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1.
通过形态观察、分子鉴定、科赫法则验证和系统进化分析对河南周口地区萹蓄所感病原菌进行鉴定.结果表明:该病原菌菌丝体外生,菌丝有隔膜.分生孢子梗圆柱形,包含3个细胞;分生孢子串生,近柱形,大小为(22.0~35.5)μm×(10.5~16.5)μm.闭囊壳近卵形,含有3~5个子囊孢子.科赫法则检测发现,病原菌回接发病与自然发病症状一致.分子生物学和系统进化分析结果显示,该病原菌ITS序列(KX757832.1)与已报道的蜡叶峨参独活白粉菌(KF111807.1)、洋常春藤独活白粉菌(KP055630.1)、胡萝卜独活白粉菌(KC480605.1)和酸模独活白粉菌(KY073878.1)序列聚为一枝,其同源性分别为98.40%、98.57%、98.40%和98.57%.初步推测,河南周口地区萹蓄所感白粉病原菌为独活白粉菌.  相似文献   

2.
为确定7种景天科多肉植物白粉病的病原菌,本研究通过显微形态观察、致病性测定和分子生物学的方法对其进行鉴定,并构建系统发育树.结果 表明:该病原菌闭囊壳暗褐色至黑色,球形或扁球形,壁细胞呈不规则多边形;附属丝5 ~18根,丝状不分枝,上下近等粗或顶端略细,褐色或基部褐色,向上渐无色;子囊3~5个,卵形或长卵形,无色,有短...  相似文献   

3.
1991年我院实习农场保护地葡萄,落花后十天左右,突然发生严重落果。取病果粒表面菌镜检,其病原菌形态特征是:分生孢子梗微淡褐色,直立,有4~6个分隔,近顶部有2~3次分枝,分枝顶端串生分生孢子,分生孢子单胞、无色、卵圆形,大小为10~15×5~7μm.分生孢子梗和分生孢子成簇于病果表面时,呈淡褐色。  相似文献   

4.
续断菊白粉病的病原菌鉴定   总被引:1,自引:0,他引:1  
采用形态学鉴定、致病性鉴定和分子系统学鉴定方法对中国商丘地区首次检出的续断菊白粉菌的系统进化关系进行了研究.结果表明,该病原菌分生孢子梗直立,圆柱形,简单无分枝,大小为108~220μm×10~12μm,包含1个足细胞,2~3个短细胞;分生孢子串生,圆柱形,无明显纤维体,大小为29~42μm×19~24μm;附着胞呈乳头形;病原菌接种叶片病症与自然状态一致,形成薄而边缘不明显的白色斑片;对其核糖体DNA内转录间隔区(ITS)序列进行PCR扩增、测序获得595bp序列(GenBank登录号:JQ010848),经MEGA 3.1软件分析,其与来自二孢白粉菌(Golovinomyces cichoracearum)的AY739111,HM449077,AB453762,AB077673序列聚为1枝,而与来自同属另3个种的ITS序列亲缘关系较远.研究表明,商丘地区的续断菊白粉菌为二孢白粉菌(G.cichora-cearum).  相似文献   

5.
利用扫描电子显微镜拍摄红血球立体像片对,并对其测绘了等值线图和测定了体积。红血球体积的测定,可以采用本文中的任何一种方法。文中还叙述了测定血球体积的三种方法,即利用红血球等值线图计算体积的方法;数字高程模型(DEM)方法;分带截面法。通过试验证明红血球的体积大小不等,形状也不完全一样,有球形、环状、卵形和椭圆等,红血球总形状是两面微凹,中间薄,最低点约0.23μm,边缘部厚,最高点约为1.51μm,其直径平均值为7.4μm(6.9~7.8μm),体积平均约为18.91μm~3(试验数据的平均值)。  相似文献   

6.
本文作者用光学显微镜和扫描电子显微镜对甘草属(Glycyrrhiza)八种植物花粉形态进行了详细观察和比较.本属花粉形态是单花粉类型;花粉粒为长球形或近园球形,极面观为三裂园形或钝园形;具3孔沟;花粉粒为中等大小(31·6~38·7μm);外壁分层明显;外壁纹饰为细网纹和网纹.用高速离心机对Gly-cyrrhiza uralensis和Glycyrrhiza glabra两种花粉进行破壁观察其外壁的内部结构.  相似文献   

7.
葡萄灰霉病病原鉴定和生物学特性研究   总被引:7,自引:0,他引:7  
对不同地区的葡萄灰霉病进行调查和采样,根据病害症状、病原形态和寄主范围对葡萄灰霉病进行鉴定,结果表明,该葡萄灰霉病菌为灰葡萄孢菌(Botrytis cinerea Pers.).该菌的生长温度范围是5~30℃,最适温度为15~25℃;生长的pH值范围是2~9,最适为3~6;光照条件对病菌的生长基本无影响;该菌的寄主范围广泛;木纳格和巨峰对葡萄灰霉病的抗性较强;甲基硫菌灵、亿嘉乐对葡萄灰霉病菌的抑制效果较好.  相似文献   

8.
灰霉病是近几年危害浙江省蓝莓产业的严重病害之一,分离和鉴定该病病原菌可以掌握其生物学特征和发病机理,为病害的综合防治提供参考.通过形态观察、核糖体DNA内转录间隔区(rDNA-ITS)序列分析和柯赫氏法则验证等方法,对引起蓝莓品种‘夏普蓝’灰霉病的病原菌进行了鉴定.结果表明:该病原菌为葡萄孢菌属的灰葡萄孢菌(Botrytis cinerea);对‘夏普蓝’进行病原菌回接后,叶片和果实分别出现褐色病斑和软化腐烂等症状,与田间自然发病一致;将该病原菌在马铃薯葡萄糖琼脂(PDA)培养基上进行培养,菌落初期呈现白色,后转为灰褐色.分生孢子为单孢,卵圆形或椭圆形,无色或淡褐色,大小为(10~15)μm×(6~9)μm;将分离菌株X1-1的rDNA-ITS序列(NCBI序列号:KT343755)与GenBank中已经报道的灰葡萄孢菌进行序列比对,发现二者相似度达100%.  相似文献   

9.
对木瓜属(Pseudocydonia)、贴梗海棠属(Chaenomeles)和榅桲属(Cydonia)植物的花粉亚显微形态进行了研究。结果表明,其花粉均属于N3P4C3型,为辐射对称的长球形,极少为超长球形。贴梗海棠属花粉大小(极轴长(P)×赤道轴长(E))为33.24~48.27μm×18.93~25.58μm;木瓜属为37.15~42.50μm×19.63~22.83μm;榅桲属为36.85~43.95μm×19.63~22.83μm。贴梗海棠属的和木瓜属花粉的表面纹饰为条纹状,前者的条纹极不规则而后者条纹近于平行,榅桲属花粉外壁近光滑。花粉亚显微形态对于3个近缘属的分类具有较大意义,支持将木瓜单独成属。另外,对所有种类的花粉形态进行了描述,并编制了分类检索表。  相似文献   

10.
山东胡枝子属植物花粉形态研究及其在分类上的意义   总被引:7,自引:1,他引:6  
报道了山东胡枝子属(Lespedeza Michx.)7种植物花粉的亚显微形态特征,花粉粒从赤道面观呈近长球形,极面观呈三裂圆形,具三条萌发沟;表面纹饰均为网状;花粉粒大小极轴长为26.3-19.0μm,赤道轴宽约为21.7-8.6μm研究结果表明,胡枝子属花粉的形态结构特征支持传统分类中的属和种级水平的分类。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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