化学杂交剂GENESIS诱导小麦雄性不育的细胞形态学观察

在小麦幼穗发育期的药隔期至四分体期,用5．0kg／hm^2剂量的GENESIS进行处理,结果表明,GENESIS可诱导小麦产生100％的雄性不育率,且不育株率超过99％以上,具有良好的诱导雄性不育的效果。小麦经GENESIS处理后,小孢子发育出现异常,败育型小孢子有单核花粉、二核花粉和不正常的三核花粉,同时还发现有四核和五核花粉以及在花粉发育过程中原生质体解体,仅留下花粉壁的空壳花粉。不育花药不开裂,花粉囊除了表皮及纤维层外,还可观察到延迟解体的绒毡层,绒毡层的延迟解体可能影响了小孢子的发育。     

雄性不育和雄性能育小麦(Triticum aestivum L.)花药和花粉发育的细胞形态学观察

本工作是小麦雄性不育杂种优势利用研究项目的一部分。从细胞形态学的角度,研究小麦细胞质雄性不育系及其保持系花药和花粉的发育,为探索雄性不育性的机理提供资料。应用石蜡切片法,对小麦“早熟1号”和“北京8号”细胞质雄性不育系及其保持系花药的发育过程进行了观察,得到如下的结果:(1)不育系花粉的败育,在发育的各个时期都发生,但败育的关键时期是在小孢子发育后期,具大液泡的小孢子不能进入配子体发育阶段。(2)不育系花药和花粉的发育,在小孢子发育早期以前,90%以上与保持系相似,是正常的;少数表现异常而导致败育。异常现象有:药室合并;小孢子母细胞解体,绒毡层发育正常;小孢子母细胞互相粘连,形成多核的原生质团;解体的小孢子母细胞与绒毡层融合形成多核的原生质团;药室中除正常发育的小孢子母细胞或小孢子外,还出现异常的巨型细胞;绒毡层提早在小孢子发育早期解体,形成多核的原生质困;绒毡层肥大生长。     

羽叶薰衣草雄性不育的细胞学研究

用光镜和电镜观察羽叶薰衣草(Lavandula pinnata L.)雄性不育小孢子发育过程的细胞形态学特征.结果表明:羽叶薰衣草花药4枚,每枚花药通常具4个小孢子囊.花药壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四面体及十字交叉型.小孢子的发育过程可分为造孢细胞期、减数分裂时期、小孢子发育早期、小孢子发育晚期.未观察到二胞花粉期和成熟花粉期.羽叶薰衣草花粉败育主要发生在单核花粉时期,细胞内物质解体并逐渐消失变成空壳花粉或花粉皱缩变形成为各种畸形的败育花粉.在此之前小孢子的发育正常.羽叶薰衣草小孢子不育机制体现在绒毡层过早解体、四分体时期以后各细胞中线粒体结构不正常、胼胝质壁与小孢子母细胞脱离、花药壁细胞中淀粉出现时间异常等. 壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四面体及十字交叉型.小孢子的发育过程可分为造孢细胞期、减数分裂时期、小孢子发育早期、小孢子发育晚期.未观察到二胞花粉期和成熟花粉期.羽叶薰衣草花粉败育主要发生在单核花粉时期,细胞内物质解体并逐渐消失变成空壳花粉或花粉皱缩变形成为各种畸形的败育花粉.在此 前小孢子的发育正常.羽叶薰衣草小孢子不育机制体现在绒毡层过早解体、四分体时期以后各细胞中线粒体结构不正常、胼胝质壁与小孢子母细胞脱离、花药壁细胞中淀粉出现时间异常等. 壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四     

芡实花粉败育的细胞学观察

芡实（ＥｕｒｙａｌｅｆｅｒｏｘＳａｌｉｓｂ．）花粉的败育主要发生在小孢子母细胞减数分裂时期和小孢子单核期与二核期。形成的不正常四分体中有一些具有不完整的横隔壁,一些则完全不形成横隔壁,而发育成具４个核的原生质团;气候异常是造成该时期不育现象的主要原因之一。小孢子单核期及二核期存在发育异常的孢子。绒毡层的提前发育、过早解体、肥大生长及延迟退化是花粉败育的一个重要原因。     

