ULTRASTRUCTURE OF CARPOSPOROGENESIS IN THE PARASITIC RED ALGA FAUCHEOCOLAX ATTENUATA SETCH. (RHODYMENIALES,RHODYMENIACEAE)

Carpospore differentiation in Faucheocolax attenuata Setch. can be separated into three developmental stages. Immediately after cleaving from the multinucleate gonimoblast cell, young carpospores are embedded within confluent mucilage produced by gonimoblast cells. These carpospores contain a large nucleus, few starch grains, concentric lamellae, as well as proplastids with a peripheral thylakoid and occasionally some internal (photosynthetic) thylakoids. Proplastids also contain concentric lamellar bodies. Mucilage with a reticulate fibrous substructure is formed within cytoplasmic concentric membranes, thus giving rise to mucilage sacs. Subsequently, these mucilage sacs release their contents, forming an initial reticulate deposition of carpospore wall material. Dictyosome vesicles with large, single dark-staining granules also contribute to wall formation and may create a separating layer between the mucilage and carpospore wall. During the latter stages of young carpospores, starch is polymerized in the perinuclear cytoplasmic area and is in close contact with endoplasmic reticulum. Intermediate-aged carpospores continue their starch polymerization. Dictyosomes deposit more wall material, in addition to forming fibrous vacuoles. Proplastids form thylakoids from concentric lamellar bodies. Mature carpospores are surrounded by a two-layered carpospore wall. Cytoplasmic constituents include large floridean starch granules, peripheral fibrous vacuoles, mature chloroplasts and curved dictyosomes that produce cored vesicles which in turn are transformed into adhesive vesicles. Pit connections remain intact between carpospores but begin to degenerate. This degeneration appears to be mediated by microtubules.     

细叶黄芪叶肉原生质体发育早期几种细胞器的变化

在细叶黄芪叶肉原生质体发育早期,细胞器的变化较大。离体培养4h后,线粒体的嵴和基质物质开始增加。培养3—5天后,线粒体的数量增加5倍以上,此时可见大部分线粒体围绕细胞核分布。在培养24h后,高尔基体开始发育,它们主要分布在细胞质周边区域。多糖细胞化学染色表明,高尔基体内沉积着大量嗜银物质。培养1天后,粗面内质网开始发育。培养3天时,部分叶绿体边缘出现一些空隙结构。随着叶绿体内膜结构的消失,淀粉粒增大,叶绿体逐渐转变为造粉质体。     

ULTRASTRUCTURAL CHANGES ASSOCIATED WITH UTILIZATION OF METABOLITE RESERVES AND TRICHOME DIFFERENTIATION IN THE PROTOCORM OF VANDA

Certain aspects of protocorm development in Vanda were examined ultrastructurally. The parenchymal cells of the protocorm accumulate substantial quantities of lipid, protein, and carbohydrate reserves which disappear gradually with the senescence of the parenchymatous region. The proteinaceous reserves appear initially as discrete bodies which become intimately associated with clusters of small tubules. The tubules eventually disperse throughout the cytoplasm and disappear following depletion of the protein bodies. The lipid reserves also appear as discrete bodies and are associated with an electron dense, laminated inclusion which appears to increase in size with the disappearance of the lipid bodies. While plastids in the meristematic cells differentiate a well-developed thylakoid system and contain little starch, those of the parenchymal cells contain large starch grains and numerous osmiophilic droplets and develop meager thylakoid systems. Membrane-bound crystalline structures of hexagonal and rhomboid cross section occur frequently in the cytoplasm of senescent parenchyma cells. Trichome initials, which differentiate from the epidermis, contain few conventional organelles and exhibit numerous membrane-bound structures containing many small crystalline inclusions. Numerous vesicles accumulate at the tips of the trichomes in spaces between the cell wall and the plasmalemma.     

