紫背天葵叶片培养体细胞胚状体发生的研究

SH液体培养基附加2,4－D（0．125mg/l),BA(0.25-0.5mg/l),CM(10%v/v)或CH（0．2%w/v),摇床培养,同一培养基中培养50天后,出现球形,心形,鱼雷,子叶胚,虽然胚状体和不定芽同样来源于叶片的表皮细胞,但它们之间有下列区别;体细胞胚状体发育有4个不同时期,而不定芽没有;球形胚形成后,能脱落分散在培养液中,芽始终和外植体连在一起;鱼雷－子叶胚有明显的苗端和根端之分,苗端有两片子叶,叶间是顶端分生组织,有原形成层结构,而不定芽仅有芽原基。     

槐树子叶组织培养中的形态发生研究

槐树子叶在MS附加0.1～5 mg/L BA 和0.1—5 mg/L 2,4-D的培养丛上培养两周,获得了灰色疏松型及白、绿色紧密型两种类型的愈伤组织。后者经培养产生不定芽并再生植株。子叶切块在MS 附加0.1～8 mg/L 2,4-D等培养基上培养3周,在切口处形成愈伤组织的同时,由其表面直接分化产生胚状体。组织学观察表明,胚状体来源于子叶的表皮及叶肉细胞,胚状体产生通过单细胞起源及多细胞出芽两种方式发生。胚状体发育依次通过球形胚、心形胚、鱼雷形胚和子叶胚等阶段形成再生植株,其发育过程与合子胚相似。     

TDZ诱导花生幼叶的不定芽和体细胞胚发生的组织学观察

花生实生苗幼叶接种于MS TDZ 0.2mg/L NAA0.4mg/L诱导培养基上经诱导培养,继而转移到无激素培养基MS可获得不定芽和体细胞胚。组织学观察表明,花生不定芽和体细胞胚均起源于愈伤组织表层,不定芽为多细胞起源,而体细胞胚起源于单个胚性原始细胞。体细胞胚的发育经历多细胞原胚、球形胚、心形胚、鱼雷胚和子叶胚等时期发育成小植株。     

胡杨器官和体胚发生方式的植株再生

目的：为以胡杨为亲本的体细胞杂交育种奠定基础。方法：以胡杨苗叶片为外植体,通过器官和体胚两种不同发生方式建立了离体再生体系。结果：附加0．75mg/L BA、0．5mg/L NAA基本培养基及3w暗培养是愈伤组织诱导的最佳条件;附加0．25mg/L BA和0．1mg/L NAA的基本培养基上不定芽的诱导率最高;1／2大量元素的MS培养基附加0．1mg/l NAA、0．05mg／L和1．5％蔗糖对不定芽生根效果最好;诱导并筛选出的胚性愈伤组织在附加了0．5mg/L BA、0．5mg／L NAA的基本培养基上诱导获得大量胚状体,干化处理后大部分能经子叶胚期萌发成苗。结论：外植体的采集周期和培养条件影响胡杨离体叶片的形态发生途径。     

禿杉组织培养研究

本文详细报道了从秃杉(Taiwania flousiana Gaussen)离体胚诱导不定芽、不定根及从无菌苗茎端培养再生植株的过程。诱导不定芽要求较低的蔗糖浓度(以3％最好);同时BA是必须的,在附加0.1—3 mg/1 BA的White培养基上,从离体胚的子叶或胚轴上诱导了不定芽的发生(以1 mg/1最好);NAA与BA结合使用,对不定芽诱导无促进作用;适当提高光照有利于不定芽的诱导。在诱导不定芽的同时,在子叶表面还观察到有许多无结构的“不定突起”。不定芽起源于子叶表皮下1—2层细胞。IBA对诱导离体胚上产生不定根效果较好。在有或无生长素的培养基上,从生长1月龄的无菌苗茎端培养获得了不定根的产生,在加有细胞分裂索的培养基上,从无菌苗上产生了腋芽。     

黄瓜胚性细胞悬浮培养及其原生质体的植株再生

黄瓜子叶原生质体来源的胚性愈伤组织,在液体培养中形成胚性悬浮细胞系,已继代两年,仍保持胚胎发生能力,不同的ABA和蔗糖浓度对胚状体的生长发育和同步化有明显影响。1mg/l的ABA和7－9％的蔗糖能显著地减少培养物的愈伤化,并同步地控制胚状体处于球形或球形后期,低浓度的蔗糖（1％）有利于胚状体的早期萌发,继代3－5天的胚性是浮细胞团酶解后,获得大量有活力的原生质体,原生质体在DPDK,液滴或浅层培养,或褐藻酸钠包埋培养中活跃分裂,形成细胞团和球形胚,转至固体培养基上或将包埋培养物直接转入液体振荡培养,胚状体可不断增殖,胚状体在大量元素减半,不加外源激素的MS培养基上发育成小植株。     

