Competition for 15N-labeled fertilizer in a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in the southern United States

The degree of tree-crop competition for nitrogen (N) and its effect on fertilizer-use efficiency and N movement were examined in a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system. Assessment of competition was accomplished via the installation of a belowground polyethylene root barrier in half the number of plots in order to provide two treatments–barrier and non-barrier. The percentage of N derived from fertilizer (NDF) and fertilizer-use efficiency (UFN) were determined using ¹⁵N-enriched ammonium sulfate (5% atom enrichment) applied at 89.6 kg N ha^–1. In cotton, the barrier treatment resulted in higher leaf (38%), stem (66%), seed cotton (55%) and total (58%) biomass compared to the non-barrier treatment. Total N content in leaf, stem and seed cotton was 67% higher in barrier compared to non-barrier treatment. Percentage of NDF in cotton leaf and stem was significantly lower in barrier (15.8% and 17.3%, respectively) compared to non-barrier treatment (20.4% and 21.2%, respectively). For UFN, this trend was reversed, with plants in barrier treatment having a higher percentage of UFN. Root trenching did not affect pecan foliar N concentration, canopy N content, NDF or UFN. In soil, N recovery at 90–120 cm depth was lower in non-barrier treatment, indicating tree root uptake of fertilizer N. Although tree roots in non-barrier treatment had access to fertilizer N, competition was mainly for N already in the soil, since fertilizer was applied after major seasonal nutrient demands of the trees had been met. Overall, the alley cropping system in this study exhibits potential for efficient N cycling, given the apparent ability of pecan trees to intercept and uptake N fertilizer from deeper soil layers and return to surface soil via litterfall.     

Rhodobryum commersoni(Schwaegr.) Par. and R. aubertii (Schwaegr.) Thér. in South India.

Abstract

A new species Tristichella dimorpha is described and illustrated and a comparison made with the two other species in the genus, T. spiculifera and T. glabrescens, and with Clastobryella cuculligera to which it appears to be closely related, particularly in sporophytic characters.     

Phykochronologische Untersuchungen in Assoziationen von Laminaria digitata (L.) Lamour. f. stenophylla (Kütz.) Harv. an der norwegischen Westküste

Zusammenfassung Die Natur der konzentrischen Zonen in den Stämmen von Laminarien ist lange Zeit umstritten gewesen. Nachdem aber im Jahre 1926 nachgewiesen wurde, daß das gesamte vegetative Wachstum bei den nordischen, regelmäßig blatterneuernden Laminarien periodisch und synchron in allen Teilen der Pflanzen erfolgt, war damit bewiesen, daß diese Zonen wirkliche Jahresringe darstellen, die im Zusammenhang mit dem jährlichen Blattwechsel stehen.Ebenso wie die Dendrochronologie die Jahresringe der Bäume als Grundlage für forstliche Untersuchungen über Bestockung, Alter, Produktions- und Verjüngungsverhältnisse im Waldbau benutzt, kann man aus den Jahresringen der nordischen Laminarien entsprechende Rückschlüsse ziehen.Bei der stetig steigenden Nutzbarmachung und Verwendung der Meeresalgen sind derartige Gesichtspunkte von aktuellem Interesse in der Algologie geworden.Vorliegende Arbeit ist ein Versuch, eine Bestandsanalyse in phykochronologischer Regie durchzuführen mit besonderer Berücksichtigung etwaiger Schwankungen in Assoziationen von Laminaria digitata f. stenophylla hinsichtlich Repopulation, Bestockung, Wachstumsverhältnissen und anderer damit verknüpfter biologischer Fragen.Die Untersuchung wurde in den Jahren 1955–1958 an der norwegischen Westküste vorgenommen.Es sei darauf hingewiesen, daß sowohl das vegetative Wachstum als auch die Repopulation bei der genannten Alge von Jahr zu Jahr innerhalb ausgedehnten Grenzen variieren kann und daß diese Pflanze eine nur kurze Lebensdauer hat. Exemplare von mehr als 6 Jahren wurde nicht angetroffen. Ihr Bestand wird deshalb recht rasch erneuert.Professor Dr. E. G. Pringsheim zum 80. Geburtstag gewidmet.     

木莲Manglietia fordiana (Hemsl.) Oliv.

