江苏玉米粗缩病病原病毒的RT—PCR检测

玉米粗缩病毒和水稻黑条矮缩病毒均可由灰飞虱传播并侵染玉米使其发生粗缩病。两种病毒相似之处较多,常规方法很难区分。本研究根据以往已发表的这两种病毒的核酸序列,分别合成了两病毒的特异引物,利用一步法反转录－聚合酶链式反应（ＴＲ－ＰＣＲ）建立了玉米粗缩病病原病毒的快速检测和诊断的方法。对江苏省盐城地区田间自然感病玉米的ＲＴ－ＰＣＲ检测结果和扩增片段序列分析表明：在该地区玉米粗缩病病样中只检测到水稻黑条矮     

我国玉米粗缩病株上发现的水稻黑条矮缩病毒

玉米粗缩病近年来在我国的主要玉米产区迅速蔓延,流行成灾,已成为影响玉米生产的重要病害之一.根据病毒粒子的形态、基因组结构及其生物学特性,国内多数研究结果认为玉米粗缩病的病原为玉米粗缩病毒(MRDV).虽然国外有少数学者根据病毒的寄主范围与MRDV存在差异, 而与水稻黑条矮缩病毒(RBSDV)相似,怀疑引起玉米粗缩病和水稻黑条矮缩病的病原均为RBSDV,但缺乏充足的证据.本研究利用RT-PCR和序列测定方法,获得了来自我国不同地区的玉米和水稻上的相关分离物的第十条基因组片段(S10)的全序列,为我国玉米粗缩病病原的鉴定提供了分子生物学方面的证据.     

南方水稻黑条矮缩病毒快速检测

南方水稻黑条矮缩病毒(southern rice black-streaked dwarf virus,SRBSDV)引起的新水稻矮缩病近年在越南北部和我国南方各省爆发,准确快速地检测病毒是病害预测的关键。本文针对该病毒的S10序列设计了一对新的引物S10F/S10R,利用一步法RT-PCR,对2010年5~8月间湖南省下属各县送来的疑似感染该病毒引起的水稻矮缩病样本进行了检测,结果显示,新引物能有效地区分阳性样品和非阳性样品。同时对PCR产物进行了序列测定,结果表明序列均与已发表的南方水稻黑条矮缩病毒序列(登录号:EU523360和EU784840)达约99%的同源性。还在此基础上构建了系统发育树,发现SRBSDV湖南、广东和海南分离物病毒位于一个相对独立的分支。研究发现相对以往的巢式RT-PCR,本文采用的新引物及一步法RT-PCR能快速检测南方水稻黑条矮缩病毒,简化了操作步骤,缩短了检测时间,适合在SRBSDV检测和病害预测中应用。     

水稻黑条矮缩病毒玉米分离物基因组S8和S9的序列分析及其原核表达

通过RT-PCR获得了玉米粗缩病病毒湖北分离物(Hbm)基因片段S8和S9的全长cDNA克隆，并测定了它们的全序列。S8全长1936bp，其编码链只含1个ORF，编码1个由591个氨基酸组成、分子量约为68kD蛋白；S9全长l900bp，含有两个非重叠的ORF，分别编码由347个和209个氨基酸组成、分子量分别约为40kD和24kD蛋白。序列分析表明，Hbm-S8和S9与水稻黑条矮缩病毒(RBSDV)中国不同分离物之间的核苷酸和氨基酸序列同源性分别为94．4％～98．9％和96．0％~99．0％，且与日本RBSDV的序列同源性高于与玉米粗缩病毒相应片段的序列同源性，进一步证明了引起我国玉米粗缩病的病原为RBSDV。SDS-PAGE分析表明，经IPTG诱导，RBSDV8和9编码的蛋白可在大肠杆菌(Escherichia coil)中高效表达。以这些蛋白为抗原，制备了抗血清。用Western blot方法在感病的玉米(Zea mays)植株中可检测到RBSDV-Hbm S8和S9 ORF1编码的蛋白。     

水稻黑条矮缩病的防控对策分析

水稻黑条矮缩病是一种常见的水稻病害,具有扩散速度快、范围广、突发性强等特点,很容易造成水稻产量下降,给农民群众造成严重经济损失。基于此,对水稻黑条矮缩病的发病原因进行剖析,总结当前水稻矮缩病防治工作中存在的问题,并提出相应解决对策,以保证水稻黑条矮缩病防控更加科学、高效。     

粤西地区水稻黑条矮缩病的发生与防控措施探究

黑条矮缩病是粤西地区水稻种植的常见病。梳理相关的研究文献,分析其发生情况、发生原因,并采取相关的防控措施,以控制黑条矮缩病的发生,为粤西地区水稻种植的稳产、高产创造有利条件。     

