Der Einfluß von Elektrolyten auf Chloroplasten beim Gefrieren und Trocknen

Summary The effect of freezing, desiccation and various electrolytes on photophosphorylation, electron transport and some enzyme reactions of isolated spinach chloroplasts has been investigated. Freezing of broken chloroplasts took place at-25°C for 3 hrs; desiccation was performed at +2°C in vacuo over CaCl₂ for 3 hrs. The influence of various electrolytes during freezing or drying or during incubation of thylakoids or stroma enzymes for 3 hrs at +2°C in electrolyte solutions was determined. After treatment, the activities of a number of enzymes and enzyme systems were measured under normal conditions, e. g. in the absence of elevated electrolyte levels in a reaction medium which contained only the substrates and cofactors which are necessary for the respective enzyme reactions.Only photophosphorylation and electron transport were affected by freezing, desiccation and high concentrations of electrolytes; various soluble enzymes investigated here were not inactivated under the same conditions. In general, mild dehydration and lower concentrations of electrolytes resulted in an irreversible inactivation of ATP synthesis but did not impair ferricyanide reduction. With increasing dehydration or at higher concentrations of electrolytes the Hill reaction was also inhibited. In a certain range of dehydration and electrolyte concentration uncoupling of photophosphorylation from electron transport took place. Sugar protects the sensitive structures against the deleterious effect of both dehydration and high concentration of electrolytes.Various electrolytes affected thylakoid membranes differently. Inactivation of the membranes increased with increasing ion radius and decreasing hydration envelope of univalent or divalent cations. Divalent cations were more destructive than univalent cations. Anions did not follow these rules. Within a group of similar anions (halides or organic anions) effectivity decreased with increasing hydration envelope. On a molar basis, polyvalent anions were less effective than univalent anions. Inactivation by anions followed Hofmeister's series in seversed order. However, exceptions were observed and it appears that various ions affect the membrane in a specific manner.Inactivation of photophosphorylation and electron transport due to freezing or desiccation is identical to that due to high concentrations of electrolytes. This suggests that during dehydration due to freezing or drying the concentration of electrolytes in the remaining solution is responsible for the inactivation of the sensitive membranes.     

Flavonglykoside in Blüten vonPaeonia arborea undPaeonia suffruticosa

Summary Three glycosides have been isolated fromPaeonia arborea: kaempferol-3--glucoside-7--glucoside (Paeonoside), apigenin-7--glucoside, and apigenin-7-rhamnoglucoside (Rhoifolin).Paeonia suffruticosa also contains these three compounds but its main glycoside is kaempferol-3--glucoside (astragalin), which is present inPaeonia arborea only in traces.     

Über die genetischen Ursachen der Samenbildung

Zusammenfassung Innerhalb von Primula malacoides Franchet wurden zwischen verschiedenen Formen Valenzkreuzungen durchgeführt. Es traten 2x-, 3x-, 4x- und 5x-Pflanzen auf. An der Entstehung dieser Valenztypen sind sowohl reduzierte als auch unreduzierte Gameten beteiligt. Auf Grund der erzielten Kreuzungsergebnisse wird versucht, Rückschlüsse auf die genetischen Ursachen der Samenbildung zu ziehen.Es wird angenommen, daß der jeweiligen Konstitution des Endosperms eine vorrangige Bedeutung für die Entstehung von lebensfähigen Samen zukommt.

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On the genetic causes of seed formation

Summary New crossings were made between different diploid and polyploid forms of Primula malacoides Franchet. 2x, 3x, 4x and 5x plants appeared. Both reduced and unreduced gametes participated in the formation of these types. Based on the results conclusions are drawn about the genetic causes of seed development. It is suggested that the endosperm constitution has prime importance for the development of viable seeds.

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Herrn Prof. Dr. Hans Stubbe zum 65. Geburtstag gewidmet.

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Quedlinburger Beiträge zur Züchtungsforschung Nr. 78.     

Estimation of the mean floristic similarity between and within sets of vegetational relevés

Various possibilities of usingSörensen's coefficient of floristic similarity in plant sociology are summarized. A new formula (11), derived from that bySörensen and based on constancy values, is suggested in order to calculate the mean floristic similarity within a set of relevés.     

Estimation of the mean floristic similarity between and within sets of vegetational relevés

Various possibilities of usingSörensen’s coefficient of floristic similarity in plant sociology are summarized. A new formula (11). derived from that bySörensen and based on constancy values, is suggested in order to calculate the mean floristic similarity within a set of relevés.     

Zytologische Beobachtungen an der hyperplastischen Nebennierenrinde des Menschen

Summary Clinical observations and the light and electron microscopic appearance of the adrenal cortex are described in a case of Cushing's disease associated with adrenocortical hyperplasia and a basophilic adenoma of the pituitary gland. The electron microscopic investigation concentrates upon the occurrence of osmiophil material in the different cytoplasmic compartments of the cell type rich in organelles and relatively poor in paraplasmic inclusions. It seems that the observation of osmiophil material in the perinuclear space, the mitochondrial matrix, Golgi vacuoles, and cytoplasmic vesicles has been made possible by a rather long fixation in Wohlfarth-Bottermann's chromium-osmium fixative. Mitochondria and related particles (named X-Einschlüsse) may contain a light center with a few dense filaments and masses resembling those described by other authors as being of deoxyribonucleic acid nature. Relatively large Golgi complexes are found, sometimes in close topographic relation with a centriole. A large population of osmiophil bodies (lipid droplets, pigment granules, microbodies) is described. Apart from these findings the cytoplasmic organization in the tissue studied is similar to that of the adrenal cortex as described in other mammals. The observations are discussed with respect to hypotheses about lipid droplet formation and to the possibility of artifacts due to preparation procedures.

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Herrn Prof. Dr. med. W. Bargmann zum 60. Geburtstag gewidmet. — Herrn Prof. Dr. E. Uehlinger, Direktor des Pathologischen Instituts der Universität Zürich, danken wir für die Überlassung des Materials und für die freundlicherweise zur Verfügung gestellte pathologisch-anatomische Diagnose, dem Schweizerischen Nationalfonds für die Unterstützung und Frau Jäger, Mlle. Challamel und Herrn Krieger für die Ausführung der histologischen und photographischen Arbeiten.     

Über Gefässpaare im Gehirn der Katze

Summary Paired vessels, consisting of one artery and one vein, have so far only been described in the brains of some lower vertebrates and in the brains of marsupials (opossum). However, as shown in this paper, similar vessels also occur in the medulla oblongata, midbrain, hypothalamus, septum pellucidum, hippocampus and in the olfactory lobe of the cat's brain. In the neocortex and in the cerebellum no such vessels could be traced.—Whereas some paired vessels are first surrounded by connective tissue (Virchow-Robin's space) and then by a layer of glial fibres, most of the vessels are only ensheathed by a coat of glial fibres. These and other histological details are described and some functional implications are discussed under the assumption that the paired vessels allow diffusion of blood gases between venous and arterial blood and vice versa.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

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