属于木兰科,木莲属,常绿乔木,高达20米。叶厚革质,长椭圆状披针形,长5—17厘米,宽1.5—6.5厘米,全缘,上面绿色,下面苍绿色或有白粉,叶柄长约     

Homalothecium meridionale (M.Fleisch. & Warnst.) Hedenäs: a distinct species from H. sericeum (Hedw.) Schimp. (Brachytheciaceae,Bryopsida) in the Iberian Peninsula

Previous molecular studies have done much to shed some light on the taxonomy and phytogeographic position of Homalothecium sericeum and H. meridionale and the present study clarifies the taxonomy and distribution of the two species across Iberia. By conducting a revision of Homalothecium specimens available in Spanish and Portuguese herbaria, we concluded that sporophytic differences are the most appropriate characters for the delimitation of each species. Scanning electron microscope examination of the peristomes of the two taxa helped distinguish between them.

We also noted that H. meridionale is a frequently distributed taxon throughout the Iberian territory, but occurs mostly in Portuguese areas with a Mediterranean influence, becoming less frequent in the Atlantic as well as in continental parts of the Peninsula. As a result of this study, based on numerous new localities in Portugal and Spain, we provide an updated map of the distribution of H. meridionale, and an account of its ecology and habitat affinities.     

关于国际遗传学联合会(I.G.F.)介绍

据国际遗传学联合会章程介绍,I.G.F.的宗旨是:促进全世界遗传学家之间的了解、合作和友谊;筹划和资助国际和地区性遗传学会议以及专题讨论会;与其它有关的国际组织保持联系并促进遗传学研究领域内的国际合作;互通情报;组织著名遗传家的访问等,借以促进遗传学的发展。     

Cryo-scanning electron microscopy observations of vessel content during transpiration in walnut petioles. Facts or artifacts?

The current controversy about the "cohesion-tension" of water ascent in plants arises from the recent cryo-scanning electron microscopy (cryo-SEM) observations of xylem vessels content by Canny and coworkers (1995). On the basis of these observations it has been claimed that vessels were emptying and refilling during active transpiration in direct contradiction to the previous theory. In this study we compared the cryo-SEM data with the standard hydraulic approach on walnut (Juglans regia) petioles. The results of the two techniques were in clear conflict and could not both be right. Cryo-SEM observations of walnut petioles frozen intact on the tree in a bath of liquid nitrogen (LN(2)) suggested that vessel cavitation was occurring and reversing itself on a diurnal basis. Up to 30% of the vessels were embolized at midday. In contrast, the percentage of loss of hydraulic conductance (PLC) of excised petiole segments remained close to 0% throughout the day. To find out which technique was erroneous we first analyzed the possibility that PLC values were rapidly returned to zero when the xylem pressures were released. We used the centrifugal force to measure the xylem conductance of petiole segments exposed to very negative pressures and established the relevance of this technique. We then analyzed the possibility that vessels were becoming partially air-filled when exposed to LN(2). Cryo-SEM observations of petiole segments frozen shortly after their xylem pressure was returned to atmospheric values agreed entirely with the PLC values. We confirmed, with water-filled capillary tubes exposed to a large centrifugal force, that it was not possible to freeze intact their content with LN(2). We concluded that partially air-filled conduits were artifacts of the cryo-SEM technique in our study. We believe that the cryo-SEM observations published recently should probably be reconsidered in the light of our results before they may be used as arguments against the cohesion-tension theory.     

Leaf explant response in in vitro culture of St. John’s wort (Hypericum perforatum L.)

For centuries Hypericum perforatum has been used in natural medicine. In the last decades, it has also attracted the attention of pharmaceutical industry due to its promising anti-depressant properties. The important factor in pharmaceutical application of plant material is its stable content of active compounds. Such stability requires standardized conditions of growth, e.g. an in vitro culture. Our aim was to establish a medium allowing for an effective regeneration of shoots from the standardized leaf explants in in vitro conditions. Cultures of the leaf explants carried out in darkness, on Murashige and Skoog agar medium, supplemented with auxins (2,4-dichlorophenoxyacetic acid, 2-metoxy-3,6-dichlorobenzoic acid, α-naphtaleneacetic acid, indole-3-acetic acid) and cytokinins (kinetin, N⁶-(benzyl)adenine, thidiazuron) resulted in callus formation. The callus produced roots on media containing indole-3-acetic acid or α-naphtaleneacetic acid alone. On media supplemented with auxins and cytokinins, indirect shoot organogenesis was also observed. The most efficient shoot formation was observed with 2.85 μM of indole-3-acetic acid and 4.44 μM of benzyladenine. Regenerated shoots were rooted on Murashige and Skoog without plant growth regulators medium or on a medium supplemented with indole-3-acetic acid. From a single leaf explant (one fifth of the leaf) after a month of the culture, 35 regenerated shoots were obtained (allowing for the formation of about 180 vegetative shoots per leaf). Successful multiplication of shoots from a standardized explant makes it possible to obtain a great quantity of uniform plant material for biotechnological purposes.     

