Zur Kenntnis der Biologie einiger Dermestes-Arten

Ohne ZusammenfassungStaufen/Breisgau. 7. Beitrag     

Negative charge — pH dependence of organic matter of forest soil under influence of liming as determined from titration curves

The dependences between negative charge and pH for organic matter of limed and unlimed profiles of sandy acidic forest soils were determined on the base of ion exchange and titration curves measurements. Subtracting the titration curves of the supernatant from the titration curves of the respective suspensions the quantities of base consumed by solid phases were determined. They were interpreted in terms of negative charge after corrections with the quantities of initial exchangeable basic cations and exchangeable hydrogen. For investigated organic material the charge increased slowly in acidic pH region and much faster in alkaline pH region. The zones of the fast increase of charge occured at higher pH's for deeper horizons, enriched with fulvic acids. The observed changes of organic matter charge due to liming were related to the increase of fulvic to humic acids ratio. The negative charges of organic matter in limed and unlimed profiles estimated for high pH were better correlated with fulvic to humic acids ratio than when estimated for lower pH levels.     

Large magnetic anisotropy of a single atomic spin embedded in a surface molecular network

Magnetic anisotropy allows magnets to maintain their direction of magnetization over time. Using a scanning tunneling microscope to observe spin excitations, we determined the orientation and strength of the anisotropies of individual iron and manganese atoms on a thin layer of copper nitride. The relative intensities of the inelastic tunneling processes are consistent with dipolar interactions, as seen for inelastic neutron scattering. First-principles calculations indicate that the magnetic atoms become incorporated into a polar covalent surface molecular network in the copper nitride. These structures, which provide atom-by-atom accessibility via local probes, have the potential for engineering anisotropies large enough to produce stable magnetization at low temperatures for a single atomic spin.     

Antimicrobial activity of textiles with selected dyes and finishing agents used in the textile industry

It is shown in this paper that cationic dyes and chemical finishing agents for textiles exhibit antimicrobial properties both in solution and when present on textile products. The dye Maxilon Navy 2RM has particularly high antimicrobial activity — its values of the minimum concentration inhibiting the growth of the studied microorganisms (MIC and MBC) are very low, in the range 0.0003–0.06 %. The tested dyes display mainly fungistatic action, while the fiber softener Sapamine OC and the dyeing fixative wet fastness improver Albafix WFF were more active against bacteria. The paper presents sensitivity series of microorganisms with respect to the tested dyes and finishing agents. Fabrics to which the substances had been applied showed reductions in microorganism numbers by 16 % to 99.9 %, depending on the type of substance and the microorganism. The studies showed that in some cases the use of a typical (justified technologically) quantity of dye or finishing agent imparts high antimicrobial activity to the textile materials, with bacteria or fungi reduced by more than 99 %.     

Effect of Drip Boron Fertigation on Yield and Fruit Quality in a High-Density Apple Orchard

ABSTRACT

This study was carried out in 2001–2003 at the Experimental Orchard of the Research Institute of Pomology and Floriculture, Skierniewice, Poland, on mature ‘Jonagold’ apple (Malus domestica Borkh.) trees (M.26 EMLA) planted at 4 × 2.5 m spacing on a sandy loam soil with low boron (B) availability. The trees were drip fertigated with B at rates of 0.5, 1, or 1.5 g tree^{? 1} over 4 weeks at 3-d intervals beginning at the stage of bud break. Plants that did not receive B via drip irrigation system served as a control. Drip B fertigation effectively increased water-soluble B concentrations in the soil and the status of this microelement in leaves of current season shoots. However, the B fertigation had no effect on tree vigor. In 2 out of 3 years, the drip B fertigation improved flower B status, fruit set, and yield. The efficiency of the drip B fertigation was not influenced by B rate. In all growing seasons, the drip B fertigation increased B level and a soluble solids concentration in the fruit flesh, but had no effect on mean fruit weight, color, titratable acidity, and fruit firmness. It was concluded that on coarse-textured soils with low B availability, the drip B fertigation of mature apple trees in high-density orchards can be recommended from the stage of bud burst to petal fall at a rate of 0.5 g tree^{? 1}.     

