枯草芽孢杆菌（Bacillus subtilis）S9对植物病原真菌的溶菌作用   总被引：19，自引：1，他引：19  

呈福  李德葆 《植物病理学报》2003,33(2):174-177

本研究共分离了976株细菌分离物，发现来自甘蔗根围的1株枯草芽孢杆菌(Bacillus subtilis)S9对立枯丝核菌(Rhizoctonia solani)、终极腐霉(Pythium ultimum)和西瓜枯萎病菌(Fusarium oxysporum f.sp.niveum)在PDA平板的对峙培养过程中不形成抑菌圈，但4d后可使上述植物病原真菌的菌丝溶解。扫描电镜观察发现S9菌株在待测的立枯丝核菌表面形成了溶菌斑。S9菌株对立枯丝核菌的作用过程是通过吸附在病原真菌的菌丝上，并随菌丝生长而生长，而后产生溶菌物质消解菌丝体。液体共培养测定也证明了S9菌株具有上述作用。本研究还发现，S9菌株对植物病原真菌的拮抗真菌绿色木霉(Trichoderma viride)、鲜红毛壳菌(Chaetomium cupreum)和球毛壳菌（Chaetomium globosum）的生长没有影响。盆栽试验证明了S9菌株可有效地控制立枯丝核菌(R．solani)引起的番茄苗期病害。S9菌株与其它拮抗真菌混合具有促进防治植物病原真菌引起的植物病害的潜力。  相似文献   

螟虫长距茧蜂研究进展     

张安盛  冯建国于毅 张思聪 《昆虫天敌》2003,25(2):89-92

本文综述了对螟虫长距茧蜂的研究概况，包括该寄生蜂的主要生物学习性、对玉米螟自然寄生率及田间防治玉米螟效果等。  相似文献   

Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field     

Hiromitsu Furuya  Tsutomu Matsumoto  Shin-ichi Fuji  Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.  相似文献   

O₃对日光温室黄瓜病虫害的防治效果   总被引：3，自引：0，他引：3       下载免费PDF全文

陈志杰  张淑莲  梁银丽  张锋  徐福利 《植物保护学报》2003,30(4):371-376

通过室内与大田试验，明确O3对日光温室黄瓜病虫害的防治效果。研究结果表明，在病害发生初期，用O3发生器隔天施放O3，每天施放3次，每次40min，间隔20min，O3浓度维持约1mg／kg，施放后7天，对黄瓜霜霉病、白粉病、细菌性角斑病及灰霉病防治效果分别为63．4％、53．6％、68．7％和65．0％。室内施放O3 60s，间隔20min，持续12h，对温室白粉虱、南美斑潜蝇成虫杀伤力为100％。O3对黄瓜植株安全，但随着黄瓜生育期的推进，对O3的忍受能力依次减弱。苗期忍耐O3最大浓度为1～2mg／kg，结果期0．4～1mg/kg，后期0．2～0．4mg／kg。O3防治黄瓜病虫害新技术具有安全、有效、方便、无二次污染等特点，尤其在黄瓜定植前对棚室进行大剂量消毒，可不留死角，且有效地解决了硫磺等药物消毒所造成棚内一些设施的破坏及对生态环境污染的难题，具有广阔的推广应用前景。  相似文献   

新疆冬小麦农田蒸散估算模型的研究   总被引：1，自引：0，他引：1  

刘绍民  傅伟东 《干旱区资源与环境》1997,11(4):68-72

本文在田间试验资料的基础上，综合考虑了影响冬小麦农田蒸散的气象、生物学特性和土壤水分等因素，选用蒸发力、冬小麦的叶面积指数和相对有效土壤湿度建立了新疆冬小麦农田蒸散估算模型，并且检验了该模型的计算效果。  相似文献   

生、炒酸枣仁镇静催眠作用的比较研究   总被引：3，自引：0，他引：3  

吕锦芳  张正  宁康健 《中兽医医药杂志》2004,23(6):3-5

采用两种催眠试验方法,观察生、炒酸枣仁煎剂对阈下剂量戊巴比妥钠入睡的影响及对阈剂量戊巴比妥钠睡眠的影响.结果阈下剂量戊巴比妥钠的入睡试验中,不同炮制酸枣仁处理差异不明显;同一炮制中高剂量作用大于低剂量;在睡眠试验中亦获得类似的结果.结果表明:生、炒酸枣仁在同一剂量下药理作用无差异,但同种炮制存在一定的剂量效应关系.  相似文献   