Gestörte Granabildung in Chloroplasten einer Chlorina-Mutante von Arabidopsis thaliana (L.) Heynh.

Zusammenfassung Die Chloroplasten in Palisadenzellen aus Rosettenblättern von Arabidopsis thaliana wurden an der grünen Normalform und einer vitalen chlorina-Mutante (ch ₃) vergleichend licht-, fluorescenz- und elektronenmikroskopisch untersucht.Die Chloroplasten der grünen Normalform zeigen in Aufsicht licht-und fluorescenzmikroskopisch eine regelmäßige Granaverteilung. Elektronenmikroskopisch entspricht die Ausbildung der Grana- und Intergranabereiche in Profilansicht den Befunden an Chloroplasten anderer höherer Pflanzen.Bei der licht- und fluorescenzmikroskopischen Analyse der Chloroplasten der Mutante fehlt eine entsprechende Granaordnung. Elektronenmikroskopisch lassen sich drei verschiedene Chloroplastentypen nachweisen: Bei Typ I kann das Thylakoidsystem in den Chloroplasten weitgehend undifferenziert bleiben; bei Typ II erfolgt eine von der grünen Normalform abweichende Schichtenbildung in den Chloroplasten, wie sie bislang nur von Anthoceros bekannt ist; bei Typ III werden in Profilansicht Stapel mit vornehmlich konjunktiver Schichtung vom Aspekt normaler Grana erreicht.An Hand von kompletten Schnittserien wird die Stapelbildung für die komplizierteren Chloroplasten-Typen II und III in räumlichen Modellen dargestellt; ihre Entwicklung wird als Folge von Invaginations-und Überschiebungsprozessen gedeutet.

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Disturbed grana-formation in chloroplasts of a Chlorina-mutant of Arabidopsis thaliana (L.) Heynh.

Summary Chloroplasts in the palisade cells of rosette leaves of Arabidopsis thaliana have been compared in the green wild type and in a vital chlorina mutant (ch ₃) using light-, fluorescence-, and electron microscopy.In the chloroplasts of the wild type in face view a regular distribution of grana was revealed by light- and fluorescence microscopy. In side view under the electron microscope the formation of grana and intergrana regions corresponds to the reported chloroplast fine structure in other higher plants.In the chloroplasts of the mutant form this normal grana formation is not visible when analysed under the light- and fluorescence microscope. Under the electron microscope, three different types of chloroplasts have been distinguished: type I, in which the thylakoid system remains largely undifferentiated; type II, in which stacking processes take place comparable to those reported for the Anthoceros chloroplast but different from those of the wild type plastid in Arabidopsis; and type III, in which the stacking of thylakoids leads to a predominantly conjunctive arrangement which may reach the aspect of normal grana in side view.On the basis of complete series of cross sections spatial models have been constructed for the more complicated stacking in chloroplasts of type II and III, and their development has been explained by invagination and sliding over processes.

     

Ribonucleinsäuresynthese in der telotroph-meroistischen Ovariole vonDysdercus intermedius Dist. (Heteroptera,Pyrrhoc.)

