银杏叶黄酮含量变化及分布规律的研究Ⅱ.不同栽培方式对叶黄酮含量的影响及盆栽银杏根内黄酮含量变化

以银杏叶用栽培园、丰产园 (果叶兼用 )和盆栽园叶片以及盆栽银杏根部为试材 ,对比分析了黄酮含量的变化。结果表明 :叶用园叶黄酮含量最高 ,丰产园次之 ,盆栽园最低 ;达到含量高峰的时间 ,前期是叶用园最早 ,盆栽园次之 ,丰产园最慢 ,后期是盆栽园和叶用园同步 ,比丰产园早半月 ;含量高峰次数叶用园、丰产园均 3次 ,盆栽园 2次 ;变化幅度盆栽园最大 ,丰产园变化相对稳定。根系中有叶黄酮存在 ,早期含量甚微 ,后期逐渐稳步增加 ,与叶片相比 ,峰值低 ,10月份后二者变化趋势相反     

虚拟样机技术及其在水稻插秧机设计中的应用

提出了基于UG/ADAMS/ANSYS软件的水稻插秧机设计解决方案,阐述了以水稻插秧机为研究对象,建立水稻插秧机的虚拟样机模型,以及对模型的仿真分析、有限元分析等。研究结果表明,用虚拟样机技术可以实现对水稻插秧机的快速、准确分析和改进试验,从而提高设计速度、缩短设计周期,减少设计成本;通过对虚拟样机的真实物理样机考核证明,虚拟样机技术可为复杂农机结构设计提供帮助。     

小麦黄花叶病毒的血清学检测

利用间接ELISA对感染WYMV的小麦病叶检测,通过比较分析影响ELISA测定结果的包被缓冲液、抗血清及酶标抗体的浓度和种类,确立了较为稳定的反应体系.利用此ELISA检测体系并结合RT-PCR方法对从四川采集的田间小麦中WYMV进行检测,确定了有较高的检测灵敏度的检测系统,为田间大量小麦病样的检测提供有效、方便的方法.     

龟井温州蜜柑不同中间砧的比较

以龟井温州作为接穗,基砧为枳,采用的中间砧有大翼叶香橙、务和香橙、枳、宜昌橙、金柑和永顺枳橙,调查、测定了各中间砧组合的亲和性,树体及枝梢生长表现、产量和果实品质。综合考虑,以务和香橙、枳作中间砧表现较好。     

红籽瓜数量性状的主成分与聚类分析

以红籽瓜自交系为试验材料,观测其11个主要数量性状,借助SPSS统计软件,进行多元统计分析。主成分分析结果表明,前5个主成分的累计贡献率达到86.05%;R型聚类分析显示,11个数量性状可分为5类,分别为:产量因子、粒重因子、生长因子、产籽因子和品质因子。两种分析共同揭示了红籽瓜各因子的性状组成,为品种培育提供理论依据。     

南水北调中线水源区富营养化研究

为了给建立南水北调中线水源区长期生态研究数据信息库及生态工程规划提供科学依据,在丹江口水库建立陶岔(渠首)自动监测点,丹江库心、大石桥(入库上游)和汉江库区丹江口坝前监测点,于2004-03—2006-05对南水北调中线水源区微生物菌群、浮游生物与理化指标进行监测。按水样采集标准方法采样,采用污水生物系统法、营养状态指数法和单因子评价法对中线水源区进行富营养化程度评价。在4个监测点共采集到浮游生物94属202种(含变种),未发现水体重污染指示种。浮游植物8门67属161种(含变种),占浮游生物种的80%,浮游植物污染指示种21属24种(含变种),β-中营养型占浮游植物污染指示种38%;浮游动物27属41种(含变种),占浮游生物种的20%,包括3种浮游动物污染指示种;水源区叶绿素a质量浓度为4.25μg/m3,营养状态指数0.0001;理化检测指标中除总氮(Ⅲ类)外,其他指标均符合Ⅰ类水质标准。中线水源区为寡污型水体,处于中营养状态,符合南水北调调水水质的要求。     

Single-base pair unwinding and asynchronous RNA release by the hepatitis C virus NS3 helicase

Nonhexameric helicases use adenosine triphosphate (ATP) to unzip base pairs in double-stranded nucleic acids (dsNAs). Studies have suggested that these helicases unzip dsNAs in single-base pair increments, consuming one ATP molecule per base pair, but direct evidence for this mechanism is lacking. We used optical tweezers to follow the unwinding of double-stranded RNA by the hepatitis C virus NS3 helicase. Single-base pair steps by NS3 were observed, along with nascent nucleotide release that was asynchronous with base pair opening. Asynchronous release of nascent nucleotides rationalizes various observations of its dsNA unwinding and may be used to coordinate the translocation speed of NS3 along the RNA during viral replication.     

Cellular immune responses of BALB/c mice induced by intramuscular injection of PRRSV-ORF5 DNA vaccine with different doses

BALB/c mice were immunized with 50 μg, 100 μg, 200 μg of pcDNA-PRRSV-ORF5 DNA vaccine respectively by intramuscular injection, with PBS and pcDNA3.1(+) as controls. Fluorescence activated cell Sorter (FACS) was used to detect the number of CD₄ ⁺ and CD₈ ⁺ T-lymphocytes. T-lymphocyte proliferation test was used to detect proliferation of the T-lymphocyte cells in peripheral blood lymphocytes of mice vaccinated with pcDNA-PRRSV-ORF5 DNA vaccine. The results showed that the difference in ConA response to T-lymphocytes in blood was highly significant between all experimental groups and the control group (P < 0.01). The number of CD₄ ⁺ T-lymphocytes in experimental groups was significantly higher than that of the control group 7 d after vaccination. The number of CD₈ ⁺ T-lymphocytes in the experimental groups was higher than that of the control group 28 d after vaccination. Mice immunized with a higher dose (200 μg) of DNA vaccine demonstrated higher cellular immune response than those immunized with a lower dose (100 μg, 50 μg) of DNA vaccine. The results demonstrated that pcDNA-PRRSV-ORF5 DNA vaccine could induce a good cellular immune response which may be dose-dependent. __________ Translated from China J Vet Sci Mar, 2006, 26(2): 111–114 [译自: 中国兽医学报] The first three authors contribute equally to this work.     

北京山区林地褐色大肥菇人工栽培技术

褐色大肥菇是坝上地区口蘑的主要品种之一,干品香味浓郁,菇质细腻。为了有效利用北京延庆四海山区冷凉的林地环境,发展北京山区林地食用菌,采用人工栽培料在林地生产褐色大肥菇,获得了成功。栽培期四海林地的日均气温在15~26.2℃之间,5~10 cm地温变化在10~19℃之间,林地闭郁度为0.6~0.7。采用牛粪、玉米秸秆4~5月堆制培养料,5~6月播种,7~9月出菇,产量5 kg/m2,产值40~50元/m2。     

大豆品种高产稳产性分析

以1997-1999年广西第六周期春大豆区域试验三年汇总结果为资料,采用高稳系数法分析各参试种的高产稳产性并将结果与产量平均数、变异系数分析相比较.结果表明,7个参试种中,桂7014、柳8829、柳8805的高产稳产性优于对照种柳豆1号,其余3个参试种的高产稳产性不如对照种.高稳系数法分析结果与试验实际相符,是一种简单、科学、可靠的方法.