鲫鱼(Carassius auratus)外周血细胞显微和亚显微结构的观察

本文记载了用光镜和电镜观察鲫鱼外周血细胞所得的结果。 用光镜观察以Wright氏染液染色的血涂片,可区分出下列各种类型的血细胞:红血细胞,淋巴细胞,血栓细胞,单核细胞,中性、嗜酸和嗜碱粒细胞。此外,在外周血液中还可以看到少量未成熟的红血细胞。 在外周血液中,嗜酸和嗜碱粒细胞的数量极少。但在头肾和脾等造血组织中这类细胞的数量较多。 鲫鱼外周血液中各种血细胞的超微结构,基本上和人类以及其他鱼类相应血细胞的超微结构相似。  

抗白粉病小麦——中间偃麦草异附加系的细胞学和RAPD鉴定

利用细胞学和ＲＡＰＤ技术，对从小麦与中间偃麦草杂种后代中选育的抗白粉病异附加系ＤＡＬ６６进行了鉴定。结果证明ＤＡＬ６６根尖细胞染色体数为４４，花粉母细胞减数第一分裂中期（ＰＭＣ ＭＩ）杂色体模型为２ｎ＝２２Ⅱ。对ＤＡＬ６６及其双亲进行ＲＡＰＤ分析，从４０个随机引物中筛选出１个特异引物（ＯＰＥ－０２）能够稳定地扩增出特异带型。  

静水压休克诱导水晶彩鲫三倍体和四倍体的细胞学机理初探

本文分析了静水压休克诱导水晶彩鲫三倍体和四倍体的细胞学机理，促使第二极体保留的压力敏感期较短，在卵子第二次成熟分裂中后期的某段时间，也就是受精后４－５ｍｉｎ时；而在这之前，为卵子启动期，施加压力会破坏卵子的激动和修整过程，造成发育受阻；其后，为压力不应期，此时第二次成熟分裂态势也趋明朗，压力对保留第二极体失去作用。本文还对促使第二极体保留生产鱼类三倍体和抑制第一次卵裂诱导鱼类四倍体的条件等问题进行  

库拉索芦荟的多倍体诱导及其变异初报

在组织培养条件下，对库拉索芦荟（Aloe vera L.)用秋水仙素进行染色体加倍的诱导处理，结果表明：用含0.06%秋水仙素处理12h后诱变频率可达50％，其效果最佳。经秋水仙素诱导的加倍群体与正常二倍体植株比较，植株的大多数叶片变厚，叶色变深，叶片变大，气孔增大而单位叶面积气孔数减少。对变异材料进行细胞学研究所发现，体细胞中期染色体为2n=4x=28，为4倍体。未加倍前的二倍体为2n=2x=14。检测中也发现有少数植株有2n=14和2n=28两种细胞型的情况。  

栉孔扇贝(♀)×虾夷扇贝( ♂ )受精细胞学观察

采用Bouin氏液固定、石蜡包埋、切片 ,用苏木精 伊红染色 ,在光学显微镜下观察栉孔扇贝 (♀ )与虾夷扇贝 (♂ )杂交的受精细胞学过程。尽管栉孔扇贝与虾夷扇贝同科不同属 ,但它们的杂交仍具有正常的受精细胞学程序。栉孔扇贝卵子处于第一次成熟分裂中期时接受虾夷扇贝的精子入卵 ,精卵混合后 6min精子入卵 ;8～ 1 0min精核略微膨胀 ;2 5～ 3 0min排出第一极体 ;1h左右 ,雌雄原核同时形成 ;1小时 3 0分钟左右 ,雌雄原核融合 ;2h左右开始卵裂。杂交过程中的精子入卵行为较本交迟缓 ,但杂交后代仍能正常发育  

红鲫与湘江野鲤杂交的受精细胞学研究

红鲫成熟卵直径680—720μm;卵膜孔为精子入卵的唯一通道,包括前庭和精孔管两部分;精孔管内径约5μm。湘江野鲤精子头部直径约2.5μm。在通常情况下,红鲫卵为单精受精。尽管红鲫与湘江野鲤不同属,但杂交仍具有正常的受精细胞学程序。红鲫卵子处于第二次成熟分裂中期接受湘江野鲤精子入卵,精子入卵5min后,出现明显的精子星光;15min后,雄性原核及雌性原核形成;25min后,雌、雄性原核融合;30min后、开始卵裂,发现1个受精卵切片上有4个即将融合的原核,这可能是由于双精受精所致。  

Hybridization between Fagopyrum (Polygonaceae) species native to China

Thirty-eight crosses between seven Fagopyrum species native to China were studied. Following normal pollination, there were very low inter-group crossabilities (only 0 3%) between five species in the large-achene group and two species (E gracilipes and E pleioramosum) in the small-achene group, and high (15 50%) within the large-achene group, i.e. E esculentum, E tataricum, E zuogongense, E pilus and E megaspartanium. Crosses between various types of (lowers (homostyle, heterostyle etc.) suggested that the intraspecific incompatibility also occurs in interspecific crosses. The hybrid seeds obtained from interspecific crosses all withered or shrivelled and lacked activity. Only one hybrid plant was obtained, tetraploid E esculentum x tetraploid E zuogongense. The hybrid displayed anomalous behaviour at meiosis, pollen grain sterility and withering of achenes, confirming the genetic differences between E esculentum and E zuogongense. The results support the hypothesis that E megaspartanium and E pilus are the possible ancestors of cultivated buckwheat  

中国桔梗多倍体诱导与鉴定

在离体培养条件下，比较了不同浓度、不同处理时间的秋水仙素对中国桔梗（Platycodon grandiflorus A．CD）进行染色体加倍的诱导效果。结果表明：用含0．1％秋水仙素处理40h后诱导频率可达50％，诱导效果最佳。经秋水仙素诱导后形成的多倍体植株与原二倍体植株比较，在形态上，多倍植株叶片变宽变大，叶色变深，茎变粗且节距长，气孔增大而单位叶面积气孔数目减少。对变异植株进行细胞学研究发现，体细胞中期染色体数目为2n=4x=36，而原二倍体的染色体数目为2n=2x=18，基数x=9，因此，变异植株（2n=4x=36）为四倍体。前者的核型公式为2n=4x=14m＋20sm＋2st，核型属于2B；后者的核型公式为2n=2x=7m＋10sm＋1st，核型也属于2B。检测发现有少数个体有非整倍体变异。  

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。  

Knob heterochromatin homology in maize and its relatives

Summary We have characterised the major DNA sequence component of knob heterochromatin in maize, teosinte andTripsacum. Sequence analysis of this DNA gives strong support to the proposal that maize originated by selection of variants in teosinte. In situ hybridization has confirmed that this repeating DNA sequence, which is the major component of maize knob heterochromatin, is also the major component of knobs in teosinte,Zea diploperennis andTripsacum. In Southern blot hybridizations the repeat has a similar basic organization in all taxa;Tripsacum, however, is differentiated from maize and teosinte by a number of sequence features. Maize and teosinte knob heterochromatin are indistinguishable with regard to the distribution of mutations in the 180-bp repeat and the presence and organization of a 202-bp variant sequence. The knob DNA sequence was not detectable in three species ofCoix, an Old World genus of the Maydeae.Within the repeat unit is a 27-bp region that shows no sequence changes in maize, teosinte orTripsacum. The remainder of the repeat unit has randomly distributed nucleotide changes. The presence of the conserved sequence region suggests that knob DNA may have a functional role in the nucleus.