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1.
The coral reefs of the Gulf of Aqaba are among the most northern ones of the world. This study, the first concerning the east coast of this topographically and hydrographically peculiar sea, considers relationships of biophysiographical and structural reef zones to fundamental abiotic environmental factors. An introduction to paleogeography, geology, petrography, topography, climate and hydrography is followed by terminological definitions used to describe the different reef areas. The investigations were carried out on two transects crossing fringing reefs of different shape. Each transect was 20 m wide and run from the shore over nearly 200 m to the fore reef in about 30 m depth. One reef, a “coastal-fringing reef”, represents an unaltered straight reef flat from shore to the reef edge 60 m away; two large pinnacles reach the surface some 125 m off the shore. The other reef, a “lagoon-fringing reef”, is divided into a 100 m wide lagoon of 0.5–2.3 m depth and a reef crest separated from the former by a rear reef. The reef platform of the lagoon-fringing reef is cut by a system of channels and tunnels; the reef edge is about 135 m off shore. Such water depth, substrate, temperature, illumination and water movement were recorded, about 200 common or dominant species (plants and animals) were collected, their distribution plotted and, together with other data and structural items, charted. Indicator species characterize the biophysiographical zones. Their variation as well as that of the structural and substrate zones depend on different zones of water movement. This basic factor also controls other ecological parameters such as food and oxygen supply as well as temperature and salinity gradients between fore reef and shore. From this point of view the ecological requirements of some indicator and other species and conversely the ecological settings of different reef areas are discussed. The different shapes of both reefs are explained on the basis of a “reef development cycle” — a hypothesis applicable to fringing reefs at unchanging sea level and based on the fact that only a small surf-influenced area of “living reef” is able to compensate for reef destruction: While a young coastal fringing reef is growing outwards, its back reef is gradually altered to a reef lagoon by erosion. After stillstand of seaward expansion the reef crest, too, is cut by a channel system eroded by rip currents. This stage is represented by the lagoon-fringing reef. Isolated pinnacles remain as remnants of the former reef crest; young coastal-fringing reefs develop from the shore. This stage is examplified by the first reef studied. Extension, growth intensity, dominant frame building corals, and the number of species of the Aqaba reefs are compared with those of Eilat and with reefs of the middle Red Sea, South India, Southwest-Pacific and Jamaica.  相似文献   

2.
Zusammenfassung Natürliche und synthetische Abscisinsäure wird in Explantaten, Blattstiel- und Internodialsegmenten von Coleus rheneltianus transportiert.In jüngeren Pflanzenteilen erfolgt der Transport vorwiegend oder ausschließlich basipetal, während in älteren Organteilen auch eine erhebliche akropetale Wanderung stattfindet. Eine Bestimmung der Transportgeschwindigkeit ergab für synthetische Abscisinsäure in älteren Blattstielsegmenten ungefähr 24–36 mm/h.
Transport of abscisic acid in explants, petiole and internode segments of Coleus rheneltianus
Summary Synthetic or natural abscisic acid isolated from tomato fruits is transported in explants, petiole and internode segments from Coleus rheneltianus.Transport in segments and explants from younger parts (2nd node or internode) is mainly basipetal. In older parts (segments and explants from 5th nodes or internodes) translocation in acropetal direction is nearly of the same order of magnitude as in basipetal direction.The velocity of transport of synthetic absisic acid was investigated in petiole segments from 5th nodes and was found to be approximately 24 to 36 mm/h.


Herrn Prof. Dr. Hans Söding in Dankbarkeit zum 70. Geburtstag gewidmet.  相似文献   

3.
Summary The dependence on external parameters of the membrane potential of Chlorella fusca (Shihira et Krauss) 211-8b, Göttingen, has been measured in media containing no salt except KCl. Near neutrality the potential is practically independent of pH. The negative potential increases with temperature from-12 mV at 5°CC to-45 mV at 20°, and remains constant thereafter, i.e., at least up to 30°. Upward temperature jumps of 5 degrees cause a fast hyperpolarisation, which is independent in magnitude of the starting temperature. The potential is influenced by illumination, and this effect increases with temperature. The light effect is reduced by 3-(3,4-dichlorophenyl)-1,1-dimethyl urea and practically abolished by carbonyl cyanide-m-chlorophenyl hydrazone.
Abkürzungen DCMU 3-(3,4-Dichlorphenyl)-1,1-dimethylharnstoff - CCCP Carbonylcyanid-m-chlorphenylhydrazon Herrn Prof. Dr. Otto Hoffmann-Ostenhof zum 60. Geburtstag gewidmet.  相似文献   

