Das Massenauftreten des grauen Lärchenwicklers Grapholitha (Semasia) diniana in Österreich in den Jahren 1946 und 1947

Ohne Zusammenfassung     

Brain and spinal cord lesions in encephalitozoonosis in the blue fox

The central nervous system lesions in encephalitozoonosis were studied in 11 naturally infected blue foxes. Immunohistochemical staining was employed in the demonstration of the parasites and identification of host cells. Consistent findings in acute to subacute stages included granulomatous meningoencephalomyelitis and vasculitis, with arterial lesions similar to polyarteritis nodosa. Chronic stages were dominated by arteriosclerosis, perivascular mononuclear infiltrations and gliosis, with less prominent granulomatous reaction. Parasites were almost constantly observed in association with active lesions both in vessels and nervous tissue. Parasitophorous vacuoles (PV) occurred in endothelial cells and in the medial layer of arteries. Neurons, including even their processes, were widely parasitized, a fact that may account for the brain being an important target organ. PV also occurred in ependymal cells of the choroid plexus and occasionally in macrophages. A great number of parasites was demonstrated in phagolysosomes of macrophages, a fact that probably reflects a relative resistance to digestion, and may consequently contribute to the development of the prominent granulomatous reaction. It was concluded that the brain lesions, except in chronic stages of mild infections, seem to be pathognomonic for encephalitozoonosis in the blue fox.     

Microbial biomass and respiration in soils derived from lignite ashes: a profile study

Microbial biomass C and soil respiration measurements were made in 17–20 yr old soils developed on sluiced and tipped coal‐combustion ashes. Topsoil (0–30 cm) and subsoil (30–100 cm) samples were collected from three soil profiles at two abandoned disposal sites located in the city area of Halle, Saxony‐Anhalt. Selected soil physical (bulk density and texture) and chemical (pH, organic C, total N, CEC, plant available K and P, and total Cd and Cu) properties were measured. pH values were significantly lower while organic C and total N contents and the C : N ratio were significantly higher in the topsoil than in the subsoil indicating the effects of substrate weathering and pedogenic C accumulation. Likewise, microbial biomass C, K₂SO₄‐extractable C, and soil respiration with median values of 786 μg biomass C g^–1, 262 μg K₂SO₄‐C g^–1, and 6.05 μg CO₂‐C g^–1 h^–1, respectively, were significantly higher in the topsoil than in the subsoil. However, no significant difference was observed in metabolic quotient between the topsoil and the subsoil. Metabolic quotient with median values of 5.98 and 8.54 mg CO₂‐C (g biomass C)^–1 h^–1 for the 0–30 cm and 30–100 cm depths, respectively, was higher than the data reported in the literature for arable and forest soils. Microbial biomass C correlated significantly with extractable C but no relationship was observed between it and total N, Cd, and Cu contents, as well as plant‐available K and P. We conclude that the presence of the remarkable concentration of extractable C in the weathered lignite ashes allowed the establishment of microbial populations with high biomass. The high metabolic quotients observed might be attributed to the heavy‐metal contamination and to the microbial communities specific to ash soils.     

Das mineralinventar der versuchsfla¨che "statischer dauerdu¨ngungsversuch v120, bad lauchsta¨dt"

Der Statische Dauerdüngungsversuch Bad Lauchstädt ist einer der wenigen Schlüsselstandorte von internationalem Ruf innerhalb der Erforschung des Umsatzverhaltens organischer Bodensubstanz. Im Rahmen des Schwerpunktprogramms 1090 der DFG "Böden als Quelle und Senke für CO 2 --Mechanismen und Regulation der Stabilisierung organischer Substanz in Böden" wurde die Versuchsfläche als ein Referenzstandort ausgewählt. Die Interaktion von Bodenmineralen mit organischer Bodensubstanz könnte einer dieser Stabilisierungsprozesse sein, aber die bisher vorliegenden Informationen über den Mineralbestand der Versuchsfläche sind unvollständig und widersprüchlich. Um diese Mängel auszuräumen, haben wir den Mineralbestand einer 98 Jahre ungedüngten Variante ("18") und einer kontinuierlich gedüngten Variante ("1") bestimmt. Je Variante wurden 4 Unterproben aus Teilparzellen entnommen, um die flächige Heterogenität des Mineralkörpers zu prüfen. Neben Grunduntersuchungen (Texturanalyse, Bestimmung des pH-Wertes und der potentiellen Kationenaustauschkapazität [KAK pot ]) haben wir zur Kennzeichnung des Mineralbestandes die Röntgendiffraktometrieanalyse (XRD), die Röntgenfluoreszenzanalyse (XRF) und Gehaltsbestimmungen an pedogenen Oxiden durchgeführt. Für die Textur wurden signifikante (p<0.05) Differenzen festgestellt. Der Boden von Variante "18" enthielt 4% mehr Sand als jener von Variante "1", während der Schluffgehalt von Variante "18" um 3% kleiner war als in Variante "1". Weder der Mineralbestand, noch pH-Wert und KAK pot liefern für beide Varianten signifikant verschiedene Ergebnisse. Die Feinerde (<2 mm) beider Varianten enthält ca. 80% Quarz, 14% Feldspäte und 6% Glimmer/Illit. Der Mineralkörper der Tonfraktion (<2 µm) besteht zu ca. 77% aus Illit. Daneben sind Quarz (11%), Kaolinit (6%) und primärer Chlorit (6%) vorhanden. Aufweitbare Dreischichtsilikate wurden nicht nachgewiesen. Die Ergebnisse der Elementgehalte zeigen sehr geringe, aber zum Teil signifikante Unterschiede zwischen Variante "18" und Variante "1". Verschiedenen Publikationen zufolge führt langjährige K-Verarmung zur Transformation von Illiten zu aufweitbaren Dreischichtsilikaten. Keine von uns untersuchte Variante zeigte Anzeichen einer solchen Veränderung. Das Ausbleiben dieser Veränderungen wird von uns auf die K-Düngungspraxis der letzten 30 Jahre oder atmogene K-Einträge aus einem benachbarten Zementwerk zurückgeführt.     