甘蓝型油菜几个雄性不育系花药发育的细胞形态学研究

选用甘蓝型油菜6个细胞质雄性不育系和1个细胞核雄性不育系为材料,与可育系比较,确定花药发育受阻的时期和方式。根据研究结果,将其雄性不育系分为三类:1.湘矮A,Po-aA,陕2A和7s-3A花药发育受阻于孢原细胞分化期,没有分化形成花粉囊。2.萝AⅠ和萝AⅡ花药发育受阻于四分体至单核花粉期。败育方式为小孢子难以从四分体中释放出来,或释放出来后细胞质液泡化,核不能分裂,花粉壁发育不良。此外,还见到绒毡层径向肥大、延迟消失和维管束分化不良等异常现象。3.宜3A为核不育系,花药发育受阻于花粉母细胞期。败育方式为花粉母细胞死亡,减数分裂异常,或不能进行减数分裂。绒毡层和维管束一般都能正常发育。     

丹参雄性不育系Sh-B的鉴定与花粉发育过程的解剖学研究

在显微水平上对新发现的丹参雄性不育系Sh-B花药发育过程进行了解剖学观察,并对其花粉活力和结实率进行了鉴定。结果显示:根据花器官及花药的形态、大小以及花丝的长度,可以将Sh-B不育株分为3个不育类型,即Sh-B1、Sh-B2和Sh-B3。这3种不育类型均属于雄性不育,其花丝不到正常可育株的1/2,花药干瘪而瘦小,内无花粉粒或花粉无活力;其根、茎、叶以及种子形态结构与正常可育植株基本相似。产生雄性不育的主要原因有:花粉囊药室内壁纤维层加厚,影响花药壁开裂;小孢子母细胞周围不产生胼胝质或产生的胼胝质很少;绒毡层细胞延迟解体;花粉粒畸形。在其花药发育的小孢子母细胞时期、四分体形成前期、单核期、双核期均可能产生雄性不育的小孢子或花粉粒。     

新型光温敏小麦不育系337S的组织结构研究

普通小麦(Triticum aestivum)不育系337S是一种对短日低温、长日高温均敏感不育的新型光温敏雄性不育系。对经过短日低温、长日高温处理的不育系花药及其小孢子的形态和发育过程进行了观察,观察结果表明,不育系337S的花药异常短小,开花后花丝短,花药难外露。花药发育过程中中层组织发育紊乱,绒毡层提前解体,影响了花粉母细胞发育所需的营养供应,导致短日低温处理下的花粉母细胞减数分裂中期Ⅰ和长日高温处理下的花粉母细胞发育时期花粉母细胞发育异常,形成异常小孢子,造成败育。     

萍乡显性雄性核不育水稻超微结构研究

利用电镜技术对萍乡显性核不育水稻可育株和不育株花粉形成及发育过程和药壁组织的基本结构及其发育进行了研究。导致了其不育花粉败育的主要原因有：（1）绒毡层细胞表现为延迟解体,乌氏体不能与小孢子细胞壁的形成,特别是纯合不育株绒毡层细胞存在乌氏体的异位分布;（2）药隔维管束异常,导致营养物质运输缺乏,薄壁细胞液泡化,排列紊乱,杂合不育株薄壁细胞互相融合,出现核转移的独特现象。     

灯盏花雄性不育种质鉴定与花药发育的细胞学研究

对云南泸西栽培灯盏花群体进行调查,发现了灯盏花雄性不育种质个体,其出现频率约为1.06×10-4.对所发现的灯盏花不育株形态特征及其花药发育过程进行了观察,并对花粉活力进行鉴定.结果显示:(1)灯盏花不育株根、茎、叶形态与正常可育植株基本相似,管状花小,花丝短,花药瘦小,无花粉粒散出或花粉无活力.(2)灯盏花在其花药发育的小孢子母细胞时期、四分体时期、小孢子时期和单核早期,由于绒毡层细胞液泡化、提前解体,不能为小孢子或花粉发育提供所需物质,导致小孢子母细胞和四分体解体,产生无花粉的花药;或小孢子和单核花粉胞内降解,形成不同形状和外壁纹饰的败育花粉.研究认为,灯盏花花药绒毡层异常是其花粉败育的主要原因.     

温光敏核不育水稻N28S 无花粉败育的显微结构观察

采用石蜡切片和荧光显微技术观察了温光敏核不育水稻N28S 无花粉败育过程中的显微结构变化, 结果显示: N28S 的小孢子母细胞形成后细胞质变得稀薄, 一部分不能进行减数分裂, 一部分减数分裂阻滞在细线期或胞质分裂异常, 最终所有细胞液泡化解体消失。在此过程中, 还观察到小孢子母细胞在细线期胼胝质壁不产生或提早消失, 以及小孢子发育后期花药壁绒毡层的异常解体。认为N28S 的无花粉败育是由小孢子母细胞的细胞质异常引起的, 胼胝质壁和绒毡层的异常是结果而不是原因。     

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.