Zusammenfassung Die RNA im Insektenovar wurde mittels der Polyacrylamid- Gelelektrophorese untersucht, um den Syntheseort, den Transport und den Einbau derselben in das reife Ei zu ermitteln. Die telotroph-meroistische Ovariole vonDysdercus intermedius bietet hierfür besondere Vorteile, da sie in wohlumschriebene Abschnitte zerlegt werden kann: Die apikale Nährkammer mit den polyploiden Trophocyten und das Vitellarium mit den von Follikelepithel umgebenen Oocyten. Die RNA wurde durch Injektion radioaktiver Vorstufen oder Inkubation isolierter Ovariolen in vitro markiert.In den Nährzellen wurde markierte r-RNA, t-RNA und nicht-ribosomale RNA gefunden. Es konnte der Nachweis geführt werden, da\ ein 39 s r-RNA-Vorläufermolekül in 2 Schritten (36s und 32s) zur 28s r-RNA entwickelt wird, während die 18s r-RNA sich direkt aus der 36s-Zwischenstufe ableitet. Niedrige Konzentrationen (0.5 g/ml) von -Amanitin hemmen die Synthese der nicht-ribosomalen RNA und lassen ein sehr klares Muster des r-RNA-processing entstehen, während eine hohe Konzentration (5 g/ml) das Processing bei der 36s Stufe abstoppt und zu einer Anhäufung dieser Molekülart führt. Passende Konzentrationen von Actinomycin D hemmen die r-RNA-Synthese, wobei distinkte Peaks von nicht-ribosomalen RNA-Typen sichtbar werden.Die in den Follikelzellen synthetisierte RNA ist allein in ihrem hochmolekularen Anteil der von den Nährzellen gebildeten RNA ähnlich. Es wurde ein provisorisch Nucleotidfraktion benanntes Material mit einer höheren elektrophoretischen Beweglichkeit als die der t-RNA gefunden und lie\ sich in den Dottergranulen lokalisieren. Es kann von der RNA durch Chromatographie an Sephadex G 100 abgetrennt werden und hat ein Absorptions-maximum bei 255 nm. Diese Nucleotidfraktion wird rasch markiert; sie wird während der Embryogenese zur Synthese von RNA aufgebraucht.Reife Eier enthalten diese Nucleotidfraktion in ziemlich gro\er Menge. Erfolgt die RNA-Analyse von frisch abgelegten Eiern 4 Tage nach einer einmaligen Injektion von radio-aktiven Vorstufen, so findet man die Marke ausschlie\lich in der Nucleotidfraktion. Hingegen tragen Eier, die 5–8 Tage nach der Injektion gewonnen wurden, die Marke fast allein in den höhermolekularen RNA-Molekülen. Diese Beobachtung stimmt sehr gut mit dem Zeitverlauf der Eireifung überein: Eine Gruppe von Oocyten braucht jeweils 4 Tage um den distalen Teil des Vitellariums zu erreichen, in welchem innerhalb von weiteren 4 Tagen die Dotterbildung und Reifung erfolgt. Es ist daher offensichtlich, da\ das Follikelepithel die Nucleotidfraktion an die Oocyte abgibt, während die RNA-Arten des Eies einschlie\lich einer stabilen polydispersen RNA-Klasse aus den Nährzellen stammen und von diesen in die Oocyte überführt werden.

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RNA-Synthesis in telotrophic meroistic ovarioles of dysdercus intermedius DIST. (heteroptera, pyrrhoc.)

Summary RNA in insect ovaries was investigated by polyacrylamide gel electrophoresis to study site of synthesis, transportation and incorporation in mature eggs. Telotrophic-meroistic ovarioles ofDysdercus intermedius were selected for this work since they could be dissected in distinct portions: the apical one with polyploid nurse cells and the vitellarium with oocytes covered by a follicular epithelium. RNA was labeled by injecting radioactive precursors or incubating isolated ovarioles in vitro.In nurse cells labeled rRNA, tRNA and non-ribosomal RNA were found and evidence was presented for the processing of a 39s rRNA precursor molecule in 2 steps (36s and 32s) into 28s rRNA while the 18s rRNA was directly derived from the 36s molecule. A low concentration (0.5 g/ml) of -Amanitin inhibited synthesis of non-ribosomal RNA thereby revealing a more distinct processing pattern for rRNA, while a high concentration (5 g/ml) blocked processing at the 36s molecule and led to its accumulation. Appropriate concentrations of Actinomycin D inhibited rRNA synthesis while distinct peaks of non-ribosomal RNA became apparent.RNA synthesized in the follicular cells was similar to the RNA made in the nurse cells only in the high molecular weight RNA. Some material, tentatively named nucleotide fraction, with a mobility higher than tRNA was detected and could be localized in yolk granules. It was separable from RNA by chromatography on Sephadex G 100 and had an absorption maximum at 255 run. The nucleotide fraction could be rapidly labeled. It seemed to be utilized in RNA synthesis during embryogenesis. Mature eggs contained a relatively high amount of the nucleotide fraction. If a single injection with precursor was done 4 days before analysing the RNA of mature eggs most of the label was found in the nucleotide fraction. Eggs collected 5–8 days after injection contained only high molecular labeled RNA. This observation correlated well with the timing of egg maturation. It takes 4 days for a group of oocytes to reach the distal part of the vitellarium where yolk production and maturation go on for another 4 days. It is apparent, therefore, that the follicular epithelium contributes the nucleotide fraction to the oocyte, while most of the other RNA, including a stable polydisperse class of RNA, is made in the nurse cells and is transported into the oocyte.

