黄瓜根腐病致病病原的鉴定   总被引：6，自引：0，他引：6  

王惠哲  李淑菊  马德华  董金皋 《华北农学报》2003,18(2):74-77

在天津市及周边地区采集病株进行组织分离，同时分离到两类病原菌，经初步的生物学特性鉴定表明，引起黄瓜根腐病的主要病原菌为甜瓜疫霉、尖孢镰刀菌和茄病镰刀菌。经接种试验，认为甜瓜疫霉为主要致病菌。  相似文献   

褐藻糖胶脱蛋白及脱色方法研究     

陈淑华  张淑平  杜秀秀  周勤生 《湖南农业科学》2011,(7):92-95

采用Sevag法、三氯乙酸(TCA)法和Sevag法与三氯乙酸法相结合的方法对褐藻糖胶进行脱蛋白研究,并研究脱蛋白与未脱蛋白对褐藻糖胶脱色的影响.结果表明,Sevag法与三氯乙酸法相结合脱蛋白效果最佳,当Sevag法操作2次,TCA溶液添加量为1.3 mL/10mL多糖溶液时,蛋白脱除率为78.68%,多糖损失率为28...  相似文献   

Effects of Grade of Oocyte–Cumulus Complex and the Interactions Between Grades on the Production of Blastocysts in the Cow, Ewe and Lamb     

JM Kelly  DO Kleemann  SR Rudiger  SK Walker 《Reproduction in domestic animals》2007,42(6):577-582

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Radar reflectivity of titan     

Muhleman DO  Grossman AW  Butler BJ  Slade MA 《Science (New York, N.Y.)》1990,248(4958):975-980

The present understanding of the atmosphere and surface conditions on Saturn's largest moon, Titan, including the stability of methane, and an application of thermodynamics leads to a strong prediction of liquid hydrocarbons in an ethane-methane mixture on the surface. Such a surface would have nearly unique microwave reflection properties due to the low dielectric constant. Attempts were made to obtain reflections at a wavelength of 3.5 centimeters by means of a 70-meter antenna in California as the transmitter and the Very Large Array in New Mexico as the receiving instrument. Statistically significant echoes were obtained that show Titan is not covered with a deep, global ocean of ethane, as previously thought. The experiment yielded radar cross sections normalized by the Titan disk of 0.38 +/- 0.15, 0.78 +/- 0.15, and 0.25 +/- 0.15 on three consecutive nights during which the sub-Earth longitude on Titan moved 50 degrees. The result for the combined data for the entire experiment is 0.35 +/- 0.08. The cross sections are very high, most consistent with those of the Galilean satellites; no evidence of the putative liquid ethane was seen in the reflection data. A global ocean as shallow as about 200 meters would have exhibited reflectivities smaller by an order of magnitude, and below the detection limit of the experiment. The measured emissivity at similar wavelengths of about 0.9 is somewhat inconsistent with the high reflectivity.  相似文献   

Radar images of Mars     

Muhleman DO  Butler BJ  Grossman AW  Slade MA 《Science (New York, N.Y.)》1991,253(5027):1508-1513

Full disk images of Mars have been obtained with the use of the Very Large Array (VLA) to map the radar reflected flux density. The transmitter system was the 70-m antenna of the Deep Space Network at Goldstone, California. The surface of Mars was illuminated with continuous wave radiation at a wavelength of 3,5 cm. The reflected energy was mapped in individual 12-minute snapshots with the VLA in its largest configuration; fringe spacings as small as 67 km were obtained. The images reveal near-surface features including a region in the Tharsis volcano area, over 2000 km in east-west extent, that displayed no echo to the very low level of the radar system noise. The feature, called Stealth, is interpreted as a deposit of dust or ash with a density less than about 0.5 gram per cubic centimeter and free of rocks larger than 1 cm across. The deposit must be several meters thick and may be much deeper. The strongest reflecting geological feature was the south polar ice cap, which was reduced in size to the residual south polar ice cap at the season of observation. The cap image is interpreted as arising from nearly pure CO(2) or H(2)O ice with a small amount of martian dust (less than 2 percent by volume) and a depth greater than 2 to 5 m. Only one anomalous reflecting feature was identified outside of the Tharsis region, although the Elysium region was poorly sampled in this experiment and the north pole was not visible from Earth.  相似文献   

Effects of drying on the release of solutes from acid sulfate soils distributed in the Mekong Delta, Vietnam     

