用秋水仙素处理不同家系白桦种子诱导四倍体的研究

采用0.1%和0.2%秋水仙素分别处理4 个家系白桦种子1、2、3 和4 d,调查其对白桦种子相对发芽率、相对 发芽势的影响和四倍体诱导率,在此基础上研究了2 种桦树共7 个家系在0.2%秋水仙素处理3 d 的条件下四倍体 的发生率。结果表明:1)秋水仙素对种子发芽率、发芽势有显著影响,随着浓度的增加发芽率和发芽势降低;同一 浓度下随着诱导时间的增加种子发芽率和发芽势呈现先降低后增加的变化趋势,在诱导3 d 时为最低。2)用 0.2%的秋水仙素处理种子3 d,发现白桦种间和家系间的四倍体诱导率明显不同,欧洲白桦4 个家系的平均诱导率 为3.76%,而3 个白桦杂种家系的平均诱导率仅为0.09%,7 个家系中YB3 的诱导率高达8.86%。      

Microsatellite Analysis of Genetic Diversity Between Loach with Different Levels of Ploidy

We used microsatellite markers to investigate the genetic parameters of three different polyploidy populations of Misgurnus anguillicaudatus from Honghu City, Hubei Province. Polyacrylamide gel electrophoresis banding patterns of diploid（2n）, triploid（3n） and tetraploid loaches（4n） were analyzed with Pop Gen software. A total of 68 alleles were obtained from seven microsatellite loci and the polymorphism information content（PIC） indices were all above 0.5. The average expected mean heterozygosity values（He） were 0.8420, 0.7186 and 0.8521; the average observed mean heterozygosity values（Ho） were 0.9674, 0.9785 and 0.8928; and the HardyWeinberg P values were 0.3078, 0.3151 and 0.3762, for diploid, triploid and tetraploid individuals, respectively. The results indicated that the three populations were highly polymorphic, with no deviations from Hardy-Weinberg equilibrium observed at all the seven microsatellite loci. This indicated a high level of genetic diversity within the populations. A cluster analysis diagram showed that the shortest genetic distance was between diploid and tetraploid loaches and they shared a close phylogenetic relationship. The triploid and tetraploid individuals had the most distant phylogenetic relationship.     

华南8号木薯及其四倍体诱导株系叶片蛋白质组及叶绿素荧光差异分析

【目的】通过对华南8号木薯及其四倍体诱导株系叶片差异蛋白质及叶绿素荧光参数的分析,在蛋白质水平上揭示两者叶片存在的差异以及其与光合效率间的关系。【方法】通过木薯嫩叶、根尖染色体压片及流式细胞观察对华南8号四倍体诱导株系进行鉴定,采用双向电泳技术分离叶片蛋白质,Delta 2D软件分析差异蛋白质并通过质谱技术鉴定,利用Western blot技术对部分差异蛋白质进行验证;采用95%乙醇直接提取法测定叶绿素含量,并用Imaging-Pam测定叶绿素荧光动力学参数。【结果】染色体压片及流式细胞结果均显示,诱导得到SC8多倍体株系为四倍体株系;得到的13个差异蛋白质点中上调表达12个,下调表达1个;经质谱技术成功鉴定到12个,其功能涉及碳代谢及能量代谢、光合作用、抗氧化、蛋白质代谢调控等;1个下调表达的蛋白质未得到成功匹配,其中参与光合作用的蛋白质占46.2%;四倍体株系叶片叶绿素a、叶绿素b和总叶绿素均显著升高;叶绿素荧光参数,包括Fo、ΦPSII、qP、NPQ和ETR均显著升高;【结论】参与碳代谢及能量代谢、光合作用等途径相关蛋白质表达水平的上调;叶绿素含量及叶绿素荧光参数的升高;表明四倍体株系叶片PSII反应中心捕光能力强、光化学转化效率高,从而提高了叶片的光合速率。     

转基因小麦中的转基因向它的近缘杂草转移的可能途径

通过测定杂交后代的基因的转移,研究草甘磷抗性基因从转基因小麦向它的近缘杂草转移的三条可能途径。理论上分析,通过有性杂交基因小麦通过如下三条途径转移它的抗性基因,１杂种自交,形成抗性分离的含有四倍体和五倍体的转基因混合群体;２Ｆ１与四倍体杂草自发杂交;３Ｆ１与六倍体转基因小麦杂交。研究证实了确定存在基因小麦 基因与它的近缘杂草转移的风险,但是由于Ｆ１自交不育,第一条途径基本上是不可能的,第二,第三条途径是基因转移的主要方式,它们的杂交后代是自交可育的,有可能成为抗性基因从转基因小麦转移到近缘杂草的桥梁,最终形成一种新的杂草,即所谓“超级杂草”。根据研究结果,建议采用生物技术创造多抗基因系以延长转基因品种的使用,采用管理措施以避免交杂发生,从而避免或减轻基因转移的风险。     

离体培养条件下金鱼草四倍体切花的诱导及培育

 离体培养条件下以金鱼草(Antrirrhinum majus)二倍体切花实生苗为材料,0.1%,0.2%秋水仙素处理12～36 h均能成功诱导出四倍体切花,其中以0.2%秋水仙素处理24 h效果最好,变异率为48%,死亡率为30%. 对诱导初期得到的具多倍体特征的苗经丛生芽途径反复切割分离实现同质稳定,生根移栽,经培育得到2个品系41株花大、花瓣厚而挺、质感厚重、花枝粗、花序长的四倍体切花。并以二倍体切花为对照对其光合作用特性、生育特性作了初步研究。     

