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  • 1
    Electronic Resource
    Electronic Resource
    Growth inhibition of pollen tubes by blocking the aromatic or branched-chain amino acid pathways of biosynthesis (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 101 (1997), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Pollen tubes of Nicotiana sylvestris growing in vitro were used to study growth inhibitory effects of glyphosate, which interferes with the biosynthesis of aromatic amino acids, and of metsulfuron methyl, which reduces the production of the branched-chain amino acids valine, leucine and isoleucine. Using the pollen tube growth test, i.e., photometric quantification of pollen tube growth in vitro, both herbicides were found to inhibit tube growth poorly in the suspension medium but strongly when the medium was replaced by a fresh one 30 min after suspension of pollen. We suggest that the enhanced sensitivity of the suspended pollen resulted from the removal of released amino acids, because addition to the fresh medium of aromatic amino acids or branched-chain amino acids significantly reduced the inhibitory effect of glyphosate or metsulfuron methyl, respectively. Different amino acid compositions were used to analyze the inhibitory concentrations of the herbicides. The data indicated that growing pollen tubes were able to synthesize aromatic or branched-chain amino acids via the shikimate/chorismate pathway or via the acetolactate synthase reaction, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb01040.x
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  • 2
    Electronic Resource
    Electronic Resource
    Carbohydrate distribution and cellular injuries in acid rain and cold-treated spruce needles (1993)
    Springer
    Trees 8 (1993), S. 75-84 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies (L.) Karst ; Freezing injury ; Acid rain ; Carbohydrate histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The cellular structures of acid rain-irrigated needles of several provenances of Norway spruce (Picea abies L. Karst) seedlings were studied after winter experimental freezing. Frost injuries and recovery were characterized by visual damage scoring and classification of mesophyll cell alterations, also using histochemical methods for carbohydrate fluorescent staining. The treatment with-30° C during the late dormancy period was sufficient to cause significant injuries and intracellular degradation in the tissues of the green needles. The most affected seedlings in terms of visual injury scoring were found among those treated with clean water or at pH 3, while freezing injury, defined as an occlusion of phenolic substances in the central vacuole of the mesophyll cells, was most abundant in the needles from spruces irrigated either with clean water or at pH 4 or pH 3. Electron microscopy revealed the details of the injury, e. g. thinning out of the cytoplasm and chloroplast stroma, darkening of the chloroplasts and eventually swelling of the chloroplasts and protoplast. PAS and ConA reactions in the needle tissue revealed intense starch accumulation in the mesophyll and transfusion tissues as early as in March, with a tendency to increase, especially in the untreated needles during the recovery period. Plasma membrane disturbances were indicated by histochemical identification of callose deposits in the mesophyll cell walls, these being most abundant in the acid rain-treated needles. All these findings suggest that freezing at −30° C was more deleterious to the seedlings pretreated with acid or clean water than to those not given additional irrigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197684
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  • 3
    Electronic Resource
    Electronic Resource
    Der Einfluß von Na-Fluorescein auf die Feinstruktur der Wurzelhaare von Lepidium sativum (1972)
    Springer
    Planta 106 (1972), S. 159-167 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytoplasmic disarrangements in the root hairs of Lepidium sativum caused by the vital stain Na-fluorescein (Uranine) after applications of different duration were analyzed by electron microscopy. After an application time of eight min there appear microbody-like structures and vacuoles in the cytoplasm. After a 16-min application severe disorganizations of membranes are brought about. There are distortions and dissolutions of the internal mitochondrial structures. The long cisternae of the ER are fragmented. Vesicle-like structures with a twofold border appear, which probably arise from Golgi cisternae transformed into “rings”. Between the cell wall and the plasmalemma, which is masked by a substance of high contrast, vacuole-like structures are formed. As these processes coincide with the extrusion of the dye from the cytoplasm, which may be observed in the light microscope, a connection between the two phenomena is assumed, the possibility of which is discussed under the aspect of decompartimentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00383995
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural and cytochemical examination of the nuclear crystalloid inclusions of Olea europaea L. mesophyll cells (1988)
    Springer
    Trees 2 (1988), S. 261-266 
    Details
    ISSN: 1432-2285
    Keywords: Nuclear crystalloid inclusions ; Olea europaea ; Cytochemistry ; Ultrastructure ; Glycoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The nuclei of mesophyll cells of olive trees contain numerous sizeable crystalloid inclusions. Cytochemical examination using epoxy resin-embedded, semithin-sectioned tissue indicated the presence of proteins and oligoor polysaccharides in these inclusions. Their electron microscopical analysis revealed a crystalline substructure consisting of intersected subunits of high order. The spacing of the lattice fibrils and the angles of intersection were determined and used to establish a model of the unit cell of crystallization. It is suggested that the nuclear crystalloids of olive trees consist of glycoprotein molecules. They differ from the intranuclear crystalloids observed in other species predominantly in the high density of their subunit arrangement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202381
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  • 5
    Electronic Resource
    Electronic Resource
    Pentachlorophenol affects mitochondria and induces formation of golgi apparatus-endoplasmic reticulum hybrids in tobacco pollen tubes (1987)
