甘薯属10种植物花粉形态扫描电镜观察

对用于育种研究的甘薯属(Ipomoea)10种植物花粉形态进行扫描电镜观察研究,以补充该属植物花粉形态学信息. 结果表明,甘薯属植物花粉粒的形状均为近球形,体积较大;花粉萌发孔多为散孔,少数萌发孔不明显;表面纹饰有3种:刺状类型、网状带刺类型和网状类型.根据花粉粒大小、刺的长短、萌发孔特征和表面纹饰类型等可以把这10种植物区分开来,同时发现I.wrightii与已有报道存在较大差异.     

长白山针阔叶混交林带花粉通量及垂直散布年际对比

长白山针阔叶混交林一号样地2005和2006年气象塔不同高度捕捉器样品花粉分析对比表明:连续两年花粉组成都足以乔木花粉为主,但存在差异,06年乔木花粉百分比较高,灌木、草本较低,同时06年花粉通量也较高,可能与05年花期降水较多,温度较低,花粉产量低有关.连续两年花粉通量在垂直高度上具有较高的一致性,特别是主要乔木花粉类型(白蜡属、桦、栎、松属花粉).这一结果有助于更好理解表土花粉对植被的指示性,森林表土样品中的草本、低矮灌木花粉类型,应主要来自样品点附近的植物;样品中的乔木、较高灌丛花粉类型,可能来自样品点附近或更大范围植物;区域性植物对花粉组合也有一定影响.     

海桑属6种植物花粉形态兼化石花粉指南

利用光镜(LM)和电镜(SEM)观察和研究海桑属6种植物的花粉形态.详细描述海桑属(Sonneratia L．f．)花粉形态学特征并建立种间检索表.根据观察和分析结果,将6种植物花粉分为四种类型,即A类型(Sonneratia alba,S．×hainanensis,s．×gulngai)、B类型(S．caseolaris)、C类型(S．ovata)和D类型(S．apetala).进而讨论海桑属花粉形态特征对化石花粉的鉴别指南,以及在古生态学研究领域的应用价值.     

安徽菜子湖早春开花植物花粉形态及生态意义

采用光学显微镜和扫描电镜对安徽安庆菜子湖早春开花植物15科22种2亚种的花粉形态进行了观察和研究。对这些植物的生态因子,包括地理位置、海拔高度、年降水量、年积温及生境进行了调查和归纳。在此基础上,根据该区域内相同或相似的生态环境条件下分布的现代植物各种花粉类型,间接得出一定花粉类型综合特征所指示的现代气候和环境,为利用菜子湖湖泊孢粉资料来研究区域气候和环境变化提供现代孢粉学资料和依据。     

安徽牯牛降植物的花粉形态及生态意义

应用光学显微镜对安徽省牯牛降8月份开花的26科44属44种2变种植物的花粉形态进行了观察和研究,提供各种花粉的鉴定特征。对这些植物的生态因子,包括海拔高度、年降水量、年积温和生境进行归纳总结。通过对这些花粉类型植物母体生态环境的归纳总结,讨论了它们的生态环境指示意义。研究结果为皖南山区沉积花粉的准确鉴定提供鉴别指南和标准对照图谱。     

中国马鞭草科植物的花粉形态

本文对我国18属91种3变种马鞭草科(Verbenaceae)植物的花粉形态进行了详细地观察研究。其中对15属27种进行了扫描电镜观察。本科为花粉多类型的科之一。根据萌发孔的数目、特征和纹饰特点,本文将马鞭草科分为9个花粉类型:1.具疣3沟花粉类型;2.具刺3沟花粉类型;3.具细网8沟花粉类型;4.具模糊颗粒-细网3沟花粉类型;5.具网3沟花粉类型;6.具散沟(6-8条)花粉类型;7.具3孔花粉类型;3.具细网3沟花粉类型,4.具模糊颗粒一细网3沟花粉类型,5.具网3沟花粉类型,6.具散沟(6-8条)花粉类型,7.具3孔花粉类型,8.具3孔沟花粉类型,9.具3(4)孔沟花粉类型。     

太白山表土花粉和气孔器与植物类型的关系研究

通过陕西太白山13个样点表土花粉组合特征和气孔器及其与植物类型之间关系的分析,结果发现:针阔混交林花粉组合能很好地反映植物类型特征,落叶阔叶林和针叶林花粉组合能较好地与植物类型相对应,高山灌丛草甸花粉组合未能反映植物类型数量特征;主要花粉类型松属、铁杉属和桦属花粉具超代表性,胡桃属和榆属花粉具适宜代表性,落叶松属、冷杉属、杜鹃花科和槭属花粉具低代表性;DCA(Detrended Correspondence Analysis)分析表明,通过花粉数据能够较好区分不同植被类型,结合气孔器特征能够准确反映植被特征。     

火红拟孔蜂蜂体携带花粉形态的研究

野外调查火红拟孔蜂采访植物种类,采用扫描电子显微镜研究火红拟孔蜂采访植物及雌蜂腹毛刷上携带花粉的形态.结果表明该蜂采访植物有20多种,其中蜂体携带花粉种类有14种,还有7种未能确定到种;远多于直接观察到采访的植物(10种)种类.蜂体花粉包括蒺藜科、豆科、藜科、旋花科、百合科、胡颓子科等,花粉形态长球形、近球形、三角形、扣合状等4种类型;纹饰包括网状、穴状、条纹状、颗粒状、脑纹状 5 种纹饰类型.蜂体花粉中的比例以四合木最大;说明对濒危植物四合木的异花授粉具重要意义.     

北极Barrow地区几种冻原植物的花粉形态

根据中一美合作协议,研究北极巴罗地区2000年以来气候和环境变化史,张青松和唐领余于1998年5—6月到阿拉斯加巴罗地区进行了为期4周的野外考察。除湖泊打钻外,还在巴罗地区采集了表土花粉和植物标本。本文是研究北极巴罗(Barrow)地区12种冻原植物的花粉形态,它们的形状有球形、近球形、扁球形、茧形和四面体形,其萌发孔有三孔沟,三沟,二合沟以及散孔等类型。花粉具辐射对称和两侧对称两种类型。这些花粉的植物体是北极地区常见的植物,分属于10个科,除三种为小灌木外,大多数为多年生或一年生草本植物。这些冻原植物花粉形态的研究为恢复北极地区古植被和古气候的研究,提供了有价值的对比资料和依据。     

中国钩藤属9种植物的花粉形态

利用光学显微镜和扫描电镜对中国钩藤属(Uncaria Schreb)9种植物的花粉形态进行了观察.结果表明,钩藤属植物的花粉为单粒,小型,辐射对称,赤道面观圆球形至近长球形,极面观3-裂圆形,具3孔沟,萌发沟裂缝状,长达两极.萌发沟中央有"内壁加厚突出"结构.外壁具条纹至细网纹饰,表面光滑无附属物.钩藤属花粉大小、形状、萌发沟和纹饰类型都较接近,属于单一型花粉.钩藤属植物的花粉形态特征是茜草科(Rubiaceae)中较为原始的类型.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.