白菜核雄性不育花药超微结构的研究

对白菜核雄性不育两用系的可育与不育花药进行了超微结构的比较观察。结果显示不育花药的造孢细胞核仁靠边分布;包裹小孢子母细胞的胼胝质厚薄不均匀,不完整等早期异常现象。减数分裂后．四分体细胞中常有多个细胞核。从四分体释放出的小孢子外壁的孢粉素物质不均匀沉积,呈不连续的单层异常结构。最后小孢子通过细胞质收缩方式败育。在可育花药中．绒毡层细胞在小孢子发育后期已显示出退化迹象,同时在细胞中开始积累脂类物质。但在同时期的不育花药中．绒毡层细胞没有显示出退化的迹象,也不合成脂类物质。从时间上看,败育花药中小孢子母细胞及小孢子的异常在先,绒毡层细胞的异常在后。本研究揭示了白菜核雄性不育花药的超微结构特征．对我们以前的光学显微镜观察结果予以补充和修正。     

白菜核雄性不育花药超微结构的研究

对白菜核雄性不育两用系的可育与不育花药进行了超微结构的比较观察。结果显示不育花药的造孢细胞核仁靠边分布:包裹小孢子母细胞的胼胝质厚薄不均匀,不完整等早期异常现象。减数分裂后,四分体细胞中常有多个细胞核。从四分体释放出的小孢子外壁的孢粉素物质不均匀沉积．呈不连续的单层异常结构。最后小孢子通过细胞质收缩方式败育。在可育花药中,绒毡层细胞在小孢子发育后期已显示出退化迹象,同时在细胞中开始积累脂类物质。但在同时期的不育花药中, 绒毡层细胞没有显示出退化的迹象,也不合成脂类物质。从时间上看,败育花药中小孢子母细胞及小孢子的异常在先,绒毡层细胞的异常在后。本研究揭示了白菜核雄性不育花药的超微结构特征, 对我们以前的光学显微镜观察结果予以补充和修正。     

大白菜新型细胞质雄性不育系6w-9605A的育性鉴定和花药败育的细胞学观察

采用石蜡切片技术,研究了大白菜(Brassica campestris L.ssp.pekinensis)细胞质雄性不育系6w-9605A及其保持系6w-9605B的花药发育过程的细胞形态学特征,确定不育系花药败育时期及方式,并对不育系6w-9605A进行花器官观察和育性鉴定.结果表明:保持系6w-9605B花药发育正常;不育系6w-9605A花药发育受阻于孢原分化时期,占总败育花药的66.7％,不形成花粉囊和花粉粒,属于无花粉囊型败育;另外33.3％的败育花药可形成花粉囊,小孢子均受阻于单核靠边期或者二胞期,败育特点为绒毡层细胞异常肥大,挤压小孢子,导致小孢子和绒毡层解体;6w-9605A的不育性稳定、彻底,不育株率和不育度均为100％.     

水稻雄性不育与可育花药的mRNA差别显示和cDNA差别片段的分析

用mRNA差别显示 ,对水稻细胞质雄性不育系、保持系和F1杂种的花药mRNA和叶片mRNA进行了比较和分析 ,以研究雄性不育花药在花粉败育时期的基因表达方式 .花药在不育与可育间显示的cDNA差别带数多于叶片 ,表明在花药中育性基因的表达比叶片中活跃和充分 .不同类型花药的基因转录方式既与花药育性程度有关也与花药败育早晚有关 ,不育、部分不育和早期败育的花药所显示的cDNA差别带数多于可育和晚期败育的花药 .在回收的 1 2个cDNA差别片段中 ,有2个可能与雄性不育相关 ,AB₄A₅ 片段只在不育花药中专一表达 ,另一片段AB₃ B₂ 含有与线粒体基因coxⅡ同源的序列 ,在不育花药中的表达受到部分抑制     

