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为了研究向日葵锈菌的致病机制,本文采用电子显微镜技术对向日葵锈菌的侵入和扩展过程进行了研究,结果表明,向日葵锈菌夏孢子萌发产生1个芽管,遇到合适结构的气孔后,在气孔上方形成附着胞从气孔侵入,胞间菌丝与叶肉细胞壁接触后分化出吸器母细胞,吸器母细胞进入叶肉细胞内部形成吸器。胞间菌丝在吸器母细胞处分化出次生菌丝,在叶肉细胞间扩展,病菌菌丝多在寄主细胞间隙或沿寄主细胞壁延伸。在病原菌侵染早期,寄主细胞的超微结构变化并不明显;侵染中、后期,被侵染叶肉细胞发生质壁分离,叶绿体膨胀变形,细胞器解体,细胞崩解。 相似文献
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以白粉病的感/抗性品系橡胶树为材料,采取不同的观测方法(光学显微镜,扫描电镜和透射电镜)对橡胶白粉菌进行动态的形态学观察对比。通过对不同抗性品系的幼叶(即铜色)和绿叶(即绿色)表皮角质层观察发现,所有幼叶角质层厚度不足0.1μm,抗性品种绿叶角质层厚度可达3μm,而感病品系的只有1μm左右,表明抗性差异与角质层厚度有明确关系。病原菌的侵染钉侵入细胞内部后,不同抗性品系表皮细胞对侵入采取了2种截然不同的胞质沉积方式。感病品系的胞质沉积仅发生在被侵染的细胞壁周围,其内部的吸器外膜周围没有发现沉积。抗性品系的胞质沉积则在吸器外膜周围,直接作用于吸器并使其萎缩。 相似文献
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为了进一步了解向日葵与向日葵锈病病菌的互作关系及品种的抗性机制,采用电子显微镜技术对向日葵品种对锈病抗性的组织学和超微结构进行研究.在电镜下观察发现,向日葵锈病菌侵染向日葵后,在感病品种和抗病品种上发育的组织学和超微结构特征有明显差异.病菌在感病品种细胞间隙分布有大量的胞间菌丝,寄主细胞发生质壁分离;叶绿体变形,叶绿体的片层结构排列零乱,直至叶绿体解体.在抗病品种上表现为菌丝生长受抑,没有观察到吸器的产生,寄主细胞的早期坏死与锈菌的发育受阻密切相关.品种的抗病性可能与饥饿阻止真菌生长有关. 相似文献
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本病系毛茸感染。抗性强的品种细胞壁肥厚以及细胞质退缩有趋早的倾向;接种分生孢子后,抗性强的品种毛茸上的孢子膨胀,发芽迟,容易从毛茸上脱离,穿透毛茸细胞壁的侵入菌丝也较少,毛茸细胞内细胞 相似文献
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为比较S. sclerotiorum侵染后,油菜不同抗性品种组织内活性氧产生情况,通过DAB和伊文思兰染色,分别检测接种病菌后不同抗感品种的氧迸发(Reactive Oxygen Intermediates, ROIs)的产生及其诱导的细胞死亡情况。结果表明,抗性品种中双9号、皖油14产生ROIs及细胞死亡的程度均轻于感病品种沪油15、史力丰。使用抗氧化剂如抗坏血酸、H2O2酶预处理叶片后,病斑比对照减小。H2O2预处理则能显著增大病斑,忍受ROIs可能是油菜抗S. sclerotiorum的机理之一。通过甲苯胺蓝染色检测细胞壁修复情况的结果表明,抗性品种叶片在菌丝定殖早期的细胞壁中多酚化合物过氧化结合物的产生量大于感病品种。 相似文献
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Qingmei Han Ramona Thieme Xiaoning Gao Zhensheng Kang Lili Huang 《American Journal of Potato Research》2013,90(6):524-532
In histological and cytological investigations, the infection process of Phytophthora infestans, the late blight pathogen, was comparatively studied in several potato cultivars and somatic hybrid genotypes and their parents using fluorescence microscopy and electron microscopy methods. The results showed that germination of zoospores of P. infestans and frequency of invading by infection hyphae did not differ among the cultivar-pathogen interactions, but, extension of hyphae in host cells markedly differed among these genotypes. In the susceptible genotypes the pathogen grew rapidly inter- and intracellularly, 12 h after inoculation (hai), and some digital like haustoria were formed and the cytoplasm of the host cells became disorganized. In the resistance genotypes, the pathogen was restricted to the site of initial penetration, although some hyphae could penetrate the epidermal cell, however, the host cells produced resistance responses, such as formed wall appositions when in contact with hyphae, and no haustoria like structures were found. In the somatic hybride genotypes, the host