【作者】 陈祖静；

【导师】 曹支敏；

【作者基本信息】 西北农林科技大学 ， 森林保护学， 2010， 硕士

【摘要】 杨树是一种重要的生态和商品林树种,由落叶松-杨栅锈菌所引起的杨树叶锈病是一种重大的杨树叶部病害。国内外研究表明,抗病性品种的应用能达到持久防治杨树叶锈病的作用。本研究从不同杨树品种与不同落叶松-杨栅锈菌生理小种的互作关系出发,对该互作过程中杨树叶片组织中的活性氧爆发、相关酶活性动态变化、组织结构中的木质素与寄主抗病性的关系进行研究,并探讨该互作过程中PCD的发生机制,以期为杨树叶锈病发生的分子机制和选育抗病杨树品种提供科学依据。研究结果表明:1、不同的杨树品种（种）接种落叶松-杨栅锈菌后ROS变化幅度差异显著。O₂^-产生速率、H₂O₂含量分别在0.5d、1d时迅速上升,与对应对照相比,各品种ROS上升的幅度在各自病程中均为最高点。在感病品种中ROS变化往往只出现一个峰值,而在抗病品种中常常出现2³个峰值,且抗锈性越高,出现第二个峰值的时间越早,ROS值也越高。整个病程中免疫、抗病组合寄主的ROS波动速度及幅度明显大于感病品种。2、杨树接种落叶松-杨栅锈菌后POD、SOD、CAT活性一直处于一个动态变化的过程,彼此间相互协同控制。SOD活性与杨树寄主抗病性呈负相关。POD活性前期变化不显著,后期与抗病性呈负相关。各品种接种后CAT活性0.5 d迅速上升,1 d后下降,3⁵ d时出现高峰,表现为抗锈性越强,CAT活性越低。3、免疫、高抗品种杨树受松-杨栅锈菌侵染后PAL活性上升速度快、强度大,各组合与对应对照的比值间存在显著差异。几丁质酶活性与杨树品种的抗病性基本呈正相关。抗病品种出现2³次高峰,且在与对应对照的比值中,免疫品种同其他品种间存在显著差异,而其余品种间差异较小。4、杨树与落叶松-杨栅锈菌互作病程中,1d²d时不亲合组合叶片组织内就有少量木质素的积累,3d时积累比较明显。在亲和组合和健康对照中叶片木质素的积累非常少,而高抗品种中积累较多。木质素的积累与杨树抗锈性无明显的相关性。5、杨树叶片切片后经DAPI染色在荧光显微镜下观察细胞核发出强烈的蓝光,不同品种杨树健康叶片的细胞核呈圆形或近圆形。抗病品种川杨受落叶松-杨栅锈菌侵染后有HR现象,且表现出明显的PCD特征,接种0.5d时细胞核开始发生变化,3⁴ d时细胞核裂解,7d后细胞核消失。感病品种太白杨接种后出现HR但不属于PCD范畴。更多还原

【Abstract】 Poplar is an important ecological and commercial forest tree species. Leaf rust is a major leaf disease, which is caused by Melampsora larici-populina Kleb. Research of domestic and foreign experts showed that the application of disease resistant species could be used to control the poplar leaf rust. The interaction between different poplar species and different Melampsora larici-populina Kleb. races was studied firstly in this paper. The relationship in this interaction between outbreak of reactive oxygen, dynamic changes of related enzyme activity and lignin content in the tissue structure in poplar leaf tissues and the host disease resistance was studied. Then PCD mechanism of the host after inoculated with Melampsora larici-populina Kleb. was discussed to provide scientific basis for the molecular mechanism of poplar leaf rust and poplar disease resistance varities screening .The conclusions showed that:1、There were significantly differences on the variation amplitude of ROS in the different poplar varieties （species） after inoculated with Melampsora larici-populina Kleb.The production rate of O₂^- and the content of H2O2 respectively rapidly increased in 0.5 d and 1 d, furthermore ROS of each varity was the highest in it’s pathogene process compared with the CK. The change of ROS in susceptible species often appeared one peak and 2 to 3 peaks in the resistant ones. Moreover, the higher resistance to rust, the sooner occuring of second peak,and the higher of ROS value. ROS was fluctuatedly changed throughout the infection process,and the rate of ROS fluctuation rate immune and resistance in the susceptible varieties was higher than susceptible.2、The activity of POD, SOD and CAT had a dynamic change all the time after poplar inoculated with Melampsora larici-populina Kleb., and they were cooperative controled by each other. The activity of SOD was negatively correlated with the poplar resistance. The POD activity did not change significantly in early period after inoculation, but it had negative correlation with disease resistance later. The CAT activity was highly increased in 0.5 d ,then decreased in 1 d,moreover appeared one peak in 3 d to 5 d.The higher resistance to rust the lower CAT activity.3、The PAL activity increased rapidly and had stronger strength in the host of immune and resistance species after inoculated with Melampsora larici-populina Kleb. There were significant differences in the ration of PAL activity in each combination to the corresponding controls. The chitinase activity was positively correlated with poplar resistance basically. There were 2³ times of peaks in the resistant poplar varieties. In the ratio with the corresponding controlls, there was significantly difference between immune and others species, but little differences in others.4、In the pathogene process between poplar and Melampsora larici-populina Kleb.,there was very little accumulation of lignin in 1 d to 2 d in the leave tissue of incompatible combinations and comparatively obvious accumulation in 3 d. But lignin almost had no accumulation in the compatible one and healthy control, while more accumulation in highly resistant poplar varieties. There was no correlation between the accumucation of lignin and poplar rust resistance.5、Using DAPI stain after slicing the poplar leaves ,there was a strong blue light in mucli under the fluorescence microscope. The nucleolus were round or nearly round in the healthy leaves of different poplar varieties. There was HR phenomena and significantly change of PCD in P. szechuanica after inoculated with Melampsora larici-populina Kleb. The nuclei began to change in 0.5d after inoculation, then cracked in 5 d, disappeared in 7 d at last. However we found HR phenomenon after the inoculation of Populus purdomii,but it did not belong to PCD process.更多还原