孢子母细胞

Botany A group of four cells, as of spores or pollen grains formed by division of one mother cell.

四分体：四个一组的来自母细胞分裂的细胞，如孢子或花粉粒

F1 hybrid has the morphological feature which is between the male and female parents and shoed strong heterosis, exuberant vitality, late ripe period and low rate of self-fertility. The average chromosome configuration of F1 in PMC MI was 18.58Ⅰ+18.59Ⅱ+0.085Ⅲ+0.028Ⅳ. At anphase Ⅰ in PMC, some laggard chromosomes arranged in equatorial plate. Micronucleus and a lot of abnormal cells can be observed at dyad, tetrad and microspore.

杂种F1形态特征介于双亲之间，具有较强的杂种优势，生长旺盛，熟期晚，自交结实率较低。F1花粉母细胞减数分裂中期Ⅰ平均染色体构型为18.58Ⅰ+18.59Ⅱ+0.085Ⅲ+0.028Ⅳ，PMC后期Ⅰ观察到部分落后染色体排列在赤道板上；二分体、四分体和小孢子时期，细胞内普遍观察到微核，且出现大量异形细胞。

Using cytohischemical staining methods, with the results of comparison the dynamics of proteins and polysaccharides in the anthe wall cells and colule cells of different developmental phases in female and male flowers, the anormogenesis of anther tapetum in the inflecting phase of from bisexual flower to unisexual flower was observed. In microspore developed phase, the tapetum functions of preserving and transportingmutritive material for microspore development and of secreting callosal enzyme for decompositing callosal cell lost no normal guadrant formed, of being abnormal meiose of pollen mother cells, and then, the stamen aborted selectively in female flowers and pistil in male flower.

利用细胞组织化学染色技术，对雌、雄花雄蕊花药壁细胞及花药内细胞发育过程中多糖及蛋白质动态进行了比较，实验中观察到雌花在从两性至单性花转变时期雄蕊绒毡层在整个发育过程中表现异常，在小孢子发育过程中未能起到贮藏、转运营养物质供小孢子发育及适时分泌胼胝质酶溶解胼胝质壁的功能，并且花粉母细胞减数分裂异常而未形成四分体结构，进而导致雌花雄蕊选择性败育，而雄花中雌蕊组织也发生了选择性败育过程。

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。

These abnormal changes mainly occurred at two stages:(1) at meiotic prophase, almost half of Peiai 64S microsporocytes exhibited aberration, with sparse free ribosomes, underdeveloped mitochondria and many swollen endoplasmic reticula.

这些变化主要发生在两个阶段：（1）减数分裂前期，约半数的小孢子母细胞的胞质出现异常，游离核糖体稀少，并具有不发育线粒体和大量泡状内质网。

Under low temperature condition, fertility restoring, anther developing normally, the tetrads formed after archesporical cell, sporogenous cells and microspore mother cell. Subsequently, microspores were free from the tetrad of fertile anther and formed mature pollen grains, tapetumof the fertile anthers began to disintegrate and disappear at last.

在低温处理条件下，育性恢复，花药发育正常，经过孢原细胞期、造孢细胞期、花粉母细胞期后，可以顺利形成四分体，可育花药的四分体可以释放出小孢子并发育为成熟的花粉粒，同时绒毡层细胞开始解体，最后消失。

The results proposed that the abnormalities of microsporocytic cytoplasm or pollen exine, rather than the tapetal development caused the pollen abortion of Peiai 64S.

据此认为，培矮64S的花粉败育可能是由小孢子母细胞或花粉外壁的异常发育造成的，而不是由绒毡层发育引起的。

The result is consistent with previous studies. Whereas, tapetal cells of sterile anthers were disintegrated since tetrad cells were disjoined, indicating that disintegration of tapetal cells is earlier occurred in sterile anther than that in fertile anther. DNA ladder revealed that the cleavage of nuclear DNA into oligonucleosome-sized fragments to

结果表明，在花粉母细胞减数分裂后的四分体解离时期，不育花药的绒粘层细胞较可育花药提前开始裂解；在不育系S-Mo17rf3rf3花药和花粉S-(rf3)中均明显出现PCD过程的DNA片段化以及线粒体细胞色素C外渗的现象，证明了玉米CMS-S的花粉败育与花药绒粘层细胞的提前凋亡和小孢子细胞的细胞程序性死亡有关。

No tapetal cells were formed or tapetam collapsed at very early stage in some anther chamber during the microsporogenesis; Pollen mother cells in another chamber were not developed and microspore vacuolized; Tapetum cells developed abnormally, giantized and crammed the anther chamber; Some tapetum cells developed normally, but PMCs developed abnomally, which deformed at sporogeneous stage, and then were abhensive each other and finally degenerated. Nearly no PMCs could complete the process of meiosis, and form the tetrad, leading to the failure of normal microspore development.

药室的绒毡层细胞不形成或提前解体；药室内的花粉母细胞不发育或小孢子液泡化；绒毡层细胞发育异常，出现巨型化而挤满整个药室；绒毡层细胞虽发育正常，但花粉母细胞发育异常，在造孢细胞时期即开始出现变形现象，随后发生粘连退化；绝大部分花粉母细胞不能完成正常的减数分裂过程形成四分体，导致小孢子退化。

These abnormal cells became dramatically vacuolated and hereafter disintegrated completely at later stage.

这类异常的小孢子母细胞在随后的发育中逐渐液泡化并最终解体。

The concept of equivalent rotationally rigidity is offered and the formula of rotationally rigidity is obtained.

主要做了如下几个方面的工作：对伸臂位于顶部的单层框架—筒体模型进行分析，提出了等效转动约束的概念和转动约束刚度的表达式。

Male cats normally do not need aftercare with the exception of the night after the anesthetic.

男猫通常不需要善后除了晚上的麻醉。