冠果草种子萌发过程的组织化学动态

冠果草的种子中没有胚乳,营养物质贮藏在胚中,其成分主要是淀粉和蛋白质。胚各部分的物质积累情况差异较大,子叶和下胚轴细胞中的淀粉粒、蛋白体数目多、体积大,胚芽和胚根分生细胞中则只贮藏少量的淀粉粒、蛋白体。在种子萌发过程中,胚各部分的淀粉粒逐渐解体,至二叶幼苗期全部消失。蛋白体的降解有严格顺序,远离胚芽的细胞中蛋白体降解较早,胚芽附近细胞中的降解较晚,而且胚芽细胞中还有新的蛋白体形成。单个蛋白体的降解     

高等担子菌双重营养缺陷突变菌株的分离

带有单一营养缺陷的凤尾菇和裂褶菌的单核体菌株经亲和性交配,各自交配产生后代,从中分离出遗传特性稳定,生理特征表型正常的双重缺陷营养害变型菌株,为原生质体融合育种研究提供了可靠的亲本菌株。     

长喙毛茛泽泻胚中营养物质的积累与消耗

长喙毛茛泽泻是一种水生濒危植物。它的种子中没有胚乳,营养物质以淀粉和帽白体的形式贮藏在胚中。胚不同部位物质积累情况差异较大,下胚轴和子地细胞中的淀粉,蛋白体数目多,体积大,胚芽和胚根分生细胞中只贮藏有少量的淀粉粒和蛋白体。     

MORPHOGENETIC ASPECTS OF A LEAFLESS MUTANT IN TOMATO I. GENERAL PATTERNS IN DEVELOPMENT

The embryo of the reduced form of the lanceolate mutant in tomato fails to undergo the heart-shaped stage of development. Cells in the shoot apical region of this leafless mutant lose their meristematic character and develop into mature parenchyma during embryogenesis. This early loss of meristem tissue leads to the determinate growth which is evident in the seedling. In contrast to normal, starch grains are visible with the light microscope in cells of the shoot tip of the mutant hypocotyl from early embryogeny up to and including the seedling stage, and protein bodies are abundant in the same tissue of fully developed mutant embryos. The shoot apical region in homozygous mutant embryos with cotyledons or cotyledon-like structures exhibits some cytochemical and morphological similarity with the normal shoot apex. Morphological variation in these forms appears to be in a continuous pattern. The extent of their development and consequent longevity is related to possible differences in rates of cell expansion and variation in environmental factors during the early stages of embryogenesis.     

黑节草未成熟种子的形态发育及其在离体培养时的表现

黑节草(Dendrobium candidum Wall ex Lind.)2—6个月种龄的胚均处于球形胚阶段,不同种龄的胚在体积大小、胚细胞数目、胚细胞内的淀粉粒含量和超微结构上有差异。在离体培养条件下黑节草种子萌发率可达95％,种子萌发后形成原球茎,原球茎可以直接发育形成幼苗,又可以由原球茎产生大量愈伤组织,由愈伤组织再分化发育成幼苗。种子萌发过程中,胚顶端分生组织细胞的淀粉逐渐消耗,淀粉的变化与分生组织和子叶的形成有明显的相关性。     