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Sach- und Personalmittel zur Durchführung dieser Arbeit wurden uns anfangs von der Stiftung für Krebs- und Scharlachforschung (Strebel-Stiftung), später von der Deutschen Forschungsgemeinschaft in dankenswerter Weise gewährt.

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Das in dieser Arbeit verwendete -Amanitin hat uns Herr Prof. Dr. Th. Wieland (Heidelberg) gro\zügig überlassen, wofür wir ihm bestens danken.

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Wir schulden Frl. Heidrun Greipel vielen Dank für stetige Hilfe bei der Präparation der Nucleinsäuren und sorgfältige analytische Arbeit.     

Gestörte Thylakoidbildung in Chloroplasten einer xantha-Mutante von Arabidopsis thaliana (L.) Heynh.

Zusammenfassung In den Palisadenzellen von Keim- und Rosettenblättern einer rezessiven xantha-Mutante von Arabidopsis thaliana fehlt den Plastiden die für normale, grüne Chloroplasten typische Schichtenstruktur. Licht- und elektronenmikroskopische Untersuchungen ergaben, daß sich dieser genabhängige Differenzierungsdefekt während der Plastidenentwicklung beim Übergang von den Tubuli des Prolamellarkörpers zu Thylakoiden manifestiert. Es entstehen aus dem persistierenden Prolamellarkörper nur einzelne abnorme Thylakoide, die zuweilen napfoder taschenartig verformt oder zu Magnograna vereinigt sein können. Besonders charakteristisch für die Mutante aber ist, daß solchen Thylakoiden häufig parallel laufende Züge einzelner Tubuli oder Fibrillen beidseitig dicht aufliegen. Auf Grund Dieser Anordnung wird die Möglichkeit eines Thylakoidwachstums durch laminalen Einbau von Tubuli erörtert.In den Blättern der Mutante wurden nur Carotinoide, jedoch keine Chlorophylle festgestellt. Zugleich finden sich in den entwicklungsgehemmten Plastiden, neben Phytoferritin-Partikeln, zahlreiche osmiophile Globuli sowie Matrixeinschlüsse unbekannter Natur. Daher wird die Frage diskutiert, ob die beobachteten Störungen der Thylakoid-Differenzierung in der Mutante auf den Chlorophyllmangel oder auf eine blockierte Strukturproteid-Synthese zurückgehen.Alle übrigen Zellorganelle sind in der Mutante ebenso gestaltet wie in der grünen Normalform. Besonders wird auf das Vorkommen von dense bodies hingewiesen und ihre Beziehung zu Sphärosomen erörtert.

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Disturbed thylakoid-formation in chloroplasts of a xantha-mutant of Arabidopsis thaliana (L.) Heynh.

