预浸和发芽过程中番茄种子细胞核的倍性变化

用细胞流检仪检测番茄种子细胞核倍性水平时发现,当年成熟的番茄种子胚细胞核ＤＮＡ绝大多数为２Ｃ水平,胚乳细胞核则为３Ｃ水平,说明成熟番茄种子细胞一般休止停留在Ｇ１期,同时我们也发现极少量的胚和胚乳细胞核分别为４Ｃ和６Ｃ水平,说明这些细胞已经进行了ＤＮＡ内复制,供试番茄种子浸种后１２ｈ左右完成吸水过程,２ｄ后胚根可突破种皮发芽,随着种子吸水过程的完成,胚根尖部分细胞开始进入ＤＮＡ复制期（Ｓ期）,而且此     

赤霉素与脱落酸对番茄种子萌发中细胞周期的调控

利用细胞流检仪检测番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ．） ＧＡ－缺陷型、ＡＢＡ－缺陷型和相应的正常品种（野生型）成熟种子胚根尖细胞倍性水平时发现：ＧＡ－缺陷型和野生型种子绝大多数细胞ＤＮＡ 水平为２Ｃ,而ＡＢＡ－缺陷型种子则含有较多的４Ｃ细胞。在标准发芽条件下,ＡＢＡ－缺陷型和野生型种子浸种１ ｄ 后胚根尖细胞ＤＮＡ 开始复制,随后胚根突破种皮而发芽。然而ＧＡ－缺陷型种子除非加入外源ＧＡ,否则既不发生细胞ＤＮＡ 复制,也不发芽。这说明内源ＧＡ 是启动番茄种子胚根尖细胞ＤＮＡ 复制的关键因素,同时也说明番茄根尖细胞ＤＮＡ 复制是种子发芽的必要条件。实验证明：ＡＢＡ 不抑制细胞ＤＮＡ 合成,但阻止Ｇ２ 细胞进入到Ｍ 期。外源ＡＢＡ处理野生型种子与渗控处理结果相似,可以大幅度提高胚根尖４Ｃ／２Ｃ细胞的比例,但抑制种子的最终发芽     

吸胀番茄种子中β－微管蛋白的合成与DNA的复制

用免疫检测技术分析了吸胀的番茄种子胚根尖细胞中的β－微管蛋白,并用流体细胞分析仪分析了其细胞核ＤＮＡ的表现形式,发现种子在吸水８～１６ｈ时,即可测得β－微管蛋白的标记,吸水４８ｈ标记密度达到高峰。而细胞周期中Ｇ２期细胞的数目在吸水２４ｈ后才有增加。双向电泳检测,证明种子萌发过程中至少存在３个不同的β－微管蛋白的异构体。用ＰＥＧ渗调引发处理的种子,β－微管蛋白的合成和ＤＮＡ复制速度高,反之,老化种子在这两个过程的速度则低。     

番茄种子发芽及渗控处理过程中的水分关系

干燥番茄（Ｌｙｃｏｐｅｒｓｉｃｏｎ ｅｓｃｕｌｅｎｔｕｍ Ｍｉｌｌ． ｃｖ． Ｍｏｎｅｙｍ ａｋｅｒ）种子浸种吸水有明显的３ 个阶段,尽管种子不同部分吸水的速度不一样,但整粒种子需１０～１２ ｈ 才能基本完成第一阶段的吸水。胚乳对种胚伸长和生长的机械压力明显阻碍种胚的吸水,即使在第二阶段整个种子水势与浸种溶液基本达到水分平衡时,种胚的水势仍然低于整个种子水势０．６～０．９ ＭＰａ。发芽过程中ＧＡ 和ＡＢＡ不直接影响番茄种子吸水。番茄种胚水势与含水量的关系呈幂指数的正相关。无论在浸种还是渗控处理过程中,番茄种胚压力势的总变化趋势是下降的     

吸胀番茄种子中β—微管蛋白的合成与DNA的复制

用免疫检测技术分析了吸胀的番茄种子胚根尖细胞中的β－微管蛋白，并用流体细胞分析仪分析了其细胞核ＤＮＡ的表现形式，发现种子在吸水８￣１６ｈ时，即可测得β－微管蛋白的标记，吸水４８ｈ标记密度达到高峰。     