黄瓜胚性细胞悬浮培养及其原生质体的植株再生

黄瓜子叶原生质体来源的胚性愈伤组织,在液体培养中形成胚性悬浮细胞系,已继代两年,仍保持胚胎发生能力,不同的ABA和蔗糖浓度对胚状体的生长发育和同步化有明显影响。1mg/l的ABA和7－9％的蔗糖能显著地减少培养物的愈伤化,并同步地控制胚状体处于球形或球形后期,低浓度的蔗糖（1％）有利于胚状体的早期萌发,继代3－5天的胚性是浮细胞团酶解后,获得大量有活力的原生质体,原生质体在DPDK,液滴或浅层培养,或褐藻酸钠包埋培养中活跃分裂,形成细胞团和球形胚,转至固体培养基上或将包埋培养物直接转入液体振荡培养,胚状体可不断增殖,胚状体在大量元素减半,不加外源激素的MS培养基上发育成小植株。     

欧石楠体细胞胚发生和植株再生

以欧石楠茎段为外植体,研究其体细胞胚胎发生和植株再生。对影响茎段不定芽分化及胚性愈伤组织诱导的主导因子进行比较分析,并研究其体胚萌发、生根及移栽;同时,采用树脂切片法对茎段脱分化产生胚性愈伤组织及体胚发育过程进行组织细胞学观察。结果表明,接种在1／2WPM基本培养基上的茎段,胚性愈伤组织诱导率为88．7％,显著高于其他处理,不定芽诱导率可达90．6％,平均分化倍数为3．6个,平均分化苗高3．82cm;体细胞经过成熟培养后。在添加1．0mg·L-1 ZT和0．3mg·L-1 IBA的1／2WPM培养基上萌发,萌发的体胚在I／2WPM附加0．2mg·L-1 NAA和0．3mg·L-1 IBA的培养基上形成完整的体胚苗植株,体胚苗生根率达到87．4％,经炼苗后移栽到蛭石：珍珠岩=3：1（V／V）的栽培基质中,成活率可达63．7％。在显微镜下可观察到球形胚、心形胚、鱼雷形胚和子叶形胚;体细胞胚以间接方式发生,表现为愈伤组织外层细胞直接发生和愈伤组织组织内部细胞发生。     

火炬松成熟合子胚离体培养过程中诱导不定芽的影响因素研究

火世松（Pinus taed L）界南方松中最重要的针叶树种之一,在环境保护,园林绿化和林业生产中有重要应用价值。有关火炬松未成熟胚的体细胞胚胎发生和器官发生的研究报道不多,其成熟合子胚的愈伤组织器官发生未见报道。本文以取自湖南省邵阳市林场的火炬松成熟种胚为外植体,在诱导其愈伤组织器官发生的基础上,系统地研究了BA浓度,基本培养基（TE）浓度和不同碳源等对愈伤组织上不定芽的发生和发育的影响,优化了火炬松离体再生的培养条件,为火炬松的无性繁殖技术应用于实验生产奠定了基础。研究结果表明：不同的浓度条件下,4mg/LBA培养基上的不定芽诱导频率和每个胚上的芽平均数最高,分别是76．3％和3．4。火炬松器官发生愈伤组织（Fig.1)上的不定芽形成于愈伤组织表面（Fig.2)。不定芽的发生常不同步（Fig.3)。不定芽在低浓度BA(1-2mg/L）条件下发育较好(Fig.4),在高浓度BA（8－16mg/L）条件下发育减慢（Fig.5),在1mg/LBA条件下伸长生长较快（Fig.6);不同浓度基本培养基的实验结果表明,当基本培养基浓度为1．25TE时,不定芽诱导频率（73．5％）;不同浓度基本培养基的实验结果表明。池基本培养基浓度为0．5或0．75TE时,不定芽基部易形成愈伤组织（Fig.7)。在1．5TE培养基上,不定芽瘦弱且发育缓慢（Fig.8);不同碳源的实验结果表明,以2％的葡萄为碳源时,不定芽的诱导频率和每个胚上的芽平均数均最高,分别是83．7％和5．8。由此可见,4mg/LBA,1.25TE基本培养基和2％葡萄糖可能是构成火炬松成熟合子胚离体高效无性快速繁殖体系的决定性和关键因素。     

金鱼草（Antitthinum majus L.）下胚轴外植体不定芽的高频再生

本文发展的技术可以使金鱼草下胚轴外植体不定芽高频再生。添加有2mg/l BAP和0．5mg/l NAA的MS培养基上再生芽出得又快又多,淡黄色愈伤组织易于形成并存活,但主要依赖的是6－BAP。MS培养基中含有0．1mg/l和6mg/l浓度的6－BP均能刺激芽的发育,最适浓度为2－3mg/l。仅加2．4－D,也能形成正常的黄色愈伤组织,但这样形成的愈伤组织在只含有0．1－6mg/l6－BAP或含有2mg/l6－BAP和0．5mg/lNAA的MS培养基上均不能分化生出再生芽来。仅加NAA,能够刺激下胚轴形成根。加入AgNO3,则抑制不定芽的再生,并导致整个外体变成棕色而死亡。组织化学分析结果表明：不定芽的再生源于下胚轴外植体表皮细胞。在不含有任何生长调节的MS培养基上,再生苗均能形成根。再生植株移栽至花盆可开花结实。     

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.