大白菜雄性败育的显微结构观察

通过对核质互作型雄性不育系169A和核雄性不育两用系88_3的细胞形态解剖学观察表明,两个不育系在开花时雄性细胞均表现100%的败育,花药的表皮细胞均具有生活力,但败育形式、时期、特点各异。169A败育发生于孢原细胞前后,以孢原细胞退化,或转变成薄壁细胞为主要特点。88_3败育从小孢子母细胞至二核花粉粒皆有发生,高峰期在四分体前后（约占80%）,小孢子母细胞不能进入减数分裂和不能完成减数分裂及小孢子不能正常发育是败育的主要形式,但败育特点均是败育一旦发生便是急剧而彻底的解体或凝集成一团。     

大白菜雄性败育的显微结构观察

通过对核质互作型雄性不育系169A和核雄性不育两用系88-3的细胞形态解剖学观 察表明,两个不育系在开花时雄性细胞均表现100%的败育,花药的表皮细胞均具有生活力,但败育形式、时期、特点各异。169A败育发生于孢原细胞前后,以孢原细胞退化,或转变成薄壁细胞为主要特点。88-3败育从小孢子母细胞至二核花粉粒皆有发生,高峰期在四分体前后（约占80%）,小孢子母细胞不能进入减数分裂和不能完成减数分裂及小孢子不能正常发育是败育的主要形式,但败育特点均是败育一旦发生便是急剧而彻底的解体或凝集成一团。     

长春蒲公英雄性不育株形态学观察与败育细胞学研究

在长春蒲公英(Taraxacum junpeianum Kitam.)株群中发现雄性不育现象,为研究其败育机理及特点,探寻其不育基因,采用形态观察法、石蜡切片技术和染色体压片法,对长春蒲公英野生型及其雄性不育株的花药发育过程和花粉母细胞减数分裂过程进行了观察。结果表明:(1)长春蒲公英雄性不育株花药中部发红、干瘪、无花粉散出。与野生型比较,雄性不育株雄蕊更短,子房更窄,种子形态更加狭长;(2)长春蒲公英雄性不育株败育时期为四分体到单核小孢子前期,败育方式为小孢子自身异常发育,绒毡层异常分解,互相粘连败育;(3)长春蒲公英雄性不育株花粉母细胞减数分裂二分体时期出现落后微核,随后产生极少四分体,并且四分体产生大量染色体桥,小孢子营养物质流失,彻底败育。因此,长春蒲公英雄性不育株败育彻底、稳定,并且有种的特点。小孢子自身异常发育和绒毡层异常分解是导致败育的主要原因。     

温敏核不育小麦可育花药和败育花药发育观察

对温敏核不育小麦百农不育系（Bainong sterility,BNS）的可育和不育花药结构进行对比观察。在减数分裂期、小孢子早期和小孢子晚期,可育花药与不育花药的结构相同。小孢子分裂形成二胞花粉后,可育花粉中随着大液泡的分解,细胞质内含物增加,其中出现一些颗粒状物质。不育花药中,小孢子也可分裂形成二胞花粉,但营养细胞的大液泡不分解,细胞质也不增加,最终花粉中的细胞质消失,花粉败育。该种温敏核不育小麦的花粉败育时间发生在二胞花粉早期,可能和其大液泡没有适时分解有关。花粉败育时间的确定为进一步深入研究该种雄性不育小麦的败育机制打下了基础。     

雄性不育和雄性能育小麦(Triticum aestivum L.)花药和花粉发育的细胞形态学观察

本工作是小麦雄性不育杂种优势利用研究项目的一部分。从细胞形态学的角度,研究小麦细胞质雄性不育系及其保持系花药和花粉的发育,为探索雄性不育性的机理提供资料。应用石蜡切片法,对小麦“早熟1号”和“北京8号”细胞质雄性不育系及其保持系花药的发育过程进行了观察,得到如下的结果:(1)不育系花粉的败育,在发育的各个时期都发生,但败育的关键时期是在小孢子发育后期,具大液泡的小孢子不能进入配子体发育阶段。(2)不育系花药和花粉的发育,在小孢子发育早期以前,90%以上与保持系相似,是正常的;少数表现异常而导致败育。异常现象有:药室合并;小孢子母细胞解体,绒毡层发育正常;小孢子母细胞互相粘连,形成多核的原生质团;解体的小孢子母细胞与绒毡层融合形成多核的原生质团;药室中除正常发育的小孢子母细胞或小孢子外,还出现异常的巨型细胞;绒毡层提早在小孢子发育早期解体,形成多核的原生质困;绒毡层肥大生长。     

