中国兜被兰属植物的花粉形态及其分类意义

兜被兰属Neottianthe全世界共约12种,中国均有分布,其中9种为我国所特有。本属花粉形态 和组成都很特殊,它是由许多单粒花粉粘结在一起形成复合花粉——花粉小块,其形状一般为狭长的三 棱锥体形。外壁表面具5种纹饰类型:(A)近光滑,或具十分微弱的小凹陷;(B)外壁具穿孔状纹饰; (c)外壁具沟渠状纹饰;(D)外壁具拟网状纹饰;(E)具典型的网状纹饰。奉属有些种类,例如:N．cal- cicola,N．monophylla,N．pseudo-diphylax和N．cucullata等4种在分类上还存在许多问题,有些分类 学家把N.calcicola,N.monophylla,N.pseudo-diphylax 3种均归并于N．cucullata。孢粉学资料表 明上述4个种花粉特征完全不同,因此,上述4种仍应各自独立为种。最后,强调指出N．camptoceras的花粉形状和外壁纹饰等特征在本属为特殊类型。     

中国柽柳科植物花粉形态的研究

本文用光学显微镜和扫描电镜观察了分布于我国的4属30种柽柳科植物花粉形态。并用透射电镜研究了柽柳属的代表种, Tamarix elongata外壁内部的超微结构。本科花粉为三沟, 少数属种为三拟孔沟。根据扫描电镜观察, 柽柳属花粉外壁表面具粗网状纹饰和细网状纹饰, 以及界于这两个类型之间的过渡类型。水柏枝属外壁表面具粗网状纹饰, 细网状纹饰, 小穿孔以及小的蠕虫状突起。红沙属和枇杷柴属均为细网状纹饰。 本科柽柳属花粉与杨柳科中柳属的花粉特征较相似, 本文提出了它们之间的区别。     

中国槲寄生属花粉形态的研究

首次系统地报道中国槲寄生属10种植物花粉形态。通过光学显微镜和扫描电镜观察,国产槲寄生属种类可按花粉的外壁纹饰分为两大类群,与形态上划分相一致。类群Ⅰ(8种)具不显著或近光滑的外壁纹饰,这一类型又可分为2个亚型:纹饰在花粉各个部位基本上是一致的和纹饰在赤道和极、沟两侧不一致的;类群Ⅱ(2种)外壁具显著的杆状纹饰。但花粉性状对形态上相近的种类鉴定意义不大。还讨论了槲寄生属花粉的可能的演化趋势。     

中国紫草科破布木属花粉形态和外壁超微结构

为了深入探讨紫草科（Boraginaceae）的分类问题,用光学显微镜和扫描电子显微镜观察了该科破布木属（CordiaL.) 10种植物的花粉形态和外壁超微结构。发现该属花粉具三孔、三孔沟、三拟孔沟和三合沟4种萌发孔类型。外壁表面具微刺状纹饰、刺状纹饰、网状纹饰和不规则的条纹网状纹状。破布木属的花粉特征表明,该属花粉在紫草科中既是独特的分类群,又是比较原始的属种。     

国产狗娃花属植物的花粉形态研究

利用光镜,扫描电镜对狗娃花属（Heteropappus)7种植物的花粉形态和结构进行了观察研究。发现该属植物花粉粒为近球形或长球形,3孔沟,具刺状纹饰,种间花粉差异主要表现在大小,形状和外壁纹饰细微变化等方面,该属花粉与紫菀属（Aster)和乳菀属（Ca-latella)的相似。表明它们有密切的亲缘关系。     

中国淫羊藿属药用植物花粉特征及其分类学意义

淫羊藿属(Epimedium L.)植物多为常用药材,分类和药材鉴定较为困难。该文采用扫描电镜对中国产淫羊藿属31种药用植物花粉的形态、大小和表面纹饰等进行了比较观察。结果显示:(1)淫羊藿属植物花粉形态多为长球形,少数为球形,大小为(15.5~25.0)×(27.3~48.1)μm,极面观多为三裂圆形,具三孔沟。(2)花粉粒外壁表面纹饰有网状、条网状、条纹状等类型。(3)花粉粒外壁纹饰如网眼的形状、大小和网脊表面特征等在各物种间有一定差异。研究结果为淫羊藿属药材鉴定与植物分类提供了重要的参考。     

樱属花粉形态研究

本文对樱属(Cerasus)9个种和变种的花粉形态进行光学显微镜观察,并结合电镜观察结果进行初步比较。结果表明,樱属花粉的极面观为圆形或近三裂圆形,赤道面观为椭圆形,三孔沟,外壁纹饰多为条纹状。属内特征基本一致,但种间存在着花粉大小、外壁纹饰的细微差别。     

猕猴桃属9种植物的花粉形态研究

本文利用扫描电镜和光学显微镜研究了猕猴桃属6种和3变种植物的花粉形态。本属花粉粒具三孔沟或三拟孔沟,外壁纹饰差异较大。可作为该属属下分组的重要依据之一。根据外壁纹饰,可将它们概括为4种类型:(1)皱块状表面具细条纹;(2)不规则的瘤状纹饰;(3)小沟状或小穿孔状;(4)较规则的瘤状纹饰类型。     

重楼属花粉形态的研究

本文对重楼属(paris L.)18个种和变种或变型的花粉形态进行了光学显微镜和电镜的观察和初步比较研究。就所观察过的种类看,花粉粒为扁球形,极面观椭圆形。左右对称。具一远极沟。外壁两层,外层厚于或等于内层。外壁纹饰有穴状、网状和皱-网状之分。不同的种类,其花粉大小和外壁纹饰均或多或少有所不同,其中有些种类的外壁纹饰比较特殊,可以作为区分种类甚至作为分组的依据或参考。     

中国菟丝子属植物花粉的扫描电镜观察

本文作者用扫描电镜(SEM)对国产菟丝子属(Cuscuta L.)10种植物的花粉形态进行了观察。具3沟萌发孔的花粉为本属基本类型。根据萌发孔的数目,外壁纹饰等特征,该属花粉可划分为三个类型:(1)具3沟,外壁具穿孔,表面散生小刺状突起;(2)具3—5沟,外壁具网状纹饰,网脊上散生小刺状突起;(3)具3—6沟,外壁具小刺状突起,穿孔偶见。本文观察结果与刘炳仑等曾报道过光学显微镜(LM)下的结果不完全一致。最后,对菟丝子属的花粉形态的演化趋势以及属内亚属间关系进行了讨论。     

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.