Factors Affecting Plant Regeneration from Tissue Cultures of Chinese Leymus (Leymus chinensis)

Chinese leymus (Leymus chinensis Trin.) is a perennial grass of the Gramineae, which is widely distributed in China, Mongolia and in Russian-Siberian. In order to explore the potential of biotechnology for genetic improvement of this forage grass, an efficient tissue culture system was established and the factors affecting plant regeneration were evaluated. Immature inflorescence segments 3–5 mm in length from eight accessions were cultured on N6 medium supplemented with 2.26–22.60 µM 2,4-D. The callus induction frequency ranged from 72.11 to 82.19%. Shoots were differentiated from the calli on N6 medium containing 4.65 µM kinetin and 4.44 µM BA. Viable regenerants were developed on hormone-free medium. Normal plants were obtained after natural vernalization in the field. The plant regeneration frequency in Chinese leymus was associated with different genotypes and different combinations of growth regulators in medium. The concentration of 2,4-D in the callus induction medium had a strong effect on successive plant regeneration. Relatively higher concentrations of 2,4-D (i.e., 9.04 and 22.60 µM) were more favorable to the plant regeneration than lower ones (i.e., 2.26 and 4.52 µM). This is the first report on plant regeneration in vitro in L. chinensis.     

一例智力低下患者7q~ 标记染色体的来源鉴定

以人类染色体显微切割、PCR技术构建的现有人类染色体特异性和染色体区带特异性探针池作为绘画探针,采用正向染色体绘画技术,结合染色体筛查方法,查明了一例7q~ 标记染色体患者的染色体附加片段来源于3q26→3qter。确定该患者的核型为46,XX,-7, der(7)t(7;3)(7pter→7q32::3q26→3qter)。应用这个策略,能够快速有效地鉴定标记染色体的来源。     

红原鸡与家鸡的亲缘关系研究

对中国红原鸡滇地亚种和海南亚种与我国茶花鸡,泰和鸡和寿光鸡等地方鸡种以及芦花鸡,洛岛红等外国鸡种进行了血型（３个位点,１３个等位基因）,蛋白质（酶）多态（５个位点,１１个等位基因）和ＤＮＡ指纹分析,结果表明,红原鸡与茶花鸡（原始型品种）的亲缘关系较近;与泰和鸡,寿光鸡,芦花鸡,洛岛红（进化型品种）的亲缘关系较远,呈红原鸡－茶花鸡－泰和鸡,寿光鸡或芦花鸡,洛岛红这样一个进化阶梯,以上结果与国外资料（     

抗BmNPV即刻早期蛋白三联ribozyme在家蚕细胞中的表达

为了阻断家蚕核多角体病毒（BmNPV）的基因表达,以BmNPV的即刻早期蛋白基因(IE)为靶序列,设计了三联ribozyme．体外切割反应表明,该ribozyme能特异地切割靶序列的mRNA;细胞实验表明,细胞中表达的ribozyme也能够特异地切割靶序列,从而使受BmNPV感染的Bm-N细胞中的多角体减少约30％．     

叶片阶段性白化小麦的叶绿体激发能分配和荧光动力学特征

叶片阶段性白化小麦是一种非常特殊的色素突变体。本文对其白色、白绿相嵌及转绿叶片的叶绿体光化活性分别进行了测定。试验表明：（１）白化和白绿相嵌叶片的叶绿体色素合成处于停滞阶段,转绿叶片则处于色素迅速合成阶段;（２）白化、白绿相嵌和转绿叶片叶绿体的激发能传递呈递增趋势;（３）三者对绿体的ＰＳⅡ活性和原初光能转化效率也呈递增趋势;（４）白化叶片叶绿体缺乏ＰＳⅠ和ＰＳⅡ外周天线色素蛋白,白绿相嵌和转绿叶片的类囊体膜多肽组分与正常叶片相近似。     

准分子激光治疗近视眼

本文对准分子激光PRK治疗近视眼息者503例的早期临床结果进行分析,近视范围为－2．0至－15．0D,根据术前屈光度不同分为三组,术后随访三个月．结果证实准分子激光是一种安全、有效、预测性较好的治疗近视眼方法．全部病人提高了裸眼视力,绝大部分保持了最佳矫正视力,且没有产生危及视力的并发症．     

桃花营养元素的分析与开发探讨

桃花含有较高的蛋白质和人体必需的各种氨基酸、维生素和微量元素。由于桃树在我国分布范围广泛,产花量大且需要人工疏花,使桃花的开发利用具有良好的条件。     

抑菌生亚急性毒性实验研究

本项研究的目的：是在一系列毒性试验的基础上进一步观察大鼠皮下给予由枯草芽孢杆菌ＢＳ２２４菌株制成的抑菌生后,对机体产生毒性反应的情况。结果表明：给药组大鼠饮食、活动正常。各项检测指标及病理组织学检查未发现异常,与对照组比较均无差异（Ｐ＞０．０５）,说明抑菌生无毒性反应。     

广州抽水蓄能电站蓄水库蓄水初期浮游生物调查

对我国首座核电站配套工程的抽水蓄能电站水库蓄水初期的浮游生物进行了调查。蓄水水库由上下两水库组成。两水库的浮游生物种类组成显著不同。上水库浮游植物共记录到３０种（属）,浮游动物１２种（属）;下水库浮游植物１９种（属）;浮游动物２５种（属）。上下两水库浮游生物数量均较贫乏,表明浮游生物群落尚处于初期发育阶段,但在局部浅水处已出现小规模的蓝藻水花,认为是水库蓄水初期必然的结果     

Isolation,characterization and application of a species-specific repeated sequence from Haynaldia villosa

A species-specific repeated sequence, pHvNAU62, was cloned from Haynaldia villosa, a wheat relative of great importance. It strongly hybridized to H. villosa, but not to wheat. In situ hybridization localized this sequence to six of seven H. villosa chromosome pairs in telomeric or sub-telomeric regions. Southern hybridization to whea-H. villosa addition lines showed that chromosomes 1V through 6V gave strong signals in ladders while chromosome 7V escaped detection. In addition to H. villosa, several Triticeae species were identified for a high abundance of the pHvNAU62 repeated sequence, among which Thinopyrum bassarabicum and Leymus racemosus produced the strongest signals. Sequence analysis indicated that the cloned fragment was 292 bp long, being AT rich (61%), and showed 67% homology of pSc7235, a rye repeated sequence. Isochizomer analysis suggested that the present repeated sequence was heavily methylated at the cytosine of the CpG dimer in the genome of H. villosa.It was also demonstrated that pHvNAU62 is useful in tagging the introduced 6VS chromosome arm, which confers a resistance gene to wheat powdery mildew, in the segregating generations.