4.
Zusammenfassung Das homofermentative Milchsäurebakterium Lactobacillus plantarum weist während der Glucosevergärung einen zeitweiligen Pyruvatstau von 120 mg/l auf, der durch Thiaminzugabe auf 10–20 mg/l reduziert werden kann. Der hierdurch intensivierte Pyruvatdurchsatz bedingt eine Verdoppelung der Acetoinsynthese, da Thiamin auch Cofaktor der Acetolactat-Synthetase ist. Ein gleichzeitiger Thiamin- und Liponsäurezusatz führt zu einer nochmaligen Verdoppelung der Acetoinausbeute. Liponsäure allein zeigt keinen Einfluß. Eine Erklärung dieses Sachverhaltes bietet die Annahme einer zusätzlichen Entstehung des Acetoins aus Acetyl-CoA zu Diacetyl und dessen Reduktion zu Acetoin. Dazu notwendiges Reduktionsäquivalent könnte die Lipoyl-Dehydrogenase liefern. Die sehr schnellen Konzentrationsveränderungen von Pyruvat und Acetoin nach Thiaminzugabe während der logarithmischen Wachstumsphase lassen eine Aktivierung des oder der Acetoin-synthetisierenden Enzyme wahrscheinlich erscheinen. Valin und Isoleucin beeinflussen die Acetoinsynthese nicht durch Rückkoppelung, sondern nur mittelbar über das Wachstum.
Acetoin formation by Lactobacillus plantarum dependent on thiamine, lipoic acid, l-valine, and l-isoleucine
Summary During the homolactic fermentation of glucose by Lactobacillus plantarum the concentration of pyruvate rises temporarily to 120 mg/l.By the addition of thiamine, this concentration is reduced to 10–20 mg/l. The subsequently intensified turnover of pyruvate leads to the doubling of acetoin synthesis. This is reasonable since thiamine is a cofactor of the acetohydroxy acid synthetase, too.When thiamine and lipoic acid are added simultaneously, again a doubling of acetoin synthesis occurs, while lipoic acid alone has no effect. This may be explained by an additional synthesis of acetoin via acetyl-CoA to diacetyl and further reduction to acetoin.The rapid changes in the concentrations of pyruvate and acetoin following the addition of thiamine during the logarithmic growth phase may be explained by the activation of one or more of the acetoin synthesizing enzymes.A feedback inhibition of acetoin synthesis by valine and isoleucine was not detected.


Herrn Prof.Dr.G. Drews, Freiburg, danke ich für anregende Unterstützung dieser Arbeit.  相似文献   

5.
6.
Das in der südtoskanischen Maremma klimatogeneQuercetum ilicis wird in regelmässigen Abständen von etwa 12 Jahren kahlgeschlagen, wodurch tiefgreifende Änderungen in der Vegetation entstehen. Es wird in den ersten zwei Jahren ein Massenauftreten von Therophyten beobachtet und bald darauf eine allmähliche Wiederentwicklung des Waldes, die durch Stockausschläge der kräftigeren Holzarten zustande kommt. Die häufig auftretenden Brände bedingen hingegen das Entstehen desEriceto-Lavanduletum als degradierte Dauergesellschaft. Die vorliegende Arbeit stellt einen Versuch dar, die wichtigsten Momente dieser Sukzession zu beschreiben, u. zw. mit floristischen Angaben und mit der Bearbeitung von Lebensformen, ökologischen Synusien, Schichtung, Verbreitungstypen und Polyploidie.  相似文献   

7.
Summary The effect of sodium arsenate on the metabolism of the green alga,Ankistrodesmus braunii (strain Marburg) increases with increasing arsenate concentration and with decreasing phosphate concentration. Above 10–4 M arsenate, in a phosphate-free medium of pH 4.1, an increase in respiratory oxygen uptake and inhibition of photosynthesis were observed. At the highest concentration used (5·10–2 M arsenate), the rate of respiration was about 250% of that of the controls, whereas photosynthesis had dropped to about 20% of the normal value. In addition, arsenate was found to be an inhibitor of the reduction of nitrite in the dark, whereas it does not inhibit the first step of nitrate reduction,i.e. the reaction nitrate nitrite. Therefore, in a solution containing nitrate, addition of arsenate leads to accumulation of nitrite. These results further support the assumption, derived previously from experiments with 2,4-dinitrophenol, that the further reduction of nitrite requires high-energy phosphate, in contrast to the first step of nitrate reduction.

