【作者】 曹奎荣；

【导师】 朱建兰；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2006， 硕士

【摘要】 针对近年来草莓根腐病普遍发生并逐年加重的现状,本试验以草莓根腐病(strawberry root rot)为研究对象,进行病原菌的分离鉴定、生物学特性研究、室内药剂筛选及不同品种的酶活性测定等试验。经过对草莓根腐病病原菌进行组织分离,共得到450个菌落,可归为五类。然后选取这些分离物中的优势菌株F1(首先对其进行单孢分离)和R1接种到健康植株,待植株发病后进行再分离。结果表明:采用的有伤和无伤两种接种方法接种结果均显示病原菌F1和R1具有较强的致病性,接种后植株发病症状与田间采集的标本症状一致。通过培养性状、形态鉴定和接种,参照鉴定标准,F1为尖孢镰刀菌(Fusarium oxysporum),R1为立枯丝核菌(Rhizoctonia solani Kuhn)。病原菌生物学特性研究结果表明:尖孢镰刀菌菌丝生长的温度范围0~35℃,最适生长和产孢温度为30℃。立枯丝核菌菌丝生长的温度范围5~35℃,最适温度为30℃。两者均在偏酸性条件下生长快,且尖孢镰刀菌产孢量大。尖孢镰刀菌菌丝在以蔗糖和硝酸钾为碳源和氮源的培养基上生长最快,产孢最多。而立枯丝核菌的最适碳源和氮源分别为淀粉和硝酸铵。光暗交替有利于尖孢镰刀菌和立枯丝核菌菌丝生长及尖孢镰刀菌产孢。室内平板测定结果表明:所选的6种杀菌剂对草莓根腐病病原菌均有抑制效果。对尖孢镰刀菌的抑菌试验发现:58%甲霜灵锰锌(96.53%)和80%代森锰锌(86.14%)抑菌率最高;其次为75%百菌清(77.05%)、50%扑海因(68.83%)和55%敌克松(66.23%);72.2%普力克(12.99%)防效最差。而对立枯丝核菌的抑菌试验发现:80%代森锰锌(97.44%)、55%敌克松(97.44%)、58%甲霜灵锰锌(98.72%),50%扑海因(99.14%)的抑菌率很高;75%百菌清(73.94%)较好;72.2%普力克(41.03%)防效差。因此,草莓根腐病进行防治时宜选用甲霜灵锰锌和代森锰锌这两种杀菌剂。通过对杜克拉等不同的5个草莓品种接种前后与抗性有关的酶活性的测定,发现接种前每个品种的各种酶活性与品种的抗病性之间无明显相关性,接种后则与抗病性密切相关。抗病性强的品种杜克拉、童子一号和卡尔特一号的超氧化物歧化酶(SOD)酶活高峰接种后8d出现,过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、过氧化氢酶(CAT)酶活高峰在接种后12d到达,酶活性提高幅度大;感病品种红实美和丰香的酶活高峰则在接种后出现地要比抗病品种迟,分别在12d和16d才出现,而且升幅小于抗病品种。更多还原

【Abstract】 Recently, Strawberry root rot ,a kind of soil-brone disease,became more and more serious in the strawberry-planting areas .In this paper,pathogen of strawberry root rot was identified and biological characteristics,pathogenicity,chemical control,enzyme activity were studied.The pathogen of strawberry root rot was isolated from disease tissues. Then inoculated the healthy plant in two means, and found the plant had the same symptom with the speciemen which had gathered from field. Then isolated from the plant again, the fungi were the same pathogen which had been isolated from speciemen. The results showed the pathogenic fungi had strong pathogenicity.The biological characteristics of two fungi were studied in the laboratory. The range of growth temperature of Fusarium oxysporum, Rhizoctonia solani Kuhn were 0~35℃,5~ 35℃respectively, and the optimum was 30℃. The optimum pH of two fungi was 6.26 and 5.35, respectively. Light, different content of nitrogen and carbon in the medium affected on the growth of the two fungi.The results indicated that all fungicides had control effect. But Metalaxyl and Mancozeb were better than Dexon、Chlorothalonil、Iprodione and Prompamocarb on Fusarium oxysporum. To Rhizoctonia solani Kuhn, Dexon、Mancozeb、Metalaxyl and Iprodione were better than Chlorothalonil and Prompamocarb. Therefore, Metalaxyl and Mancozeb were the best fungicides to control strawberry root rot.Strawberry varieties with different resistance were inoculated by Fusarium oxysporum and Rhizoctonia solani Kuhn. The activities of peroxidase(POD), polyphenol oxidase (PPO), phenylalanine ammonialyase(PAL), Catalase(CAT) and Superoxide Dismutase (SOD) were mensurated before and after inoculation. The results showed that there were no relationships between disease resistance and the enzyme activities before inoculation; However,variations of enzyme activities of POD,PPO,PAL,CAT and SOD were closely related to disease resistance of strawberry after inoculation.In resistant variety,the maximum value of SOD content was appeared in 8d after inoculation, the maximum value更多还原