区分可育花粉和不育花粉的简便染色方法

花粉是种子植物雄蕊花药的粉状体,由花粉母细胞通过减数分裂而形成的四个具单核的花粉粒通常有两层壁,即内壁和外壁,甚至还有周壁。由于其表面具有坚硬的外壁,所以无法对花粉粒的可育性进行直接判断。这样,在进行生殖生物学的研究中,需要对花粉粒的活性进行鉴别。花粉粒能...     

卷丹的细胞学研究

对百合属卷丹进行了细胞学观察,发现卷丹为同源三倍体,其核型公式是２ｎ＝３ｘ＝３６＝９ｍ（ＳＡＴ）＋３ｓｍ＋３ｓｔ９ＳＡＴ）＋３ｓｔ＋３ｔ（ＳＡＴ）＋１２ｔ＋３ｔ。卷丹花粉母细胞的减煺分裂属首镒报道,观察到在前期Ⅱ有染色体落后及新形成花粉粒中染色体解旋结慢等现象。     

甜椒胞质雄性不育雄配子发育的解剖学和超微结构研究

运用石蜡切片和电子显微镜超薄切片方法观察了甜椒(Capsicum annuum L．)细胞质雄性不育系8A和保持系8B雄配子发育过程。结果表明：不育系和保持系都能正常进行减数分裂,绒毡层细胞无明显差异,形成了正常的四分孢子。在四分体单核居中期后,不育系的绒毡层细胞异常膨大并伸进药室,挤压花粉粒,同时绒毡层细胞提前降解,不育系单核晚期花粉粒开始崩出内含物。致使不育系的雄配子在双核花粉粒形成之前就完全裂解,不能发育成正常的花粉粒。此外,超薄切片还观察到不育系花粉粒在单核早期绒毡层细胞线粒体空泡化,这种变化表明雄性不育的遗传缺陷包括在花药发育早期发生的线粒体结构变化。     

黄花烟草单倍体植株花粉粒败育的观察

甘肃黄花烟草未授粉子房培养的愈伤组织再生的单倍体植株(2n:2x=24),生长矮小,叶片和花也较小。花粉粒有两种类型:小型直径平均17.41微米,大型直径平均42.37微米,都无沟槽和萌发孔,外壁雕纹显著增厚。二倍体植株正常花粉粒直径平均26.28微米。根据单倍体植株花粉粒败育过程的细胞学观察,约80%的花粉母细胞减数分裂正常,形成四分体,进一步发育成小型的单核花粉粒;但停滞在单核阶段,不能进入有丝分裂,以致不能形成成熟的二核花粉粒;最后细胞核和细胞质解体消失,成为空壳的败育花粉粒。另外的20%的花粉母细胞,由于1—2个落后染色体的存在,减数分裂不能正常进行,变为一种大型的四核花粉粒;最后细胞核和细胞质解体消失,成为空壳的败育花粉粒。     

诸葛菜花粉粒表面伴刀豆球蛋白A受体扫描电镜观察

诸葛菜花粉粒表面伴刀豆球蛋白Ａ受体扫描电镜观察刘智慧,郑常文,董长江,黄玉祥,罗鹏（四川大学生物系,成都６１００６４）张明珍（四川师范大学生物系,成都６１００６６）有花植物的有性生殖过程是从花粉粒与柱头表面某些识别物质的特异性作用开始的,尽管花粉粒和...     

青阳参小孢子发生和雄配子体发育

利用常规石蜡制片技术、荧光显微技术、光镜细胞化学技术、电子显微镜技术对青阳参小孢子发生和雄配子体发育进行了详细观察。结果显示,小孢子孢原细胞起源于皮下组织并在两个地方分化;孢原细胞平周分裂形成初生壁层和初生造孢层,初生壁层细胞再经过平周分裂形成2层细胞,其中最内一层即为绒毡层,绒毡层为分泌型绒毡层,既为小孢子发育提供营养来源,又分泌分泌物形成包围花粉粒的膜;初生造孢层细胞直接行使小孢子母细胞的功能;成熟花粉粒中含有大量淀粉粒、蛋白质、内质网、叶绿体、脂体和大液泡;包围花粉粒的膜和花粉粒之间的膜含有蛋白质成分和脂类成分;小孢子细胞核分裂形成营养细胞和生殖细胞,营养细胞和生殖细胞间没有细胞板形成,生殖细胞呈透镜型、比营养细胞小。     

陕西省常见蜜源植物花粉形态的研究

运用扫描电子显微镜,对陕西省境内３０种常见蜜源植物的花粉粒进行了观察研究,描述了花粉粒的大小、萌发孔类型及其表面纹饰等形态特征。结果表明：绝大多数种的蜜源植物,其花粉粒的形态特征明显不同。本文还就花粉粒形态特征,在鉴定蜜源植物花粉的属种,确定蜂蜜的产地、评价蜂蜜的品质等方面进行了探讨。     

玉竹生殖细胞壁在发育中的变化

应用光镜细胞化学和电镜方法,研究了玉竹生殖细胞发育过程中壁的结构和性质,证明了生殖细胞在刚形成时分隔它与营养细胞的壁是含胼胝质和纤维素的,从生殖细胞行将与内壁脱离开始,直至完全游离在花粉粒的营养细胞质中的发育时期,壁变薄和不显示苯胺蓝和荧光增白剂的荧光,但对ＰＡＳ是正反应的,当生殖细胞进入花粉管后和在有丝分裂前,细胞具有弱的ＰＡＳ正反应的包被,在结构形态上与曾在精细胞中描周质相似。研究结果证明玉竹     

六个不同类型荞麦花花粉粒形态的电镜观察比较研究

对二倍体甜荞长花柱类型 (ES2 s)、二倍体甜荞短花柱类型 (ES2 S)、四倍体甜荞长花柱类型 (ES4s)、四倍体甜荞短花柱类型 (ES4S)、四倍体有翅细野荞 (GR4HI)、四倍体无翅细野荞 (GR4HO)等 6个不同荞麦类型花的花粉形态学进行了电镜观察。结果表明 :这些荞麦类型的花粉粒都是椭圆形 ,都有网状纹饰、3孔沟等特征。二倍体甜荞染色体加倍后形成的四倍体甜荞 ,相对于二倍体甜荞而言 ,花粉粒显著增大和明显变圆。无论二倍体还是四倍体甜荞 ,其长花柱型花的花粉粒都比其对应短花柱型花的花粉粒要小。尽管四倍体甜荞和四倍体细野荞在染色体数目和倍性上一样 ,但是它们在花粉粒的大小上有显著差异。四倍体细野荞有翅类型和无翅类型的花粉粒大小和形态差异不显著     

含笑属(木兰科)植物花粉形态及其系统学意义

利用扫描电子显微镜对含笑属12个分类群的花粉形态进行了观察和研究。花粉粒椭圆形,两侧对称,异极,具远极单萌发沟,中等大小;形成一较为自然的分类群。虽然花粉粒的大小和表面雕纹不同种间具有一定的差异,但不足以为现有的属下分类系统提供足够的证据。     

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.