几种党参属植物及其近缘种花粉形态的比较

对6种桔梗科（党参属Codonopsis4个种以及桔梗属Platycodon和风铃草属Campanula各1种）花粉进行了光镜及扫描电镜的观察比较,发现党参属不同种花粉的形态特征很不相同,易于区别,如党参花粉极面观多为7裂圆形,外壁形面具乳突状的短刺,川党参花粉极面观圆形,刺在沟的两旁排成两列,小花党参花粉极面观近圆形至7裂圆形,外壁表面的刺比其它种的都大,鸡蛋参花粉外壁表面的刺柔软而稍为弯曲,其长度为上述各种刺的数倍,桔梗属和风铃草属花粉与党参属花粉的差异更大,桔梗属花粉粒扁球形,极面观五角形,少数四或六角形,风铃草属花粉粒更为特殊,极面观近圆三角形,具3孔,花粉外壁的刺不仅锐利而且很粗,花粉形态在党参属不同种间以及党参属与桔梗属和风铃草属之间的差异为其分类学提供了进一步的孢粉学资料。     

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。     

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.     

新疆胡颓子属三种植物的花粉形态及其分类学意义

该文采用主成分分析和聚类分析方法,运用扫描电镜对新疆胡颓子属(Elaeagnus Linn.)落叶组大果沙(E. moorcroftii)、尖果沙枣(E. oxycarpa)和沙枣(E. angustifolia)共计18个样品的花粉形态进行了观察和研究;全面描述了新疆胡颓子属3个种花粉的极轴长、赤道轴长、极面观、赤道面观、孔沟形态和外壁纹饰等形态特点,并对其进行数据分析,通过对聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果表明：(1)3个种的花粉均为中等大小;萌发孔类型均为三孔沟型。(2)花粉极面观形状从三角形、钝三角形到圆三角形;赤道面观形状从菱角形、半圆形到扁圆形;外壁纹饰从皱波状到穴状。(3)以筛选出的5个反映花粉形态的主成分指标进行聚类,结果显示所选指标不能区分种;以代表花粉形态的极面观形态和赤道面观形态为指标进行聚类同样也无法区分3个种;以花粉粒大小为指标进行聚类发现,大果沙枣的花粉大小可以区别于其他2个种。研究表明除了大果沙枣花粉的大小,尖果沙枣和沙枣的花粉形态不宜直接应用于种的划分。该研究结果为新疆胡颓子属落叶组植物花粉的种间鉴定和品种划分以及进化关系的研究提供了孢粉学依据。     

槭树科花粉形态及其系统学意义

报道了槭树科(Aceraceae)槭属21组33种和金钱槭属2种植物的花粉形态。本科花粉近球形至长球形,极面观为三裂圆形。从花粉萌发孔类型看,金钱槭属Dipteronia具三孔沟,槭属（Acer)除4组具三孔沟外,其余均为三沟。从花粉外壁纹饰看,金钱槭属2个种和槭属的大多数种为条纹状,罕为细条纹－拟网状和皱波状。通过花粉形态分析,并结合其它方向的证据,我们认为：（1）Sect.Palmata,Sect.Spicata和Sect.Microcarpa可能是槭属中与金钱槭属关系最密切的类群;（2）A.distalum和A.nipponicum代表了近缘的两个单种组;（3）A.pseudoplatanus不同于Sect.Acer的其它4个种而与A.saccharum可能存在更为密切的关系;（4）Sect.Carpinifolia(细条纹－拟网状外壁纹饰）和Sect.Negundo(皱波状外壁纹饰）则可能代表了槭属中最特化的类群;（5）按槭树科花粉三孔沟到三沟的演化规律,Dipteronia较Acer原始。     

中国鸡矢藤属花粉形态

用扫描电子显微镜对中国鸡矢藤属(Paederia L.)6种1变种植物的花粉进行观察。结果表明:鸡矢藤属植物的花粉均为单粒,辐射对称,小型或中型,极面观3-裂圆形至钝三角形,赤道面观呈长圆球形或近长球形,具3个萌发沟,无内萌发孔。外壁纹饰网状、细网状或穿孔状,孔边缘具小刺状突起或无。臭鸡矢藤(P.foetida)和白毛鸡矢藤(P.pertomentosa)具有花粉二型现象,其中白毛鸡矢藤(P.pertomentosa)是首次报道。花粉二型现象与花柱二型现象可能没有直接的关联性,与前人的观点一致。推测鸡矢藤属外壁纹饰的可能演化趋势为:穿孔、网状、细网状→粗网状;网眼内无棒状突起→网眼内有棒状突起。鸡矢藤属花粉的外壁纹饰变化较大,且无内萌发孔,是茜草科花粉过渡类型的特征。     