Insecticide-induced increase in the protein content of male accessory glands and its effect on the fecundity of females in the brown planthopper Nilaparvata lugens Stål (Hemiptera: Delphacidae)

The brown planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is a classical resurgent rice pest induced by insecticides. The past focus on resurgence mechanisms has been on the stimulation of the reproduction of adult females induced by insecticides. To date, the role that males play as a resurgence of N. lugens has not been investigated. The present study examined changes in protein levels in both male accessory glands and female ovaries induced by the insecticides triazophos and deltamethrin as well as the stimulating effect of treated males on the fecundity of adult females via mating following foliar sprays of the insecticides. For adults that had been exposed as nymphs to treated rice plants, the protein content in both the male accessory glands and in the female ovaries of N. lugens were significantly affected by male mating status, insecticide and insecticide concentration. There was a higher protein content in male accessory glands when males were exposed to triazophos as third instars compared to fifth instars, and there was a higher protein content before mating compared to after mating. In addition, the protein levels in male accessory glands after mating for individuals exposed to high doses of the two insecticides as 3rd and 5th instars were significantly lower than untreated control except for exposed to triazophos as 3rd instar, indicating that treated males transferred more male accessory gland protein to adult females via mating. The protein content was also affected by different combinations of treated mating pairs. Adult males (♂_t) developed from third instar nymphs treated with triazophos stimulated the fecundity of the female significantly via mating (♂_t × ♀_ck) with untreated females (♀_ck) (control females), increasing the reproductive rate by 43.5% as compared to the mating (♂_ck × ♀_ck) of untreated males and females. Also, the fecundity of the females after the mating (♂_t × ♀_t) of treated males and females was significantly higher than that after the mating (♂_ck × ♀_t) of untreated males with treated females. These findings indicated that the reproductive effects of insecticide on males can be transferred to females via mating. The present findings provide valuable information for understanding the potential role that males play in the pesticide-induced resurgence of N. lugens.     

Minerals controlling arsenic distribution in floodplain soils

As a consequence of intensive mining of the western Erzgebirge since medieval times, floodplain soils of the Mulde river contain large concentrations of arsenic (As) (>50 mg kg⁻¹). Arsenic in soil is often bound to poorly crystalline Fe and Mn (hydr)oxides, which may dissolve under reducing conditions. Part of the As may also exist in primary minerals, predominately sulphides, or in secondary minerals formed upon weathering. In order to better understand the impact of seasonal flooding, we surveyed As‐bearing mineral phases, especially of iron (Fe) (hydr)oxides. Because Fe (hydr)oxides are clay‐sized, soil samples were fractionated into six particle‐size fractions. The fractions were digested with aqua regia for determination of total element concentrations, extracted with hydroxylammonium chloride (NH₃OHCl; selective for Mn (hydr)oxides and NH₄ oxalate), and analysed by X‐ray diffraction and scanning electron microscopy. The largely similar distribution of As and lead (Pb) suggested the potential co‐existence of the two elements in primary or secondary mineral phases. However, neither As–Pb minerals nor any other As mineral were detected. Association with Mn oxides was negligible. The predominant As‐bearing phases were poorly crystalline Fe (hydr)oxides, which also incorporated large amounts of Pb and were affected by redox dynamics.