ULTRASTRUCTURE OF TETRASPOROGENESIS IN PALMARIA PALMATA (RHODOPHYTA)1

The tetrasporangial initial in Palmaria palmata (L.) O. Kuntze (formerly Rhodymenia palmata (L.) Greville) arises from a cortex cell which enlarges and deposits a protein-rich wall layer. This cell undergoes mitosis to form a tetrasporocyte and a stalk cell. Synaptonemal complexes are formed in the sporocyte nucleus while in the cytoplasm floridean starch is deposited in association with ER or with particles presumed to be ribosomes. Microbody-like structures become numerous between the nuclear envelope and perinuclear ER, and clusters of non-membranous, spherical structures also are associated with the nucleus. Chromatin condensation is reversed following pachytene and a prolonged diffuse stage ensues, when dictyosomes and ER produce vesicles which deposit mucilage rich in sulfated and acidic polysaccharides around the tetrasporocyte. A conspicuous lenticular thickening of the mucilage sheath develops at the apical end of the sporangium. Dictyosomes are frequently associated with mitochondria which may be associated with chloroplasts. Following nuclear divisions the tetrasporocyte is cleaved into four spores by sequentially initiated, but simultaneously completed periclinal and anticlinal furrows. When mucilage deposition ceases, the dictyosomes begin to produce vesicles with glycoprotein-rich contents. These vesicles are abundant in released tetraspores, and they probably contain adhesive material aiding in the attachment of the liberated spores.     

ELECTRON MICROSCOPY OF THE LICHEN PHYSCZA AZPOLIA (EHRH.) NYL.1,2

The ultrastructure of the lichen Physcia aipolia was studied in the desiccated and hydrated states. No significant structural variation between these 2 states was noted for the fungus. The fungus contains unusual ellipsoidal structures heretofore unobserved. Their possible role in the formation of membrane is discussed. The plasmalemma of the fungus is convoluted while that of the alga is smooth. The convoluted projections have a “double-unit membrane” structure similar to fingerlike projections of the ellipsoidal bodies. With O_sO₄ fixation crystals are pre-served, enclosed in unit membrane sacs which extend to the convoluted surface. The pyrenoid of the associated alga does not produce starch in the desiccated condition, and electron-dense granules are present in the matrix associated with chloroplast lamellae which enter this area. In the hydrated condition, the alga contains abundant starch in the pyrenoid region, and the electron-dense granules are displaced to the preriphery of the pyrenoid starch. Mitochondria, endo-plasmic reticulum, and ribosomes are not clearly defined in the desiccated state while they are more so in the hydrated condition. Golgi bodies were not observed in the either lichen component. Finally, no fine structural basis for indicating an exchanged of materials between the alga and fungus was observed except, possibly, the convoluted plasmalemma of the fungus and the smooth plasmalemma of the alga.     

Lytic bodies from cereals hydrolysing maltose and starch

Protein bodies and spherosomes from sorghum contained carbohydrase activity against maltose, starch and p-nitrophenyl-α-d-glucoside. Maltase activities in sorghum and also in maize lytic bodies were very high; carbohydrase activities of lytic bodies from whole wheat, whole barley, sorghum aleurone, sorghum embryo and maize embryo were considerably lower. The pH response of sorghum lytic bodies was bimodal with an optimum in the range of 3·4–4·2 and a minimum or a shoulder near pH 3·8. Protein bodies from sorghum, maize, wheat and barley reduced the iodine-colouring capacity of soluble starch to give a purple colour typical of a β-limit dextrin. With spherosomes colour reduction was usually more rapid, eventually taking the breakdown of starch beyond the achroic point. The lytic bodies produce both maltose and glucose from starch, except in the case of maize when only glucose was found. The data suggest that protein bodies contain a linked β-amylase-maltase system and that spherosomes contain a linked α-amylase-maltase system.     

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。     

槐种子发育过程中子叶细胞显微结构的变化和过氧化物酶同工酶变化的动态

槐（SophorajaponicaL．）种子发育过程中,子叶细胞大量合成和积累储藏物质,光镜和电镜下用组织化学方法观察到开花后30d,叶肉细胞高度液泡化,其中分布着大量的质体、粗面内质网、一些线粒体和小脂体。淀粉粒开始积累。开花后60d,淀粉粒和脂体不断长大,数量明显增多,液泡中蛋白体开始形成。从花后90d开始,液泡中有大量蛋白体形成且不断长大,有些蛋白体变得不规则形。至种子成熟期,叶肉细胞几乎完全被蛋白体及脂体所填充。淀粉粒及大多数细胞器消失。基于上述观察,还对种子发育过程中子叶细胞过氧化物酶活力及同工酶港的变化进行了观察和分析。     

