减数分裂

Result There was no significant difference to the number and length of parenchyma cell in the uppermost internode between Shuangdi Pei eS and Shuangdi S in meiosis and dikaryon pollen stages;there was significant difference to those in tikaryon pollen stage, and there was very significant difference to those in anthesis and the 7th day after anthesis,and on the 7th day after anthesis,the difference to the number and length of parenchyma cell in the uppermost internode between Shuangdi Pei eS and Shuangdi S was the greatest.

长穗颈双低培eS与双低S穗颈节间薄壁细胞数及细胞平均长度在减数分裂期和二核花粉期差异不明显，于三核花粉期差异达显著水平，始花当天和始花后第7天均达极显著水平，其中始花后第7天时两者的差异最大。

By phenotype observation, combined with root tipchromosome counting, PMC MI pairing analysis and chromosome C-banding, a ditelosomic addition line 94K227 and a disomic addition line 94K280 was identified among BC2F2 and BC2F3 population respectively.C-banding results showed that 94K227 contains 1 pair of long arms in chromosome B, and 94K280 contains 1 pair of chromosome D from R.

用普通小麦-纤毛鹅观草双倍体与普通小麦中国春连续回交两次，然后连续自交，通过形态观察、根尖细胞染色体计数、花粉母细胞减数分裂中期Ⅰ染色体配对分析及染色体C－分带，在BC2F3和BC2F3群体中，分别筛选到一个端二体异附加系94K227和一个二体异附加系94K280，其中C-分带显示94K227添加的是纤毛鹅观草染色体B的一对长臂， 94K280添加的是纤毛鹅观草的一对染色体D。

Segregation Distorter is a meiotic drive system of natural occurrence. Heterozygous SD／SD＋ males transmit the SD chromosome in vast excess over the normal homolog.

黑腹果蝇中的分离变相因子［Segregation Distorter］是一种非常典型的具有减数分裂驱动性质的特殊遗传因子。

Rising of fertilization membrane during induced maturation indicates insemination is not necessary to form the fertilization membrane. The oocyte will not become fertilizable until GVBD has happened and can still be fertilized after the second polar body extrusion.

卵母细胞只有在生发泡破裂之后才具有受精能力，从生发泡破裂到第二极体排出前的整个减数分裂过程中，卵母细胞都可以受精，但是只有在第一极体排出前受精的卵母细胞才能发生卵裂。

During conjugation, the complementary mating type cells unite pairwise undergo meiosis, exchange gametic nuclei and separate again.

在接合生殖期间，交配型互补的细胞相互识别配对，进行减数分裂、交换配子核，然后分开。

Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

基于这些观察，我们预测该遗传算法，基因信号传输时，在孢子的方式，因为蛋白质的产品和/或基因这些基因的转录可以引入花粉携带突变基因，而合成的基因遗传传递以配子体的态度，因为这些基因是优先减数分裂后表示。

2N gametes are the result of meiotic mutation during micro- and mega-sporogenesis that bear the sporophytic rather than the gametophytic chromosome number. This paper reviewed the genetic markers including the morphologic, cytological, isozymes and DNA markers, which have been employed in the generation, inheritance, heterozygosity and marker-assisted breeding of 2n gametes based on the frequency of large pollen grains, cytological analyses, unexpected occurrence of polyploidy progeny and the associations between parents and progenies.

文章综述了植物2n配子发生及其遗传标记研究现状，论述涉及有关形态学标记、细胞学标记、同工酶标记乃至DNA标记等遗传标记在2n配子研究中的应用，指出通过花粉形态观察、大小孢子母细胞减数分裂行为观察、杂种后代倍性鉴定以及亲子分子标记相关分析等，对2n配子发生、2n配子遗传类型与杂合性以及2n配子在育种实践中的有效性等进行研究。

1Unequal number of univalents with decreased degree of synapsis and lagging chromosomes occurred in meiosis.The abnormal chromosomal behavior correlated with heterogenicity gave rise to unequal allocation of homogenous chromosomes to daughter cells and resulted in the deletion of functional chromosoms,thus led to the occurence of a certion proportion of aborted pollens.(2)The interaction between genetic imbalance and such environmental factors as temperature,etc.,further drew forth physiological and even structrural imbalance,with abnormal development of pollen mother cells and tapetal cells,and consequently resulted in no or very few production of pollens.The difference in the interaction between environment and genotype reflected on the unstability of pollen abortion in different years.

1在减数分裂中有数目不等的联合程度较差的单价体以及落后染色体出现，这种与异质性相关的染色体行为异常，导致同源染色体向子细胞的不均衡分配，造成具功能染色体的缺失，从而引起毛白杨一定比率的败育花粉的产生；(2)遗传上的不平衡与温度等环境因子相互作用，进一步引发毛白杨生理乃至结构上的不平衡，花粉母细胞和绒毡层细胞发育异常，从而造成不产粉或产粉较少；环境与基因型互作的差异性导致了花粉败育的年度不稳定性。

The results showed that all of them could detect the presence of ZFY DNA sequences except a 46 XX"male"and a 46 XX hermaphrodite, our findings confirmed that Ferguson-Smith〔1966〕 forwarded the hypothesis that the X-Y intercharge model for XX maleness can be regarded as an abnormal exchange initaited in a region proximal to TDF and extending to the telomere,and,also strongly suggested that ZFY gene palyed an important role in sex determining of human.

结果除一例46XX两性畸形，一例46XX&男性&外，余均能检测到ZFY DNA序列(ZFY DNA序列存在于46XX真两性畸形和45XO Turner's综合症，在国内外尚未见报道)。证实了1966年，Ferguson-Smith提出的理论：在父源减数分裂期间，X-Y发生不等交换，导致Y染色体DNA插入性易位。XX男性是由于Y染色体上的TDF基因转移至X染色体上所致。

The chromosome behavior of the meio sis at MI of the hybrids between every 2 of 5 OTE types and between vevry one of the hybrids with Tr.aestivum was observed.

通过八倍体小偃麦与普通小麦杂交，八倍体小偃麦相互间杂交，观察了杂种F1花粉母细胞减数分裂行为。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。