辣椒细胞质雄性不育花药败育及淀粉粒分布的细胞学观察

用PAS反应对辣椒细胞质雄性不育系8214A和保持系8214B花药中的淀粉粒分布进行研究.在减数分裂前,保持系花药与不育系花药的结构和淀粉粒分布相似.保持系花药减数分裂后,药壁绒毡层细胞开始液泡化并体积增大,在药隔薄壁细胞中积累了许多较小的淀粉粒;在小孢子晚期,绒毡层细胞退化,在药隔薄壁细胞中淀粉粒体积增大;在二胞花粉时期,随着花粉大液泡的消失花粉中出现淀粉粒;花粉成熟时,其细胞质中积累了丰富的淀粉粒.不育系花药减数分裂后,由于药室腔的空间不能扩大,四分体被挤压在一起,最终四分体小孢子败育.不育花药的维管组织发育正常,但较多的淀粉粒积累在药隔薄壁细胞中.该种辣椒雄性不育系中.花粉的败育发生在四分体时期.绒毡层细胞结构异常可能影响糖类物质向药室的正常转运.该种辣椒雄性不育系的绒毡层异常与花粉败育有关.     

Two new male-sterile mutants of Zea mays (Poaceae) with abnormal tapetal cell morphology

Two new recessive male-sterile mutants of Zea mays (Poaceae), or maize, were studied to identify the timing of pollen abortion and to examine the involvement of anther wall cell layers. The results of test crosses indicated that these mutants were not allelic with any known male-sterile mutants of maize. Light and transmission electron microscopy were used to compare pollen development in homozygous male-sterile mutants to that in fertile heterozygous siblings. In both mutants, microspores abort soon after release from the meiotic tetrad. However, the two mutations have strikingly different phenotypes. Large lipid bodies accumulate in the tapetal cells as the microspores vacuolate and die in the mutant ms25. Large vacuoles appear in both the tapetal cells and the young microspores as they begin to disintegrate in the mutant ms26. Because abnormal tapetal cell morphology is detected in both mutants, it is possible that both of these mutations affect the expression of genes in tapetal cells.     

Cytological investigation of male sterility in sorghum caused by a dominant mutation (<Emphasis Type="Italic">Ms</Emphasis><Subscript><Emphasis Type="Italic">tc</Emphasis></Subscript>) derived from tissue culture

Male sterility mutations are an important tool in the investigation of anther and pollen development and for obtaining hybrid seeds in plant breeding. Cytological analysis of microsporo- and microgameto-genesis in sorghum plants with dominant mutation of male sterility (Ms_tc) derived from tissue culture has been carried out. Using substitution backcrosses, this mutation was introduced first into the nuclear background of the fertile sorghum line SK-723 and from this line into Volzhskoe-4w (V-4w). The mechanism of Ms_tc action on anther and pollen development differed in different nuclear backgrounds. In SK-723, phenotypic expression of Ms_tc began before the beginning of meiosis, which resulted in degeneration of sporogenous tissue in some anthers and in significant disturbances of anther morphology. In microsporocytes that did not degenerate, the frequency of non-specific meiotic abnormalities characteristic of the fertile line SK-723 significantly increased. In addition, in the mutant plants, a number of specific meiotic abnormalities--almost complete desynapsis, and formation of syncytial structures--were observed, apparently the consequence of Ms_tc action. In mono- or bi-nucleate microspores, degenerative processes resulting in formation of empty or anomalously coloured pollen grains led to almost complete male sterility. In the V-4w nuclear background, changes in anther structure and meiotic disturbances were infrequent. The degenerative processes began at the uni- or binucleate microspore stage and resulted in formation of empty or abnormally coloured pollen grains, and in partial pollen sterility. Thus, the same nuclear male sterility-inducing mutation in different nuclear backgrounds affects different stages of pollen development.     