Summary A monohybrid recessive xantha-mutant of Arabidopsis thaliana was grown aseptically on mineral agar +2% sucrose up to maturity. The cotyledons and rosette leaves were non-green during all developmental stages, their yellow colour bleaching with age.Palisade cells of various leaves of mutant plants were investigated light- and electron microscopically. All of the organelles of these cells, except the plastids, had a normal appearance. Special attention was paid to the existence of dense bodies, and their relationship to sphaerosomes and lysosomes was outlined.In the mutant plastids the typical thylakoid differentiation present in the chloroplasts of the green Arabidopsis plant is entirely lacking. Within the palisade cells the plastids are normal in number and size. Under the light microscope they appear as hyaline vesicles with usually two primary grana. Their outline is characterized by numerous invaginations and protrusions; however, it is still uncertain to what extent this amoeboidy is only an artifact.The specific gene dependent block in the plastid development is apparently effective during the conversion of tubules of the prolamellar body to thylakoids. From the persistent prolamellar bodies in the mutant only single abnormal thylakoids originate. These often have a deformed cup- or ventricle-like shape and occasionally are piled up as magnograna. In a characteristic manner tubules and fibrils are closely associated in parallel rows with the outsides of the thylakoids. The fibrils having a mean diameter of 75 Å are connected with the tubules which are derived from the prolamellar body. From this striking aggregation the possibility of a laminal fusion of tubules as a process of normal thylakoid growth is deduced.By pigment analysis of mutant leaves no chlorophyll but only carotenoids were detected. However, many osmiophilic globules as well as large bodies of unknown composition (proteinaceous?) appear in the plastid matrix. Therefore the question is discussed whether the disturbances of the thylakoid differentiation is due primarily to a blocked chlorophyll formation or to an inhibition of the synthesis of some structural membrane proteids.Phytoferritin particles which up to now have not been observed either in normal or in mutant plastids of Arabidopsis were frequently found in the plastid matrix of this xantha-mutant.

     

库蚊一新种(Culex cheni sp.nov.)

在1957年7月,作者在广州市郊夏收后稻田积水,采集库蚊幼虫一批,经隔离培养获得羽化成虫、蛹皮及幼虫皮,另保存四龄幼虫一批,经研究后认为是库蚊属的一新种。现将其中雌蚊10个,雄蚊9个及其幼虫皮,并将幼虫形态描述如下: 一、成虫 雌蚊 头部复盖有淡色至棕色弯窄鳞及直竖叉状鳞片,头顶部两侧有扁平淡色鳞     

Chiasma frequency variation inCepaea hortensis (Müll.) and a comparison withC. nemoralis (L.)

Chiasma frequency variation has been studied in 12 populations ofCepaea hortensis and the results compared with those previously obtained forC. nemoralis from the same populations. Variation in chiasma frequency is effectively restricted to a single large bivalent. In both species there are significant differences between populations in chiasma frequency. Although mean population mean chiasma frequencies are similar inC. hortensis andC. nemoralis, C. hortensis is less variable thanC. nemoralis. This can be seen, to a greater or lesser extent, at several levels-(i) within cells, (ii) between cells, (iii) between snails, and (iv) between populations-and is most noticeable when interstitial chiasmata are considered separately from terminal chiasmata. Data from 6 populations suggest that chiasma frequency remains stable between successive years. It is suggested that, since sympatric populations were studied, the most likely explanation for differences in chiasma frequency statistics between the two species is thatC. hortensis andC. nemoralis are responding differently to similar selective pressures.     

Brachythecium funkii Schimp. and B. japygum (Głow.) Köckinger & Jan Kučera comb. nov., two Alpine species hitherto included in B. cirrosum (Schwägr.) Schimp.

Morphological and molecular studies support the recognition of three alpine species within the traditional concept of Brachythecium cirrosum, which requires the resurrection of two earlier described taxa, B. funkii and B. japygum, comb. nov., from synonymy. According to nuclear and chloroplast sequence data, the latter two taxa proved to be closely related to B. tommasinii and B. tenuicaule, whereas the affinities of B. cirrosum within Brachythecium are rather unclear. B. funkii is a coarser plant than B. cirrosum and also differs in shorter leaf acumens and much larger lamina cells. On the other hand, B. japygum (better known under the illegitimate name Eurhynchium histrio) can be distinguished from B. cirrosum in the prostrate and densely pinnate to subdendroid growth form, longer leaf acumens and wider lamina cells with lumens wider than walls. All three species also differ from each other in the morphology of the alar cell group. Despite their shared preference for calcareous rocks, the three species show marked differences in habitat requirements.     