response was different according to their parents as shown by transmission electron microscopy. In the hybrid genotype 1508/2, like in the wild species S. bulbocastanum, no hyphae were found in host cells. In the other genotypes, hyphae of P. infestans spread intercellularly and formed haustoria, but the cytoplasm of hyphae and haustoria was disorganized and host cell resistant responses often appeared, such as, host cells were disorganized and necrotic and cell wall apposition were observed. 相似文献
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三唑酮种衣剂对小麦幼苗上白粉病菌萌发和侵染影响的组织学观察 总被引:4,自引:0,他引:4
采用组织病理学染色技术 ,观察和测定了三唑酮种衣剂包衣处理的小麦幼苗上白粉病菌孢子萌发、侵染的发展过程。结果表明 ,药剂处理对白粉病菌初生芽管、附着胞芽管的萌发及成熟附着胞的形成无抑制作用 ,但明显提高附着胞的畸形率 ;抑制初生吸器原体的形成和指状体的发育 ,降低入侵率 ;抑制初生菌丝的发育、次生菌丝和次生吸器的形成。分析认为 ,三唑酮种衣剂包衣处理在降低小麦白粉病菌的初始菌源数量和控制白粉病的流行危害中具有重要作用 相似文献
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采用混合交配型菌液针刺茎基部法对2叶期高抗玉米自交系齐319和高感自交系黄早四接种玉米丝轴黑粉菌,观察苗期叶片形态及超微结构的变化。结果表明,齐319接种后叶片出现褪绿斑点,产生的侵染菌丝和冬孢子极少,集中分布在发病严重部位的细胞间隙中,植物细胞结构完整。黄早四接种后33%幼苗出现局部坏死现象,有较多的侵染菌丝及冬孢子产生,植物细胞结构遭到严重破坏,出现质壁分离,细胞壁折叠、消解,叶绿体片层紊乱、瓦解现象",花环型结构"被破坏。丝轴黑粉菌引起的苗期叶片表型及细胞结构在抗感品种间存在显著差异。 相似文献
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Jiao-yu WANG Xiao-yan WANG Ling LI Xin ZHANG Yan-li WANG Rong-yao CHAI Guo-chang SUN 《水稻科学》2012,19(3):252-258
Inoculation methods for rice blast fungus Magnaporthe oryzae to Brachypodium distachyon were developed to investigate the infection process and symptom development in comparison with those on rice (Oryza sativa) and barley (Hordeum vulgare).M.oryzae could infect leaves,sheathes,stems and panicles of B.distachyon and cause blast disease.Spraying conidial suspension on either intact seedlings or leaf segments induced typical symptoms on B.distachyon.During the intact seedling inoculation,the symptom developed on B.distachyon leaves closely resembled that on rice;but the lesions on B.distachyon had better uniformity in shapes and sizes than those on rice or barley.In the leaf segments inoculation,only initial and low-developed lesions could be found on rice,while normal symptoms on B.distachyon and barley.Inoculated with low-virulent mutants of M.oryzae,B.distachyon produced low-level symptoms.The symptom level of each mutant on B.distachyon corresponded well to that on rice.In addition,typical infection processes presented on B.distachyon leaves:forming melanized appressoria,penetrating into host epidermis and then forming hyphae in epidermal cells.According to these results,B.distachyon can be used as a candidate for studying fungus-plant interactions and as a probable source of disease resistance. 相似文献
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活性氧积累与小麦抗白粉病关系的研究 总被引:2,自引:0,他引:2
为了解活性氮积累与小麦白粉病抗性的关系,采用DAB染色法对小麦与不同白粉病