南方水稻黑条矮缩病的发生规律与防治措施探究

病虫害的传播对农业种植有很大影响。就水稻种植而言,水稻黑条矮缩病的发生不仅会影响作物生长,还会对粮食产量造成很大影响。因此,相关种植人员要积极寻找预防措施,做好水稻黑条矮缩病的综合防治工作,以便减少黑条矮缩病害对水稻种植的影响。基于此,分析南方水稻黑条矮缩病的发生规律,探讨相关的防治措施。     

南方水稻黑条矮缩病的发生规律与防治措施

南方水稻是我国农业种植的主要农作物之一,病虫害的传播直接影响水稻种植的质量。水稻黑条矮缩病作为一种新型病害,不仅会给水稻的健康生长带来不利影响,还会使水稻的产量显著降低。因此,分析南方水稻黑条矮缩病的发生规律,并采取有效的措施进行防治具有重要意义,其能减少黑条矮缩病导致水稻生产量降低的问题发生,为促进我国农业可持续发展奠定基础。     

水稻黑条矮缩病抗病品种的筛选及其抗病机制初探

为有效防治水稻黑条矮缩病的大面积发生,本研究通过室内大量饲养无毒灰飞虱,饲毒后对浙江省20个主栽水稻品种进行传毒,人工接种水稻黑条矮缩病毒(rice black-streaked dwarf virus,RBSDV) 后移栽田间,观察病苗症状,测量株高,统计发病率并分析病毒含量。结果表明,籼稻品种深两优5814和Y两优302的抗性较强,粳稻品种淮5和秀水14的抗性较弱。此外,病毒侵染后,籼稻品种深两优5814和Y两优302的OsMYC2和OsNPR1的mRNA表达水平显著高于粳稻品种淮5和秀水14。上述结果表明,籼稻品种深两优5814和Y两优302抗病毒能力与其体内茉莉酸(JA)和水杨酸(SA)激素水平相关,这为今后筛选抗RBSDV材料提供了新的策略和思路。     

SRBSDV结构蛋白P10和非结构蛋白P9-1抗体的制备及应用

为丰富南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)的预测预报体系,本研究利用Gateway原核表达系统,将SRBSDV结构蛋白P10和非结构蛋白P9-1进行了大量表达,纯化的表达蛋白分别免疫新西兰大白兔(Oryctolagus cuniculus)获得抗血清,抗血清的间接酶联免疫吸附分析(indirect enzyme-linked immunosorbent assay,in-ELISA)效价分别为1∶6 400和1∶3 200,Western blot检测结果表明,制备的2种抗体均具特异性.利用免疫捕获RT-PCR(immunocapture RT-PCR,IC-RT-PCR)和斑点酶联免疫吸附分析(dot enzyme-linked immunosorbent assay,dot-ELISA)方法比较两种抗体检测水稻(Oryza sativa)和白背飞虱(Sogatella furcifera,WBPH)带毒率的应用效果,结果表现一致,说明SRBSDV结构蛋白P10和非结构蛋白P9-1均可用于病毒的田间检测,为病害的预测预报奠定了基础.     

Physical Properties of the Soils of Sibay City of the Republic of Bashkortostan

Eurasian Soil Science - The results of the study of the properties of urban soils of the city of Sibay located in the mining region of the Republic of Bashkortostan are presented. A specific...     

食用仙人掌萎蔫气象条件分析

塑料大棚内种植的食用仙人掌在土壤墒情较好时也有萎蔫现象发生，通过试验观测和对仙人掌生理习性的分析，发现阴雨过后天气突然放晴温度急剧上升易使仙人掌发生萎蔫现象，并提出了田间管理的应对措施。     

Heterogeneity of Organic Matter of Aggregates of Protocalcic Chernozems

Eurasian Soil Science - Layers were step-by-step removed from macroaggregates (2–1 mm in diameter) of Protocalcic Chernozems via successive abrasion in a revolving rotator during 5, 10, 15,...     