Mit 8 Textabbildungen  相似文献   

8.
Summary As supposed in a previous paper, Heitz (1960), the lamellar thin-thick pattern is found in four algae of very different taxonomic position. It is suggested that the presence of thin and thick lamellae as well in the chloroplasts with grana as without grana, is a common, significant characteristic. Perhaps there is a functional difference between the two kinds of lamellae. The thick lamellae in the midst of the two thin lamellae in the Algae (and in the liverwort Anthoceros) are perhaps the precursors of the many thick lamellae in the so called grana of the higher plants.

Die Arbeit wurde mit Unterstützung durch die Deutsche Forschungsgemeinschaft ausgeführt, der ich ebenso danke wie den technischen Assistentinnen Fräulein Döemer und Fräulein Möschler.  相似文献   

9.
Zusammenfassung Die Grö\e und HÄufigkeit der osmiophilen Plastoglobuli nimmt mit steigendem Alter der Spinatchloroplasten zu. Die Plastoglobuli besitzen in ganzen oder aufgebrochenen Chloroplasten, in Sedimenten und in isolierter Form die gleiche Grö\enverteilung wiein situ. Es gibt keine Hinweise, da\ beim Ultraschallaufschlu\ ganzer Chloroplasten Plastoglobuli durch Entmischung der Thylakoide entstehen. Beim Zentrifugieren von broken chloroplasts wird nur ein kleiner Teil der Plastoglobuli freigesetzt. Der grö\ere Teil befindet sich mit den Chloroplastenbruchstücken im Sediment.Wie bei anderen Pflanzen enthalten auch die Plastoglobuli von Spinat vorwiegend die lipophilen Plastidenchinone vom Benzochinontyp (Plastochinon 45, Plastohydrochinon,-Tocopherol und-Tocochinon), geringe Mengen an Vitamin K1 und Spuren an Carotinoiden, jedoch keine Chlorophylle. Zwischen dem Lipochinongehalt der Chloroplasten und der Grö\e und HÄufigkeit der osmiophilen Plastoglobuli besteht eine direkte Korrelation.
The plastoglobuli of spinach: Their size, isolation, and lipoquinone composition
Summary The size and frequency of the osmiophilic plastoglobuli of spinach chloroplasts increase with increasing age of chloroplasts. The plastoglobuli of whole or broken chloroplasts, of sediments and in the isolated form show the same size distribution asin situ. There is no evidence that plastoglobuli may arise from thylakoid lipids by ultrasonic treatment of whole chloroplasts. During the centrifugation of broken chloroplasts only a small portion of the plastoglobuli is releazed, the greater portion remains in the sediment together with the chloroplast fragments.The plastoglobuli of spinach—like those of other plants—mainly contain the excess plastidquinones of the benzoquinone type (plastoquinone 45, plastoquinol,-tocopherol,-tocoquinone), little vitamin K1 (a naphthoquinone), traces of carotenoids, but no chlorophylls. The lipoquinone content of spinach chloroplasts increases parallel to the augmentation of the size and frequency of the plastoglobuli.


Der Deutschen Forschungsgemeinschaft danke ich für ihre Unterstützung und FrÄuleinMargarethe Wirtz für tüchtige technische Mitarbeit.  相似文献   

10.
11.
Dietrich Gradmann 《Planta》1970,93(4):323-353
Summary 1. In sea water at 25°C cells of Acetabularia crenulata exhibit a resting potential (RP) of-170 mV between cytoplasm and external medium. At temperatures below 10°C, or upon addition of 10-3m dinitrophenol in darkness, the cell shows a second steady potential (RP) of about-70 mV. Among the cations of sea water, i.e. K+, Na+, Mg++, only K+ was found to affect RP and RP. If the ionic strength of the medium is reduced by addition of isotonic mannitol solution, RP decreases, while RP is not influenced. RP is explained as a potassium diffusion potential, while for the existence of RP an electrogenic chloride pump is inferred which is driven by ATP of the photo- or oxidative phosphorylation (system X).-2. Starting from RP, the current-voltage relationship consists of two linear portions for inward (R e ) and outward current (R a ), respectively, merging at RP (Fig. 3). Presumably they represent potassium conductances. For a given cell, the expression RT/F ln R e /R a yields a value which fits the RP of the cell (Fig. 20).-3. Starting from RP, a N-shaped current-voltage relationship was obtained for depolarisation (Fig. 3). The deviation from the potassium conductance is supposed to be due to the shunt of the potassium channel and the system X (voltage-dependent resistance). An electric circuit diagram was derived from voltage and current clamp experiments (Fig. 21); the elements of the circuit were tentatively analogized with cell functions.-4. Action potentials of about 120 mV, lasting from 30 to 300 sec may arise spontaneously. They can be triggered by lowering the temperature or depolarisation (voltage clamp, current clamp, light-off-cf. Figs. 2,11). The mechanism of the action potential can be derived from the properties of the chloride pump. Action currents were recorded upon different depolarizing steps by voltage clamp to yield current-coltage curves at different times after stimulation (Fig. 13).-5. Pulses of white light shift the potential off RP: light-on elicits a small depolarisation, light-off a large transient hyperpolarisation. The primary event of this response is a change of current (Fig. 19), the voltage change being its consequence. This result is interpreted on the basis of the circuit diagram.
Abkürzungen AP Aktionspotential - RP stabiles Potential bei ca.-170 mV - RP stabiles Potential bei ca.-70 mV Dissertation der Math.-Nat. Fakultät der Universität Tübingen.  相似文献   