Cytological and ultra-structural study on microsporogenesis of cytoplasmic male sterility in <Emphasis Type="Italic">Raphanus sativus</Emphasis>

The cytological development of microspores and tapetum in cytoplasmic male sterile (CMS) line A₁₄ and its maintainer B₁₄ in radish were studied using light- and transmission electron microscopy (LM and TEM). The microspores of the CMS line began to abort soon after they were released from tetrads in pollen sacs with light microscopy investigation, while abnormal behavior of pollen mother cells (PMC) were observed during its meiotic stage in its ultra-structural study, including degeneration of organelles and irregularity of nuclear membrane. At the same time, development of tapetal cells was similar to that of the maintainer. With further development of the anther, the tapetal cells of CMS line showed an abnormal increase in size and other appearances, such as fewer organelles and indistinct cytoplasm. The microspores of the CMS line were always distinguishable from the maintainer line with irregular structure, more osphilic deposits and abnormal exine. It is inferred that abortion of microspores is attributed to mutation of genes controlling male sterility, which further leads to hypertrophy of tapetum and destruction of ultra-structure.     

笔竹大小孢子发生及雌雄配子体发育研究

为探讨笔竹(Pseudosasa viridula)结实率低的原因,该文通过采用石蜡切片的方法结合显微技术对笔竹大小孢子发生及雌雄配子体的发育过程进行研究.结果表明:(1)笔竹的雄蕊多为3枚,极少有6枚,每枚花药具有4个花粉囊.(2)花药壁发育为基本型,由4层细胞构成,由外向内依次为表皮细胞、药室内壁细胞、中层细胞和绒...     

Genetic control of male fertility in Arabidopsis thaliana: structural analysis of premeiotic developmental mutants

We have taken a mutational approach to identify genes important for male fertility in Arabidopsis thaliana and have isolated a number of nuclear male/ sterile mutants in which vegetative growth and female fertility are not altered. Here we describe detailed developmental analyses of four mutants, each of which defines a complementation group and has a distinct developmental end point. All four mutants represent premeiotic developmental lesions. In ms3, tapetum and middle layer hypertrophy result in the degeneration of microsporocytes. In ms4, microspore dyads persist for most of anther development as a result of impaired meiotic division. In ms5, degeneration occurs in all anther cells at an early stage of development. In ms15, both the tapetum and microsporocytes degenerate early in anther development. Each of these mutants had shorter filaments and a greater number of inflorescences than congenic male-fertile plants. The differences in the developmental phenotypes of these mutants, together with the non-allelic nature of the mutations indicate that four different genes important for pollen development, have been identified.     

Genetic control of male fertility in Arabidopsis thaliana: structural analyses of postmeiotic developmental mutants

Seven new male-sterile mutants (ms7–ms13) of Arabidopsis thaliana (L.) Heynh. (ecotype columbia) are described that show a postmeiotic defect of microspore development. In ms9 mutants, microspores recently released from the tetrad appear irregular in shape and are often without exines. The earliest evidence of abnormality in ms12 mutants is degeneration of microspores that lack normal exine sculpturing, suggesting that the MS12 product is important in the formation of pollen exine. Teratomes (abnormally enlarged microsporocytes) are also occasionally present and each has a poorly developed exine. In ms7 mutant plants, the tapetal cytoplasm disintegrates at the late vacuolate microspore stage, apparently causing the degeneration of microspores and pollen grains. With ms8 mutants, the exine of the microspores appears similar to that of the wild type. However, intine development appears impaired and pollen grains rupture prior to maturity. In ms11 mutants, the first detectable abnormality appears at the mid to late vacuolate stage. The absence of fluorescence in the microspores and tapetal cells after staining with 4′,6-diamidino-2-phenylindole (DAPI) and the occasional presence of teratomes indicate degradation of DNA. Viable pollen from ms10 mutant plants is dehisced from anthers but appears to have surface abnormalities affecting interaction with the stigma. Pollen only germinates in high-humidity conditions or during in-vitro germination experiments. Mutant plants also have bright-green stems, suggesting that ms10 belongs to the eceriferum (cer) class of mutants. However, ms10 and cer6 are non-allelic. The ms13 mutant has a similar phenotype to ms10, suggesting is also an eceriferum mutation. Each of these seven mutants had a greater number of flowers than congenic male-fertile plants. The non-allelic nature of these mutants and their different developmental end-points indicate that seven different genes important for the later stages of pollen development have been identified. Received: 14 August 1997 / Accepted: 7 October 1997     

