【作者】 王莉；

【导师】 贺运春；

【作者基本信息】 山西农业大学 ， 植物病理学， 2005， 硕士

【摘要】 本试验以室内培育的不同抗性棉苗品种为试材,测定了棉苗感染黄萎病菌和用病原菌毒素粗提液处理后植株体内的过氧化物酶(POD)、超氧化物歧化酶(SOD)、丙二醛(MDA)含量、电导率和可溶性蛋白的动态变化,并分析了这些生理生化变化与植物抗病性的相互关系;同时运用植物病理解剖学原理和方法,对病株不同部位的组织横断面连续切片,观察不同抗性品种之间的组织结构差异、病原菌在病株体内的存在状态、分布规律以及扩展动态。在此基础上,得出以下结论: 1.棉苗在接种一个月的四片真叶期开始发病,病叶边缘最初呈现褪绿、水渍状萎蔫,然后逐渐扩大至整个叶片萎蔫。这与黄萎病典型的田间症状有差异。 2.对于POD酶活性,经接菌和毒素粗提液处理以前,无论根部或是叶部,抗病品种的活性均高于感病品种;处理以后,无论根部或是叶部,抗感品种的POD活性均比对照有所上升。但抗感品种在处理比对照的变幅上存在差异。对于SOD酶活性,经接菌和毒素粗提液处理后,不同抗感品种不同部位间存在差异。叶部组织在处理后,抗病品种的SOD酶活性升高,而感病品种的SOD酶活性下降。根部组织经处理后,无论抗感品种SOD酶活性均比对照有所下降。 3.经接菌和毒素粗提液处理后,不同抗性品种、不同部位MDA含量、电导率的动态变化趋势均趋于一致。即经处理后,无论抗感品种的根部与叶部,其MDA的含量、电导率均比对照有所上升,且感病品种MDA的含量、电导率明显大于抗病品种,同时,感病品种处理比对照的增减比率变幅也明显高于抗病品种。 4.经接菌或毒素粗提液处理以后,与对照相比,不同处理不同部位间可溶性蛋白升降有差异。但是,从总体上看,抗病品种的可溶性蛋白含量总是大于感病品种。 5.采取发病的棉苗做石蜡切片,在光学显微镜下观察到,不同抗性品种组织结构间存在差异。抗病品种的主根和茎导管细胞壁比感病品种厚;导管直径比感病品种大;导管数目、髓射线数、单位面积的薄壁细胞数比感病品种多。 6.不同抗性品种病株,观察的各部位均有菌丝体、侵填体和胶状物的存在,并且受侵染的导管壁有增厚的现象。 7.病株不同部位维管束中的病导管率在病株体内的纵向分布自下而上呈递减的趋势。而且不同抗性品种的病株,抗性越差,受病菌侵染的导管数越多。更多还原

【Abstract】 In this paper, Two cotton varieties with different resistance to verticillium dahliae that were cultivated indoors were used as experimental material to studied disease resistance mechanism. The activities of superoxide dismutase (SOD)、 peroxides (POD)、 MDA content、 relative electrical conductivity and dissoluable protein content in leaves and roots cell of different cotton cultivars were measured after inoculated with V. dahliae and treated with crude extract of V.dahliae. The relationship between physiological-chemical changes and disease resistance were analyzed. Meanwhile, on the base of pathological plant anatomy, The continuous section slices of different position of disease plants were observed by means of optical microscope .The results showed as follow:1. The cotton have symptom coming on in four real leaf time. Originally, disease leaf appeared chlorotic , water stain and slight wilt .Then, symptom spread around whole leaf. Finally, whole leaf deficit water and wilt.2.As for activity of POD, before inoculated with V.dahliae and treated with toxin , both leaves and roots, the activity of POD of the resistant cultivar were higher than the susceptible cultivar. After inoculated and treated, the activity of POD of both the resistant and susceptible cultivar were higher than control, but the change range of both sides were different. As for activity of SOD, After inoculated with V.dahliae and treated with toxin, The difference exists between cultivars and positions. After treated, in leaves ,the activity of SOD of the resistant cultivar increased, but that of the susceptible cultivars decreased. While in roots treated, both the resistant and susceptible cultivar were lower than control.3.After inoculated with V.dahliae and treated with toxin , The change tendency MDA content and relative electrical conductivity were similar between cultivars and positions. After treated, MDA content and relative electrical conductivity increased, and MDA content and relative electrical conductivity of the susceptible cultivar were higher than the resistant cultivar significantly. Meanwhile, the change range of the susceptible cultivar were larger than the resistant cultivar.4. After inoculated with V.dahliae and treated with toxin , The change of dissoluble protein content have difference between treatment and position. But in total level, the content of the resistant cultivar were larger than the susceptible cultivar.5. It was observed that there were more pith rays, more quality of xylem parenchyma cell and more thickness of vessel cell in the resistant cultivars, comparing with the susceptible ones through optical microscope.6. Through optical microscope, Mycelia, tylose, and gum in the infected vessel were found. Also infected vessel walls of disease were thicker than which of the vessels of health plants.7. The infected vessels rate of disease plants became lower with the different position of disease plants from bottom to top. And the inferior the resistance, the more the infected vessels are.8. All results showed that vessel blockage was not the major fact causing plant wilting . while toxin was the major factor.更多还原