荞麦水合花粉和花粉管中的被膜小泡

荞麦水合花粉粒和生长中的花粉管中内质网潴泡形成的囊袋状结构较少见,但内质网囊袋中含有丰富的被膜小泡,直径约为100－150nm。刚刚形成的花粉管中,被膜小泡主要来自于花粉粒营养细胞的细胞质。生长中的花粉管的被膜小泡可由高尔基体分泌形成。另外还观察到内质网的碎裂也是荞麦花粉管中产生被膜小泡的一种机制。花粉管的被膜小泡中含有花粉管壁的前体物质,与花粉管的壁融合参与花粉管的生长。被膜小泡可能含有与脂体和造粉质体水解有关的酶,参与此类物质的降解。荞麦花柱和柱头细胞内含物的解体物质参与花粉管的生长。     

朱顶红花粉萌发过程中营养细胞质的超微结构变化

本文应用透射电镜对朱顶红成熟花粉水合、活化和萌发的动态过程中营养细胞质的结构和组成变化进行了观察。成熟花粉具质体、线粒体、内质网、高尔基体。微丝束以聚集体的形式存在。花粉活化后,细胞器的数目和结构发生显著变化：质体和线粒体的片层明显增加,内质网片层狭窄,高尔基体活跃产生小泡,脂体降解及微丝聚集体散开。花粉萌发后,细胞质中出现周质微管和被刺小泡,此期细胞器的变化不明显。微丝以纤丝状遍布整个花粉管中。     

朱顶红花粉萌发过程中营养细胞质的超微结构变化

本文应用透射电对朱顶红成熟花粉水合、活化和萌发的动态过程中营养细胞质的结构和组成变化进行了观察,成熟花粉具质体、线粒体、高尔基体。微丝束以聚集体的形式存在。花粉活化后,细胞器的数目和结构发生显著变化;质体和线粒体的片层明显增加,内质网片层狭窄,高尔基体活跃产生小泡,脂体降解及微丝聚集体散开。花粉萌发后,细胞质中出现周质微管和被刺小泡,此期细胞器的变化不明显。微丝以纤丝状遍布整个花粉管中。     

知母绒毡层和乌氏体细微结构的研究

从个体发育来看,知母绒毡层具有3个明显的特点;（1）在小孢子母细胞阶段,绒毡层细胞中有丰富的细胞器,如粗糙内质网,脂体,造粉体和小泡等,粗糙内质网－脂体－小泡常常联系在一起,形成细胞器复合体。（2）在单核花粉阶段,绒毡层细胞质中出现大量小泡,它们可以融合成小泡,而且在小泡或大泡中开始沉积与脂体电子密度相似的亲锇物质,这些物质或者充满整个小泡,或者沉积在小泡周缘,此刻,也是乌氏体形成并达到高峰的阶段。（3）在成熟花粉阶段,绒毯层细胞几乎被具膜束缚的小型脂粒和巨型脂体所占据,这些亲锇物质是质体起源的,也许它们是花粉鞘的先质。     

知母绒毡层和乌氏体细微结构的研究

从个体发育来看,知母绒毡层具有3个明显的特点;（1）在小孢子母细胞阶段,绒毡层细胞中有丰富的细胞器,如粗糙内质网,脂体,造粉体和小泡等,粗糙内质网－脂体－小泡常常联系在一起,形成细胞器复合体。（2）在单核花粉阶段,绒毡层细胞质中出现大量小泡,它们可以融合成小泡,而且在小泡或大泡中开始沉积与脂体电子密度相似的亲锇物质,这些物质或者充满整个小泡,或者沉积在小泡周缘,此刻,也是乌氏体形成并达到高峰的阶段。（3）在成熟花粉阶段,绒毯层细胞几乎被具膜束缚的小型脂粒和巨型脂体所占据,这些亲锇物质是质体起源的,也许它们是花粉鞘的先质。     

玉竹雄配子的发育——着重阐明质体在生殖细胞和营养细胞中的分布和变化

玉竹(Polygonatum simizui Kitag)小孢子在分裂前,质体极性分布导致分裂后形成的生殖细胞不含质体,而营养细胞包含了小孢子中全部的质体。生殖细胞发育至成熟花粉时期,及在花粉管中分裂形成的两个精细胞中始终不含质体。虽然生殖细胞和精细胞中都存在线粒体,但细胞质中无DNA类核。玉竹雄性质体的遗传为单亲母本型。在雄配子体发育过程中,营养细胞中的质体发生明显的变化。在早期的营养细胞质中,造粉质体增殖和活跃地合成淀粉。后期,脂体增加而造粉质体消失。接近成熟时花粉富含油滴。对百合科的不同属植物质体被排除的机理及花粉中贮藏的淀粉与脂体的转变进行了讨论。     