QTLs for potato tuber resistance to Dickeya solani are located on chromosomes II and IV

The goal of this research was to identify quantitative trait loci (QTLs) for potato tuber resistance to the soil- and seedborne bacterium Dickeya solani and for tuber starch content, to study the relationship between these traits. A resistant diploid hybrid of potato, DG 00-270, was crossed with a susceptible hybrid, DG 08-305, to generate the F₁ mapping population. Tubers that were wound-inoculated with bacteria were evaluated for disease severity, expressed as the mean weight of rotted tubers, and disease incidence, measured as the proportion of rotten tubers. Diversity array technology (DArTseq) was used for genetic map construction and QTL analysis. The most prominent QTLs for disease severity and incidence were identified in overlapping regions on potato chromosome IV and explained 22.4% and 22.9% of the phenotypic variance, respectively. The second QTL for disease severity was mapped to chromosome II and explained 16.5% of the variance. QTLs for starch content were detected on chromosomes III, V, VI, VII, VIII, IX, XI, and XII in regions different from the QTLs for soft rot resistance. Two strong and reproducible QTLs for resistance to D. solani on potato chromosomes IV and II might be useful for further study of candidate genes and marker development in potato breeding programmes. The relationship between tuber resistance to bacteria and the starch content in potato tubers was not confirmed by QTL mapping, which makes the selection of genotypes highly resistant to soft rot with a desirable starch content feasible.     

Replacement of Fish Meal with Plant Feedstuffs in the Diet of Red Drum,Sciaenops ocellatus: Effects on Production Characteristics and Tolerance to Aquaculture‐Related Stressors

The continued expansion of intensive aquaculture activities requires that substitutes for fish meal‐based protein be identified. In this study, we evaluated partial (50 and 75%) replacement of fish meal in red drum, Sciaenops ocellatus, diets with soy protein concentrate (S) and barley protein concentrate (B). Growth, feed efficiency, survival, tolerance to low temperature, and tolerance to handling in warm, hypersaline water were evaluated. Only the diet with a 50% replacement of fish meal with S yielded results comparable to fish fed a nonsubstituted fish meal diet. However, the low‐temperature studies were complicated by differences in mean fish weight among the groups. The results of this study indicate S may be partially substituted for fish meal in red drum diets.     

Velvetbean (Mucuna pruriens) extracts: impact on Meloidogyne incognita survival and on Lycopersicon esculentum and Lactuca sativa germination and growth

Velvetbean (Mucuna spp.) is a summer annual that has been used as a cover crop to reduce erosion, fix nitrogen and suppress weeds and plant-parasitic nematodes. Crude aqueous extracts (1:15 dry weight plant/volume water) were made from velvetbean plant parts, and various concentrations of the extracts were evaluated in vitro for toxicities to different stages of Meloidogyne incognita (Kofoid and White) Chitwood and for suppression of hypocotyl and root growth and inhibition of germination of tomato (Lycopersicon esculentum L.) and lettuce (Lactuca sativa L.). Germination was only affected by the full-strength extract from leaf blades. Lettuce root growth was the most sensitive indicator of allelopathic activity of the plant part extracts. Lettuce and tomato root growth was more sensitive to the extract from main roots than to extracts of other plant parts, with lethal concentration (LC50) values of 1.2 and 1.1% respectively. Meloidogyne incognita egg hatch was less sensitive to extracts from velvetbean than the juvenile (J2) stage. There was no difference among LC50 values of the extracts from different plant parts against the egg stage. Based on LC50 values, the extract from fine roots was the least toxic to J2 (LC50 39.9%), and the extract from vines the most toxic (LC50 7.8%). The effects of the extracts were nematicidal because LC50 values did not change when the extracts were removed and replaced with water.     

Surface area and CEC as related to qualitative and quantitative changes of forest soil organic matter after liming

Water vapor adsorption isotherms were used for estimation of (apparent) surface areas of samples of limed and unlimed plots of an acidic sandy forest soil. Samples were taken at two microrelief (ridge and furrow) positions from five subsequent 10 cm layers. Values of surface area and CEC correlated linearly with organic matter content but only for four bottom layers. Surface areas and CEC values calculated per the unit mass of organic carbon were higher in upper layers than in lower layers for control samples. For limed samples an opposite trend was observed. The estimated average (apparent) charge densities of organic matter showed a better correlation with humic to fulvic acids ratio. Values of surface charge densities for every investigated profile increased with depth and they were lower in limed than in unlimed profiles.