Chromosomes out of nuclei can be seen both at prophase ⅱ and tetrad period .

前期Ⅱ和 四 分 体时期可观察到核外染色体；

Pollen abortion of MS-4 was in the single nucleus pollen grain stage after the division of microspore tetrad .

MS-4花粉败育的时期，是在 小孢子 四 分 体分开至单核花粉粒时期。

From tetrad stage to microspore stage the ABA content in sterile buds was higher than fertile buds .

四 分 体到小孢子单 核期和 小孢子 二 核后期至成熟花粉期不育花蕾ABA含量仍高于可育花蕾。

The pairing and segregating of homologous chromosomes at the frist and second division of meiosis were conformed with PMC meiosis and finally the tetrad were formation .

在 减数第一和第二次分裂中，同源染色体的配对和分离基本正常，最后形成 四 分 体。

Microspore abortion occured after the tetrad formation .

小孢子败育发生在 四 分 体形成以后。

The Huangshan A-type granites with tetrad REE : constraints on Mesozoic lithospheric thinning of the southeastern Yangtze craton ?

高度演化的 黄山A型花岗岩：对扬子克拉通东南部中生代岩石圈减薄的约束？

In tetrad stage the structures of tapetal cells begin to dissociate .

四 分 体时期，绒毡层细胞内部结构开始解体。

Tapetum cell hyperplasia from the tetrad to the single nucleus early period .

绒毡层细胞在 四 分 体&单核早期发生增生；

At both tetrad and pollen mother cell stages the amount of polysaccharides in pollen cells of male sterility line was slightly higher than that of its maintainer lines .

在花粉母细胞和 四 分 体时期，不育系细胞中多糖物质的含量稍高于保持系细胞中的含量，但它们之间差异不显著。

The megaspore mother cell undergoing meiotic divisions produces a T-shaped or rarely linear tetrad .

大孢子母细胞减数分裂产生T形 四 分体和少数线形 四 分 体。

Microspore mother cells meiosis was conformed to simultaneous type with mostly tetrahedral and decussate tetrad .

小孢子母细胞减数分裂属于同时型， 小孢子在 四 分 体中的排列方式多数为四面体形，少数为十字交叉形。

Abnormal tetrad rates in different generations were 0.16 0.13 and 0.36 respectively .

异常 四 分 体频率各代分别为0.16、0.13和0.66。

The results are as follows : During anther early development only few ATPase precipitates located in small vacuoles and the nucleus of microspore mother cell and tetrad microspore .

结论如下：在花药发育过程中，小孢子母细胞和 四 分体内的ATPase很少，仅在细胞核及小液泡中分布有少量的ATPase。

The process of pollen abortion begins with vacuole formation and gradual enlargement in the tetrad .

花粉败育的过程从 四 分 体开始，细胞质内液泡逐渐增大，接着细胞器 解体，细胞核解体。

In the course of the embryonic development after the microspore tetrad is formed although some forms of the microspore were under developed and lose of protoplasm but some have formed normal microspore .

在胚胎发育过程中， 小孢子 四 分 体形成后，虽然出现有些小孢子形状不规则，原生质少或无等现象，但也有发育正常的花粉粒。

At this point esch chromosome consist of a pair of chromatids and the two associated chromosomes are termed a tetrad .

此时每条染色体由一对染色单体构成，这两条联合的染色体称为 四 分 体。

It appears however that the formation of megaspore tetrad associated with the high GA3 / ZT ratio .

高水平的ZT/IAA有利于大孢子母细胞和 花粉 粒的形成，而大孢子 四 分 体的形成则需要高的GA 3/ZT比值。

The tetrad analysis of some hybrids led the discovery of two complementary genes systems .

通过 四 分 体分析发现一些杂种有两种互补基因系。

Callose exists mainly in transverse walls during dyad triad and tetrad stages a little in side walls .

二分体、三 分 体、 四 分 体时期，胼胝质荧光主要存在于大 孢子之间的横壁上，侧壁内胼胝质荧光较弱。

The abnormality of tetrad callose wall degradation and tapetum development was associated with the abortion of microspore .

导致小孢子败育的原因与 四 分 体 胼胝质壁不适时解体和绒毡层细胞发育异常、延迟解体有关。

The characteristics of tetrad was that the nucleus and Golgi bodies being in the active state .

四 分 孢子 的 显著特征是细胞核和高尔基体呈活跃状态。

The sporogenous cell functioned directly as megaspore mother cell . The tetrad of megaspores was linear in arrangement and every megaspore might be functional .

孢原细胞平周分裂形成一个周缘细胞和一个造孢细胞，造孢细胞直接发育成大孢子母细胞， 四 分 体大孢子呈线形排列，它们均可成为功能大孢子；

Our main results were as follows : the ovary of male I degenerated and disappeared quickly upon megaspore tetrad degeneration and developed into macrosporocytes ;

结果发现：色木槭一期雄花（雄I）在大孢子 四 分 体 退化形成功能性大孢子 时期，子房 萎缩并迅速退化消失；

Callose was initially deposited in the walls of these sexual embryo sac cells following the embryo sac mother cell via meiosis callose also deposited in the megaspore tetrad walls .

胼胝质首先在这些有性胚囊起始细胞的细胞壁上积累，随着胚囊母细胞减数分裂的进行，在大孢子 四 分 体的细胞壁上也有胼胝质沉积。

First we construct the symmetrized null tetrad from which the spin coefficients and Dirac equation are derived .

首先，构造对称化零 标架，计算旋系数，导出Dirac方程，并对其进行化简。

There is only one layer of parietal cells at the stage of sporogenous cell megaspore mother cell and tetrad .

造孢细胞，大孢子母细胞和 四 分 体时期，周缘细胞仅1层。

Study on Simultaneous Determination of Pigments in Tetrad Mixtures by Spectrophotometry with Wavelet Transform-Principal Component Regression Method

小波变换-主成分回归法在 四组分食用色素同时测定中的应用研究

The merit of viewing the four as a tetrad rather than selecting only three to form a triangle is that it gives greater prominence to quality .

把这四个 变量看成是 四 元的而不是选出三个组合成三角形，它的优点在于：它给质量上带来了很多显著的帮助。

This phenomenon occurs in the early tetrad stage .

这个现象在早期 四 分 体阶段出现。

Otherwise the chromosome morphology involving Haynaldia chromatin was observed at preleptotene I and the frequencies of chromatin nucleus at tetrad stage and at microspore stage were investigated .

此外，观察了前期I的簇毛麦染色体形态，统计了 四 分 体 和 小孢子中小麦和簇毛麦染色质微核频率。