中国贵州杜鹃属两新种

报道了中国贵州杜鹃属植物2新种--枇杷叶杜鹃(Rhododendron eriobotryoides Xiang Chen & Jia Y.Huang)和金波杜鹃(R.jinboense Xiang Chen & X.Chen).枇杷叶杜鹃与皱叶杜鹃(R.denudatum)相似,但本种叶背毛被较薄而稀疏,花丝基部密被微柔毛,花柱通体被腺体.金波杜鹃与短脉杜鹃(R.brevinerve)相似,但前者的叶长圆状椭圆形,叶片上卷呈U形,花序具较多花,花冠较长,花丝基部密被微柔毛,子房密被绒毛.目前,仅发现2新种各有1个含数株的种群,资源量十分稀少,依据IUCN红色名录标准均属于极危物种(CR),需要加以重点保护.     

广西杜鹃花研究(一)

<正> 1.岩谷杜鹃 新种 图1 (杜鹃亚属,长尾种子组) 附生小灌木,高20—6O厘米;枝圆柱状,密布小疣瘤,近似越橘杜鹃Rh.vaccinioides Hook.f.和匍枝杜鹃Rh.euonymifolium Lévl.;不同于前者为:叶密集,非散生,边缘外折,花黄色;不同于后者为叶向枝端聚生,较小,花萼裂片长圆形,被缘毛,花较小;不同于二者为子房和蒴果有鳞点而且被毛,可资区别。     

头花杜鹃、陇蜀杜鹃及杜鹃属植物叶绿体基因组比较分析

头花杜鹃(Rhododendron capitatum)和陇蜀杜鹃(R. przewalskii)是极具观赏价值的野生花卉和药用植物。为探讨头花杜鹃和陇蜀杜鹃叶绿体基因组的遗传结构及进化特征,该研究利用 Illumina HiSeq 4000 平台对头花杜鹃和陇蜀杜鹃的叶绿体全基因组进行测序,经组装和注释后,结合 7 个已发表的杜鹃属植物叶绿体全基因组进行比较基因组学分析和系统发育分析。结果表明:(1)头花杜鹃和陇蜀杜鹃叶绿体全基因组呈典型的环状四分体结构,均由一个大单拷贝区(105 990、109 191 bp)、一个小单拷贝区(2 617、2 606 bp)和一对反向重复区(45 825、47 516 bp)构成,全长分别为200 257、206 829 bp。(2)头花杜鹃和陇蜀杜鹃叶绿体基因组中共鉴定出 263 个SSR位点,大部分 SSR 偏好使用 A/T 碱基,密码子偏好使用 A/U 结尾。(3)杜鹃属植物叶绿体全基因组中普遍存在基因丢失以及基因组重排等结构变异现象。该研究丰富了杜鹃属植物的基因组资源,为头花杜鹃、陇蜀杜鹃的资源开发、遗传进化、育种及系统发育相关研究提供了理论参考。     

中国杜鹃属一新种

报道了中国贵州杜鹃属一新种——百纳杜鹃(Rhododendron bainaense Xiang Chen&Cheng H.Yang)。百纳杜鹃与红棕杜鹃(R.rubiginosum Franch.)相似,但本种的叶为长圆形至卵形,叶背鳞片大小近似、琥珀色、凹陷,花冠较小、白色带浅粉色且不具斑点,花丝基部近无毛或仅部分被微柔毛,花药淡褐色。目前该新种的资源量十分稀少,野外调查仅发现1个种群含3株,应该给予重点保护。     

濒危植物都支杜鹃雄蕊数目描述的修正

通过对都支杜鹃5个种群（包括模式产地）的雄蕊数目进行统计、对馆藏标本进行查询和对模式标本采集人进行采访,修正了现有文献对都支杜鹃雄蕊数目（一个关键鉴别特征）的描述——应是12~15枚,而非10枚;本文还对同地点栽培的都支杜鹃和云锦杜鹃的形态进行观察,发现都支杜鹃与云锦杜鹃诸多形态特征差异显著,支持都支杜鹃是一个独立的“好种”。     

