【作者】 朱秦；

【导师】 强胜；

【作者基本信息】 南京农业大学 ， 植物学， 2003， 硕士

【摘要】 波斯婆婆纳（Veronica persica Poir）是危害小麦、油菜等夏熟作物田的世界性恶性杂草。胶孢炭疽菌婆婆纳专化型（Colletotrichum glorosporidies Penz．f．sp．veronicae S．Qiang et Q．Zeng）是在对该草生物防治研究过程中，从波斯婆婆纳植株上分离的一株自然致病菌。实验室研究结果表明，该菌株对波斯婆婆纳属杂草侵染力和寄主专化性强，对小麦、油菜等作物安全，具备发展为防除波斯婆婆纳的真菌除草剂的潜力。本文研究了胶孢炭疽菌作为生物除草剂防除波斯婆婆纳的产业化潜力，旨在加速该菌的产业化进程。 首先通过对波斯婆婆纳生防菌株胶孢炭疽菌婆婆纳专化型QZ—97a培养发酵方法、培养基的种类、pH和水分含量及培养时间的研究，试图发展该菌分生孢子大批量生产工艺。结果表明，液体和固体发酵均能用于该菌的大批量生产，而液-固体联合发酵可以获得最高的产孢量。多种固体基质可以作为培养基，麦麸豆粕最佳，当加水量在固体培养基千重的1.2倍，pH值范围为6.5-7.5，接种固体培养基6天后单位重量的干物质产孢量达到了8.30×10⁹个／克。波斯婆婆纳粉对固体培养基的产孢有增效作用。 通过这种方法生产的干孢子粉每克含有大量的分生孢子(接近10¹⁰个)，贮藏简便。将不同含水量的胶孢炭疽菌婆婆纳专化型菌株QZ-97a分生孢子粉置于4℃和室温下，密闭或开放贮存。每隔15天取样测定孢子的萌发率，每隔60天测定芽管长度。结果表明，4℃下密闭贮藏6个月，分生孢子萌发率和芽管长度无明显降低，室温贮藏分生孢子萌发率和芽管长度降低地也不明显。贮藏10个月后，各种贮藏孢子的活力都显著下降。总体上看，4℃、含水量为4％、密闭贮藏孢子活力最稳定，420天后，孢子萌发率为70.4％，芽管长度为贮藏60天时孢子芽管长度的43.2％。含水量为9.6％、开放室温下贮藏的孢子粉活力下降最大，相应的孢子萌发率和芽管长度值分别为35.5％和12.7％。因此，温度和孢子粉含水量是影响孢子货架期的两个主要因素。分生孢子粉对温度有一定的耐受性，随温度升高，敏感性增强，60℃以上分生孢子的活力下降显著，处理15分钟，孢子芽管长度下降50％。 胶孢炭疽菌孢子与化学除草剂间生物学相容性好。与6种常用除草剂相容性的测定结果显示，分生孢子在供试除草剂中均能够很好地萌发，即使在田间常规使用浓度胶饱炭疽菌作为防除波斯婆婆纳的生物除草剂产业化相关技术的研究下，袍子的萌发率也均大于78.3%.供试除草剂对袍子芽管生长的抑制随着除草剂浓度上升而明显增大，田间常规使用浓度下，饱子芽管在使它隆、2甲4氛钠盐及两者的复配剂中仍能够生长.除草剂药效生物测定表明，在1/10和2/10田间常规使用浓度下，使它隆对波斯婆婆纳的防效最好.因此，使它隆是菌药混用较好的候选除草剂。 蔗糖、葡萄糖等营养物质能够促进该菌袍子的萌发.以煤油、卵磷脂和吐温为组分的助剂2对袍子的萌发有抑制作用，但可以抑制波斯婆婆纳的生长势.助剂与袍子协同作用能够增强袍子对4一6叶期杂草的防效，但助剂浓度升高，防效增高不显著。低剂量的使它隆与该菌袍子及助剂复配使用，在不保湿的情况下，对波斯婆婆纳的防效显著提高.并且随着使它隆使用浓度的提高，对波斯婆婆纳的致病进程加快，防效增加.含助剂2%的105个/m1的袍子悬浮液与常规剂量15%使它隆复配可使4一6叶期的波斯婆婆纳在自然条件下致死。 通过对几种接种方法进行比较研究，用离体叶片法检测炭疽菌袍子的活力是较有效的方法.在12，卜时光照12小时黑暗交替条件下，损伤浸渍法接种的症状最为明显.更多还原

