用分段放缩法证明不等式

本文提出1种新的证明不等式的方法－分段放缩法。先将不等式转化成函数不等式，然后在每个局部区间上证明不等式。     

药用植物珍珠梅腋芽茎段的离体培养

以珍珠梅的腋芽茎段为外植体,探索不同杀菌时间、不同培养基、不同激素配比和浓度对珍珠梅离体培养的影响.结果表明,用0.1%HgCl2溶液,加入Tween-20,灭菌5 min处理,外植体染菌率较低,为4.8%;初代培养基以MS+6-BA0.6 mg/L的萌芽率最好,达100%,增殖倍数最高,为3.7;珍珠梅继代培养适宜的培养基为MS+6-BA0.6 mg/L+NAA0.2 mg/L,其萌芽率、增殖倍数分别为82.4%,3.7;生根培养基以1/4MS+IBA0.2 mg/L+IAA0.2 mg/L较好,生根率、平均根数分别为85%,8,且多为实生根.     

墨西哥菊叶薯蓣茎段再生繁殖技术

【目的】建立高效稳定的菊叶薯蓣组织培养快繁体系,以保持品种的遗传稳定性。【方法】分别以室内和田间培育的墨西哥菊叶薯蓣藤茎茎段为外植体起始材料,比较依次用0.55%次氯酸钠、体积分数70%酒精和1.0g/L HgCl2消毒不同时间对外植体的消毒效果,并通过不同植物生长调节剂及其浓度组合筛选适合菊叶薯蓣组培快繁的茎段不顶芽诱导培养基、继代培养基和生根培养基。【结果】以室内培养的墨西哥菊叶薯蓣藤茎为起始材料,依次用0.55%次氯酸钠消毒5 min,体积分数70%酒精消毒1 min,1.0 g/L HgCl2消毒8 min,最后用无菌水清洗3次,获得材料的污染率可控制在5%;筛选出茎段不定芽诱导培养基为MS+3.0 mg/L BA+0.2 mg/L NAA,不定芽诱导数可达4.3个,诱导率达95%,且不定芽质量较好;将分化的不定芽转至MS+1.0 mg/L BA+0.2 mg/L IBA继代培养基,单茎芽增殖率可达到3.5;茎芽在1/2 MS+1.0 mg/L IBA生根培养基上可以诱导出良好的根系。【结论】按上述方法培育的菊叶薯蓣生根试管苗炼苗后,移栽至珍珠岩+粗沙+田园土按体积比2∶1∶1配置的介质中,移栽成活率可以达到85%以上,表明所建立的墨西哥菊叶薯蓣组培快繁体系是可行的。     

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.     

利用染色体片段置换系定位水稻粒型QTL

水稻粒型是衡量稻米外观品质的重要指标之一,鉴定和定位水稻粒型QTL对开展水稻粒型分子育种具有重要意义.本研究以8个染色体片段置换系为材料,选用分布水稻12条染色体上的153个SSR标记检测染色体片段置换系的置换片段,采用代换作图法对控制水稻粒型的3个主效QTL进行定位.结果表明:153个SSR标记中有104个标记在亲本间具有多态性,多态率为68.0%;8个染色体片段置换系在第3和第5染色体分别有6个和2个置换片段,置换片段长度分别为14.8 cM、16.6 cM、 15.5 cM、18.9 cM、29.1 cM、35.0 cM、17.9 cM 和17.0 cM,平均长度为20.6 cM;8个置换片段上共鉴定出3个粒型QTL,控制粒长的qGL-3-1 和qGL-3-2分别被界定在水稻第3染色体RM5551与RM6832及RM6832与RM3513之间,遗传距离分别为14.8 cM和5.3 cM的范围内,控制粒宽的qGW-5被界定在水稻第5染色体RM267与RM169之间遗传距离约11.7 cM的范围内.利用染色体片段置换系能准确地定位水稻粒型QTL,qGL-3-1、qGL-3-2和qGW-5的鉴定和初步定位为其进一步精细定位及分子标记辅助选择奠定了基础.     

棉属野生种克劳茨基棉(Gossypium klotzschianum)基因组向陆地棉的渐渗

 棉花远缘种质是改良栽培种的丰富资源,野生种遗传变异的有效利用依赖于鉴定并渐渗理想的野生种DNA进入栽培种的能力。为了检测二倍体野生种克劳茨基棉染色质在陆地棉中的渐渗情况,构建了一个来自于（陆地棉×克劳茨基棉）×陆地棉的BC₁ F₂群体,并用320个覆盖棉花基因组的SSR标记来监测外源种质的转入;只有38个标记在BC₁F₂群体中显示了分离,这些标记分布于14条染色体,组成了18个渐渗片段;通过比较发表的棉花遗传图谱,这18条渐渗片段的总长为595 cM;同时两个形态性状（黄色花瓣和开放花蕾）被定位于13号染色体。通过分子和形态鉴定,结果证实克劳茨基棉染色质已被渐渗进陆地棉遗传背景中。利用这种特异的标记将会促进理想的外源基因转入栽培棉。     

Identification of QTLs for Plant Height and Its Components by Using Single Segment Substitution Lines in Rice （Oryza sativa）

QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of the first internode from the top, 5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.     

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。     

Identification of Multiple Alleles at the Wx Locus and Development of Single Segment Substitution Lines for the Alleles in Rice

Amylose content (AC) is a key determinant of the cooking and processing quality of rice (Oryza sativa). It has been reported that the amylose content is mainly controlled by the Wx locus [1]. By using RFLP analysis, two alleles, largely corresponding to t…     

曼地亚红豆杉离体培养及植株再生

以红豆杉带侧芽茎段为外植体进行离体繁殖.结果表明:在WPM、MS、B53种基本培养基中,WPM为红豆杉离体培养最适的基本培养基;初代培养的最适培养基为WPM+4.0mg·L-12-ip+30.0mg·L-1Ad;芽继代增殖的最适培养基为WPM+4.0mg·L-12-ip+1.0mg·L-1IAA;生根壮苗的最适培养基为1/2WPM+0.5mg·L-1IBA+0.1mg·L-1NAA.