国产蔷薇科李亚科的花粉形态

本文报道了国产李亚科（Ｐｒｕｎｏｉｄｅａｅ）１０属１１种植物花粉形态。花粉近球形至长球形,极轴２０００～４４１２μｍ,赤道轴１７８５～３６９５μｍ。极面观三裂圆形,赤道面观椭圆形至圆形。具三孔沟,内孔常为长方形。沟较长,两端较窄。但在Ｓｉｎｏｐｌａｇｉｏｓｐｅｒｍｕｍｕｎｉｆｌｏｒａ中除了３孔沟外,还有周孔沟。花粉外壁明显分化为覆盖层和柱状层,在光学显微镜下表面常模糊,扫描电镜下外壁纹饰均为条纹状。孢粉学结合形态学和细胞学证据说明本亚科为一单系发生的类群。Ｐｒｉｎｓｅｐｉａｕｔｉｌｉｓ和Ｓｉｎｏｐｌａｇｉｏｓｐｅｒｍｕｍｕｎｉｆｌｏｒａ（Ｐｒｉｎｓｅｐｉａｕｎｉｆｌｏｒａ）这两个种在花粉特征和外壁纹饰上差异很大,从而支持将Ｐｒｉｎｓｅｐｉａ和Ｓｉｎｏｐｌａｇｉｏｓｐｅｒｍｕｍ分别处理为两个属但不支持将广义的Ｐｒｉｎｃｅｐｉａ（含Ｐｒｉｎｃｅｐｉａ和Ｓｉｎｏｐｌａｇｉｏｓｐｅｒｍｕｍ）独立为亚科。此外,由于Ｅｘｏｃｈｏｒｄａ的外壁纹饰同Ｐｒｕｎｏｉｄｅａｅ中较原始的类群（如Ｌａｕｒｏｃｅｒａｓｕｓ）相近,结合细胞学和形态学证据,支持将Ｅｘｏｃｈｏｒｄａ移置至Ｐｒｕｎｏｉｄｅａｅ之下     

茴芹属16种植物的花粉形态及系统学分析

利用光学显微镜和扫描电镜对茴芹属16种植物的花粉形态进行了观察,其中12种为首次报道。结果表明,茴芹属16种植物花粉大小为（19.75～33.03）μm×（11.52～17.41）μm,极轴与赤道轴的比值（P/E）为1.40～2.28,体积大小指数（P×E）^1/2为16.71～23.97,属于中型花粉,具三孔沟,萌发孔位置为边萌发孔。花粉粒赤道面观有近矩形、赤道收缩形、椭圆形和近菱形等类型,其中近矩形和赤道收缩形占多数;极面观为三角形或三角圆形。扫描电镜下,其外壁表面纹饰赤道面观为脑纹状,极面观近光滑或为穴纹状。在伞形科芹亚科中,茴芹属植物的花粉具有中等进化、比较进化的形态特征。研究认为,花粉形态可为个别物种的分类处理提供孢粉学证据。     

中国紫草科天芥菜亚科花粉形态及其系统学意义

为了深入研究紫草科Boraginaceae的分类问题,用光学显微镜和扫描电子显微镜观察了中国紫草科天芥菜亚科Heliotropioideae天芥菜属Heliotropium 6种,砂引草属Messerschmidia 2种和紫丹属Tournefortia 1种植物的花粉形态.它们的花粉为长球形,赤道面观为椭圆形,极面观为六裂圆形或八裂圆形,少数为三角形.萌发孔有三种类型:(1)三孔沟与三假沟交替排列;(2)四孔沟和四假沟交替排列;(3)三孔沟.外壁表面具微弱的小穿孔,皱波状纹饰或表面近光滑.上述结果表明天芥菜亚科三个属之间有密切的亲缘关系.花粉特征表明紫丹属在天芥菜亚科中可能是比较原始的,天芥菜属的演化水平比紫丹属和砂引草属要高,而砂引草属介于其他两个属之间.花粉形态特征显示天芥菜亚科是厚壳树亚科Ehretioideae到紫草亚科Boraginaceae的过渡类型.紫丹属的花粉具三孔沟的萌发孔类型表明天芥菜亚科与破布木亚科Cordioideae有一定的亲缘关系.     

延龄草科四属花粉形态的研究

对延龄草科重楼属Paris L.延龄草属Trillium L.Medeola L.属和Scoliopus Torr.属以及百合科百合属Ｌilium L.和萱草属Ｈemerocallis L.花粉进行了光镜和电镜的观察和比较。结果表明,在延龄草科中,重楼属,Medeola属和Scoliopus属花粉具有较多的相似性：具单一远极沟,极面观椭圆形,外壁为网状纹饰或皱波－网状纹饰。而延龄草属花粉与它们的差异则较大,为圆形,无萌发孔,外壁非网状纹饰,而是颗粒状,疣状,芽孢状,星状和微刺状等纹饰。百合属中的Lilium michauxii和萱草属中的金针菜Hemerocallis citrina花粉均为单一远极沟,外壁表面为网状纹饰。但其网脊特别粗,具不规则突起并形成棱角（H.citina)或由许多排列成念珠状的、形状不一的分子组成（Lilium michauxii),结构特别复杂。就其萌发孔类型和纹饰特征看,它们与延龄草科中的重楼属,Medeola属和Scoliopus属花粉具有较多的性。花粉外壁的层次结构在延龄草科各属之间（延龄草属除外）,甚至在延龄草科与百合科之间均没有多大的差异。     

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.