the protoplasm. The cell wall of intercellular hypha and haustorial mother cell were thichened irregularly. The mitochondria became swollen and increased in mumber,then hypha disintegrated gradually. The cytoplasm were degraded into central vacuole gradually and haustorial mother cells lost their physiological function. The extrahaustorial membrane was wrinkled, the extrahaustorial matrix is widened and great amount of fibril or granular deposits accumulated here. The cell walls of hostorial body degraded gradually and perforated, At the end, the haustorial body were malformed and necrosed. At the same time, the structural defense reactions such as formation of cell wall apposition, papilla, encasement of haustorium and necrosis of host cell were essentially more pronounced in the infected wheat leaves of the Yilipu than in the susceptible one. All constitute essential factors of resistance.(3) As compared on susceptible wheat cultivar, the observation of Yilipu following infection by the pathogen revealed a striking resistant characteristics in histology and ultrastructure.(4) The observation discovered that pathogen could invade epidermal cell of wheat leaves and developed into haustorium in it .It suggested that resistance to rust fungi could expressed in epidermal cell besides mesophyll cell.更多还原