查询词典 meiosis

In plants that undergo ALTERNATION OF GENERATIONS, spores are produced by meiosis by the sporophyte generation, so are usually haploid; they germinate to produce the haploid gametophyte generation.

在具有世代交替的植物体中，由孢子体世代进行减数分裂产生孢子，因此多为单倍体。它们将发育为单倍体的配子体世代。

In organisms showing ALTERNATION OF GENERATIONS, the gametes may be produced by mitosis in the haploid generation, or by meiosis in the diploid generation and give rise directly to gametes or gamete-producing cells.

在表现出明显世代交替的生物体中，配子可能是由单倍体世代发生有丝分裂产生，亦可由二倍体世代减数分裂直接产生配子体或配子母细胞。

The F2 nullisomic amphidiploid with low chromosome number (2n=44-49) wasaccompanied with abnormal meiosis (7.45 Ⅰ+ 19.50 Ⅱ), but its fertility (19.2%) wasmuch higher than 〓's.

F2非整倍体的染色体数较低(2n=44-49)。

During anaphase I of meiosis pairs of chromatids still connected at their centromere move to the spindle poles.

在减数分裂后期 I 中，由于纺锤丝的牵引，使成对的同源染色体各自发生分离，并分别向两极移动。

Meiosis is the most important reproduce and favoured by organisms. The key events of meiosis identified are pairing, synapsis, genetic recombination, segregation.

李丽减数分裂是生物体重要的有性生殖方式，它提供来自母本和父本的基因信息，产生具有生物多样性的子代，使其能够适应环境的变化而不断进化。

The testis index, testis volumes were same as the annual changes of testis mass. The curves of annual variation were all unimodality.2 The spermatogenetic cycle of Myospalax cansus comprises seven stages with significant features: Stage I , from February to April, the testis were at the stage of spermatogonia proliferation. In this period, testis index and the number of spermatogonia began to rise. Other spermatogenic cells had not yet formed; Stage II to III, from March to April, primary spermatocyte meiosis period. The testis index was highest in this stage, and spermatogenic cells were in spermatocyte stage, the primary spermatocyte meiosis generated to secondary spermatocyte; Stage IV, from April to May, spermatocytes continued to split, germ cells appeared in seminiferous tubules; Stage V, in May, sperm formation, spermatids of seminiferous tubules were transformed to spermatozoa, a large number of sperms existed in the lumen; Stage VI, spermatozoa emission period, from May to June, testis index were a significant drop and mature spermatozoa excluded gradually; VII, the testicular activity ceased basically from July to September, November to January of the following year, the spermatogenic activity ceased completely. Therefore, Myospalax cansus are animals of seasonal reproduction, spermatogenesis cycle is discontinuous type.

睾丸系数、体积和重量的年周期变化规律一致，变化曲线呈现单峰型。2甘肃鼢鼠雄性生殖腺的年周期活动由7个特征明显的时期构成：Ⅰ期，2～3月份，精原细胞增殖期，睾丸系数开始上升，精原细胞进行有丝分裂，其他生精细胞尚未形成；3～4月份为Ⅱ～Ⅲ期，初级精母细胞成熟分裂期，睾丸系数达到最大，生精细胞大多处于精母细胞阶段，初级精母细胞减数分裂生成次级精母细胞；Ⅳ期，4～5月份精母细胞继续进行分裂，精细胞在生精小管内出现；Ⅴ期，5月份，精子形成期，曲细精管中精细胞变态成精子，在管腔中存在大量的精子；Ⅵ期，精子排放期，5～6月份，睾丸系数显著下降，成熟精子从生精小管上脱离，逐渐排除；Ⅶ期，精原细胞停滞期，7～9月份睾丸生精活动基本停滞，11～翌年1月，生精活动完全停止。

The situation of abnormal development of male cells is as follows:microspore mother cell can't enter into meiosis because of intense vacuolation,shrink and disintegration of its cytoplasm;although vacuolated microspore mother cell can enter into meiosis,it can't form normal dyad and degenerate in the middle process;dyad and tetrad become vacuolated and can't develop normally;cytoplasm of microspore shrinks around the nucleus at the stage of central nucleus microspore,the shape of microspore is twisted into crescent or irregular shape,at last its cytoplasm and nucleus are disintegrated and crescent vacant microspore presents;nutritive substances can't be accumulated at the stage of vacuolated microspore,cytoplasm is disintegrated,and microspore turns into a big vacant pollen.

雄性细胞异常发育有几种情况：小孢子母细胞强烈液泡化，细胞质收缩解体，不能进入减数分裂；小孢子母细胞液泡化，虽能进入减数分裂，但不能形成正常二分体而中途退化；二分体、四分体细胞液泡化，不能进行正常发育；单核小孢子中央期，细胞质收缩包围核，小孢子形状扭曲呈月牙形或不规则形，最终细胞质和核解体而呈月牙形的空壳小孢子；单核液泡期的小孢子不能积聚营养物质，细胞质解体而成为大的空壳花粉粒。

For further studying the genetic mechanism of the reproductive isolation phenomenon of interspecific hybrid, paraffin sections of testes from 13 sexually mature male mules (Equus asinus×Equus caballus) and 12 hinnies (Equus caballus×Equus asinus) were prepared, and the samples of Giemsa meiosis and AgNO 3 synaptonemal complexes were observed and compared with spermatocyte meiosis of horse and donkey under light microscope and electronic microscope.

为了进一步探讨种间杂种生殖隔离现象的遗传机理，本研究采用性成熟公骡的睾丸为材料，制备组织切片和减数分裂联会复合体标本进行观察，发现个别性腺发育较好的个体虽然减数分裂存在大量异常，但确有少数精母细胞完成了减数分裂并产生精子。

The events occurring during these stages differ in meiosis and mitosis, notably in that bivalents (pairs of homologous chromosomes) are formed in meiosis, whereas homologous chromosomes remain separate in mitosis.

在减数分裂和有丝分裂中，前期发生的事件是不同的，尤其是二价染色体区别最为明显，在减数分裂中形成，而在有丝分裂中同源染色体是分离的。

The results showed that the varieties and activity of POD isoenzyme expression exist in difference in anther of male sterility line and maintainer in different development stage in sweet pepper and hot pepper. POD isozyme activity of anther was very low in meiosis stage in male sterility line of sweet pepper. There is a POD special band in meiosis and pollen mature stage in male sterility line of pepper respectively.

结果表明不育系与保持系，在花药发育的不同时期POD同工酶表达种类及表达活性之间存在差异，其中甜椒不育系在减数分裂期POD同工酶的活性非常低，辣椒雄性不育系在减数分裂期及花粉成熟期分别多一条POD特征带。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