Characterization of donor genome contents of backcross progenies detected by SSR markers in rice

Backcrossing is a trait introgression method of renewed importance in crops. The evolution of introgressed or substituted segments through backcross generations has been analyzed theoretically using simulations. In this study, the content of donor genomes, including donor segment number (DSN), donor segment length (DSL), and donor genome size (DGS), were directly analyzed in six crosses over three successive backcrosses using a set of single sequence repeat (SSR) markers covering the entire rice genome. The results of this analysis demonstrated that the average DSN in each genome was 8.39 in BC₂F₁, 4.13 in BC₃F₁, and 2.41 in BC₄F₁, decreasing nearly by half with each backcrossing. The average DSL was 33.43 cM (centiMorgans) in BC₂F₁, 29.04 cM in BC₃F₁, and 25.07 cM in BC₄F₁, display a progressive decrease slightly greater than 10% in each additional backcross generation. Meanwhile the average DGS was 280.51 cM in BC₂F₁, 119.97 cM in BC₃F₁, and 60.53 cM in BC₄F₁, decreasing 57.2% from BC₂F₁ to BC₃F₁ and 50.4% from BC₃F₁ to BC₄F₁. This revealed that the reduction in DGS was approximately 50% with each backcrossing. These results provide a guide for introgression or substitution of target chromosome segments from donors into recipients in backcross programs. Zhang-Ying Xi and Feng-Hua He contributed equally to this work.     

论中小企业的人力资源管理

人是企业的核心,只有“人”的问题得到很好的解决,企业才会在竞争中立于不败之地。人力资源是企业的不竭动力和源泉,人力资源的良性的循环和互动才会给企业的壮大带来持续动力。本文将就笔者在工作中所见到的一些中小企业所面临的问题来提出问题并以笔者自己的观点来加以解决。     

基于数字存储技术的中央监控报警系统的设计与实现

基于数字存储技术的中央监控报警系统经过几年的发展,广泛应用在各种场合。本文设计的监控报警系统方案以大楼的重要部位为主要监控目标,提供了安全监控和侵入报警的管理,采用微机控制矩阵系统,集中完成视频切换控制、水平/俯仰/变焦控制及自备检测功能。     

蓼科杀虫植物——辣蓼

论述了辣蓼(Polygonum hydropiper L.)的分布、毒性、药用性、化学成分及其对昆虫的生物活性;并对辣蓼在植物源农药应用方面存在的问题及发展前景进行了一些探讨.     

丙稀酸甲酯在天然胶乳硫化胶膜表面的接枝共聚

采用氩等离子体激发及紫外辐射引发技术可以使丙稀酸甲酯接枝共聚到天然橡胶硫化胶膜表面。接枝处理硫化胶膜表面接触角测定结果表明,随着接枝反应的进行,较多的聚丙烯酸甲酯接枝到硫化胶膜表面,使硫化胶膜表面接触角显著下降。采用等离子体激发 2 min,紫外光照射 16 min 的处理条件,可使硫化胶膜表面与水的接触角由 105°下降至约 60°。接枝处理硫化胶膜表面形态分析结果表明,接枝后的聚丙烯酸甲酯分子链在硫化胶膜表面互相叠加,使胶膜表面变得粗糙,从而使天然橡胶硫化胶膜表面亲水性能得到改善。     

A new phenolic glycoside from the aerial parts of Dryopteris fragrans

A new phenolic glycoside, 3,5-dimethyl-6-hydroxy-2-methoxy-4-O-D-glucopyranosyl-oxy-acetophenone (1), was isolated from the aerial parts of Dryopteris fragrans. The structure was elucidated on the basis of spectroscopic methods.     

市政工程建设监理现状与监理经验

在工程建设监理正向着制度化、规范化和科学化方向发展,面对尚不够完善的工程建设管理体系．如何从事好监理工作,是监理行业的一大难题。本文通过云南市政土程建设与监理现状分析,结合市政工程建设的特点,对如何从事好市政工程监理工作进行系统的分析与探讨。     

罗汉果遗传转化受体再生体系的建立及发根农杆菌转化初探

以罗汉果品种“青皮果”试管苗的茎段和叶片为外植体,研究适合于遗传转化的受体再生系统,并进行了发根农杆菌转化的初步研究。试验结果表明茎段的再生能力强于叶片,且对农杆菌敏感,是进行遗传转化合适的受体材料。在MS基本培养基附加BA 1mg/L、KT 1mg./L、NAA 0.2mg./L、蔗糖30 mg/L培养基中,20d龄的茎段不定芽诱导率为100%,平均每个外植体诱导的不定芽数达到9.7个,移苗成活率90%以上;外植体培养前的割伤处理有利于提高出芽数;发根农杆菌转化茎段诱导出毛状根。罗汉果毛状根的诱导和培养将为罗汉果药用成分的研究和开发提供新的途径。     

桔小实蝇自然种群生命表的组建与分析

通过对桔小实蝇自然种群田间系统调查和室内实验种群的饲养观察,组建了以作用因子组配的桔小实蝇在不同寄主上的自然种群生命表。结果表明,桔小实蝇在青枣、杨桃、枇杷、柑桔、番石榴和芒果上的种群趋势指数分别是91．5、103．5、120．8、127．3、172．2和183．8。表明在这些果园中,桔小实蝇的种群密度是上一代的91．5～183．8倍。在果园中,“捕食及其它”因子是影响桔小实蝇种群数量发展的重要因子,其幼虫期在青枣、杨桃、番石榴、芒果、枇杷、柑桔上的排除作用控制指数分别为2．907、2．618、2．591、2．415、2．193和1．866。     

Deposition patterns in bulk precipitation and throughfall in a subtropical mixed forest in central-south China

The chemistry and deposition pattern in bulk precipitation andthroughfall (TF) were examined and evaluated based on the 3-yearobservations in Shaoshan subtropical deciduous-conifer mixedforest in central-south China. The TF chemistry was notablychanged when passing through canopies, which probably was attributedto the dry deposition (DD) on leaf surface and the canopy exchanges.Base cations' (Ca²⁺, Mg²⁺ and K⁺) fluxes were significantlyenriched in TF, in particular for K⁺. The annual K⁺ canopy exchangewas 12 times larger than DD, and canopy exchange of Ca²⁺, Mg²⁺and K⁺ was four times as high as the DD. The canopy exchangeof base cations in association with weak acid accounted for28.4 per cent of total leached base cations, which was one ofthe important factors to modify the TF chemistry.