云南10种杜鹃属植物的叶片覆被物特征及其系统学意义

采用扫描电子显微镜对云南10种杜鹃属植物叶片毛被与鳞片特征进行了研究,并结合已报道的中国45种杜鹃属植物毛被与鳞片特征进行了聚类分析,探讨叶表皮毛被与鳞片在该属植物中的系统学意义。结果表明:(1)常绿杜鹃亚属的8种植物叶背面具毛被却无鳞片结构,杜鹃花亚属的2种植物叶背面均具鳞片结构。(2)基于叶表面毛被与鳞片特征对55种杜鹃属植物进行聚类分析显示,有鳞片杜鹃与无鳞片杜鹃分别聚为2类,聚类结果与杜鹃属植物在亚属水平上的传统分类基本一致,表明叶表面毛被与鳞片特征在杜鹃属植物各亚属的分类中具有较好的参考价值。(3)从亚组水平看,55种杜鹃属植物的聚类结果对云锦杜鹃亚组、有鳞大花亚组、露珠杜鹃亚组具有较好的分类学界定,但在三花杜鹃亚组、高山杜鹃亚组、大理杜鹃亚组、大叶杜鹃亚组、树形杜鹃亚组存在明显的交叉现象,表明叶表皮覆被物特征不足以作为这些亚组在分类处理上的关键性状。(4)该研究聚类结果表明,糙叶杜鹃与其他有鳞杜鹃之间亲缘关系较近,支持糙叶杜鹃归并到杜鹃花亚属。     

烈香杜鹃化学成分的研究

从烈香杜鹃的乙酸乙酯提取物中分离得到五个化合物,通过波谱分析鉴定其结构。其中5-羟基-6,7-二甲氧基黄酮,烈香杜鹃素I和烈香杜鹃素Ⅱ为首次从该属植物中分离得到。     

桃叶杜鹃组织培养技术研究

选用桃叶杜鹃试管苗的芽苗、叶片进行离体培养,通过正交试验设计并结合方差分析、多重比较从中选出了不同中间繁殖体的最佳培养基配方.试验结果表明:改良MS和6-BA及KT不适合桃叶杜鹃的组织培养,相对较低浓度的TDZ却能诱导植株分化,建立起桃叶杜鹃的离体培养体系,达到保护名贵杜鹃的种质资源,加速繁殖的目的.     

不同预处理方法对牛皮杜鹃和小叶杜鹃种子萌发的影响

采用3种方法(用100、200、400、600和800 mg·L-1GA3浸种24 h、用清水浸种6、12和24 h以及用超声波处理10、20和30 min)对牛皮杜鹃(Rhododendron aureum Georgi)和小叶杜鹃(R.parvifolium Admas.)种子进行预处理,以未经预处理的种子为对照,选择发芽率、发芽势和发芽指数以及萌发时滞、萌发高峰期、发芽持续时间为分析指标,对预处理后种子的萌发状况进行了比较分析。结果表明:采用适宜的预处理方法对牛皮杜鹃和小叶杜鹃种子的萌发有促进作用;总体上看,GA3浸种的促进作用优于另外2种预处理方法。用不同质量浓度GA3浸种24 h,2种植物种子的发芽率、发芽势和发芽指数均极显著高于对照,萌发时滞和萌发高峰期均较对照缩短;其中,用400 mg·L-1GA3浸种的牛皮杜鹃种子和用600 mg·L-1GA3浸种的小叶杜鹃种子的发芽率最高,分别达到73.50%和81.00%。用清水浸种6 h的牛皮杜鹃种子和用清水浸种24 h的小叶杜鹃种子的发芽率分别显著和极显著高于对照。用功率50 W、频率40 kHz的超声波分别处理10或20 min后,2种植物种子的发芽率均极显著高于对照,其中,用超声波处理20 min的牛皮杜鹃种子和用超声波处理10 min的小叶杜鹃种子的发芽率最高。清水浸种和超声波处理对2种植物种子的萌发时滞、萌发高峰期和发芽持续时间的影响均不明显。研究结果显示:用400mg·L-1GA3浸泡24 h和用600 mg·L-1GA3浸泡24 h分别是牛皮杜鹃和小叶杜鹃种子的最优预处理方法,可极显著提高2种植物种子的发芽率并缩短发芽时间。     

杜鹃花族花粉形态及其系统学意义

利用光学显微镜和扫描电子显微镜对杜鹃属（Rhododendron L.）和仿杜鹃属（Menzie-sia Smith.)26种植物的花粉形态进行了观察和比较研究,其中大部分种为首次报道。杜鹃属和仿杜鹃属的花粉均为四合花粉,呈正四面体排列。四合体为圆角三角形,连接紧密。杜鹃属四合体平均直径在30.29-62.45μm之间,仿杜鹃属四合体直径为26.38-32.19μm,单粒花粉为球形或近球形,具三沟孔。在四合体上,相邻花粉粒上的沟相接,有时可见粘丝存在。杜鹃属和二鹃属花粉大小和花粉粒外壁纹饰均不同,具有明显的属间差异。在扫描电镜下,杜鹃属亚属内组（或亚组）之间花粉粒具有不同的外壁纹饰,可为分类学研究提供孢粉学方面的证据,具有重要的分类学意义。花粉分析在杜鹃属内不能作为分亚属的主要特征,但可用于某些种的分类学研究。     

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.