菌的互作中活性氧的积累进行了研究。结果表明,小麦对来自白粉病菌附着胞、初生芽管以及次生菌丝的侵染均能够产生活性氧的积累。在感病的小麦品种与白粉病菌的亲和性组合中,活性氧的积累相对较少;在附着胞的侵染位点上活性氧的积累较多;而在受到再次侵染时,表皮细胞侵染位点上产生的活性氧几乎检测不到。在不亲和组合,特别是非寄主组合(小麦/大麦白粉病菌)中,活性氧的积累强度相对较大。同时,不管在什么组合中,气孔周围的短型表皮细胞的活性氧积累往往比长型表皮细胞多,尽管短型的表皮细胞往往表现为更感病。说明活性氧是植物抗病反应的一个指标,与细胞防卫反应的强度有关,但尚不是细胞抗病性唯一的、决定性的因素。 相似文献
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Summary In the cell wall matrix of higher plants, cellulose fibrils are embedded in a network of pectic substances, hemicelluloses
and structural proteins. But plant pathogenicErwinia carotovora bacteria secrete a mixture of enzymes including pectinases, cellulases and proteases to degrade the cell walls of host plant
tissue. Tuber tissue of 31 potato genotypes was exposed to a mixture ofErwinia enzymes before the degree of cell wall lysis was determined by a Neutral-red vital staining method. The data indicate that
the resistance of cell walls to the action ofErwinia enzymes differed significantly among the potato cultivars and clones. The decrease in cell viability caused by the action
of enzymes ranged from 7% for cv. Maxilla to >46% for cv. Arnika. An increased rate of N-fertilization coincided with enhanced
susceptibility of cell walls to the action ofErwinia enzymes. There was a correlation between the amount of cell wall substances in tuber tissue and the resistance of cell walls
to enzymic degradation. 相似文献
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斑马纹病是剑麻的主要病害之一,本研究以剑麻斑马纹病高感品种H.11648为材料,分别在接种烟草疫霉0、24、36、48、72 h取样,用电镜观察H.11648叶片细胞超微结构变化,同时分析过氧化氢酶(CAT)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)等防御酶活性变化情况。结果表明:H.11648在接种24 h,可见大量休止孢,叶绿体结构被破坏,植物组织开始降解,随着时间延长,附着孢出现,吸器形成,植物组织解体更严重,接种72 h,可见大量菌丝。在整个接种过程中,CAT、PAL和PPO活性显著增强,72 h达到最高,分别为501.44、25.73、1 742.67 U/(g.min)。SOD和APX活性显著下降,72 h达到最低,分别为2 888.62 U/g和841.96 μmol/(g.min)。POD活性先下降72 h又上升,但均显著低于接种前POD活性。本研究从细胞学和生理水平为探讨剑麻与烟草疫霉互作关系提供了理论基础。 相似文献
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本研究建立了一种橡胶树叶片中胶孢炭疽菌的染色方法,通过显微观察明确胶孢炭疽菌在橡胶树叶片中的侵染结构,为橡胶树炭疽病的预测预报提供理论依据。在脱色剂(0.15%三氯乙酸乙醇溶液∶氯仿=5∶1)处理12 h,1%刚果红染色剂抽滤染色3 h的条件下,能清晰观察到胶孢炭疽菌在橡胶树叶片上的发育进程和侵染结构。结果表明,在28 ℃、100%相对湿度培养条件下,接种橡胶树淡绿期叶片2~6 h为分生孢子萌发高峰期,12 h后分生孢子萌发率大于85%;8~12 h为附着胞形成高峰期,接种12 h约75%的芽管顶端产生附着胞,少数附着胞中央部位开始形成侵染钉;24 h为侵染钉形成高峰期,同时分生孢子萌发形成多个芽管;36 h时附着胞顶端再次萌发产生次级附着胞,从而进一步侵染周围细胞,叶片出现零星病斑;48 h时芽管不断分支异化成菌丝并产生次级分生孢子,叶片出现大量典型的炭疽病病斑;72 h后菌丝在叶片表面纵横扩展,随机分支,逐步形成网状分布。随着菌丝的扩展,叶片组织发生一系列的病理变化,侵染部位组织出现褐色坏死病斑。本研究建立了一种着色效果好,简便易行,经济有效的橡胶树叶片中胶孢炭疽菌的染色方法,进一步明确了胶孢炭疽菌的侵染结构。 相似文献
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大豆叶片结构与灰斑病抗性的研究Ⅱ.大豆叶片组织结构与灰斑病抗性的关系 总被引:8,自引:0,他引:8
对大豆灰斑病抗病品种和感病品种的叶片组织结构,主要包括栅栏组织层数,栅栏组织密度,上下表皮细胞密度,蜡质含量及叶比重等,进行了比较研究。试验结果表明抗病品种叶片的栅栏组织排列整齐,紧党性,而且层数相对较多,可以抵抗病菌的侵入和扩展,成为抗病的一个结构屏障;抗病品种的叶片蜡质含量高于感病品种,表明大豆叶片本身具有的蜡质层是抵抗和延迟病原菌侵入的另一个结构屏障。在叶比重上,抗病品种与感病品种没有明显差异。 相似文献