Über Den Artbastard Arabidopsis Suecica (FR.) Norrl. × A. Thaliana (L.) Heynh. Und Die Beziehungen Zwischen Den Gattungen Arabidopsis Heynh. Und Cardaminopsis (C. A. Meyer) Hay

Ohne ZusammenfassungMit 9 Textabbildungen O. Renner zum 75. Geburtstag gewidmet.Die Arbeit wurde mit Unterstützung der Deutschen Forschungsgemeinschaft ausgeführt.Fräulein Dr.Adele Zenker und FräuleinRuth Farny danke ich für die wertvolle Hilfe.Großen Dank schulde ich auch den in Kap. II genannten Herren, durch deren Hilfe ich das reichhaltige Samenmaterial erhalten habe, sowie den Herren Prof. Dr.Melchior (Berlin) und Dr.Hiitonen (Helsinki) für ihre Beratung in taxonomischen Fragen.HerrnFrank H. Stodola, U.S. Dept. of Agriculture, Peoria, Illinois, und HerrnCurt Leben, Lilly Research Laboratories, Indianopolis, Ind., danke ich für die Überlassung der Gibberellin-Präparate.     

α-Subunit G-protein antisense oligodeoxynucleotide effects on supraspinal (i.c.v.) α2-adrenoceptor antinociception in mice

An in vivo antisense strategy was used to examine the involvement of G-protein subunits in supraspinal (intracerebroventricular; i.c.v.) α₂-adrenoceptor-mediated antinociception. Mice that were injected with 33-mer antisense oligodeoxyribonucleotides (6 nmol) or vehicle were tested (tailflick) with an agonist (clonidine, guanfacine or BH-T 920) administered i.c.v. 18–24 h later. G_i3α antisense treatment attenuated BH-T 920 and clonidine-induced antinociception. G_i2α antisense produced differential effects on the three agonists. G_i1α and G_sα antisense treatment had no significant effect. Together with the previous demonstration that i.c.v. μ-opioid antinociception is mediated via G_i2α, the present results suggest that different receptors may mediate antinociception via different G-protein subunits and, hence, that specific subunits might offer novel targets for drug discovery.     

Taxonomisch-chorologische Studie über die ArtLeucanthemum rotundifolium (W. K.) DC.

Die Arbeit befasst sich mit der Nomenklatur, Morphologie, Phytogeographie, Chorologie, Phytozönologie und Ökologie der ArtLeucanthemum rotundifolium (W. K.) DC. innerhalb ihres Gesamtareals. Auf Grund der Analyse aller untersuchten Faktoren werden die Endergebnisse vom taxonomischen Gesichtspunkte vorgelegt.L. rotundifolium wird mit der am nächsten verwandten ArtL. vulgare Lam. s. l. verglichen.     

Cryopreservation of in vitro-grown shoot tips of 'Troyer' citrange [Poncirus trifoliata (L.) Raf. × Citrus sinensis (L.) Osbeck.] by encapsulation-dehydration

. In vitro-grown shoot tips excised from preconditioned stock shoots of 'Troyer' citrange were successfully cryopreserved by encapsulation-dehydration. Optimal survival of cryopreserved shoot tips was achieved when encapsulated shoot tips were dehydrated to 17.1% water content. The sucrose concentration in the preconditioning medium significantly influenced the growth and dry matter percentage of the stock shoots as well as subsequent survival of the cryopreserved shoot tips. Maximal growth of stock shoots was obtained in sucrose concentrations in the range of 0.15 M to 0.29 M, while the dry matter percentage increased as sucrose concentration increased up to 0.44 M. The survival of cryopreserved shoot tips increased from 40% to approximately 80% as the sucrose concentration for stock shoots increased from 0.09 M to 0.22 M or 0.29 M. The benzyladenine concentration in the post-culture medium significantly affected the survival and regrowth of the cryopreserved shoot tips. Survival of the shoot tips was lowest when they were post-cultured on benzyladenine-free medium. However, high benzyladenine concentrations (3-4 µM) induced callus formation. Optimal recovery was obtained in post-culture medium containing 2 µM benzyladenine and 0.05 µM !-naphthalene acetic acid. The extraction of shoot tips from alginate beads greatly improved the regrowth of cryopreserved shoot tips.     

记洛川大角鹿(新种)Megaloceros luochuanensis(sp.nov.)

陕西洛川黑木沟有发育完好的黄土剖面。各黄土层中几乎都产有哺乳类化石,找到者以鼢鼠类为主。中更新统中(或中上)部的洛川大角鹿(Megaloceros luochuanensis)是一新种,其主要构造特征介于扁角大角鹿及河套大角鹿之间。