【Abstract】 Birdseye speedwell (Veronica persica Poir) is a major weed worldwide that significantly reduces yield of many different crops. In the search for biological control methods for birdseye speedwell, Colletotrichum gloeosporidies Penz. f.sp. veronicae S.Qiang et Q.Zeng, isolated from naturally infected birdseye speedwell, was virulent to the Veronica species but was safety to such crops as wheat, rape, soybean, cotton and com under laboratory or greenhouse conditions, which had the potential to be developed as mycoherbicide for birdseye speedwell. The aim of this study was to evaluate and improve the some related techniques for the commercialization of Collectotrium gloeosporiodies f.sp. veronicae as a potential mycoherbicide for birdseye speedwell.Firstly, the studies on fermentation methods, kinds, pH and water content of cultural media, and cultural time were conducted in order to develop a technique of mass-production of conidia of Collectotrichum gloeosporioides as a biological agent for Veronica persica. The research results showed that the conidia of this fungus could be mass-produced in both of submerged and solid substrate, but the highest harvest of conidia was made under the fermentation combined mycelia produced in submerged substrate and conidia sporulated in solid substrate. The wheat-bran and bean-cake substrate was the best one selected from the solid media tested, which all were suitable for the culture of this fungus. The highest yield at 8.30 x 109 conidia g-1 dry weight was obtained under pH 6.5-7.5 and water content equaled to 1.2 time dry-weight of solid media and after six-day culture. The addition of Veronica persica powder could promote to sporulate in solid media.The raw conidia powder produced by combined liquid-solid substrate fermentation contains abundant conidia (nearly 1010 conidia g-1 dry weight) , and it can be stored with simple equipment. While the fresh conidial powder of Collectotrichum gloeosporioides Penz. f.sp. veronicae Sheng Qiang et Qing Zeng was stored at 4癈 and room temperature in open or close capsule, germination rates and length of germ tube of conidia wereexamined at 15 and 60 days intervals, respectively. Results showed that there were no significant differences in germination rates and length of germ tube of conidia stored at 4 癈 and room temperature within 6 months. However, the germination rates and length of germ tube of conidia decreased significantly after storage for over 10 months at 4C or room temperature. In general, the conidia viability were most stable when the conidia powder with 4.0% water content was stored closely at 4C because the germination rates were 70.4% and the length of germ tube decreased only by 43.2% by the end of 420 days comparing to that by 60 days. Whereas, the conidia powder with 9.6% water content stored openly at room temperature were declined the most obviously, the corresponding values were 35.5% and 12.7% respectively. Therefore, storage temperature and water content of conidia were two key factors, influencing the shelf-life of Collectotrichum gloeosporioides f.sp. veronicae conidia. The conidia were heat-treated in oven at 40~60 C for 15~120 min to observe tolerance to high temperature of conidia. Results showed that the conidia powder was partly tolerant to temperature, while the susceptivity increased obviously with temperature rising. A regression analysis showed that the length of germ tube of conidia were decreased by 50% when heat-treated at 60C for 6 min comparing with that of control.The compatibility of Collectotrichum gloeosporioides conidia with six widely used herbicides was investigated by comparing germination rates and germ tube length of conidia in liquid containing 0.1-1.0 fold of concentration recommended for field spray. The results showed that the conidia germinated well in herbicides tested, even at the field-spray concentration recommended, the germination rate was more than 78.3%. The results also showed that negative effect of herbicide on the growth of conidia germ tube increased signific更多还原