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1、 毕 业 论 文题目：放线菌T111发酵液理化性质及发酵产物对核盘菌抑菌机制初探学 院 植 物 保 护专业班级 06植检1班 届 次 2010 学生姓名 学 号 指导教师 二O一年 六 月 十 日目 录中文摘要4英文摘要41 前言51.1 生防菌应用的种类61.2 拮抗放线菌的主要作用机制71.3 本研究的目的及意义82 材料与方法82.1 材料82.2 拮抗放线菌发酵液抑菌活性测定方法92.3 T111发酵液的理化性质92.4 放线菌T111发酵产物对核盘菌的抑菌机制研究103 结果与分析113.1 T111发酵液的理化性质113.1.1发酵液抗菌谱113.1.2 贮存稳定性123.1.3
2、热稳定性133.1.4 酸碱稳定性133.1.5 紫外光稳定性143.2 T111发酵产物对核盘菌的抑菌机制结果153.2.1 T111发酵产物对核盘菌菌丝生长的影响结果153.2.2 T111发酵产物对核盘菌菌丝形态的影响结果153.2.3 T111发酵产物对核盘菌菌核形成及单重的影响结果163.2.4 T111发酵产物对核盘菌菌核萌发的影响结果173.2.5 T111发酵产物对核盘菌菌丝体细胞膜渗透势的影响结果184 讨论195 参考文献206 致谢21CatalogueChinese abstract4English abstract41 Introduction51.1 The cat
3、egory of antagonism fungus61.2 The antagonistic mechanisms of Streptomyces71.3 Purpose and significance of the study82 Material and methods82.1 material82.2 Antifungal abilities of fermentation conditions92.3 Physical and chemical properties of T111 strain92.4 Antagonistic mechanisms to Sclerotinia
4、sclerotiorum of T111103 Results and analyse113.1 Physical and chemical properties of T111 strain113.1.1 Inhibition spectrum of fermentation extracts of T11113.1.2 Effects of storage time on the activity of fermentation extracts123.1.3 Effects of temperatures on the activity of fermentation extracts1
5、33.1.4 Effects of pH on the activity of fermentation extracts133.1.5 Effects of UV irradiation time on the activity of fermentation extracts143.2 The result of antagonistic mechanisms to Sclerotinia sclerotiorum 153.2.1 Inhibition toxicities on mycelium growth of S. sclerotiorum153.2.2 Effect of fer
6、mentation broth of T111 on sclerotium mycelium shape153.2.3 Effect of antifungal substance of T111 on sclerotium formation time and single weight163.2.4 Effect of antifungal substance of T111 on sclerotium bourgeon173.2.5 Effect of antifungal substance of T111 on membrane osmotic potential184 Discus
7、sion195 Reference206 Thanks21放线菌T111发酵液理化性质及发酵产物对核盘菌抑菌机制初探 摘要：为明确放线菌T111的理化性质，研究了其抗菌谱，及贮存时间、温度、酸碱条件、紫外光照射等对其发酵液稳定性的影响。结果表明，T111发酵液对黄瓜菌核、黄瓜蔓枯、棉花红腐病菌等有较高的抑制活性；贮存稳定性和热稳定性良好，4贮存60d抑菌活性为对照的88.3%，80处理60min抑菌活性为对照的90.9%；对pH值较敏感，在pH 57时活性较高；对紫外线稳定，紫外光照射12h，其活性基本不受影响。初步研究了T111发酵产物对核盘菌的抑菌机制，采用菌丝生长速率法测定了其对黄瓜菌核
8、病菌Sclerotinia sclerotiorum菌丝生长的毒力，及其对菌丝形态、菌核形成、菌核萌发和菌体细胞膜透性的影响。结果表明，T111发酵产物对核盘菌菌丝生长的EC50值为12.5g/mL，低于对照药剂乙霉威及嘧霉胺；经发酵产物处理后，菌丝形态出现黄化、畸形等现象，但尚未发现细胞质外渗；菌核形成的时间有所延长，数量有所减少，且重量略有降低；在发酵产物浓度为250g/mL时不能完全抑制菌核萌发；对菌体细胞膜渗透势的影响不大。关键词：黄色链霉菌；黄瓜菌核病菌；发酵液；理化特性；抑菌机制Characterizations of T111 fermentation extract and a
9、ntagonistic mechanism to Sclerotinia sclerotiorum Abstract: the physical and chemical properties of the fermentation extract were studied by using agar-well diffusion method. The results showed that the fermentation extracts had high inhibitory activities on Sclerotinia sclerotiorum, Ascochyta citru
10、llina and Fusarium moniliforme var. intermedium. And it was well-stored and thermalstable, 88.3% of the initial activities remained after stored 60d at 4, 90.9% of the initial activities remained after heating at 80 for 60min. The fermentation extract was sensitive to the changes of pH, only in the
11、pH range of 5-7 was stable; the antifungal activities were almost not destroyed when it was under UV irradiation for 12h. To ascertain the antagonistic mechanisms of the antifungal substance to S. sclerotiorum, the inhibition activities on mycelium growth against S. sclerotiorum were determined by m
12、ycelium growth rate method in lab. And its effect on this pathogens biology characteristics, such as mycelium shape, sclerotium formation, sclerotium germination and membrane osmotic potential were also studied. The results showed that its EC50 value was 12.5g/mL, which was lower than Diethofencarb
13、and Pyrimethanil. After treated with the antifungal substance, the mycelia became etiolation and malformation, but had not yet found in the cytoplasm extravasation. This antifungal substance could delay the formation of sclerotium, the sclerotium numbers decreased contrasted that of the water contro
14、l, and the weight reduced slightly. At the concentration of 250g/mL of this antifungal substance, it could not restrain the sclerotium germination completely. And it had no significant effect on the membrane osmotic potential. Key words: Streptomyces flavus; Sclerotinia sclerotiorum（Lib.）de Bary; Fe
15、rmentation extract; Physical and chemical properties; Antagonistic mechanisms.1、前 言植物土传病害，其病原菌一般为多寄主微生物，通常侵染植物根部，引起植物根部乃至全株性病害。土传病害的发生和流行通常属于积年流行病害，年度间波动不大。在防治方面，化学防治和抗病育种目前只对部分病害有效，对大多数病害防效不甚理想1。黄瓜菌核病就是近几年来严重为害温室黄瓜产量的一种重要土传病害，该菌以菌核的状态在自然条件下可以长期存活，防治非常困难。目前生产上主要依靠化学防治，但由于抗药性的发生，使得菌核病菌对多种杀菌剂存在着较高的抗性。目前正在寻找一种简单、有效、安全的植物病害防治方法，即生物防治。生物防治是指通过除人以外的一种或多种生物来降低病原微生物数量或减弱病原菌的致病能力，从而减少病原微生物所致病害的发生2。它是通过植物、病原物、生防菌、植物表面及其周围微生物群落和自然环境等因素的互作关系，来达到促生防病的作用3。拮抗微生物具有不易使病原菌产生抗性、对环境安全、生产工艺相对简单以及不少微生物