9种除草剂对花生白绢病菌的影响   总被引：1，自引：0，他引：1  

杨广玲  王金信  刘伟 《植物保护学报》2004,31(4):406-410

在实验室条件下测定了氟乐灵、乙草胺、异丙甲草胺、异恶草酮、乳氟禾草灵、乙氧氟草醚、三氟羧草醚、恶草酮、二甲戊乐灵等9种除草剂对花生白绢病菌Sclerotium rolfsi Sacc.的影响.结果表明:9种除草剂对花生白绢病病菌的毒力有较大差异,三氟羧草醚和乙氧氟草醚的毒力较高,IC50分别为7.88mg·L-1和18.91mg·L-1;9种除草剂对菌丝干重均有抑制作用,且随剂量的升高而升高,乙氧氟草醚和三氟羧草醚抑制作用最明显,在100mg·L-1和50mg·L-1时抑制率均达90%以上;除乙草胺和异丙甲草胺部分剂量外,其他除草剂对菌核数量均有不同程度的抑制作用,三氟羧草醚作用最为明显,在供试剂量下抑制率均达96%以上;除乙草胺、氟乐灵在供试剂量下对菌核单重有抑制作用外,其他除草剂在多数剂量下对菌核单重均有刺激作用,三氟羧草醚在50mg·L-1时,是对照菌核单重的8.34倍;而各种除草剂在供试剂量下,对菌核萌发均没有影响.  相似文献   

(土娄)土区不同蔬菜对钾肥的肥效反应     

赵护兵  同延安  赵尊练  司立征  高义民 《干旱地区农业研究》2004,22(1):138-141

在陕西省关中土娄土区布置线辣椒、甘蓝、白菜、芹菜钾肥大田试验,研究不同蔬菜对钾肥的肥效反应。结果表明,增施钾肥可使蔬菜硝态氮含量降低11.8%～116.0%,维生素C含量增加0.4～147.4mg/kg;产量增加9.3%～33.8%;明显促进营养生长和生殖生长;400cm深土壤剖面硝态氮累积量减少22.7～48.0kg/hm2,尤其在80～220cm剖面减少最为明显。  相似文献   

Using traffic flow theory to model traffic mortality in mammals     

van Langevelde  Frank  Jaarsma  Catharinus F. 《Landscape Ecology》2004,19(8):895-907

Traffic has a considerable effect on population and community dynamics through the disruption and fragmentation of habitat and traffic mortality. This paper deals with a systematic way to acquire knowledge about the probabilities of successful road crossing by mammals and what characteristics affect this traversability. We derive a model from traffic flow theory to estimate traffic mortality in mammals related to relevant road, traffic and species characteristics. The probability of successful road crossing is determined by the pavement width of the road, traffic volume, traversing speed of the mammals and their body length. We include the traversability model in a simple two-patch population model to explore the effects of these road, traffic and species characteristics on population dynamics. Analysis of the models show that, for our parameter ranges, traffic volume and traversing speed have the largest effect on traffic mortality. The population size is especially negatively affected when roads have to be crossed during the daily movements. These predictions could be useful to determine the expected effectiveness of mitigating measures relative to the current situation. Mitigating measures might alter the road and traffic characteristics. The effects of these changes on traffic mortality and population dynamics could be analysed by calculating the number of traffic victims before and after the mitigating measures. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Pocono mesic till barrens in retreat: topography,fire and forest contagion effects     

Maurice  Keith R.  Welch  Joan M.  Brown  Christopher P.  Latham  Roger Earl 《Landscape Ecology》2004,19(6):603-620

The Pocono mesic till barrens (PMTB) are a unique assemblage of fire-maintained shrub communities that support numerous rare species. Historically these barrens covered a large area in the vicinity of Long Pond, Pennsylvania, USA. However, due largely to regional fire suppression instituted in the early 1960s, over 70% of the area covered by barrens succeeded to fire-intolerant forest that does not support the rare species. We investigated the influence of forest proximity on barrens succession across three geomorphic types during periods of high fire frequency and fire suppression, testing the hypothesis that forest processes such as seed rain, shading, and detrital enrichment of soils enhances barrens succession through a contagion effect. Evidence of a forest contagion effect should be shown by increased rates of barrens succession with increasing proximity to the nearest forest edge. In order to detect a forest contagion effect, barrens persistence and barrens succession were modeled in proximity zones of 0-50 m, 50-100 m, 100-200 m, and greater than 200 m from the nearest forest edge. We used existing GIS data layers for fire, geomorphology, and vegetation distribution in 1938, 1963, and 1992. The layers were modified and overlain using ArcView software to determine persistence and succession rates for each unique combination of layers in each proximity zone from 1938 to 1963 (pre-fire suppression) and 1963 to 1992 (post-fire suppression). ANCOVA results indicate that proximity to the nearest forest edge significantly affected barrens persistence rates in both time periods, but succession rates were significantly affected in 1938 to 1963 only. Twenty-eight percent of the 1938 barrens succeeded to forest by 1963; 56% of the 1963 barrens became forest by 1992. Results support previous findings that barrens persistence is enhanced by increased fire frequency, and that barrens persist longer where they overlie flat glacial till than on other geomorphology types.  相似文献