四倍

The structure and expression pattern of each storage protein was investigated using one-dimensional SDS-PAGE. Our results showed that the protein content of each fraction in endosperm of autotetraploid rice line is mostly higher than that of its corresponding diploid rice line.

结果表明：同源四倍体水稻胚乳蛋白各组分含量与相应的二倍体相比，大部分呈增加趋势；同源四倍体水稻胚乳蛋白的亚基类型与相应的二倍体水稻基本一致，仅在全蛋白电泳和清、球蛋白电泳中各发现1条差异条带。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cytoplasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methylation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribution of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cyto-plasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methy-lation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribu-tion of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastcysts fellowed by fusion of cytoplasm and nucleus and cleavage in vitro.After fusion of cytoplasm, the DNA methylation levels of the fused embryos was very high as well as two-cell diploid embryos in vivo.Then the embryos was rapiddly demethylated when the nucleus begin to fuse, resulting the lowest DNA methylation levels when the nucleus fused completely.After that, the DNA methylation levels of fused embryos were gradually increased until the blastocysts stage.However, whereas an asymmetric distribution of DNA methylation was established in an vivo-derived blastocysts with a higher methylation level in the inner cell mass than in the trophectoderm, in most vitro-derived tetraploid blastocysts, we can not detect the asymmetric distribution.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在囊胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid organisms may arise by the fusion of two diploid gametes that have resulted from the nondisjunction of chromosomes at meiosis, or by nondisjunction of the chromoosomes during the mitotic division of a zygote.

四倍体的产生可能是由于两个二倍体配子发生融合，这种二倍体配子又是在减数分裂中染色体不发生分离而形成。四倍体也可能因为受精卵进行有丝分裂时染色单体未发生分离而形成。

With the stable genetic tetraploidy and the fertility in the nature environments, this allotetraploid population presented the key factors to form a new species with 200 chromosomes.

异源四倍体鲫鲤稳定的染色体数目和正常的性腺结构以及自然条件下的生殖传代行为，说明该异源四倍体鲫鲤已成为一个染色体数目为4n=200、遗传性状稳定的新型四倍体鱼群体，具备形成新种所需的关键因素。

With the stble genetic tetraploidy and the fertility in the nature environments, this allotetraploid population presented the key factors to form a new species with 200 chromosomes.

异源四倍体鲫鲤稳定的染色体数目和正常的性腺结构以及自然条件下的生殖传代行为，说明该异源四倍体鲫鲤已成为一个染色体数目为4n=200、遗传性状稳定的新型四倍体鱼群体，具备形成新种所需的关键因素。

"You are a philosopher, Thrasymachus," I replied, and well know that if you ask a person what numbers make up twelve, taking care to prohibit him whom you ask from answering twice six, or three times four, or six times two, or four times three,'for this sort of nonsense will not do for me,'--then obviously, that is your way of putting the question, no one can answer you.

"你才是哲学家，斯拉斯马科斯，"我答道，而且是那种因先问人多少组成十二然后又不准人回答二倍的六、三倍的四、六倍的二、四倍的三并视'诸如此类的这些答案对我毫无意义'而著名的哲学家——很显然，这就是你提出问题的方式，当然没有人能回答你的问题。

Herbacium were isobilateral leaves, and those of G. hirsutum and C. barbadense were dorsiventral leaves. The reciprocal F〓 of cross G. arboreum×G. herbacium were also isobilateral leaves, while reciprocal F〓 cross of G. hirsutum×G. barbadense were also dorsiventral leaves. The quadrispecific hybrids F〓 were isobilateral leaves, regardless of their cytoplasms. The structures of the leaf stalks and the stems were analogous to each other among the four cultivated cotton species except their diameters varied with species.

四个栽培棉种及其种间杂种F〓的形态学和细胞遗传学观察四个栽培棉种的植株、叶片、茎杆以及花器等器官都有明显的差异；叶片、茎杆以及叶柄的横切面结构观察结果表明，两个二倍体栽培棉种的叶片横切面构造为等面叶，两个四倍体栽培棉种却均为背腹叶；F〓正反交的叶片也为等面叶，F〓正反交F〓仍为背腹叶，而它们的四元杂交种均为等面叶；四个栽培棉种的叶柄和茎的横切面结构基本一致，只是直径形状和和维管束多少的不同，四元杂种的叶柄和茎的横切面结构的差异不明显。

Pitardii,all from the Jinshajiang Valley of Yunnan and Sichuan, were cytologically studied in this work. Among 34 populations of C.reticulata studied here, 21 were found to be tetraploids (2n=60), 11 hexaploids (2n = 90), and the remaining two diploids (2n = 30). Tetraploid was reported in C. reticulata for the first time and its karyomophology was studied.

reticulata及其两个近缘种(怒江山茶C.saluenensis和西南山茶C.pitardii)进行了细胞学研究。34个居群的云南山茶花中，21个居群是四倍体类型(2n=60)，11个居群是六倍体类型(2n=90)，另2个居群为二倍体(2n=30)，云南山茶花的四倍体类型为首次发现，并且进行了核形态研究。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。