    Springer
    Protoplasma 141 (1987), S. 112-120 
    Details
    ISSN: 1615-6102
    Keywords: Nicotiana sylvestris ; Pollen tube growth ; Pentachlorophenol ; Golgi apparatus ; ER ; Mitochondria ; Semivivo technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The toxic effect of pentachlorophenol (PCP) on the growth and ultrastructure of tobacco pollen tubes was tested using a semivivo technique of tube culture. In this technique the pollen tubes were allowed to grow in the pistilin situ for 24 hr before they protruded from the cut end of the style and came into contact with the medium containing PCP. The inhibitory effect of different PCP concentrations was determined by measuring the length of tube bundles. The intracellular action of PCP was analysed by electron microscopy. This biocide caused four obvious alterations in the pollen tube ultrastructure: (1) swelling of the mitochondrial saccules; (2) enlargement of the dictyosomes by the increase of the cisternal diameter and the number of cisternae per stack; (3) formation of cup-shaped Golgi apparatus-endoplasmic reticulum hybrid structures (GER hybrids) showing continuities of ER and Golgi cisternae; (4) formation of stacked and/or concentric arrangements of rough ER cisternae. It is suggested that swelling of saccules was directly due to the uncoupling of oxidative phosphorylation whereas the changes of the endomembrane system were caused by energy depletion due to the inhibition of ATP synthesis. These changes are consistant with dynamic concepts of dictyosome and ER function when membrane formation exceeds membrane use in the production of secretory and transition vesicles. Thus, the enlargement of the dictyosomes and the formation of GER hybrids are thought to result from inhibition of budding of vesicles from the Golgi apparatus or from both the ER and the Golgi apparatus, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01272892
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  • 6
    Electronic Resource
    Electronic Resource
    Der Einfluß des Vitalfarbstoffes Chrysoidin auf die Feinstruktur von Zwiebelschalen-Epidermiszellen (1970)
    Springer
    Protoplasma 71 (1970), S. 443-449 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die durch den Vitalfarbstoff Chrysoidin G/Y verursachten, lichtmikroskopisch nicht mehr wahrnehmbaren Veränderungen in den Oberepidermiszellen der Zwiebelschalen vonAllium cepa werden einer elektronenmikroskopischen Analyse unterzogen. Dabei erweist sich das Kompartimentierungssystem als besonders empfindlich gegenüber der Einwirkung dieses Azofarbstoffes. Es kommt zu einer gesteigerten Entwicklung lomasomenähnlicher Vesikel, zur Deformierung und stellenweisen Auflösung des ER und wahrscheinlich auch zum Austritt der osmiophilen Substanzen aus den Globuli der Leukoplasten. Diese Erscheinungen werden unter dem Aspekt einer Schädigung der Biomembranen durch den Farbstoff diskutiert. Dabei wird speziell eine Depolarisierung der am Membranaufbau beteiligten Strukturiipide durch das einwertige Chrysoidin-Kation in Betracht gezogen.
    Notes: Summary Chrysoidin G/Y used as a dye in vital staining causes cytoplasmic disorganizations a part of which cannot be recognized in the light microscope. After staining epidermal cells from the upper surface of the scaleleaf ofAllium cepa were analyzed by electron microscopy. Above all it is the system of cytoplasmic compartments that proves to be rather sensitive to the influence of the azo dye. There is an increased formation of lomasome-like vesicles; the ER is disarranged and locally dissolved, and probably osmiophilic substances are extruded from the globuli of the leucoplasts. These phenomena are discussed with special reference to damages done to biomembranes by the dye. Especially a depolarization of the structural lipids incorporated in the membranes, effected by the univalent chrysoidin cation, is taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279687
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  • 7
    Electronic Resource
    Electronic Resource
    Die Morphologie der Schleimsekretion im Fruchtknoten vonAptenia cordifolia (1976)
    Springer
    Protoplasma 89 (1976), S. 221-233 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Fruchtknoten vonAptenia cordifolia enthÄlt wÄhrend der Samenentwicklung einen proteinreichen Polysaccharidschleim. Verschieden alte schleimproduzierende Placentarpapillen werden einer elektronenmikroskopischen Analyse unterzogen. Kurz vor dem Einsetzen der Schleimproduktion ist das rauhe ER noch spÄrlich entwickelt. Der Golgi-Apparat ist unauffÄllig und wenig aktiv. Zu Beginn der Schleimbildung sind als hauptsÄchliche Strukturkomponenten hypersekretorische Dictyosomen und ER-umschlossene Vakuolen (storage vesicles) zu beobachten. Es wird angenommen, da\ diese Komplexe aus rauhem ER und vermutlich mitèinander verschmolzenen Golgi-Vesikeln die charakteristischen Synthese-Einheiten für den Polysaccharid-Protein-Schleim darstellen, da sie nachweislich neben Polysacchariden auch Proteine enthalten. Membranfusionen zwischen Vesikeln und dem Plasmalemma deuten auf Exocytose-Prozesse unter Beteiligung des Golgi-Apparates hin. Daneben wird eine holocrine Ausscheidung des in den storage vesicles zunÄchst gespeicherten Polysaccharid-Protein-Schleimes bei Degeneration des Protoplasten vermutet.
    Notes: Summary During seed development the gynaeceum ofAptenia cordifolia produces a mucilage rich in carbohydrates and protein. The mucilage-producing placentary papillae are analyzed in different developmental stages by electron microscopy. Just before mucilage production is started, the rough ER occurs but sparsely. At that time the dictyosomes are inconspicuous and of low activity. When mucilage production commences, one can observe hypersecretory dictyosomes and ER-ensheathed vacuoles (storage vesicles) as the main structural components. It is suggested that the complexes of rough ER and probably fused Golgi vesicles are the synthetizing units of the carbohydrate protein mucilage, since in these complexes both components can be identified cytochemically. Fusion sites of plasmalemma and vesicles indicate processes of exocytosis-probably involving the Golgi apparatus. In addition, a holocrine excretion of the mucilage initially enclosed in the storage vesicles via degeneration of the protoplast is assumed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275741
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