12.
Über die Blattbildung der Ophioglossaceen,insbesondere von Ophioglossum   总被引:1,自引:0,他引:1  
Wilhelm Troll 《Planta》1933,19(3):547-573
Ohne ZusammenfassungMit 16 Textabbildungen.  相似文献   

13.
Dr. Helga Winter 《Planta》1954,44(6):636-668
Ohne ZusammenfassungMit 10 Textabbildungen.Dissertation der Naturwissenschaftlichen Fakultät der Universität Erlangen.Herrn Prof. Dr.J. Schwemmle, der die Anregung zu der vorliegenden Arbeit gab, danke ich für das Interesse und die Förderung, die er meiner Arbeit zuteil werden ließ. Mein Dank gilt ferner den Herren Dr.F. Wachsmann und Dr.Breuer, die mir bei der Bestrahlung der Objekte behilflich waren.  相似文献   

14.
The effects of rearing and feeding conditions, as well as of body size and origin on sexual differentiation have been examined in elvers collected on the Atlantik coast (River Ems) and in the Tyrrhenian Sea. Raised at 17°, 20°, 23°, 26° or 29° C and at constant photoperiod, the elvers received either commercial fish food or cod roe. Eels from the Tyrrhenian Sea mostly developed into males. To some extent, at temperatures optimal for growth (26° C) and feeding a cod-roe diet, a shift of sex ratio in favour of females was observed in Atlantic eels. The results obtained contradict those ofFidora (1951), who, rearing elvers in ponds, found the percentage of male eels to be positively correlated with increasing stock density. Although in the present study, stock density was 200 times higher than inFidora's experiments, the percentage of females was much higher than that of males. The results obtained supportBellini's (1907) findings that big elvers preferentially develop into females, but small elvers into males. Irrespective of elvers' origin, water temperature and diet, the onset of sexual differentiation dependends upon attaining a certain body length (15–25 cm), but not on age. Whereas under natural conditions females are supposed to grow faster than males, under the conditions tested the males grew faster than the females. It is concluded, that, in addition to genetic factors, various environmental factors may influence sex determination in eels.  相似文献   

15.
16.
Zusammenfassung Durch die Hemmstoffe Amytal (5·10-3 m), 2,4-Dinitrophenol (1,25·10-4 m) und Phenazinmethosulfat (10-6 m) wird die Bacteriochlorophyllbildung bei Rhodospirillum rubrum unter anaeroben Bedingungen im Dunkeln völlig verhindert. Der Abbau der Speicherstoffe (Kohlenhydrate) verläuft genau so rasch oder schneller als ohne Hemmstoffe.Die Hemmung der Bacteriochlorophyllsynthese unter anaeroben Bedingungen im Licht ist vom spezifischen Anfangsbacteriochlorophyllgehalt der Zellen abhängig. Nach einer semiaeroben oder anaeroben Vorkultur der Bakterien, bei der der Photosyntheseapparat in gewissem Umfange ausgebildet wird, ist der Einfluß der genannten Hemmstoffe auf die Bacteriochlorophyllsynthese und das Wachstum im Licht deutlich geringer als in pigmentlosen Zellen.Bei einem spezifischen Bacteriochlorophyllgehalt von 1,5 g/mg Protein kann bereits eine Nettozunahme der Kohlenhydrate bei anaerober Kultur im Licht erfolgen.
The influence of amytal, 2,4-Dinitrophenol, and Phenazinemethosulfate on the biosynthesis of bacteriochlorophyll in anaerobic cultures of Rhodospirillum rubrum
Summary Amytal (ethylisoamylbarbituric acid; 5·10-3 m), 2,4-Dinitrophenol (1.25·10-4 m), and Phenazinemethosulfate (10-6 m) completely inhibits the synthesis of bacteriochlorophyll in anaerobic cultures in the dark. The degradation of carbohydrates runs in the same rate or quicker than without inhibitors.The rate of inhibition of bacteriochlorophyll synthesis under anaerobic conditions in the light is dependent from the specific content of bacteriochlorophyll in the cells on the beginning of culture. After a semiaerobic or anaerobic preculture some bacteriochlorophyll is present and the influence of the inhibitors on the bacteriochlorophyllsynthesis and the growth rate is diminished. If the specific bacteriochlorophyll content is 1,5 g/mg protein or higher a netto increase of the carbohydrates in anaerobic light cultures takes place.

