【作者】 高同军；

【导师】 强胜；

【作者基本信息】 南京农业大学 ， 植物学， 2006， 硕士

【摘要】 菌株QZ-2000是从马唐植株上分离得到的一株自然致病菌，前期的研究表明该菌株对马唐属杂草侵染力强，对玉米和大豆等作物安全，具备发展为生物除草剂防除恶性杂草马唐的潜力。敌散克是南京农业大学杂草研究室在多年的研究基础上拟开发的生物除草剂产品，它是以画眉草弯孢霉马唐专化菌株QZ-2000的活体分生孢子为主要活性成分，通过合适的方法接种后，使杂草寄主马唐叶片感病、停止生长、甚至杀死，从而削弱马唐对作物的竞争力，达到控制杂草的目的。本文对敌散克加工中的剂型、配方、及田间控草技术进行了研究，旨在加速该菌的产业化进程。本文首先对菌株QZ-2000大批量生产过程中的培养基配方及比例、培养基加水量、培养基割块大小、不同配方培养基致病力、及菌丝产孢过程进行了研究。结果表明，麦麸-米糠和麦麸-锯屑培养基的最佳配方比例分别为3：1和2.5：1，不同配方培养基产生的孢子致病力没有明显差异；培养基的加水量应以干物质总重的1.6倍为宜；培养基产孢过程中最佳的割块大小应为1cm左右；另外通过观察发现，菌株QZ-2000分生孢子产生方式应为内生芽殖型(Enteroblastic)。由于真菌孢子本身是活体，孢子产生后一直和培养基及菌丝连在一起，能否顺利地将其分离出来是敌散克产业化生产的第一步。在基本不影响孢子萌发率和侵染力的前提下，本文研究了在孢子分离过程中所能忍受的机械强度和适宜于工厂化生产的分生孢子分离方法。结果表明，分生孢子分离过程中所能忍受的机械强度为搅动振荡5秒左右，一般在生产中以3秒钟即可令大部分分生孢子从培养基上脱离下来，然后用6mm和3mm玻璃珠辅助，通过分级过筛方法可以顺利分离分生孢子，孢子分离率可达92.6％，孢子粉与产孢培养基的重量产率可达5％左右。在自然情况下，QZ-2000的分生孢子不具有湿润性，本文研究了可以增加分生孢子湿润性和悬浮性的助剂。结果表明：湿润性试验中，WPA9503效果最好；悬浮性试验中WPA9503、WPA9511、EPA8081效果均比较好；货价期试验表明3种助剂长期贮存对孢子萌发率和侵染率无明显影响。综合来看，WPA9503应为最佳的孢子粉助剂。WPA9503的用量以占孢子粉制剂总重量的15％为宜。为了增加敌散克田间应用效果，本文利用配方设计中常用的正交和均匀设计方法，对各种备选配方组分和用量进行了研究。结果表明在孢子液中加入1000ppm的甘油、80ppm的抗氧化剂、80ppm的甘露醇对Qz-2000的致病作用有促进作用。在朱云枝和徐春凤试验的基础上，连续三年进行敌散克田间试验，探索在自然条件下敌散克的控草效果。结果表明田间应用敌散克时，接种孢子液浓度应该维持在5×10~5个／ml左右，在加入合适的保湿剂、增效助剂的基础上，和低剂量的化学除草剂复配使用，田间控草效果可以维持在80％左右，如果施药后天气适宜，控草效果可以达到90％以上。表明该制剂已基本具备了发展为成熟产品条件，有很好的推广应用前景。更多还原

【Abstract】 Strain QZ-2000, isolated from naturally infected large crabgrass, was virulent to thelarge crabgrass and was safety to the crops such as corn and soybean under laboratory,greenhouse and fields, which was strongly indicated to have potential forcommercialization. So the strain QZ-2000 had fairly potential to be exploited asbioherbicide for large crabgrass. Disancu was a bioherbicide developed by Weed ResearchLaboratory, Nanjing Agriculture University using the conidia of strain QZ-2000 during pastseveral years. The mechanism of Disancu’s control weed was to infect leaves of crabgrassafter inoculation of conidia so as to halt the weeds growing and to weaken competition ofweeds and finally to achieve the goal of control weed. The aim of this study was to improvesome key techniques for commercialization of Disancu such as mass-production,formulation, adjuvant, prescription and the technique of weed control in the fields.Firstly, the studies were conducted on process of the mass,production of QZ-2000conida in order to determine the prescription of substrate, the proportion of sawdust or ricebran and wheat bran, water content, the solid substrate block size. The results indicated thatthe proportions of the rice bran-in-wheat bran and sawdust-in-wheat bran substrate were 3:1and 2.5:1 respectively. The virulence was not significantly different between those twokinds of substrate prescriptions, rice bran-in-wheat bran and sawdust-in-wheat bran. Theoptimal water content of substrate is 1.6 times to the dry material of substrate, and theoptimal size of solid substrate is 1cm in the course of sporulation. Furthermore, the processof sporulation of strain QZ-2000 was observed under the optical microscope and the resultsindicated the style of sporulation of the strain is entroblastic.Because fungus spore itself is a living specimen and the spores always adhere to themycelium in substrate, isolating spores from substrate safely is critical step of bioherbicideproduction. The mechanical strength of stir which conidium can endure in the sporeseparation process was studied. The results indicated that the conidia can endure the mechanical strength of stir in 5 seconds. Generally, 3 seconds was enough to seperateconidia from substrate. Then addition of two kinds of glass beads with diameter 6 mm and3 mm were benefial to separate conidia from substrate through step-sizing sieves. With thismethod, the rate of conidia separated from substrate achieved 92.6%, the conidiaproduction rate, the proportion of conidia weight and substrate wight, achieved about 5%In nature, the conidia of stain QZ-2000 did not have wettability; adjuvents werescreened to improve their wettability. The results indicated that the adjuvant WPA9503 hadthe best wettability and the adjuvant WPA9511, WPA9503 and EPA8108 had the similaraerosol, The shelf-life experiment indicated that three kinds of adjuvants had not significantinfluence on infectious potential and germination rate of conidia. WPA9503 was the bestadjuvant, which had a optimal proportion of 15% in solid powder.In order to increase the effect of Disancu in fields, the prescription of components thatmight enhance the potential of infection and control weeds had been investigated with themethod of orthodox and uniformity design which were universally used in prescriptioninvestment. The results indicated 80ppm triethanolamine, 1000ppm glycerol, 80ppmantioxidant in solution of spores can increase effects of strain QZ-2000 in control weeds inthe laboratory.The trial experiments were continuously conducted to evaluate efficacy of Disancuunder natural conditions on the basis the investment of Yunzhi Zhu and Chunfeng Xuduring past three years. The results indicated the concentration of spore suspension shouldmaintain up to 5×10~5 spore/ml in trial. Combining with optimal adjuvant, keeping-humiditymaterial, and low dosage herbicide, the control rate to large crabgrass of Disancu couldachieve about 80%. In particular, under the condition of optimal weather, the control ratewould mount up to 90%. The results of field experiments indicated that the bioherbicide,Disancu, had the potential in development for the successful product condition and wassuccessfully applied in the fields.更多还原