Piping and erodibility of loessic soils in Bergisches Land,Nordrhein‐Westfalen

In soils derived from loess on a range land site in the Rhenish Slate Mountains pipes were found at 120—190 cm depth above denser solifluction material. The pipes were 5—30 cm wide and 15—30 cm high. Various soil physical and chemical properties were determined and checked for their suitability as piping indicators. Silt contents reached 808 g kg^—1 in the piped soil sections where bulk densities were low to medium in comparison with clay rich and denser horizons beneath. Aggregate stabilities indicated by dispersion features, percolation rates, and dispersion ratios were suitable parameters to indicate piping vulnerability. Organic carbon contents tended to be low in the piped horizons, but there was no relationship between base saturation, ESP or EC values, and piping in the investigated soils.     

Effects of teat position on selected milk components of primiparous sows during lactation

The composition of sow colostrum and milk from single teats were characterized in 20 primiparous German Landrace sows at ten points throughout lactation time (after birth of the first piglet, and subsequently at 12 and 24 h, 3, 5, 7, 14, 21, 28 and 35 d postpartum). In these samples contents of protein, IgG, lactose and fat were analyzed. In the first 3 days of lactation protein- and IgG-contents drastically decreased, on the other hand the levels of energy resources lactose and fat increased. Significant effects of the single teat and the teat pair on the content of protein at farrowing and 12 h later as well as on the contents of IgG and lactose 12 h postpartum were found. The highest contents of protein and IgG were analyzed in colostrum of teats in the median udder section, the colostrum of cranial teats had the highest content of lactose. At days 3 and 5 of lactation milk showed large coefficients of variation (cv) in milk composition from teat to teat as well as from sow to sow (intraindividual cv: protein: 22%, IgG: 45%, lactose: 20%, fat: 34%; interindividual cv: protein: 36%, IgG: 85%, lactose: 27%, fat: 47%). During lactation period the intraindividual variation of milk parameters was lower than the interindividual variation. Possible reasons for these results are discussed.     

Response of soil microbial biomass and enzyme activities to the transient elevation of carbon dioxide in a semi-arid grassland

Although elevation of CO₂ has been reported to impact soil microbial functions, little information is available on the spatial and temporal variation of this effect. The objective of this study was to determine the microbial response in a northern Colorado shortgrass steppe to a 5-year elevation of atmospheric CO₂ as well as the reversibility of the microbial response during a period of several months after shutting off the CO₂ amendment. The experiment was comprised of nine experimental plots: three chambered plots maintained at ambient CO₂ levels of 360 μmol mol⁻¹ (ambient treatment), three chambered plots maintained at 720 μmol mol⁻¹ CO₂ (elevated treatment) and three unchambered plots of equal ground area used as controls to monitor the chamber effect.Elevated CO₂ induced mainly an increase of enzyme activities (protease, xylanase, invertase, alkaline phosphatase, arylsulfatase) in the upper 5 cm of the soil and did not change microbial biomass in the soil profile. Since rhizodeposition and newly formed roots enlarged the pool of easily available substrates mainly in the upper soil layers, enzyme regulation (production and activity) rather than shifts in microbial abundance was the driving factor for higher enzyme activities in the upper soil. Repeated soil sampling during the third to fifth year of the experiment revealed an enhancement of enzyme activities which varied in the range of 20-80%. Discriminant analysis including all microbiological properties revealed that the enzyme pattern in 1999 and 2000 was dominated by the CO₂ and chamber effect, while in 2001 the influence of elevated CO₂ increased and the chamber effect decreased.Although microbial biomass did not show any response to elevated CO₂ during the main experiment, a significant increase of soil microbial N was detected as a post-treatment effect probably due to lower nutrient (nitrogen) competition between microorganisms and plants in this N-limited ecosystem. Whereas most enzyme activities showed a significant post-CO₂ effect in spring 2002 (following the conclusion of CO₂ enrichment the previous autumn, 2001), selective depletion of substrates is speculated to be the cause for non-significant treatment effects of most enzyme activities later in summer and autumn, 2002. Therefore, additional belowground carbon input mainly entered the fast cycling carbon pool and contributed little to long-term carbon storage in the semi-arid grassland.     

Zur Untersuchung der verschiedenen Formen von Chlorophyll in der lebenden Pflanze durch Anwendung der Derivativ-Spektrophotometrie

Zusammenfassung Die Anwendung der Derivativ-Spektrophotometrie ermöglicht eine bessere Auflösung der sich sehr stark überlagernden Absorptionsbanden der verschiedenen Chlorophyll a-Formen in vivo im Vergleich zur üblichen spektroskopischen Technik. Untersuchungen von Gleichungen zur Beschreibung der Form von Absorptionsbanden und ihren 1. und 2. Ableitungen führen zu dem Ergebnis, daß sich durch die Differentiation die Halbwertsbreite verringert und damit das Auflösungsvermögen erhöht. Die 2. Ableitung zeigt sich dabei der 1. Ableitung überlegen.Apparative Möglichkeiten für die direkte Registrierung differenzierter Absorptionskurven werden untersucht. Unter Anwendung eines dabei auftretenden einfachen Prinzips wurde eine Apparatur gebaut, mit der neben der Extinktion und ihrer 1. Ableitung auch die 2. Ableitung nach der Wellenlänge registriert werden kann, die bisher nicht für Untersuchungen der Blattpigmente herangezogen wurde.Einige mit diesem Gerät aufgezeichnete Spektren demonstrieren die Vorteile der Derivativ-Spektrophotometrie, insbesondere für die Untersuchung der photosynthetischen Pigmente in vivo.

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Summary The strongly overlapping absorption bands of chlorophyll a forms in vivo are better resolved by derivative spectrophotometry than by ordinary absorption spectra. It was possible to demonstrate by eximation of equations describing the form of absorption bands and their first and second derivatives, that the half width of an absorption band is reduced by differentiation and therefore the resolving power is increased. The second derivative is shown to be superior to the first one.By examining apparative possibilities for recording directly differentiated absorption curves a simple principle was found, according to which an apparatus was constructed, that allows to record the direct absorbance spectrum, its first and its second derivative.Till now the second derivative of the absorption spectrum is not used for studying the leaf pigments.Some spectra, recorded with this apparatus, demonstrate the advantages of derivative spectrophotometry, especially for analysing photosynthetic pigments in vivo.

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Silicon identification in prosthesis-associated fibrous capsules

The use of correlated microscopic techniques, including the scanning electron microscopic modes of backscattered electron imaging and energy dispersive x-ray analysis, aid in defining the process of dispersion of silicon-containing material around silicone rubber (polydimethylsiloxane) prosthetic devices.     

Bacterial spot of capsicum and tomato in Yugoslavia

The causal agent of bacterial spot of capsicum and tomato grown in different regions in Yugoslavia was investigated. Isolations were made from diseased material collected in recent years. The biochemical and physiological characteristics of isolated bacteria were studied by standard bacteriological tests. The race of the pathogen was determined on differential cultivars of capsicum and tomato. The causal agent of the disease was identified according to the concepts of the time as Xanthomonas campestris pv. vesicatoria. Strains isolated from diseased capsicum were non-pectolytic and non-amylolytic, and did not infect tomato plants. According to the reaction of capsicum cv. Early Calwonder and its isogenic lines, these strains belonged to'pepper races'1 and 3 of X. vesicatoria. Tomato strains showed pectolytic and amylolytic activity and were not pathogenic to capsicum. Accordingly, the capsicum strains could now be considered to be X. axonopodis pv. vesicatoria and the tomato strains X. vesicatoria.