Abkürzungen im Text BChl Bacteriochlorophyll - 2,4-DNP 2,4-Dinitrophenol - PMS Phenazinmethosulfat  相似文献   

17.
Abstract

Model reactions with 2-methylthiopteridin-4,7(3H,8H)-diones (3-5) and 4-benzyloxy-8-methyl-2-thiopteridin-7(8H)-one (11) showed that peracid oxidations lead to the corresponding 2-methylsulfonyl-6-oxo derivatives 8, 9, 10 and 12. The structurally analogous pteridine-N-8-ribosides 19-21 and 26 revealed the same behaviour, which allowed the synthesis of 8-β-D-ribofuranosylleu-copterin (30) from 4-benzyloxy-8-(2,3,5-tri-O-benzoyl-β-D-ribofu-ranosyl)-2-methylthio-pteridi-7(8H)-one (26) via the intermediates 27-29. The newly synthesized compounds have been characterized by elemental analysis and UV spectra.  相似文献   

18.
Heike Wägele 《Zoomorphology》1984,104(4):246-251
Zusammenfassung Ziel dieser Studie ist die anatomische und histologische Beschreibung der Atmungsorgane und des Kreislaufes von Phyllidia pulitzeri Pruvot-Fol, 1962. Der an Hand von Schnittserien rekonstruierte Kreislauf, insbesondere der Kiemenkreislauf, und die ventralen Kiemenblättchen werden mit denen typischer Doridacea (Archidoris und Corambe) verglichen.Innerhalb der Phyllidiidae behält der Sinus lateralis seine Funktion bei: Er leitet die durch Hautatmung mit Sauerstoff angereicherte Hämolymphe aus dem Notum in das Atrium. Ebenfalls leitet er die Hämolymphe aus den ventralen Kiemenblättchen in das Herz. Die für die kiementragenden Doridacea so typischen caudo-medialen Eingänge der afferenten und efferenten Kiemengefäße in das Atrium fehlen bei den Phyllidiidae.Die Lage der Atmungsorgane, die Art der Vervielfältigung der Kiemenblättchen, das Fehlen einer Raphe und eines unabhängigen Kiemenkreislaufes, die Vergrößerung des peripheren Körperkreislaufes in die ventralen Blättchen deuten darauf hin, daß die Kiemen von Phyllidia pulitzeri sekundäre Ausstülpungen des ventralen Notumepithels darstellen.Da das Herz und die Sinus laterales bilateral symmetrisch auf der Eingeweidemasse liegen, scheinen das Kreislaufsystem und die Atmungsorgane apomorphe Merkmale zu sein, die innerhalb der Doridacea nur einmal entstanden.
Respiratory organs and vascular system of Phyllidia pulitzeri (Gastropoda, Opisthobranchia, Doridacea)
Summary The anatomical and histological details of the respiratory organs and the vascular system of Phyllidia pulitzeri Pruvot-Fol, 1962, are described. The vascular system, especially of the ventral gill leaflets, is reconstructed and compared with that of typical Doridacea (Archidoris and Corambe).Within the Phyllidiidae the sinus lateralis maintains its function of returning the blood from the notum to the atrium. This blood is oxygenated by cutaneous respiration. The sinus lateralis also returns the blood from the ventral leaflets. The caudo-medial entrances of the afferent and efferent branchial vessels into the atrium, so typical of all gill-bearing Doridacea, are missing in the Phyllidiidae.The position of the respiratory organs, the mode of multiplication of the gill leaflets, the lack of the raphe and of an independent branchial vascular system, and the enlargement of the peripheral vascular system into ventral leaflets show that the gills of Phyllidia pulitzeri are secondary specializations of the epithelium of the ventral notum.The heart and the sinus laterales lying bilaterally symmetrical on the viscera, the vascular system, and the respiratory organs seem to be apomorphic features that evolved only once within the Doridacea.
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19.
20.
Ohne ZusammenfassungGekürzte Fassung der Dissertation der mathematisch-naturwissenschaftlichen Fakultät der Universität Göttingen Untersuchungen zum Stoffwechsel vonClostridium butyricum Prazm.  相似文献   

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