青海省耕地资源开发利用分析及对策研究

分析论述了青海省耕地资源开发利用的现状、特点和问题。在此基础上,提出了对青海省耕地资源进行研究的框架体系和思路,同时基于GIS/RS技术设计了相关的技术路线。最后依据所做设计对青海省耕地资源开发利用做了初步分析,并进行了相关的对策研究分析。     

Characterization of physical and chemical properties of Varzea soils of Goias State of Brazil

Abstract

Brazil has approximately 30 million hectares of lowland areas, known locally as “Varzea,”; distributed throughout the country. Soils in these areas have the potential to support agricultural production, but very little is known about their fertility. The current experiment was undertaken to characterize the chemical and physical properties of representative “Varzea”; soils collected at 0–20, 20–40, 40–60, and 60–80 cm depth intervals from 23 sites in Goias State of Brazil. Organic matter contents averaged 42 g/kg in the surface 20 cm of soil and should make a significant contribution to overall nutrient availability. Soil pH increased slightly with depth from a mean value of 5.2 in the surface 20 cm of soil to a mean value of 5.4 in the 60–80 cm depth interval. Several soils had exchangeable Al values ≥ 1.0 cmol Al/kg, but soil Al saturation was generally less than the 60% level frequently associated with Al toxicity. However, cereal and legume production could benefit from lime addition in many of these soils. Although base saturation was fairly low in some soils, exchangeable Ca and Mg levels were, in general, adequate throughout the profile. Extractable P levels were adequate in most surface soil samples. Extractable K levels in these soils were generally low, and the application of K fertilizers should be beneficial, especially in conjunction with lime addition. The high clay content “Varzea”; soils of the Brazilian lowlands have some drainage problems but generally exhibit favorable chemical properties for crop production when compared to soils of the well‐drained Cerrados.     

Estimation of potential nitrogen-fixing activity of agrophytocenoses soils of the subtropical zone of Russia

An estimation of potential nitrogen-fixing activity of various soil types under agrophytocenoses of tea, filbert, peach, and pawpaw which grow in the area of Greater Sochi is given. High indicators of nitrogen fixation activity in the soil in the course of vegetation were characteristic of agrocenoses of pawpaw, peach, and filbert. The lowest level of nitrogen fixation was noted in the soil of a tea plantation. A negative correlation dependence of potential nitrogen-fixing activity on the acidity of the soil solution was established. A study of the seasonal dynamics of the activity of nitrogen fixation of soils of agrocenoses of the subtropical zone of Russia made it possible to distinguish a less active winter and more active spring-summer-autumn periods.     

物联网安全及解决措施

物联网是一个集信息通信、数据交换、传感器技术与软件工程于一体的综合性产业,探讨和分析了物联网的结构体系与发展中遇到的安全问题。     

荔枝种子结构的扫描电镜观察

荔枝种子从果实中剥离出来后, 即使在室内条件下, 也极易失水干缩, 潮湿环境中又易发霉而腐烂。扫描电镜观察表明: 种皮上布满纹孔, 水分散失面积很大; 种脐部为疏松的海绵组织, 且营养丰富。据此, 生产上应对种子彻底清洗, 并保存于适当湿度的环境中, 以提高其发芽率。     

Kinetics of Popping of Popcorn

The rate of popping of popcorn was measured in oil and in air. Kinetic data for lifetimes of individual kernels from a large population were obtained in oil at six constant temperatures (180–250°C) and also in an air‐popper at 202°C. The data are characterized by an induction period, which is, significantly, followed by a first‐order decrease in the number of unpopped kernels versus time. The activation energy for the first order process is 166.7 kJ/mol between 180 and 210°C, and 53.8 kJ/mol between 210 and 250°C. These data are consistent with a model that assumes 1) that the rate of heat transfer into a kernel follows Newton's law of cooling; 2) that in a sample of kernels there exists a distribution of critical pressures; 3) that for an individual kernel, the probability of popping is directly proportional to the difference between the internal aqueous vapor pressure and the kernel's critical pressure; and 4) that the measured rate constant at any temperature is an average overall of the kernels in the sample with critical pressures equal to or less than the internal aqueous vapor pressure. Minimum popping temperatures predicted by the model are 181 ± 2°C (oil) and 187 ± 2°C (air), in good agreement with previously reported direct measurements.     

三门峡水库库岸坍塌成因分析与防治措施研究

三门峡水库自1960年9月蓄水运行以来,库岸坍塌现象频繁发生,平均每年塌岸0.5～0.7亿m3.指出了造成库岸坍塌的原因主要是地质环境的影响以及水力条件的变化;不同的地形、地貌、地质结构和岩性特征,表现了不同的塌岸强度,其中黄土塬区为极强塌岸段,黄河Ⅱ级阶地为强烈塌岸段,黄河Ⅰ级阶地为中等强烈塌岸段;分析了引起库岸坍塌的主要水力条件有大气降水、地表水和地下水,并且不同水力条件及其变化特征,对库岸坍塌影响的方式和程度也不同;最后给出了防治库岸坍塌应采用标本兼治的原则,治标是指对塌岸进行必要的加固、支挡、衬砌等;治本就是根据引起塌岸的原因以及不同地质环境条件下的塌岸特征和水力条件,因地制宜,因害设防,从根本上进行综合治理.