云南松花粉形态研究

在云南松(Pinus yunnanensis Fr.)小孢子发生发育过程中,花粉母细胞、四分孢子及花粉粒均见有粘连现象。花粉气囊的形态、大小变化复杂多样。除一般具两个正常气囊的花粉粒外,还观察到气囊不发育、具一个气囊、二个异形气囊、三个气囊和四个气囊的花粉粒。成熟花粉壁从外至内可分为外壁外层、外壁内层、内壁外层和内壁内层,它们的构成成分及形态均有明显差别。贮存后花粉的内壁结构发生了明显变化。     

4个普通小麦同核异质系的遗传特征研究

培育出具有Ｄ＾２型细胞质的普通小麦核质杂种可育系Ｄ＾２－ＣＡ８０５７,来源于Ｄ＾２型细胞质变的不育系ｍｓＤ＾２－ＣＡ８０５７和来源于普通小麦ＣＡ８０５７细胞质变异的不育系ｍｓＡ－ＣＡ８０５７。     

杜鹃精细胞的超微结构及DNA荧光观察——着重阐明质体双亲遗传的细胞学基础

迎红杜鹃 ( Rhododendron mucronulatum Turcz.)的成熟花粉为二细胞型 ,精细胞在花粉管中形成。花粉管中的两个精细胞及与营养核之间互相联结 ,形成雄性生殖单位。两个精细胞的细胞质中均含有丰富的细胞器 ,包括质体、线粒体、小泡及微管 ,内质网和高尔基体稀少。具正常结构的精细胞质体在切面上多呈环形或哑铃形 ,内膜不发达 ,基质电子密度高。线粒体为球形或棒状 ,基质电子密度较低。 DNA特异性荧光染色显示 ,生殖细胞及精细胞中均含有大量类核 ( nucleoid) ,两个精细胞中的类核数量无明显差异。结果证明了杜鹃精细胞中存在大量具 DNA的可遗传细胞器 ,为杜鹃属植物的双亲细胞质遗传方式提供了细胞学证据。     

Ultrastructural and DNA Epifluorescence Observations of the Sperm Cells of Rhododendron-- with Emphasis on Biparental Plastid Inheritance

The mature pollen grains of Rhododendron mucronulatum Turcz. conform to the 2-celled type. Sperm cells differentiated within the pollen tube about 24 hours after germination in vitro and paired together, one of which being linked with the vegetative nucleus, forming a male germ unit (MGU). Abundance of plastids, mitochondria, microtubules and single-membrane-bounded vesicles could be visualized in each sperm cell, however, endoplasmic reticulum and Golgi apparatus were scarce. The electron-dense plastids with normal structure gave ring-like or dumbbell appearance in sections. Mitochondria were smaller and less electron-dense' in contrast to the plastids. DNA epifluorescence technique revealed that the generative and sperm cells contained numerous organelle nuclei (nucleoids). There was no difference in nucleoid number between the two sperm cells in a pollen tube. The results confirmed the possible existance of cytoplasmic inheritance potential of the male gametes of Rhododendron.     

ULTRASTRUCTURE OF BETA POLLEN. I. CYTOPLASMIC CONSTITUENTS

Cytoplasmic structure of developing pollen grains of Beta vulgaris L. was studied with the electron microscope. The following stages were investigated: tetrads, ely microspores, vacuolate microspores, and binucleate pollen grains. Two unique cytoplasmic features were encountered— the reticulum complex and cytoplasmic microtubules—both of which were present from the last meiotic stage to the binucleate pollen-grain stage. The reticulum complex is connected to the nuclear membrane and juxtaposed to the plasma membrane and may function in synthesis or movement of materials through the pollen cytoplasm.     

EVOLUTION OF EXINE STRUCTURE IN THE POLLEN OF PRIMITIVE ANGIOSPERMS

Diversity in the structure of the exine in 35 families of the ranalean complex is compared through a series of representative scanning electronmicrographs, and evolutionary trends in exine structure of primitive angiosperms are outlined, along with discussion of the significance of these data for understanding the evolution of exine structure in flowering plants as a whole. In order to reduce ambiguity in the palynological literature, it is suggested that persons undertaking light microscope studies of unstained, acetolyzed pollen grains adopt the morphological terms sexine-nexine in describing pollen wall layers while restricting their use of the chemically defined terms ektexine-endexine largely to pollen studies carried out with the transmission electron microscope. This study emphasizes that a clear understanding of the palynological concept of structure versus sculpturing is a necessary prerequisite for the taxonomic/ phylogenetic use of pollen wall morphology. Finally, data from investigation of a number of ranalean families of primitive angiosperms support the conclusion that the direction of a recurrent and major evolutionary trend in exine structure of flowering plants proceeds from pollen that is tectate-imperforate to tectate-perforate pollen to semitectate pollen, and more rarely, to pollen grains that are intectate.     

杉科植物花粉形态的研究

杉科(Taxodiaceac)是裸子植物的重要科之一。全科共有10属16种。本文用光学显微镜和扫描电镜观察了本科7属10种植物花粉,并用透射电镜研究了其中5个属代表种的外壁内部的超微结构。     

我国睡莲科花粉形态的研究

本文对我国睡莲科5属11种2变种的花粉形态进行了系统的研究。每种花粉都通过光学显微镜和扫描电镜进行观察和照相。同时对莲和白睡莲二种花粉作了超薄切片,对它们的外型结构进行了透射电镜的观察和照相。并结合有关分类学和孢粉学资料,讨论了本科的原始性、异质性及演化上的问题。     

我国旋花科植物花粉形态的研究

本文用光学显微镜和扫描电镜对16属46种2变种的旋花科植物花粉形态进行了观察。本科的花粉为多类型。3沟为基本的萌发孔类型。根据萌发孔的形状、位置和数目,本科花粉可分为3沟、4-11沟、散沟和散孔4个类型。根据孢粉学资料、本文对菟丝子属(Cuscuta)在旋花科中的分类位置及其本科萌发孔的演化趋向等问题进行了讨论。     

芥蓝与芸苔属几个常见种花粉形态的比较

本文通过对芸苔属(Brassica L.)几个常见种芥蓝(B. alboglabra Bailey)、芥菜(B.juncea(L. )Coss.)、油菜(B. campestris L.)和花椰菜(B. oleracea var. botrytis L.)等花粉形态的光学显微镜和扫描电镜的观察比较,得知它们的花粉形态特征比较一致。而与杨萍等关于芥蓝的花粉形态特征——无极,具散孔这一报道截然不同;亦与黄增泉(Huang Tseng-chieng)关于芥菜的花粉特征——不具萌发孔的报道不同。作者的研究表明,上述几个种的花粉均具3沟,沟长而明显。外壁具网状纹饰,网眼较粗。但种与种间其花粉大小有所不同。作者不同意杨萍等关于“由于芥蓝的花粉形态与芸苔属其它种的花粉明显区别,说明芥蓝与芸苔属其它种不很亲缘”的观点,而认为,从花粉形态看,芥蓝与芸苔属其它种是基本一致的,把它们置于同一自然类群是合理的。