大葱小孢子母细胞至二胞早期花粉发育的超微结构观察

用电镜观察了章丘大葱 (AlliumfistulosumL .)从小孢子母细胞至二胞早期花粉发育的超微结构。终变期的花粉母细胞 ,胼胝壁外方的相邻初生壁间及胞间隙内 ,存在胞间物质 ,四分体期 ,此物质尚部分存在。小孢子母细胞减数分裂前 ,细胞质内含有脂滴 ,小孢子有丝分裂以后 ,脂滴增多增大。小孢子分裂后期 ,质体已积累淀粉粒 1至多个。二胞早期花粉之营养细胞质内 ,有些含淀粉质体亦含脂滴。各发育期 ,核糖体及多聚合糖体丰富 ,并有很多的粗面内质网、高尔基体及小泡、线粒体 ,显示蛋白质、糖类及其它物质合成及运输作用的活跃。小孢子缺中央大液泡。有丝分裂后期 ,细胞器集中于未来的营养细胞极。小孢子胞质分裂期 ,有些内质网贴近或与花粉质膜相连 ,它们或有可能互相融合 ,扩大质膜面积而适应花粉的生长。还讨论了不同时期高尔基体小泡的作用。     

枸杞花药发育过程中脂滴和淀粉粒的分布特征

宁夏枸杞(Lycium barbarurn L．)花药发育过程中,淀粉粒和脂滴两种营养物质的积累和分布具有一定的特点：在造孢细胞时期,药隔薄壁细胞,表皮和药室内壁细胞中开始积累淀粉粒,而造孢细胞、绒毡层细胞和中层细胞中则没有淀粉粒。在四分体时期,绒毡层细胞开始积累脂滴并且数量逐渐增加。到小孢子晚期,绒毡层细胞降解,内含脂滴流入药室中。在小孢子发育过程中既没有淀粉粒也没有脂滴积累,直到二胞花粉的大液泡消失后花粉粒中才开始积累脂滴,然后又开始出现淀粉粒。枸杞成熟花粉中的营养储存物是脂滴和淀粉粒。     

西瓜种子发育和萌发过程中子叶细胞超微结构的变化

西瓜种子子叶内贮存物质开始积累时,细胞质内有大量核糖体、质体、线粒体,内质网片段和囊泡,种子脱水期至成熟期,细胞器的数量减少,成熟种子子叶细胞的细胞壁不连续,几乎观察不到细胞器的存在,种子萌发过程中内质网,线粒体,质体的数目逐渐增多,叶肉细胞的质体发育成叶绿体,种子形成过程中,在子叶细胞大液泡分隔的同时,膨胀的内质网囊泡内积累蛋白质（直径0.1-0.4μm),这些小的蛋白质球体最终进入液泡形成大的蛋白体（直径1-3μm);萌发种子贮存蛋白质被水解的同时,一些脂体进入液泡并被分解,同时液泡融合;脂类物质开始积累的时间早于蛋白质,积累的量较蛋白质多,但在萌发种子中被彻底水解的时间晚于蛋白质,淀粉粒的数量在种子形成时减少,种子萌发时在表皮细胞和叶肉细胞内都重新合成。     

鹅掌楸属植物的多糖壁前体和花粉管的生长

本文观察描述了中国鹅掌楸（Ｌｉｒｉｏｄｅｎｄｒｏｎｃｈｉｎｅｎｓｅ）和北美鹅掌楸（Ｌ．ｔｕｌｉｐｉｆｅｒａ）花粉在异已柱头萌发和花粉管生长期间多糖壁前体的发生、形态结构和生理功能．１、多糖壁前体在形态上有Ｐ－粒子（Ｐｏｌｙｓａｃｃｈａｒｉｄｅｐａｒｔｉｃｌｅｓ）,被膜小泡（ｃｏａｔｅｄｖｅｓｉｃｌｅ）和小泡（ｖｅｓｉｃｌｅ）三种。２、Ｐ－粒子于单核花粉期已经发生,至花粉管延伸期为发生高峰。多糖壁前体是在高尔基体,内质网和线粒体的相继、连续作用下,由淀粉质体、蛋白体和脂滴降解形成．３、Ｐ－粒子的形态随不同发育时期而变化,早期为成群的电子透明小泡,或为蛋白质束缚的挤压成多面体形,后期为内含颗粒或微纤丝的无被膜粒子或具刺被膜粒子。４、Ｐ－粒子移至管端．或融合或单个通过周质内质网（ＣＥＲ）,释放内容物参与管端壁的形成,被膜小池和小泡移至花粉管次顶端区向质膜外分泌,参与花粉管壁内层的形成,或移至管端,提供膜片。最后讨论了亲和性与超微结构特征的关系．     