THE CONTROL OF SEXUAL MORPHOGENESIS IN THE ASCOMYCOTINA

(1) A series of factors controls sexual morphogenesis in the Ascomycotina, a process involving the formation of novel structures such as ascocarps (fruit bodies) and asci (sacs containing spores) during sexual reproduction. (2) Environmental and genetic factors must be correct before Ascomycetes may sexually reproduce. Compatibility in many heterothallic species is under polygenic control, with the mating type loci and also other genetic factors determining the productivity of sexual crosses. (3) Classical genetic studies have shown that sexual morphogenesis involves the expression of a series of developmentally regulated genes, and this has been confirmed by recent molecular studies which have demonstrated changes in patterns of mRNA and protein synthesis during ascocarp formation. (4) Hyphal differentiation leading to the formation of mature fruit bodies occurs in response to a series of signals, which include various physical and chemical factors. (5) Chemical sex factors have been identified which are believed to have important regulatory or nutritional roles in sexual morphogenesis. These include the following. (a) Diffusible sex hormones which may regulate developmental switching between asexual and sexual modes of reproduction, including (i) pheromones involved with the induction of gametangia and gamete attraction, and (ii) sex morphogens involved with triggering particular stages of fruit body formation. (b) Sexual growth substances which are required as nutrients, and may be precursors for the production of sex hormones, or metabolites used in the synthesis of novel sexual structures. Most of these sex factors are lipids. (6) Certain sex morphogens and sexual growth substances have been shown to exhibit activity in a variety of fungal species, suggesting that fungi of related phylogenetic descent may utilize similar metabolites or signalling factors during sexual reproduction. (7) Phenoloxidase enzymes may catalyse hyphal aggregation in developing fruit bodies. (8) Initial stages of ascocarp development may occur independently of the events of the sexual cycle. However, a link(s) with the functional ascogenous hyphae is needed for the formation of morphologically mature ascocarps. (9) Suitable environmental conditions are sufficient to trigger sexual morphogenesis in homothallic Ascomycetes. However, an extra level of control is present in heterothallic species, with a compatible partner required to complete sexual reproduction. This may be partly because novel regulatory products, formed by the combined action of the mating type loci of different partners, are required for further ascocarp development. (10) Further research is required to identify more fungal chemical sex factors and to determine the role of environmental stress in controlling sexual morphogenesis, and how this may be related to temporal patterns in the expression of mating type genes.     

光质与人参淀粉酶活性、总糖和淀粉含量的关系

研究了生长在同等透光率六种滤光膜覆盖下的人参淀粉酶活性、总糖和淀粉含量的季节性变化。人参叶片的淀粉酶活性、总糖和淀粉含量明显低于根部,叶片酶活性的高峰在红果期,糖和淀份含量在成熟期最高;根部与叶片相反,酶活性高峰在成熟期,糖和淀粉含量在红果期最高。红光、红蓝和红蓝绿复合光下人参的淀粉酶活性,总糖和淀粉含量均较高,单质蓝光和绿光下偏低。红光对糖分的合成与积累有明显促进作用,但有红光参与的复合光更有利于人参的生长。     

In Vitro Induction of Regeneration of Fruit-Like Structure in Lycopersicon esculentum Mill.

