【作者】 廖海丰；

【导师】 祝树德； 刘贤进；

【作者基本信息】 扬州大学 ， 农业昆虫与害虫防治， 2003， 硕士

【摘要】 苏云金杆菌(Bacillus thuringiensis)是近缘于蜡状芽孢杆菌能产生晶体具芽孢，寄生于体内引起昆虫发病的杆菌。本文从昆虫神经毒性反应角度，通过对B．t．与其他新型胃毒性生物杀虫剂的联合作用机制进行研究，特别是与一些动、植物源的毒蛋白类物质如蝎毒、沙蚕毒素等的联合作用机制进行研究，以期指导B．t．等生物源胃毒杀虫剂的合理混用，并在此基础上提出B．t．与生物源杀虫物质的混配使用技术。本研究得出下列结果： 1 B．t．与转δ-内毒素基因棉(下称转基因棉)联合作用后使得棉铃虫对B．t．的敏感性增强，但多代取食转基因棉的试虫却对B．t．的敏感性下降。通过对试虫体内的酯酶比活力的测定发现，多代取食基因棉的试虫乙酰胆碱酯酶及羧酸酯酶比活力增强，两项指标比活力分别增强了1.69及1.78倍。 2 中毒症状调查结果发现，蝎毒素、沙蚕毒素、阿维菌素及楝素与B．t．混配处理后的试虫同时表现出明显的多种累加症状，且症状出现时间也明显提前。处理混剂后大部分试虫出现明显症状的时间要比B．t．提前24小时左右。 3 B．t．与蝎毒素、沙蚕毒素、阿维菌素、楝素及氰戊菊酯混配，利用共毒因子法，考虑到以B．t．为主，选出几种增效作用比较明显的混剂配方。其配比是B．t．与蝎毒素为4：1，B．t．与沙蚕毒素为10：1，B．t．与阿维菌素为16：1，B．t．与楝素为50：3，B．t．与氰戊菊酯为40：1的配比。室内测定结果显示各混剂对棉铃虫有较高增效作用，致死中浓度分别为75.405mg／L，116.830mg／L，20.110mg／L，80.593mg／L，27.992mg／L。共毒系数分别为217.9、254.8、1064.0、443.4、1082.6。 4 测定混剂对棉铃虫中肠神经肌肉动作电位结果表明，B．t．与蝎毒素、沙蚕毒素及阿维菌素混配均导致了试虫中肠神经肌肉动作电位的发放频率或振幅的加剧。B．t．和蝎毒素混剂处理平均自发放频率加药前为0.9±0.08次／秒，加药后1分钟为1.4±0.25次／秒，2分钟后为2.9±0.31次／秒。平均振幅加药前为0.12±0.029mv，加药1分钟后为0.18±0.053mv，2分钟后为0.31±0.032mv。以B．t．和沙蚕毒素混剂处理平均自发放频率加药前为0.8±0.10次／秒，加药后3分钟为1.3±0.14次／秒，6分钟后为2.8±0.31次／秒。平均振幅加药前为0.10±0.018mv，加药3分钟后为0.15±0.017mv，6分钟后为0.34±0.044mv。以B．t．和阿维菌素混剂处理平均自发放频率加药前为 l．2 i 0二24次／秒，加药后 5分钟为 0．sic．09次／秒，8分钟后为 2，2士 0．17次／秒。平均振幅加药前为 0．14土 0刀29my，加药 5分钟后为0刀9士0刀17my，8分钟后为0。28上0．054my。 以上结果表明，Bt与转基因棉呈协同增效作用，其增效机理与酯酶及乙酸胆碱酯酶有关；Bj．与蝎毒素、沙蚕毒素及阿维菌素及多种杀虫剂联合处理有较广泛协同效应，其增效机理可能与B．t．的神经毒性作用协同相关。这种协同效应在抗性治理和害虫防治，包括转基因作物利用中具有潜在的应用价值，值得进一步研究。更多还原

【Abstract】 Bacillus thuringiensis(B.t.) has been widely used because of its specificity for target insects, low development cost and environmental compatibility. This thesis aims at guiding a reasonable combination of B.t. and other biological insecticides and also introducing the practical combination technique of B.t. and other biological insecticides in the perspective of insect never toxication. The result is obtained by carrying out on the combination mechanism of B.t. and other newly developed biological insecticides, especially researches on the combinational functions of some animal and plant toxins, for example , Buthotoxin and Avermectin.The following is the main results of the research.(1) The susceptibility of larvae of less army worm Helicoverpa armigera to B.t. was increased when the larvae were fed with transgenic cotton compared to those fed on the non-transgenic cotton, but decreased after 10-generation’s feeding with the bt transgenic cotton plants. Biochemical analysis showed that the activities of acetylcholinesterase and carboxylesterase were obviously higher in those larvae fed on the transgenic cotton.(2)Observation on the poisoning symptom showed that the poisoning of the insects treated with B.t.+ Buthotoxin, B.t.+ Avermectin, B.t.+ Nereistoxin and B.t.+ Azadirachtin mixture were enhanced and accelerated for about 24hrs..(3) Greenhouse tests indicated that joint treatment with B.t. and Nereistoxin, Avermectin, Buthotoxin and Azadirachtin presented better control effects than any single toxicant. The LC50 value of each mixture is 75.405mg/L,116.830 mg/L,20.110 mg/L,80.593mg/L5 27.992 mg/L respectively, and the C.T.C values of LC50 is 217.9, 254.8,1064.0, 443.4 and 1082.6 respectively.(4)Electrophysiological effects of the mixtures on the midgut never-muscle systemshowed synergistic symptoms. The frequency and amplitude of spontaneous action potentials was increased obviously. The average frequency and amplitude value caused by the joint treatment with B.t, and Buthotoxin is as follow: 0.9±0.08 times/second and 0.12±0.029mv before the treatment, 1.4±0.25 times/second and 0.18?.053mv at 1minute, 2.9±0.31 times/second and 0.31±0.032mv in 2 minutes . The value for the joint treatment B.t. and Avermectin is 0.8±0.10 times/second and 0.10±0.018mv before the treatment, 1.3±0.14 times/second and 0.15±0.017mv in 3minutes , 2.8± 0.31 times/second and 0.34±0.044mv in 6minutes . The value for the Joint treatment B.t. and Nereistoxin,. is 1.2±0.24 times/second and 0.14±0.029mv before the treatment , 0.8±0.09 times/second and 0.09±0.017mv in 5minutes , 2.2±0.17 times/second and 0.28±0.054mv in 8 minutes .For conclusion, the author believed that the synergistic mechanism of B.t and Bt-transgenic cotton relate to the acetylcholinesterase and carboxylesterase, and there existed different kinds of joint action between B.t. and many other toxicants, and which is useful in insect pest management, or resistant management of the transgenic cotton plants.更多还原