【作者】 朱键鑫；

【导师】 黄奔立；

【作者基本信息】 扬州大学 ， 植物病理学， 2008， 硕士

【摘要】 本试验对近130个黄瓜品种（杂交组合）对白粉病的抗性进行了初步鉴定。其中,田间露地栽培鉴定54份,高感材料有6份,中感材料有14份,中抗材料有5份,未发病的高抗材料有29份。大棚栽培鉴定55份,高感材料有10份,中感材料有12份,中抗材料有5份,未发病的高抗材料有28份。对露地和大棚同期栽培的10份黄瓜材料白粉病抗性鉴定结果表明,栽于大棚的品种发病重于露地,有些品种则露地和大棚栽培白粉病发生相差不大,如J201;另一些品种（津优30号、L203等）则在露地基本不发病,而在大棚则有一定程度的发病;GY2、GY4等在露地和大棚均未发病,表现了较好的抗性。室内子叶期人工接种33份材料,由于条件适宜,发病程度远重于田间发病。其中高感材料3份,中感材料12份,中抗材料15份,未发病的高抗材料3份。试验选择对白粉病抗性有一定差异的8个黄瓜品种,研究不同抗性品种在组织结构和接种白粉病菌后生理生化特性变化的差异。叶片组织石蜡切片显微结构表明:高抗白粉病的品种其组织结构紧凑,细胞壁较厚,栅栏组织排列整齐、紧密,海绵组织紧贴栅栏组织,且都较清晰。而发病最重的高感品种“平望乳瓜”的叶片组织的切片出现大量空隙,较难见到完整细胞,细胞壁较薄。中抗品种的细胞壁要薄于高抗品种,栅栏组织虽不及高抗品种紧密,但要远好于“平望乳瓜”等高感品种。其余品种虽能见到清晰的栅栏组织,但空隙仍较大。叶片组织细胞排列整齐、紧密,细胞壁较厚可能是黄瓜抗白粉病的主要原因之一。对不同抗性品种叶片接种前后不同时间内与植物抗性相关的酶活性进行了研究。抗病品种的苯丙氨酸解氨酶（PAL）活性在接种后出现了明显的上升,高抗品种“GY14A”在接种1d和5d出现明显的活性峰,并以接种1d后的峰值最大,与其它品种差异显著,是感病品种“DE843”的1.69倍以上;中抗品种“津优30号”在接种3d后活性达最大值,是感病品种的1.75倍以上;感病品种接种后未见活性上升。过氧化物酶（POD）活性接种后以高抗品种上升幅度最大,接种后1d POD活性即超过其它中抗和感病品种,差异显著,是感病品种的1.22倍。感病品种的POD活性在接种后3d达峰值,但仍低于抗病品种,以后活性下降明显快于抗病品种。抗病品种多酚氧化酶（PPO）活性以接种早期（接种后3d内）活性较高,其后则与抗性关系不明显。抗病品种超氧化物歧化酶（SOD）的活性,接种后上升较为明显,并且一直维持在较高水平,至接种5d后高抗品种的SOD活性迅速下降。感病品种大多在接种后先出现下降,接种3d后才出现明显上升。从接种前后过氧化物酶（POD）同工酶谱的变化可以看出,接种前品种的抗性与POD同工酶谱带条数和染色的深浅（酶活性）无相关性。接种后,最为明显的变化是高抗品种原有的同工酶谱带染色明显深于其它供试品种（活性增强）。且所有供试品种均增加了一条谱带,但以高抗品种染色较深,其次是中抗品种,感病品种大多较浅。另外,抗病品种叶片中的可溶性糖含量要低于感病品种,说明高糖有利于白粉病的发生,而不同抗性品种还原糖含量则无显著差异。高抗品种可溶性蛋白含量在接种后1d出现明显的高峰,是其它供试品种含量的2倍,中抗品种和感病品种则未见上升。叶片木质素含量抗病品种要高于感病品种。接种后,不同品种植株叶片内过氧化氢（H₂O₂）含量均有上升,但以感病品种的H₂O₂积累快,至接种3d H₂O₂含量达到高峰。高抗品种的叶绿素含量较高,其次是中抗品种,而感病品种的叶绿素含量一直低于抗病品种,尤其是高感品种。更多还原

