苦荞胚性愈伤组织诱导与植株再生研究

以苦荞子叶和下胚轴为外植体,进行了不同浓度激素组合的MS和SH固体培养基对胚性愈伤组织诱导及植株再生的研究。结果发现,MS培养基比SH培养基更有利于胚性愈伤组织诱导;2,4-D是诱导愈伤组织的有效激素,KT能有效促进胚状体的形成;下胚轴和子叶都能有效诱导出胚性愈伤组织和再生植株。下胚轴在MS 1.5mg·L-12,4-D 1.5mg·L-1BA培养基,子叶在MS 2mg·L-12,4-D 0.5~1.5mg·L-1BA上能高效诱导出愈伤组织;愈伤组织在MS 2mg·L-12,4-D 0.1mg·L-1KT培养基中继代,能有效诱导胚性愈伤组织;来自下胚轴的胚性愈伤组织在1/2MS 2.0mg·L-1BA 0.5mg·L-1KT 0.1mg·L-1NAA培养基上能够高频再生出芽,来自子叶的胚性愈伤组织在1/2MS 1.0mg·L-1BA 0.1mg·L-1KT 0.1mg·L-1NAA培养基上芽诱导率较高;MS 1mg·L-1NAA是适宜的再生苗生根培养基。     

红肉小果型番木瓜品种'美中红'体胚的诱导

用红肉小果型番木瓜品种‘美中红’为外植体,探讨不同成熟度的幼胚、不同浓度2,4-D和培养条件对其体胚的诱导以及体胚形成过程的结果表明:以子叶和内外种皮都为白色且个体较大的番木瓜幼胚(90~120d)在含10mg·L-12,4-D的培养基中和黑暗条件下诱导愈伤组织的效果最佳,愈伤组织的诱导率随着2,4-D浓度的增加而增加。番木瓜愈伤组织最先发生于形态学上的胚根下端,体胚多发生于形态学上的胚芽上端。     

白刺花胚性愈伤组织诱导及体细胞胚发生和萌发

探讨不同因素对白刺花下胚轴、子叶2种外植体胚性愈伤组织诱导及体细胞胚发生和萌发的影响。以B5和MS为基本培养基,研究2,4-D、6-BA和TDZ对白刺花下胚轴和子叶胚性愈伤组织的诱导;在MS培养基上添加不同浓度2,4-D,研究胚性愈伤组织增殖情况;采用ABA,探究对体细胞胚发生的影响。结果表明:下胚轴比子叶更易诱导胚性愈伤组织,筛选出2种外植最佳的胚性愈伤组织诱导培养基均为MS+2.0 mg/L 2,4-D+0.5 mg/L TDZ+0.5 mg/L 6-BA,胚性愈伤组织诱导率分别为77.3%和41.0%。15.0 mg/L ABA、0.2 mg/L 2,4-D和2.0 mg/L 6-BA有利于体细胞胚发生,1/3MS+0.2 mg/L NAA+0.1 mg/L 6-BA+2.0 g/L活性炭+25 g/L蔗糖+7 g/L琼脂的培养基可使体细胞胚萌发率达80%以上,再生植株移栽成活率高达90%。白刺花外植体种类及培养基类型均会影响胚性愈伤组织的诱导,其中下胚轴诱导效果优于子叶;MS培养基较适合启动细胞脱分化形成愈伤组织,2,4-D对胚性愈伤组织的增殖保持有调控作用,ABA有利于体细胞胚的发生。     

黄山栾树体细胞胚的发生和组织学观察

黄山栾树无菌苗的节间和叶柄离体培养后,其体细胞胚发生的结果表明：节间愈伤组织可诱导产生体细胞胚,而叶柄愈伤组织则生根：节间愈伤组织诱导培养基为MS＋3．0mg．L～2,4．D＋0．5～3．0mg．L-1NAA;节间胚性愈伤组织诱导培养基为MS＋2．0nag．L-2,4-D;胚性愈伤组织转移到无植物生长调节剂的MS培养基上可发育成正常植株。组织学观察表明,体细胞胚在胚性愈伤组织中有的发生于愈伤组织表层细胞,有的发生在愈伤组织内部。黄山栾树体细胞胚的形成经历球形胚、心形胚、鱼雷胚和子叶胚几个阶段,这与合子胚的发育途径相似。     

小麦遗传转化受体系统建立的研究

选用‘小偃22’和‘宁春16’小麦品种的成熟胚和幼胚进行培养,研究不同种类的胚和培养因子对愈伤组织诱导和分化的影响。结果表明,幼胚和成熟胚的愈伤组织诱导率无明显差异,但较高浓度的2,4-D有利于成熟胚的诱导,而幼胚培养时2,4-D浓度的影响效果因品种而异;两种外植体分化率的高低与KT/IAA的配比均有密切关系,但高浓度的激素水平不利于成熟胚的分化;诱导培养基中低浓度的2,4-D有利于所诱导的愈伤组织的分化。同时,在诱导培养基中添加低浓度的KT能显著提高两品种成熟胚愈伤组织的分化率;各种培养基处理与品种间都存在显著的互作效应,‘小偃22’成熟胚培养的最佳培养基组合为MSD 3.0 mg/L 2,4-D和MSD 0.5 mg/LIAA 1.0 mg/L KT,幼胚培养为MSD 4.0 mg/L 2,4-D和MSD 0.5 mg/L IAA 1.0 mg/L KT;‘宁春16’成熟胚培养为MSD 4.0 mg/L 2,4-D和MSD 1.0 mg/L IAA 1.0 mg/L KT,幼胚培养时为MSD 1.0 mg/L 2,4-D和MSD 2.0 mg/L IAA 2.0 mg/L KT。     

