【作者】 乔宏萍；

【导师】 宗兆锋；

【作者基本信息】 西北农林科技大学 ， 植物病理学， 2003， 硕士

【摘要】 果、蔬采后病害一直困扰着世界各国水果和蔬菜市场，化学防治是控制采后病害的主要措施，然而大量使用杀菌剂严重威胁着人类的健康，迫切需要研究控制采后病害的新方法，开发出无公害的新制剂以达到控制果、蔬采后损失的目的。本研究采集自发产生的重寄生放线菌，在初步明确其生物学及生态学习性、对靶标病原菌的作用谱及作用机理的基础上，用其发酵液和活菌制剂对常见温室蔬菜病害和果、蔬采后病害进行控制，为将其开发成有效的生物制剂、应用于现代农业生产奠定基础。 偶尔发现的重寄生菌F46和PR在室内镜检确定后，用选择性培养基和特定诱捕分离法分离保存。经过对2株重寄生菌的培养特征、生理生化特性和细胞学组分的观察分析，将菌株F46归于链霉菌(Streptomyces sp.)金色类群，PR归于链轮丝菌属(Streptoverticillium. sp)。 选用13种常见的植物病原菌，采用皿内颉颃性测定法得出，2种重寄生放线菌对低等真菌的作用效果最好，对半知菌亚门中靶标菌的作用效果次之，对子囊菌的作用效果最差。从作用机理上看，2种重寄生菌对梨状毛霉和大豆腐霉是溶菌作用，而对其它靶标菌为重寄生作用。它们对其寄主菌以外的病原真菌也具有重寄生作用，没有寄生专化特性。电镜观察到了F46或PR对靶标菌具有明显的菌丝缠绕、产生吸器等重寄生现象。 在对2株重寄生菌的生态学习性研究中发现，PR在土壤中不能存活，F46在加毛霉菌菌丝体的土壤基质中其存活数量随着时间的延长而呈现上升趋势。F46和PR均可定殖于黄瓜幼苗体内，PR的定殖能力强于F46。 F46和PR对常用的几种杀菌剂抗性测定结果发现，菌株F46可以和低剂量的五氯硝基苯、链霉素、腐霉利及甲基托布津混合使用，菌株PR能够同低剂量的五氯硝基苯、链霉素、腐霉利及甲霜灵共同使用 果、蔬采后病害防治结果表明，F46和PR对梨状毛霉、灰葡萄孢和扩展青霉引起的苹果采后腐烂病有一定的控制作用，提前接种效果好于同时接种，对毛霉的防效最佳，在低温下的防病效果明显优于高温下的防效。在10℃条件下，菌株F46和PR对草莓灰霉病都具有明显的防治效果，不同处理间防治效果差异不显著。F46在10℃条件下对番茄采后灰霉病的控制效果都好于20℃条件下的防效，提前接种的防效略好于同时接种的。PR对番茄灰霉病的防病效果在不同处理间没有明显差别。2种重寄生菌对温室黄瓜霜霉病的防治效果不明显，均未超过50％。更多还原

【Abstract】 Postharvest decay of fruits and greenhouse diseases of vegetables represented one of the most severe causes of losses and reduction in quality all over the world. Synthetic fungicide was the main measure used to control the diseases. As increasing in public concern over the health and environment safety, chemical fungicide has been restricted in vegetables and fruits. Biological control of plant pathogens has became one of the most promising alternatives in agricultural production.The hyperparasites strain F46 was isolated from the leaves of tomato in greenhouse and the strain PR was isolated from the leaves of wheat. On the basis of the morphological features, the physiological and biochemical characteristics and the cell wall chemotype, strain F46 was identified to Streptomyces sp. and strain PR was classified into Streptoverticillium sp..Twelve parasitic fungi, including Pythium aphanidermatum, Mucor piriformis, Ceratocystis fimbriata, Gaeumannomyces graminis, Alternaria spp., Botrytis cinerea, Colletotrichum gloesporioides, Fulvia fulvum, Fusarium oxysporum f. sp. vasinfectum, Penicillium expansum, Trichothecium roseum, Verticillium dahliae, and Gram-negative bacteria Erwinia carotovora pv. carotovora were used to test the antagonistic effects of two hyperparasite strains. The results shown that strain F46 and strain PR have different inhibiting effects on the target pathogens. The inhibiting effect of the strain PR was better than the strain F46. It has been found that lysis phenomena of two hyperparasitic strains on M. piriformis and P. aphanidermatum, and hyperparasitism on others target pathogens. The haustoria and twist hyphae of F46 and PR on target pathogens were observed under the electronic microscopy.The ecological studies with two hyperparasites shown that strain PR did not survive in the soil and strain F46 could survive especially in the soil added with the mycelia of M. piriformis. Two hyperparasites strains were able to colonize in the stern of cucumber seeding, the colony ability of strain PR was better than strain F46. Two hyperparasites had different tolerance to the eight tested fungicides commonly used in greenhous, including carbendazim, chlorothalonil, mancozeb, metalaxyl, procymidone, quintozene, thiophanate -methyl and streptomycin.Biocontrol potential of the hyperparasitic actinomyces strain F46 and strain PR against apple postharvested decay, gray mold of strawberry and tomato were evaluated in the storage condition. The control efficacy of two strains on M. piriformis was more effective than on B. cinerea and P. expansum in apple decay. Comparing the inoculation oftarget pathogens and hyperparasites at the same time, a better control effect was obtained when the biocontrol agents was inoculated at 24h before challenge inoculation. There was significant difference in control efficacy in the different temperature and two biocontrol agents. B. cinerea of strawberry was effectively controlled by strain F46 and strain PR at 10℃. A lower incidence of gray mold in tomato fruit was calculated in challenging with F46 at 10℃ storage condition than at 20℃, but treated by strain PR had not significantly difference between 10℃ and 20℃. The primary results in greenhouse shown that the control efficacy of two strains of hyperparasites against Pseudoperonospora cubensis in cucumber was not up to 50%.更多还原