水稻纯合胚致死突变研究

以ＥＭＳ的处理并结合组织培养技术成功地获得胚致死突变的纯合再生植株。该植株生长发育正常,除种子无发芽能力外,纯合突变体的一切性状均与亲本品种表现一致。观察到胚败育的各种表现：（１）仅具有一个球形胚。（２）完全没有胚器的分化。（３）仅具胚根的分化而无胚芽的分化。（４）胚芽分化不完全。（５）胚芽与胚根之间没有输导组织相连接或者输导组织发育不完全等等。（纯合突变体×正常品种）杂种当代的种子（Ｆ１）发芽正常,而由Ｆ１及Ｒ１植株上所产生的种子（Ｆ２及Ｒ２）约有３／４具发芽能力,而１／４无发芽能力。统计分析的结果表明胚致死突变受隐性单基因控制。据我们所知,获得胚致死突变纯合体的成熟植株,本研究乃是首例报告,至少在水稻上是如此。在以利用无融合生殖之固定杂种优势的“一系法”杂交水稻生产的设想中,胚致死突变可作为胚乳的提供者而加以利用。     

华山新麦草胚和胚乳的发育研究

采用常规石蜡切片法,观察了华山新麦草胚和胚乳的发育过程,结果表明,华山新麦草胚和胚乳的发育过程与一般禾本科植物基本相同,胚胎发生属紫宛型,顶细胞和基都参与胚体的形成,胚胎发育经过二细胞原胚,多细胞原胚,球形原胚,梨形原胚,分化胚和成熟胚阶段,成熟胚具有胚根,胚芽,盾片,胚牙鞘,胚根鞘,外胚叶等典型禾本科植物成熟胚的结构,胚乳发育类型为核型,包括游离核阶段,细胞化阶段和生长成熟阶段,待大量游离核形成之后才形成细胞壁,紧贴胚囊的一层胚乳细胞最后形成种子的糊粉层,其余的胚乳细胞最后充满淀粉粒,其特点为：（1）有双球形原胚的现象;（2）反足细胞解体较早;（3）胚乳游离核时期和细胞时期胚乳细胞核的核仁多样。     

文摘

杜仲成熟干胚乳愈伤组织的诱导和植株再生［中］／朱登云…／／农业生物技术学报．－１９９８,６（４）．－３０７～３１２杜仲成熟干种子经ＧＡ３溶液浸泡后,去掉种胚,切取胚根端胚乳接种在愈伤组织诱导培养基上,５～７ｄ后多数胚乳顶端局部膨大。将膨大部分切下转入...     

刺五加胚和胚乳发育的研究

刺五加Eleutherococcus senticosus(Rupr .et Maxim．)Maxim的胚胎发生类型为茄型。其卵细胞受精后,合子经历15天左右的休眠期才进行第一次分裂。合子分裂通常发生在胚乳细胞化之后,经棒形胚、球形胚、至果实成熟时发育到心形胚。棒形胚后期至心形胚初期,胚柄最为发达。刺五加的胚乳发育类型为核型。其初生胚乳核的休眠期为1天左右。当胚乳游离核数目增加到200至300时,胚乳以自由生长细胞壁的方式细胞化,胚乳细胞以典型的有丝分裂方式进一步增殖,增加细胞数目。球形胚时期,胚乳细胞内开始贮藏营养物质。少数种子的胚乳里存在巨大细胞核的异型胚乳细胞。在胚乳游离核为32至64个时,分化出珠被绒毡层;球形胚时期,珠被绒毡层解体。珠被绒毡层解体后,胚乳表层细胞分化为分泌层。球形胚至心形胚阶段,约有5％的种子里,胚与胚乳组织发生弥散样降解。成熟果实中,含有大量的瘪粒种子和虫咬种子;饱满种子率为40％左右。饱满种子中,胚乳组织占据种子体积的绝大部分,胚所占比率很小。讨论了不同发育时期胚和胚乳的营养供应。     

桃儿七种子解剖结构及其萌发生长期形态特征

为探明种皮和胚乳是否是限制桃儿七种子萌发的主要因素,利用组织切片和显微技术,对桃儿七种子及其不同萌发期（1、7、14、21、28 d）解剖结构和播种后一定时期内（7~210 d）的植株生长形态进行观察。桃儿七种子由种皮、胚乳和胚构成。种皮包括外种皮和内种皮,外种皮致密规整,由外至内分别为栅状石细胞和表皮层细胞,内种皮由5~6层海绵细胞组成。胚乳占种子体积的绝大部分,包括珠孔胚乳和外胚乳。胚由胚根、胚轴和子叶组成,被致密种皮、多层珠孔胚乳和外胚乳包围。萌发期1~7 d胚根和胚轴开始伸长,7~14 d两片子叶分离,14~21 d胚根突破珠孔胚乳和种皮,21~28 d胚根、胚轴和子叶继续扩张伸长。种子播种210 d后可平均形成3片功能真叶和5条不定根。致密种皮（物理休眠）和多层胚乳（机械休眠）是限制桃儿七种子萌发的两个主要因素。     

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.