【Abstract】 Preliminary identification on the resistance of 130 cucumber cultivars(cross combination) to powdery mildew was conducted in this research. Among them, 54 cucumber cultivars were identificated in open-field, which included 6 high-susceptible, 14 mid-susceptible, 5 mid-resistant and 29 high-resistant cultivars without disease occurrence. In greenhouse, 55 cucumber cultivars were identificated, which included 10 high-susceptible, 12 mid-susceptible, 5 mid-resistant and 28 high-resistant cultivars without disease occurrence. Ten cucumber cultivars were chosen and identificated on resistance to powdery mildew both in open-field and greenhouse at the same period time. The results demonstrated that the degree of disease occurrence in greenhouse was more serious than open-field. Different cultivars showed different resistance to powdery mildew when they were cultivated in open-field and greenhouse. The cultivars GY2, GY4 showed better resistance both in two conditions. 33 cultivars were inoculated in vitro at cotyledon stage, the disease damage was more serious than in the open-field along with the better condition, 3 cultivars were high-susceptible, 12 were mid-susceptible, 15 were mid-resistant and 3 uninfected were high-resistant cultivars.Eight cultivars which had differences on the resistance to powdery mildew were chosen to study the tissue structure, physiological and biochemical characters with different resistant cultivars after being inoculated with Sphaerotheca fuliginea.The microstructure of leaves by paraffin section showed that the tissue structure of high-resistant cultivars was more compact; the cell wall was thicker; the palisade tissue arranged more formal and close; the spongy tissue was tightly close to the palisade tissue and could be seen more clearly. The microstructure of high-susceptible cultivar“PingwangRugua”, which was most serious infected, appeared a great deal of interspace among cells and was not easy to see a whole cell clearly, and the cell wall was thinner. The cell wall of the mid-resistant cultivars was thinner than the high-resistant cultivars. And the palisade tissue of the mid-resistant wasn’t more close than the high-resistant, much more better than the high-susceptible cultivars such as“PingwangRugua”. The palisade tissue of the rest cultivars could be clearly seen, but the interspace was still larger. It may be one of the main reasons of the cucumber resistance to powdery mildew by formal and close cell arrangement, and thicker cell wall in leaf tissue. Some kinds of enzyme activities related to the resistance were investigated before and after inoculation at different time on cultivars with different resistance. The PAL activity of the resistant cultivars appeared obvious rise after inoculation. The PAL activity of the high-resistant cultivar“GY14A”appeared an obvious activity peak one day after inoculation. They had obvious difference from other cultivars and were 1.69 times more than that of the susceptible cultivar“DE843”. The PAL activity of the mid-resistant cultivar“JinYou No.30”peaked three days after inoculation and was 1.75 times more than that of the susceptible cultivars. The POD activity of the high-resistant cultivars displayed the maximum rise and were 1.22 times more than that of the susceptible cultivars. The POD activity of the susceptible cultivars peaked three days after inoculation. The PPO activity of the resistant cultivars was higher at the early inoculation stage(3 days after inoculation) and then had no obvious relationship with resistance. The SOD activity of the resistant cultivars appeared an evident rise and maintained at higher level, then declined rapidly five days after inoculation. The SOD activity of the most susceptible cultivars at first declined and then obviously rose three days after inoculation.There is no relationship between the cultivar resistance and peroxidase isozyme profiles linked to the shade of gel bands colour before inoculation by comparion of the change of the peroxidase isozyme profiles before and after inoculation. After inoculation, the obvious change was found that the primary peroxidase isozyme profiles of the high-resistant cultivars were darker than any other cultivars which indicated that the peroxidase activity was increased. Apart from that all of the cultivars enhanced an additional gel band, and the band of the high-resistant was darker followed by the mid-resistant and the susceptible cultivars.In addition, the soluble sugar content in the resistant cultivars was lower than that of the susceptible, which indicated that high-sugar was good for the occurrence of powdery mildew. The reducing sugar content of different resistant cultivars didn’t show obvious difference. The soluble protein content of the high-resistant cultivars appeared an obvious peak value one day after inoculation. The mid-resistant and mid-susceptible cultivars were not increased in soluble protein content. The leaf lignin content of the resistant cultivars was higher than that of the susceptible cultivars. After inoculation, the hydrogen peroxide content was increased in all cultivars, but accumulated quickly in the susceptible cultivars, and reached the peak value three days after inoculation. The chlorophyll content of the high-resistant cultivars was higher, followed by the mid-resistant and the susceptible cultivars especially the high-susceptible cultivars.更多还原