ABA诱导毛酸浆下胚轴体细胞胚状结构的直接发生

研究了ABA与2,4-D等植物激素对毛酸浆组织培养的影响。其中,以浓度为1.0mg/L的2,4-D对毛酸浆下胚轴愈伤组织诱导结果最好。在子叶、子叶柄、下胚轴以及胚根四者当中,下胚轴对2,4-D的反应状况最好。结合ABA与2,4-D在MS培养基上能够有效地诱导出高质量的球形胚状结构。经过4周的培养,在2.0mg/L2,4-D和1.0mg/L ABA组合的情况下,球形胚状结构的诱导频率可达96.7％,每块外植体平均能产生6.7个球形胚状结构。球形胚状结构可以至少在5代以内反复发生。进一步讨论了ABA对毛酸浆体细胞胚发生的影响以及体细胞胚发生与环境胁迫的可能关系。     

亚麻品种'双亚5号'的胚性愈伤组织诱导和体细胞胚胎发生

亚麻品种'双亚5号'的种子在MS 1.0 mg·L-1 2,4-D 30 g·L-1蔗糖培养基上可诱导出愈伤组织,将其转入MS 0.5mg·L-1KT 0.5mg·L-1NAA培养基上培养10周后诱导出大量胚性愈伤组织,结构较致密,浅黄色,表面有成团的紧密粘附在一起的小颗粒形态.但其继代周期不宜太长,继代次数不宜多,否则易回到非胚性化状态.胚性愈伤组织转A.MS 1.5 mg·L-1(T 1.0 mg·L-1 2,4-D分化培养基上培养40 d后可获得大量的球形胚状体.少量球形体胚可萌发形成正常的子叶胚初期形态,较多的球形体胚形成次生体胚或仅有单极性的畸形胚状体.组织解剖学观察表明,诱导出的是亚麻胚性愈伤组织和胚状体.     

小桐子愈伤组织的诱导

本文以小桐子的叶片、叶柄、茎段及下胚轴和子叶作为外植体,研究不同外植体类型对愈伤组织诱导的影响,结果表明叶柄的诱导率最高,其次为茎段的诱导率。同时以小桐子的下胚轴作为外植体,研究植物生长调节剂种类及浓度配比对愈伤组织诱导的影响,结果显示6-BA与2,4-D的组合更适宜小桐子愈伤组织的诱导,MS+6-BA0.5mg/L+2,4-D0.1mg/L为小桐子愈伤组织诱导的最佳培养基,其愈伤组织诱导率高达96.7%。本研究为小桐子愈伤组织的分化、植株再生及相关的遗传转化研究提供了参考。     

大豆未成熟胚培养中高浓度植物生长素的作用及其植株再生

用大豆(Glycine max(L.)Merr.)未成熟胚为外植体,在含高浓度 NAA 或2,4-D 的培养基上可诱导绿色结构体和体细胞胚状体。叶状、花状和喇叭形状的绿色结构体在含30mg/l2,4-D 的 MS-1培养基上可重新愈伤组织化。这种由高浓度2,4-D 诱发并保持的愈伤组织,转到低激素水平的培养基上后,能诱导出大量的同类形状的新结构体。绿色结构体可以进一步发育成叶丛状,但顶端不伸长。使用含2m g/l GA,和0.1mg/l IBA 的培养基,能促进顶端伸长和根的发育,获得正常植株。由未成熟胚的子叶(其时种子长度约4—6mm)诱导的愈伤组织具有再生能力。在含高浓度2,4-D(5-30mg/l)的培养基上诱导出的愈伤组织具有较高的产生绿色结构的潜力。而高浓度 NAA(10mg/l)培养基产生的愈伤组织具有较强的产生根状体的潜力。培养的外植体或愈伤组织在含5mg/l 2,4-D 的培养基上,不需要经常的继代培养,即可长期保存。     

‘SK4—316’胡萝卜体胚的诱导和培养

以'SK4-316'胡萝卜无菌苗的下胚轴为外植体,研究不同培养基配方和培养条件对愈伤组织诱导、体细胞胚间接发生及其同步化培养的影响,以及不同脱分化时间、脱分化培养基及外植体续存时间对体细胞胚直接发生的诱导及其培养的影响.结果表明:含3%蔗糖、0.8%琼脂的1/2MS + 2,4-D 2.5 mg/L + 6-BA(或KT)0.5 mg/L + CH 300 mg/L是诱导愈伤组织的良好培养基;1/2MS + 2,4-D 1.25 mg/L + KT 0.25 mg/L + 6-BA 0.25 mg/L(含3%蔗糖)适于愈伤组织分化并诱导体胚发生,0.02% ABA对体胚的诱导有促进作用,0.06% ABA或15% PEG能促进体胚成熟;外植体在MS + 2,4-D 1.0 mg/L固体培养基上脱分化培养48 h,再转入MS + CH 300 g/L液体培养基中可诱导体胚直接发生,但随着外植体续存于诱导培养基中时间的延长,体胚发生变异的几率也渐增.     

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.