Studies of pollen maturation in cotton: the storage reserve accumulation phase

Summary This study follows the maturation of the pollen grain of cotton (Gossypium hirsutum L.), particularly the development of the vegetative cytoplasm and the various storage products formed. CTEM, HVEM, stereoscopy, and cyto-histochemistry were used to examine the events occurring during the 9 days before anthesis. Starch began to accumulate in plastids at anthesis minus 9 days and reached a peak concentration shortly before anthesis; lipid deposition followed a similar pattern, but started at 6 days before anthesis. Lipid bodies were always seen closely oppressed to the endoplasmic reticulum (ER). Dictyosomes appear active during the entire 9 days; first producing vesicles involved in the formation of the intine and, later, producing vesicles stored in the pollen grain. The dictyosome vesicles appear to contain polysaccharides and concentrate in layers around the lipid bodies. Ribosomes increase in number from 6 days before anthesis and are particularly numerous in the mature pollen. From anthesis minus 6 days until anthesis, the ER cisternae become increasingly inflated and, in the hours immediately before pollen release, form pockets filled with lipid bodies and dictysosome vesicles. The mature pollen has a core region filled with ER pockets and a peripheral cytoplasm in which such pockets are generally lacking.This research was supported in part by NSF Grant BMS575-22-23 and Grant N.RR-00592 from the Division of Research Resources, National Institutes of Health     

Determination of a position of a functional pore in the tobacco pollen

Pollen hydration and germination on the "wet" stigma of Nicotiana tabacum L. were studied by SEM and TEM to reveal the role of the stigma in selecting the germinative pore, and in establishing the axis of polarity in the pollen grain. Pollinated stigmas were fixed with glutaraldehyde or osmium tetroxide vapour, or processed with rapid freeze fixation and freeze substitution. Fixation was performed in 5, 15 or 30 min and 3.5 h after pollination. The tube easily emerged from either pore, this process not depending on the pollen grain orientation relative to the stigma. The orientation of pollen tubes remained random till their length becomes longer than the pollen grain diameter. The TEM analysis of ultrastructural changes in poral regions during pollen hydration and germination showed that the germinative pore was positioned just near the generative cell and vegetative nucleus. Within the first 5 min after pollination a new layer of the electron-lucent wall adjacent to the plasma membrane was formed in the region of a future germinative pore. Following 15 min, marked changes were revealed in the cytoplasm region, close to the germinative pore. Minute dictyosome vesicles were accumulated near the plasma membrane. Small mitochondria and short ER cisternae were distal to a zone of secretory vesicles. The data suggest that the axis of polarity in the germinating pollen grain is predetermined by a spatial organization of the vegetative cell.     

Electron microscopic and cytochemical studies of the mouse subcommissural organ

Summary In mice most of the ependymal cells of the subcommissural organ (SCO cells) are densely packed with dilated cisternae of the endoplasmic reticulum (ER) containing either finely granular or flocculent materials. The well developed supra-nuclear Golgi apparatus consists of stacks of flattened saccules and small vesicles; the two or three outer Golgi saccules are moderately dilated and exhibit numerous fenestrations; occasional profiles suggesting the budding of coated vesicles and formation of membrane-bound dense bodies from the ends of the innermost Golgi saccules are seen. A few coated vesicles and membrane-bound dense bodies of various sizes and shapes are also found in the Golgi region.The contents of the dilated ER cisternae are stained with periodic acid-silver methenamine techniques. In the Golgi complex the two or three inner saccules are stained as deeply as the dense bodies, and the outer saccules are only slightly stained. The stained contents of ER cisternae are more electron opaque than those of the outer but less opaque than those of the inner Golgi saccules and the dense bodies.Acid phosphatase activities are localized in the dense bodies, some of the coated vesicles in the Golgi region, and in the one or two inner Golgi saccules.On the basis of these results the following conclusions have been reached: (1) In mouse SCO cells the finely granular and the flocculent materials in the lumen of ER cisternae contain a complex carbohydrate(s) which is secreted into the ventricle to form Reissner's fiber; (2) the secretory substance is assumed to be synthesized by the ER and stored in its cisternae, and the Golgi apparatus might play only a minor role, if any, in the elaboration of the secretory material; (3) most of the dense bodies in the mouse SCO cells are lysosomal in nature instead of being so-called dark secretory granules.Sponsored by the National Science Council, Republic of China.     

