亚美马褂木不同生根类型硬枝扦插苗生长研究

以珍珠岩基质中亚美马褂木硬枝扦插苗为研究对象,研究了扦插苗生根类型、不定根数、不定根长、苗高、基径、鲜样质量和根芽距等生长指标,为选择高生长和高生根率无性系提供参考。结果表明:亚美马褂木扦插苗不定根形成有3种生根类型即皮部生根类型、中间生根类型和愈伤生根类型,其中愈伤生根类型扦插苗成活数量多,中间生根类型扦插苗生长最好,愈伤生根类型扦插苗生长较好。扦插苗鲜样质量与不定根数、不定根长、苗高和基径等相关系数达极显著正相关,苗高与不定根数和基径、不定根数与基径等相关系数达极显著正相关,不定根数与生根类型相关系数达极显著负相关。     

Stepwise in-straw dilution and direct transfer using open pulled straws (OPS) in the mouse: a potential model for field manipulation of vitrified embryos

In the present study, mouse blastocysts were employed to investigate the feasibility and efficiency of stepwise in-straw dilution and direct transfer using the open pulled straw (OPS) method. In experiment I, the effects of various vitrification solutions (VS) on embryo survival were examined. After thawing, the expanded blastocyst rates (97.59 and 95.05%) and hatching rates (80.48 and 78.95%) achieved in the EDFS30 [15% ethylene glycol (EG), 15% dimethyl sulfoxide (DMSO), Ficoll, and sucrose] and EFS40 [40% EG, Ficoll, and sucrose] groups were no different from those (96.15% and 83.33%) of the control group. However, the rates in the EFS30 [30% EG, Ficoll, and sucrose] (87.80 and 55.43%) and EDFS40 [20% EG, 20% DMSO, Ficoll, and sucrose] (95.69 and 70.97%) groups were significantly lower than those (96.15 and 83.33%) of the control group (P<0.05). In the experiment II, the effects of the volume of VS in the OPS on the survival of embryos after in-straw thawing were investigated. When the length of the VS in the column was less than 1 cm, the in vitro viability of embryos thawed by stepwise in-straw dilution was no different among the experimental and control groups. The embryos could be successfully thawed by immersing the OPS in 0.5 M sucrose for 3 min and then 0.25 M sucrose for 2 min. In experiment III, the effect of immersion time of the OPS in diluent (PBS) on the viability of vitrified embryos was investigated. After in-straw thawing, OPSs were immersed immediately in 1 ml PBS for 0 to 30 min. When the immersion time of the OPSs in PBS was less than 12 min, in vitro development of the in-straw thawed embryos was no different from that of the controls. In experiment IV, in-straw thawed blastocysts were directly transferred to pseudopregnant mice to examine their in vivo developmental viability. The pregnancy (91.67%) and birth rates (42.42%) of embryos in-straw thawed and directly transferred were no different from those of the unvitrified controls (90.90 and 40%) and embryos thawed by the conventional method (84.61 and 46.94%). These results demonstrate that mouse embryos vitrified with OPS could be successfully thawed by stepwise in-straw dilution and transferred directly to a recipient and that this method might be a model for field manipulation of vitrified embryos in farm animals.     

二化螟dsRNA降解酶基因的克隆与表达分析

为解析二化螟Chilo suppressalis体内参与降解双链RNA(double-stranded RNA,dsRNA)的关键核酸酶的功能,克隆二化螟不同的非专一性核酸酶（non-specific nuclease,NUC）基因,并对这些基因进行生物信息学分析和组织定量表达分析,同时对dsRNA降解酶（dsRNA degrading nuclease,dsRNase）活力的组织分布进行研究。结果显示,共克隆获得5个NUC基因,其中有4个编码dsRNase亚家族基因（CsdsRNase1～CsdsRNase4）和1个编码Endonuclease G亚家族基因（CsEndoG）。5个NUC基因的开放阅读框核苷酸序列长度范围为828～1 338 bp,编码275～445个氨基酸残基,其分子量大小为31.68～49.57 kD,预测等电点为5.48～9.42。CsdsRNase1和CsdsRNase2含有信号肽序列,两者相似度极高,且与家蚕Bombyx mori和斜纹夜蛾Spodoptera litura中具有dsRNA降解酶活力的dsRNase同源聚类;CsdsRNase1和CsdsRN...     

植物表达载体pGMAR-BADH的构建

将甜菜碱醛脱氢酶基因BADH和植物表达载体pGMAR通过内切酶BamHI和KpnI双酶切,T4连接酶进行连接反应。重组质粒在大肠杆菌菌株DH5α内扩增,提取并纯化质粒。经鉴定,基因BADH已被完整、正确的插入到pGMAR载体中,并成功将BADH插入到载体pGMAR的两个MAR序列之间。     

THE STUDY OF STRAIN FATIGUE CRACK PROPAGATION BEHAVOURS OF VANADIUM BEARING HSLA STEEL

In this paper, the strain fatigue: crack propagation rates of vanadium bearing HSLA steel with different micro-structures are measured under constant load conditions, and the relationship between the crack propagation rate and the microstructures of steel is also studied.     

直墙拱形巷道围岩应力场分析

为得出直墙拱形巷道围岩应力分布规律,应用复变函数弹性理论推导了直墙拱形巷道围岩应力分布的解析表达式。对直墙拱形巷道边界的围岩应力和巷道水平线方向的围岩应力分布规律进行分析,并考虑直墙拱形巷道断面高宽比和侧压系数对其影响规律。研究表明：在不同巷道断面高宽比、侧压系数下,直墙拱形巷道围岩应力集中区域主要集中在直墙底部底角处、拱形顶板中点附近和底板中部3个位置。不同巷道断面高宽比下,直墙拱形巷道沿水平线的应力分布规律基本相同。侧压系数大于1时,采用巷道断面高宽比小于1较有利于巷道稳定;侧压系数小于等于1时,采用巷道断面高宽比大于1较有利于巷道稳定。     

A Research on the Way of EMBET in the Tracking Systems'' Accuracy-analysis During Satellite Launch

In the past, the criterion for calibration has almost invariably been the stellar oriented ballistic camera,the method is a point to point comparison on the identical coordinate system. Deficiencies is follows: The request of weather is severe(cloudless night); The period is often long; the measure equipment of high precision can't be calibrated. While EMBET methods is used in calibration, it does not need criterion and it demands only that the measure elements is larger than 3,and the trajectory and many system errors of the measure elements can be simultaneously calculated with the measure data sequences. The error models of related equipments' measure elements and the EMBET of typical equipment group are given. The EMBET method is successfully used in Accuracy-analysis of Satellite Launch.