二倍体与四倍体盾叶薯蓣叶片叶绿素和过氧化物酶及过氧化氢酶的比较

对二倍体和四倍体盾叶薯蓣叶片叶绿素色素含量、过氧化物酶和过氧化氢酶活性进行比较,结果表明,四倍体叶片的叶绿素a,b的含量为1.368,0.291 mg/L,二倍体分别为1.319 mg/L,0.251 mg/L,差异极显著;叶绿素含量为1.659 mg/L,二倍体为1.642 mg/L;而类胡萝卜素的含量为0.283 mg/L,二倍体的为0.289 mg/L,但差异不显著.四倍体的过氧化物酶活性为0.254 0 U/(mg.min),二倍体为0.105 3 U/(mg.min),差异极显著;四倍体过氧化氢酶活性为127.06 mg/(g.min),二倍体为126.00 mg/(g.min),但差异不显著.说明四倍体盾叶薯蓣的光合作用、抗逆性要优于二倍体.     

合浦珠母贝三倍体的卵诱导四倍体

将合浦珠母贝三倍体的卵与二倍体的精子授精,用０．５μｇ／ｍＬ细胞松弛素Ｂ抑制精卵第一极体的释放诱导四倍体。研究了处理起始时间及持续时间对胚胎孵化率和四倍体诱导率的影响及幼虫的生长及存活。实验结果表明：持续时间与胚胎孵化率呈负相关,而与四倍体诱导率呈正相关,持续时间一般为１５￣１８ｍｉｎ,处理起始时间一般在第一极体出现前３￣５ｍｉｎ。在胚胎期,四倍体诱导率平均为２０％。在幼虫培养阶段,幼虫死亡严重,     

Hydrostatic pressure treatment during the first mitosis does not suppress the first cleavage but the second one

Suppression of cell division causes chromosome set doubling. Some chemical agents or physical shocks such as temperature or hydrostatic pressure are effective tools for suppression of cell division. As spindles are obviously inactivated or disorganized by these treatments, it has been supposed that inactivation or disassembly of spindles blocks the anaphase movement of chromosomes and a duplicated nucleus is formed without cell division. The present study demonstrated that hydrostatic pressure treatment (650 kg/cm² for 6 min) around the time of metaphase of the first cell cycle of the rainbow trout embryos did not suppress the first cleavage but the second one. Spindles disassembled by the hydrostatic pressure or heat shock regenerated soon after treatment, resulting in the occurrence of the first mitosis. Interestingly, a monopolar spindle was assembled in each blastomere in the second cell cycle, and disjunction of duplicated chromosomes and the cleavage was prevented, leading to the chromosome set doubling. From the third cell cycle, normal cell division resumed. No significant difference was found between the area of the nucleus plate of the treated embryos and twice the area of the nucleus plate of control embryos in the third cell cycle, meaning that the chromosome sets had been doubled at the end of the second cell cycle. The process of chromosome set doubling caused by heat shock seemed to be fundamentally the same as that caused by hydrostatic pressure. To the best of our knowledge, this is the first time that the mechanism of chromosome set doubling in animal eggs treated with hydrostatic-pressure or heat shock has been clarified.

Haploid–diploid or diploid–tetraploid mosaics sometimes occur among individuals treated for cleavage inhibition. The mechanism of such occurrence of mosaicism is, however, not clear. In this study, we found interesting two-cell stage embryos, which had a monopolar spindle in one blastomere and a bipolar spindle in the other during the second mitosis in a batch subjected to tetraploidization treatment. These embryos have a high potential of developing diploid–tetraploid mosaics. This paper also discusses the mechanism of occurrence of these aberrant embryos and discusses their relationship to diploid–tetraploid mosaicism.     

冷休克诱导天然雌核发育银鲫♀×鲤鱼♂四倍体

本文报道了天然雌核发育方正银鲫四倍体杂种的初步研究。1984年,银鲫♀×鲤鱼♂授精2分钟后的受精卵在0～1.5℃的水中冷处理20分钟,获得四倍体杂种。1986～1990年,杂种子1代和它的回交杂种(F_1和第1～4次的回交杂种雌鱼)与雄鲤进行了回交。它们的染色体数目约为200±,红细胞核体积约为银鲫的1.3倍。1987年同池饲养的四倍体回交子代的体重是三倍体银鲫的1.47倍。四倍体杂种基本上保持了银鲫的性状与习性,而且相当稳定,同时它们也能够繁殖。因此,它们可作为水产养殖的鲫鱼新品种。     

甜瓜同源四倍体的创制及其初步定性研究

通过未成熟胚子叶的组织培养创造体细胞无性系变异,诱导出了齐甜1号的同源四倍体甜瓜,激素质量浓度以BA3.0mg/L为佳,加倍率为14.3%。对再生的同源四倍体及二倍体甜瓜植株进行了茎、叶、花、果实、种子的形态观察,及各项形态指标和主要品质指标的测定。结果表明:除果形指数变小外,四倍体植株的茎、叶、花、果实、种子各项形态指标的值均显著大于二倍体。同时,四倍体甜瓜维生素C、可溶性糖含量也显著高于二倍体。