It is possible to induce in vitro regeneration of fruit-like structures from tissue pieces excised from young pistil and young fruit of Lycopersicon esculenturn Mill. These fruit-like structures could be cultured in vitro to maturation, meanwhile they became red coloured. Under dissection it was observed that the fruit-like structure consists of fruit flesh and fruit coats without seeds and plancentae. Tests of exogenous hormones and explant ages revealed: 1. Supplement with exogenous cytokinins alone could induce the explants excised from the pistils to regenerate the fruit-like structures, and the highest induced frequency (50%) was obtained when 0. 5 mg/L zeatin was supplemented. Exogenous auxin seems unnecessary. 2. When tissues of young fruit were used as explants, all explants excised from 4—12 mm (diameter) young fruits could be induced to differentiate the fruit-like structures on medium supplemented with exogenous hormones. However, the hightest frequency of induction (62.5%) was obtained only in tissues of explants excised from 8 mm (diameter) sized fruit and cultured on medium supplemented with 2 mg/L of 6-BAP and 1 mg/L of NAA where regermination of the fruit-like structures took place. In order to investigate the expression of cell totipotency arisen in the regeneration of the fruit-like structure a concept of partial expression of plant cell totipotency was proposed and discussed.     

UNUSUAL FILAMENTOUS STRUCTURES IN THE PARAGONIA OF MALE DROSOPHILA

Drosophila paulistorum is a complex of five incipient species which when crossed produce sterile hybrid males and fertile females. Sterility of the male progeny can sometimes be induced by injecting females of one strain (Mesitas) with a homogenate of males of another strain (Santa Marta) or of hybrids between these strains, and then crossing the recipient females to Mesitas males. Filamentous structures have been found in cytoplasmic vacuoles in paragonial cells in males of these and other similar strains and their hybrids. These structures, which contain RNA, possess a helical substructure and resemble certain viruses. Large filamentous structures found in the lumen of the paragonia are also described.     

Instantaneous amyloid fibril formation of alpha-synuclein from the oligomeric granular structures in the presence of hexane

Amyloid fibrils found in various neurodegenerative disorders are also recognized as high-performance protein nanomaterials with a formidable rigidity. Elucidation of an underlying molecular mechanism of the amyloid fibril formation is crucial not only to develop controlling strategy toward the diseases, but also to apply the protein fibrils for future nanobiotechnology. alpha-Synuclein is an amyloidogenic protein responsible for the radiating filament formation within Lewy bodies of Parkinson's disease. The amyloid fibril formation of alpha-synuclein has been shown to be induced from the oligomeric granular species of the protein acting as a growing unit by experiencing structural rearrangement within the preformed oligomeric structures in the presence of an organic solvent of hexane. This granule-based concerted amyloid fibril formation model would parallel the prevalent notion of nucleation-dependent fibrillation mechanism in the area of amyloidosis.     

玉米叶肉细胞和维管束鞘细胞中光合产物的分析

玉米苗照光后,叶肉细胞和维管束鞘细胞大量积累淀粉和可溶性糖(包括蔗糖),其中淀粉95％以上在维管束鞘细胞中。阻断光合产物输出时,两类细胞中蔗糖和淀粉积累都显著增加。离体维管束鞘细胞也能合成蔗糖。离体玉米叶内原生质体饲喂NaH~(14)CO_3并照光后,通常90％以上的~(14)C参入到有机酸和氨基酸中,3～10％参入糖和淀粉中。玉米叶肉原生质体具有直接利用CO_2合成碳水化合物的能力。     

Instantaneous Amyloid Fibril Formation of α-Synuclein from the Oligomeric Granular Structures in the Presence of Hexane

Amyloid fibrils found in various neurodegenerative disorders are also recognized as high-performance protein nanomaterials with a formidable rigidity. Elucidation of an underlying molecular mechanism of the amyloid fibril formation is crucial not only to develop controlling strategy toward the diseases, but also to apply the protein fibrils for future nanobiotechnology. α-Synuclein is an amyloidogenic protein responsible for the radiating filament formation within Lewy bodies of Parkinson's disease. The amyloid fibril formation of α-synuclein has been shown to be induced from the oligomeric granular species of the protein acting as a growing unit by experiencing structural rearrangement within the preformed oligomeric structures in the presence of an organic solvent of hexane. This granule-based concerted amyloid fibril formation model would parallel the prevalent notion of nucleation-dependent fibrillation mechanism in the area of amyloidosis.