Ultrastructure of the lateral organs in larvalArgas (Persicargas) arboreus (Ixodoidea: Argasidae)

The ultrastructure of lateral organs (LO) in the larval tickArgas (Persicargas) arboreus is described before and after feeding and up to the 1st day of moulting. Three pairs of LO are associated with three pedal nerves arising from the synganglion. In unfed ticks, each LO is ensheathed by a neural lamella and consists of 6–7 neuronal cell bodies; their cytoplasm is mostly occupied by cisternae of rough endoplasmic reticulm (RER). In fully engorged ticks, the enlarged neuronal cells contain vacuolar cisternae of smooth endoplasmic reticulum (SER), coated vesicles and mitochondria. Golgi bodies are involved in the formation of neurosecretory granules which dominate, with the SER vacuoles, the cell cytoplasm before moulting. The vacuoles, coated vesicles and neurosecretory granules are similar to those found in the vertebrate steroid-secreting cells. Condensing vacuoles may fuse with lysosome-like bodies to form larger ones; these are possibly responsible for the cell breakdown when secretory products are no longer required. Ultrastructural observations of LO suggest that they are neuroendocrine glands and that, in engorged larvae, they may secrete a hormone involved in the control of moulting.     

Fine Structures of Oocytes and Accessory Cells of the Ovary in the Starfish Patiria (Asterina) pectinifera at Different Stages of Oogenesis and After 1-Methyladenine-Induced Maturation

Morphological changes in the growing and maturing oocytes of Patiria ( Asterina ) pectinifero were studied by electron microscopy. Oogenesis is of the solitary type. An extensive system of rough endoplasmic reticulum (ER) and Golgi complex (GC) develops in the ooplasm forming the cortical, yolk and secretory granules in its peripheral regions. The contents of the latter granules are released from the oocyte and form the vitelline membrane. At early stages of oogenesis, extensive multiplication of mitochondria results in formation of a large aggregate of these organelles in the perinuclear cytoplasm ("yolk nucleus"). After maturation of full grown oocytes has been induced by 1-methyladenine, the membranous cell structures are rapidly rearranged: vast aggregates of ER cisternae in the surface cytoplasm layer and single ER cisternae among yolk granules are disintegrated to small vesicles; the GC is reduced. These processes are suggested to be somehow related to changes in hydration of the cytoplasm and in rigidity of its surface layer. In maturing oocytes, the yolk granules form characteristic linear rows, trabeculae, traversing the cytoplasm and their boundary membranes fuse in zones of contact. Some granules are converted to multivesicular bodies, thus suggesting the activation of hydrolytic enzymes that form part of the yolk in echinoderms.     

Cotton embryogenesis: The pollen cytoplasm

Summary The ultrastructure and composition of cotton (Gossypium hirsutum) pollen, exclusive of the wall, was examined immediately before and after germination. The pollen grain before germination consists of two parts: the outer layer and a central core. The outer layer contains large numbers of mitochondria and dictyosomes as well as endoplasmic reticulum (ER). The core contains units made of spherical pockets of ER which are lined with lipid droplets and filled with small vesicles; the ER is rich in protein and may contain carbohydrate while the vesicles are filled with carbohydrate. Starch-containing plastids are also present in the core as are small vacuoles. The cytoplasm of the pore regions contains many 0.5 spherical bodies containing carbohydrate. After germination the ER pockets open and the lipid droplets and small vesicles mix with the other portions of the cytoplasm. With germination the pore region becomes filled with mitochondria and small vesicles. The vegetative nucleus is large, extremely dense and contains invaginations filled with coils of ER. A greatly reduced nucleolus is present in the generative cell which is surrounded by a carbohydrate wall. The cytoplasm of the generative cell is dense and contains many ribosomes, a few dictyosomes and mitochondria, many vesicles of several sizes, and some ER. No plastids were identified. The generative nucleus is also dense with masses of DNA clumped near the nuclear membrane. An unusual tubular structure of unknown origin or function was observed in the generative cell.     

Structure of pollen grains of Tradescantia reflexa with special reference to the generative cell and the ER around it

A pollen grain in Tradescantia reflexa consists of two cells, the generative and the vegetative cells, the generative cell being surrounded completely by the vegetative cell. The generative cell has many lobes or surface invaginations. A complicated network of rER extends throughout the entire vegetative cytoplasm, forming a system of channels made up by the cisternae of rER. Lipid granules are surrounded by ER. Branches of the rER enter all the concavities of the invaginations and attach to the plasma membranes at the bottoms of the invaginations. In the generative cell, no reserve substances, such as lipids, are seen. There is little ER, mitochondria are few in number, and Golgi bodies seem to be less active within this type of cell. Bundles of microtubules run parallel to the long axis of the generative cell. No microtubules or microfilaments can be detected at or near the bottoms of concavities, either on the generative or the vegetative side. ER is the sole cell element that bears a positional relationship to the invaginations. It appears, therefore, that rER is intimately involved in the shaping of the invaginations. This is the first report that a cell element other than microtubules and microfilaments can be involved in the formation of the outer shape of a cell. The possibility that materials from decomposed lipid droplets are transported through the rER to the generative cell is also discussed.