【作者】 颜惠霞；

【导师】 徐秉良；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2009， 硕士

【摘要】 南瓜白粉病(powdery mildew)是一种广泛发生的世界性病害,长期困扰着南瓜的生产,给生产造成了一定的经济损失,成为南瓜生产中的一个限制性因素。本试验通过对南瓜白粉病病原菌的形态学观察和鉴别寄主感病反应,结果表明,引起甘肃省武威地区南瓜白粉病的病原菌为单囊壳属单囊壳菌(Sphaerotheca fuliginea (Schlecht.Ex Fr.) Poll)。并对甜瓜、黄瓜、苦瓜、丝瓜、冬瓜,西葫芦等10种瓜类进行接种,测定其寄主范围。结果表明,引起甘肃省武威地区南瓜白粉病的病原菌对甜瓜、黄瓜、苦瓜、冬瓜、西葫芦等9种葫芦科植物均具有侵染力,但是对丝瓜无侵染力。采用田间自然接种鉴定和室内苗期接种鉴定的方法,研究了10个南瓜品种对白粉病的抗性。结果表明,品种间的抗病性差异均达到了显著水平,其中品种三星、红栗、甜栗表现为高抗;品种二星、日本、金钩、京域表现为抗病;品种光板、天然、红福表现为感病。经相关分析表明,田间自然鉴定结果与室内苗期人工接种鉴定结果的相关系数R2=0.9112,达到显著水平,即室内苗期接种鉴定结果与田间自然鉴定结果是一致的。对南瓜白粉病发病因素的研究表明,温度为25～30℃,湿度在80～90﹪,苗龄为2片真叶时,是最容易发病的。对孢子悬浮液接种浓度和放置时间的试验设计研究表明,白粉菌的孢子悬浮液接种浓度为2.5×105～5.0×l05个/mL、放置时间在0.5h以内时,南瓜最易发病。不同品种南瓜对白粉病的抗性与组织结构研究表明:叶片表面的气孔数目和分生孢子的萌发率与南瓜品种对白粉病的抗病性呈负相关,而叶片表面气孔的大小和表面绒毛与南瓜品种对白粉病的抗性无相关性。以6个对白粉病有不同抗性的南瓜品种为材料,研究人工接菌后叶片叶绿素含量、过氧化物酶(P0D)和苯丙氨酸解氨酶(PAL)活性的变化及其与抗病性的关系。叶绿素含量测定结果表明:南瓜叶片中叶绿素的含量与南瓜品种对白粉病的抗性呈正相关,相关系数R2 = 0.9137,达极显著水平。酶活性测定结果表明:抗病和感病南瓜品种未接种白粉菌前,抗病品种三星的健康植株过氧化物酶(P0D)和苯丙氨酸解氨酶(PAL)的活性均高于感病品种红福的活性,但是差异不显著;接种白粉病菌后,供试品种间叶片PAL活性和POD活性均升高,其中抗病品种间PAL活性升高幅度显著大于感病品种,其变化与病情指数呈负相关,而抗感品种的POD活性升高幅度差异不显著,但是抗病品种出现两次酶活性高峰,而感病品种只有一次酶活性高峰;POD活性和PAL活性与南瓜品种对白粉病的抗性密切相关。更多还原

【Abstract】 Powdery mildew of pumpkin is a widespread disease worldwide, the long-standing problem of pumpkin production, to produce a certain result in economic losses as a pumpkin production of a limiting factor. The disease causing Pumpkin powdery mildew was observed and identified in WuWei districts of Gansu .The chief pathogens, according to microscopy, spore germination experiment and identification of the host response to infection, were identified as Sphaerotheca fuligine. And the determination of host range for the melon, cucumber, balsam pear, snake gourd, winter melon, pumpkin 10 categories for vaccination. The results showed that the region arising from Wuwei, Gansu Province pumpkin powdery mildew pathogen of melon, cucumber, bitter gourd, wax gourd, pumpkin and other 9 kinds of Cucurbitaceae force are infected, but non-infected sponge gourd force.Resistance of ten Pumpkin cultivars to powdery mildew was studied by means of natural infection in the field and artificial inoculation in the laboratory. The results showed that the resistance to powdery mildew among the Pumpkin cultivars was significant different. Xanxing, Hongli and Tianli were resistant; Guangban,Tianran and Hongfu were susceptible. Moreover, the level of resistance to the disease between field natural elaluation and laboratory artificial inoculation was significant positive correlation.The result indicated that the primary pathogen was ascus subphylum ,Sphaerotheca fuligine,the inoculation concentration was 2.5×105 to 5.0×l05 spores/mL,laying within 0.5h and the treatment of two euphylla, , the temperature for 25 to 30℃, the humidity in 80 to 90﹪is easiest to be taken bad of pumpkin.The result showed that the resistance was negative correlated to stomatal number and the germination rate of conidia. Statistical analysis indicated that the stomatal density were not correlated with the resistance to powdery mildew in six pumpkin cultivars. The variation of some biochemical index of pumpkin cultivars such as the content of chlorophyll, the activity of peroxidase (POD) and activity of phenylalnine ammonia-lysae were analyzed by testing pumpkin seedling whose leaves have been inoculated and uninoculated. The result showed that the resistance was positively correlated to the content of chlorophyll. And responses of peroxidase (POD) and phenylalnine ammonia-lysae (PAL) of pumpkin seedling leaves were analyzed after inoculation with Sphaerotheca fuligine. The results showed that the activities of POD and PAL of non-inoculated (CK) were similar among cultivars; The activities of POD and PAL in the susceptible cultivars increased more than that of resistant after inoculation with Sphaerotheca fuligine , and the changes were negatively correlated with the pumpkin resistance against powdery mildew , while the increasing rate of the activities of PAL in the susceptible was less than that of resistance after inoculation , and the changes were positively correlated with the resistance. And the activity of POD emerged two higher points after inoculation of resistant,but only one of susceptible.It was concluded that the changes of POD and PAL activities in the inoculated leaves were closely correlated with the pumpkin resistance against powdery mildew.更多还原