Masayuki KAWAHIGASHI  Nhut Minh DO  Ve Bao NGUYEN  Hiroaki SUMIDA 《Soil Science and Plant Nutrition》2008,54(4):495-506

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中越水稻迁飞性害虫稻飞虱、稻纵卷叶螟发生关系分析   总被引：3，自引：0，他引：3  

陆明红  刘万才  胡高  翟保平  Hoang Anh Tuan  Do Hong Khanh 《植物保护》2018,44(3):31-36

中越两国同属东亚季风区,水稻病虫害在发生危害上为一个整体。每年水稻稻飞虱、稻纵卷叶螟(以下简称"两迁"害虫)随着季节和气温变化,在两国间往返迁飞,发生为害,相互影响。研究两国水稻迁飞性害虫发生的关系和影响规律,对于提高监测预警的早期预见性和防控工作的主动性,有效控制其危害具有重要意义。2010年以来,中越两国实施了中越水稻迁飞性害虫监测与防治合作项目,通过连续多年开展交流合作,初步明确了越南"两迁"害虫发生规律。本文简要分析了影响越南"两迁"害虫发生的主要因素,探讨了中越两国水稻"两迁"害虫发生规律的相关性,对提高中国"两迁"害虫中、长期预报能力和综合治理水平发挥了积极作用。  相似文献   

鹿源细小病毒的分离与鉴定     

汪晓郓  时坤  刁燕  尹茉莉  冯海峰  杜锐 《经济动物学报》2009,13(1)

选用PK-15传代细胞系从吉林农业大学鹿场采集的梅花鹿粪样病料中分离出一株病毒,经血凝试验、血凝抑制试验及电镜观察对该病毒进行鉴定。结果表明:该病毒为鹿源细小病毒。  相似文献   

Protective effects of bio-active ceramic water on alcohol-induced hepatic injury in pigs   总被引：1，自引：0，他引：1  

Lee CW  Jeong WI  Noh DH  Jeong DH  DO SH  Kim YK  Kwon OD  Kim TH  Jeong KS 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(4):403-409

Among many detrimental injuries, alcohol is implicated in hepatitis, fatty liver, hepatic fibrosis, and cirrhosis. The purpose of this study was to evaluate the protective effect of bio-active ceramic water on alcohol-induced hepatic injury in pigs. Twelve male Landrace pigs were divided into 3 groups. Groups 1, 2, and 3 were fed with bio-active ceramic water + normal liquid diet, bio-active ceramic water + liquid diet containing 15% ethanol, and tap water + liquid diet containing 15% ethanol for 12 weeks, respectively. For serological, histopathological, and immunohistochemical analysis, all pigs were sacrificed at week 12. In group 3, serum ALT and AST levels increased, and mild fatty change and moderate necrosis were detected in the liver. Collagen fibers, myofibroblasts, and CYP2E1 were also increased or activated in group 3. In group 2, there were mild hepatic injuries compared to group 3. However, injuries and activations were not observed in the liver in group 1. We suggest that the bio-active ceramic water used in the present study had protective capability against ethanol-induced hepatic injury and that having no toxic effect on the pig liver. The bio-active ceramic water might be useful as a therapeutic drinking water in patients suffering from alcoholic liver diseases.  相似文献   

Doublecortin-immunoreactive neuronal precursors in the dentate gyrus of spontaneously hypertensive rats at various age stages: comparison with Sprague-Dawley rats     

Hwang IK  Yoon YS  Choi JH  Yoo KY  Yi SS  Chung DW  Kim HJ  Kim CS  DO SG  Seong JK  Lee IS  Won MH 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(4):373-377

Spontaneously hypertensive rats (SHRs) are widely accepted in medical research because this model has been used for studies in neurodegenerative diseases such as vascular dementia and stroke. In the present study, we observed newly generated neuronal precursors using doublecortin (DCX, a marker of neural proliferation and differentiation) in the subgranular zone of the dentate gyrus in SHRs compared to Sprague-Dawley rats (SDRs) at various age stages. DCX immunoreactivity, immunoreactive cell numbers and its protein level in the dentate gyrus of the SHRs were higher than those in the SDRs at postnatal month 1 (PM 1). At PM 8, DCX immunoreactivity, immunoreactive cell numbers and protein levels in both groups were markedly decreased compared to those at PM 1; however, they were higher than those in the SDRs. They were decreased in the both groups with age: DCX immunoreactive cells in the SDRs were few at PM 12. Our results indicate that newly generated neuronal precursors are more abundant in SHRs than in SDRs during their life.  相似文献