Exine development in Nymphaea colorata (Nymphaeaceae)

We show a sequence of developmental events in microspores and tapetal cells in Nymphaea colorata based upon transmission and scanning electron microscopic observations. There are parallel cytoplasmic processes and surface coatings in microspores and tapetal cells. Uptake is indicated by the passage of lanthanum as a tracer from anther locule into the microspore cytoplasm and by the condition of the cytoplasmic surface of microspores. The callose envelope is not a barrier to transfer of lanthanum. During formation of the proexine glycocalyx tiny spiral elements, components of the exine substructural units, were oriented in different directions in the surface coating of microspores and tapetum. Lipoidal globules are associated with the spiral elements. After the uniform proexine stage, three regions of different exine structure and their gradations become differentiated in the sporoderm: 1) a proximal region with thick tectum and foot layer, thin columellae and a compact layer of lamellated endexine; 2) a distal pole region with separately disposed endexine lamellae; and 3) an equatorial encircling-sulcate aperture region which consists of infratectal layer, foot layer, and endexine lamellae. Based upon the presence of structurally comparable surface coats in microspores and tapetal cells, experimental uptake of lanthanum nitrate, and the co-ordinated processes in tapetum and microspores, we conclude that there is probably a reciprocal controlling influence between the microspores and the tapetum and other sporophytic tissues.     

凤仙花花药发育中多糖和脂滴组织化学研究

以不同发育时期的凤仙花花药为实验材料,采用组织化学方法,对花药发育中的结构变化及多糖和脂滴物质分布进行观察。结果表明:(1)凤仙花的花药壁由6层细胞组成,包括1层表皮细胞,2层药室内壁细胞,2层中层细胞和1层绒毡层细胞。其中绒毡层细胞的形态不明显,很难与造孢细胞区分,且在小孢子母细胞时期退化。(2)在小孢子母细胞中出现了一些淀粉粒,但减数分裂后,早期小孢子中的淀粉粒消失,又出现了一些小的脂滴;随着花粉的发育,小孢子形成大液泡,晚期小孢子中的脂滴也消失;小孢子分裂形成二胞花粉后,营养细胞中的大液泡降解、消失,二胞花粉中又开始积累淀粉;接近开花时,成熟花粉中充满细胞质,其中包含了较多的淀粉粒和脂滴。(3)在凤仙花的花药发育中,绒毡层细胞很早退化,为小孢子母细胞和四分体小孢子提供了营养物质;其后的中层细胞退化则为后期花粉发育提供了营养物质。     

Pollen ontogenesis in Oenothera: a comparison of genotypically normal anthers with the male-sterile mutant sterilis

Summary A 12-stage normal table of anther development in Oenothera, is presented. The stages are characterized by developmental steps in the reproductive cells and the tapetum, including waves of amylogenesis and lipogenesis as well as the production of the sporoderm layers. This is compared to a corresponding table for the male-sterile (mst) mutant sterilis (ster). Differences between the development of fertile and mst anthers appear after the liberation of the microspores from the tetrads. Male sterility results from a malfunction of the tapetum in the production of ektexine sporopollenin precursors, which aggregate in the tapetal cells. The consequence is the absence of ektexine from the microspores. The endexine is then dissolved, presumably by an enzyme. This process leads to naked microspores whose unprotected cytoplasms are attacked by hydrolytic enzymes present in the thecal fluid. At anthesis the anthers contain only undefined remnants of microspores and tapetum.