【作者】 杨春林；

【导师】 彭化贤； 张敏；

【作者基本信息】 四川农业大学 ， 植物病理学， 2009， 硕士

【摘要】 在田间用哈茨木霉（Trichoderma harzianum）Th-30生防制剂处理土壤或植株,通过对蔬菜不同生育期的农艺性状、经济性状、产量和病害发展情况的考察,研究木霉的促生作用及生物防治效果。结果表明,哈茨木霉菌株Th-30对辣椒的促生、增产作用明显,对辣椒植株的促生率为17.1%,增产15.68%,且对辣椒疫霉（Phytophthora capsici）和尖镰孢（Fusarium oxysporum）引起的根腐病具有一定的防治作用。哈茨木霉菌株Th-30能提高黄瓜的地上部生物学产量,明显增大黄瓜藤蔓的节间距,有效增加黄瓜的坐果率,对黄瓜枯萎病和黄瓜白粉病也有很好的生物防治效果。试验表明,哈茨木霉菌株Th-30对白菜、芹菜、番茄幼苗均有显著的促生作用,能增加植株的株高、地茎、叶片数,提高蔬菜的品质和产量并能有效控制芹菜病毒病的发展,且对供试植株安全。用还原糖法测定木霉菌株Th-30的几丁质酶活性,采用单因素和正交试验设计,研究了碳源、氮源、温度、pH值等发酵条件对哈茨木霉菌株Th-30生产几丁质酶的影响,并初步探讨木霉几丁质酶粗提液对番茄灰霉病菌（Botrytis cinerea）的拮抗作用作。结果表明,哈茨木霉菌株Th-30以7.0g/L几丁质、2.0g/L蛋白胨、营养盐溶液50mL/L、微量元素1.0mL/L为培养基,在起始pH5.5、温度28℃、装瓶量50mL/250mL、接种量8%、诱导96h获得的几丁质酶活性最高。哈茨木霉菌株Th-30几丁质酶粗提液对番茄灰霉病菌有明显的拮抗作用,对番茄灰霉病菌生长的抑制率为67.61%～71.31%,对灰霉病菌孢子产生及萌发的抑制率分别为80.95%、81.43%,对病菌孢子致病性的抑制率为65.22%～70.51%。采用紫外线诱变与药剂驯化相结合的方法,以哈茨木霉菌株Th-30为出发菌株诱导得到4株能在含常用杀菌剂福美双（Thiram）2×10⁵μg/L的培养基上正常生长的耐药性变异菌株。毒力测定表明,福美双对几株变异菌株的EC₅₀均相对于亲本菌株(EC₅₀为0.21×10⁵μg/L)提高了近2×10⁵μg/L。筛选出一株优秀的变异菌株UV-4,在高浓度农药环境下正常生长并产生具有生防功能的几丁质酶,其耐药性几丁质酶（福美双含量为1×10³μg/L）对黄瓜炭疽病菌（Colletotrichum lagenarium）孢子繁殖能力的抑制率为85.43%,对黄瓜炭疽病菌孢子致病力的抑制率为68.88%,并对病原菌菌丝的细胞壁具有降解作用。试验表明人工诱导获得的突变木霉菌株UV-4的抗药性及对病原菌拮抗活性都得到改良,且具有遗传稳定性,与靶标农药混用能达到协同防治蔬菜上的真菌病害的目的。更多还原

【Abstract】 The growth-promoting function and biological control effects of Trichoderma harzianum Th-30 on several vegetables were studied in our experiments.And agronomic characters,traits,theoretical yield and infection ratio of disease in different growth stage were examined.The result suggesting that the treatment of Trichoderma harzianum Th-30 has obvious growth-promoting effect on capsicum and could significantly increase yield of capsicum.It has a good control efficacy of Trichoderma harzianum Th-30 on capsicum root rot caused by Phytophthora capsici and Fusarium oxysporum.The results indicated that Trichoderma harzianum Th-30 has obvious growth-promoting effect on cucumber also. It could not only improve cucumber economic properties,but also increase plant height of cucumber and the quantity of leaves.And it could significantly improve several vegetables plant height,length of root,yield,and economic properties.All of the data showed a good control efficacy of Trichoderma harzianum Th-30 on cucumber fusarium wilt disease and powdery mildew.It also has obvious biocontrol effect and decreased the infection ratio of virus disease caused by CeMV on celery without any injury on vegetables.The activity of chitinase extracted from Trichoderma harzianum Th-30 was detected by the method of measuring reducing sugar.The medial components and culture conditions of Trichoderma harzianum Th-30,such as carbon source,nitrogen source, temperature,pH,were optimized by single factor and orthogonal tests.Antagonistic activity of chitinase against Botrytis cinerea was studied.The results indicates that the optimal medial components for inducing chitinase from T.hazrianum Th-30 were composed of 7.0g/L chitin,2.0g/L peptone,50mL/L nutrient salt,1.0mL/L trace element. The optimal culture conditions for producing chitinase were as follows:5mL medium filled in 250mL flask with 8%inoculum size of the culture,initial pH5.5,at 28℃, incubating for 4 days.And the results also showed that the chitinase extract from T. harzianum Th-30 has significantly effect on B.cinerea.The inhibitory efficiency on hypha growth of B.cinerea was 67.61%～71.31%.Inhibitory efficiency of chitinase to B.cinerea on propagating and germinating of spores were 80.95%and 81.43%.The efficiency against the pathogenic ability of B.cinerea was 65.22%～70.51%.4 mutant Trichoderma harzianum strains which were produced by Trichoderma harzianum Th-30 were obtained by UV-light and thiram stress on PDA medium.Thy are resistant to thiram and can grow normally on the medium mixed with thiram of 2×10⁵μg/L.The result of toxicity test showed that EC₅₀ of thiram to the mutant strains were 2×10⁵μg/L higher than parent strain Th-30,to which EC₅₀ of thiram is only 0.21×10⁵μg/L. A mutant strain numbered UV-4 which can produce biocontrol functional chitinase in high thiram stress was screened.Its inhibitory efficiency of chitinase extracts from UV-4,which is tolerant to thiram,on the ability of Colletotrichum lagenarium for producing spore were 85.43%.The efficiency against the pathogenic ability of C.lagenarium was 68.88%.And it can degrade the cell wall of mycelium of Colletotrichum lagenarium also.The tests indicates that the mutant strain UV-4 was modified on properties of fungicide tolerance and efficiency against on pathogenic fungi.And it was stable on genetic.It has synergistic effect with target fungicide for disease controling on vegetables.更多还原