Detection of early stages of wood decay by acoustic emission technique

Acoustic emissions of pine wood samples (Pinus sylvestris L.) previously infected with the soft-rot fungi (Chaetomium globosum Kunze) and brown-rot fungi (Coniophora puteana (Schum. ex Fr.) Karst.) were measured in the perpendicular to grain compression test, in the radial direction. It was found that even a minimum mass loss (below 1%) caused by enzymatic deterioration of the wood substance resulted in an increase in acoustic emission level in the compression test measured perpendicular to grain in the radial direction. A particularly sensitive indicator of wood enzymatic destruction were cumulative counts of acoustic emission related to the value of the applied compression load. Received 4 March 1997     

Ingestion of Black Chokeberry Fruit Extract Leads to Intestinal and Systemic Changes in a Rat Model of Prediabetes and Hyperlipidemia

This report presents a complex analysis of changes proceeding in the gut, blood and internal organs of rats with induced oxidative stress, glucose intolerance and hyperlipidemia after dietary supplementation with an extract from black chokeberry (Aronia melanocarpa) fruit, that is a condensed source of polyphenols (714 mg/g), especially anthocyanin glycosides (56.6%). The disturbances mimicking those observed in metabolic syndrome were induced by a high-fructose diet and simultaneous single injection of streptozotocin (20 mg/kg). Dietary supplementation with the chokeberry fruit extract (0.2%) decreased activity of maltase and sucrase as well as increased activity of lactase in the mucosa of the small intestine. Its ingestion led also to the improvement of antioxidant status, especially, the concentration of a lipid peroxidation indicator (TBARS) in organ tissues (liver, kidney and lung) was normalized; some cholesterol-lowering and distinct hypoglycemic actions were also observed. The mechanism of glucose reduction is likely to be multifactorial, and we suggest the factors related with the decreased activity of mucosal disaccharidases important for further investigation. In conclusion, chokeberry fruit derivatives may act as a promising supplementary therapeutic option in the prevention and treatment of disorders occurring in metabolic syndrome, as well as their complications.     

Enzyme polymorphism and adaptation in strawberry clover (Trifolium fragiferum L.)

Enzymatic survey of eight loci in 22 populations of Trifolium fragiferum L. sampled in three regions in Poland showed regional differences with regard to five genetic parameters describing genetic polymorphism and variability. Differences were attributed to the following climatic variables: annual precipitation, temperature and solar radiation. Continental climatic conditions were favorable for accumulation of genetic polymorphism and variability. Vegetative reproduction versus sexual reproduction had a higher incidence rate under milder climatic conditions. This former mode of reproduction also affected patterns of distribution of variation within regions, by reducing the intra-populational component of total variability.     

Über die Prüfung des Forstsaatgutes

European Journal of Forest Research -     

The use of metapopulation and optimal foraging theories to predict movement and foraging decisions of mobile animals in heterogeneous landscapes

Metapopulation and optimal foraging theories predict the presence of animals and their duration, respectively, in foraging patches. This paper examines use of these two theories to describe the movements and patterns of foraging in patches used by Caspian gulls (Larus cachinnans) at inland reservoirs during the chick-rearing period. We assumed that birds would move differently across diverse habitats, with some types of land cover less permeable than others, and some landscape features acting as corridors. We also expected larger and less isolated patches, and patches that were close to corridors, to have a higher probability of the presence of foraging birds, and that they would be more abundant, forage for a shorter time, and hunt smaller prey than in small, more isolated patches surrounded by barriers. Forests seem to be a much less permeable type of land cover, whereas rivers became corridors for Caspian gulls during foraging trips. Probability of bird presence was positively related to the size of foraging patches and negatively linked with distance to the nearest river, distance to the nearest foraging patch, and the presence of forests in the vicinity. The same factors significantly affected bird abundance. Contrary to expectations, the duration and success of foraging were not influenced by any variable we measured, suggesting that although larger patches contain a higher abundance of fish, their density and the probability of capturing prey were relatively stable among the various patches. However, gulls that foraged in more isolated ponds that were located further from the river and the colony, and also surrounded by forest, captured larger fish more often than birds that foraged near the colony in less-isolated patches. Pooling metapopulation and optimal foraging concepts seems to be valuable in describing patch use by foraging animals. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Biochemical and morphometric analysis of Rosa tomentosa and Rosa rubiginosa during application of liquid culture systems for in vitro shoot production

Two liquid culture systems, rotary shaker (RS) and temporary immersion system (TIS) for the propagation of Rosa rubiginosa and Rosa tomentosa were investigated and compared with solid medium culture. Shoot tips were grown on basic Murashige and Skoog medium with 20 mg dm^?3 Fe EDDHA, 1 µM BA, 1.5 µM GA₃ and 3% sucrose for six weeks. Of the different culture systems, liquid cultures resulted in better growth and development of roses. Both RS and TIS cultures improved biomass growth, multiplication rate, leaf blade area and plant height; however, RS reduced the shoot dry mass content. There were no changes in the content of chlorophyll a, b, a + b in plants developed in the tested systems. Use of a solid medium favoured the accumulation of phenolic compounds, soluble sugars, and carotenoids, but it was accompanied by browning and necrosis of shoots. Plants propagated in TIS were characterised by the high content of phenolic compounds and soluble sugars, but they had the highest multiplication rate. Use of TIS resulted in eight times the number of shoots for R. tomentosa and twice as many for R. rubiginosa compared to solid medium.     

New winter oilseed rape varieties – seed quality and morphological traits depending on sowing date and rate

Many studies have focused on research about impact of time and density of sowing on the agronomic characteristics of different crops. However, the number of studies investigating such a response on the qualitative composition of different types of winter oilseed rape varieties is still limited. The aim of the research was to determine the effect of sowing date and density on yield, protein and oil content and quality of winter oilseed rape varieties: open-pollinated, a typical hybrid of traditional type of growth and a new semi-dwarf hybrid, which biology and yielding have not been thoroughly established. This experiment was conducted applying four sowing dates (August 14, August 25, September 4, September 15), three winter oilseed rape cultivars (PR45D03 -semi-dwarf hybrid, PR46W31 – hybrid, Californium – open-pollinated) and four sowing rates (30, 40, 50, 60 seeds/m²). Among the compared sowing dates, August 25 proved to be optimal for yielding of the tested winter oilseed rape cultivars. Semi-dwarf variety contained less protein and glucosinolate in seeds, but more oil in comparison to other studied varieties (hybrid and open-pollinated). The yields did not differ significantly within a density of 40, 50, 60 seeds/m², so it is important result, especially for the agricultural practice.     

An assessment of the concentrations of PCDDs/Fs in contaminated bottom sediments and their sources and ecological risk

Purpose

The purpose of the study was to determine the levels of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F), two types of persistent organic pollutant (POP), in an urban retention reservoir located in an industrial zone within a coal-mining region. It also assesses the potential ecological risk of the PCDDs/Fs present in bottom sediments and the relationship between their content and the fraction of organic matter.

Materials and methods

The sediment samples were collected from Rybnik Reservoir, located in the centre of the Rybnik Coal Region, Silesia, one of Poland’s major industrial centres. Seventeen PCDD/F congeners in the surface of the sediments were analysed using high-resolution gas chromatography and high-resolution mass spectrometry (HRGC/HRMS).

Results and discussion

The toxic equivalency (TEQ) of the PCDDs/Fs in the sediments ranged from 1.65 to 32.68 pg TEQ g^?1. PCDDs constituted 59–78% of the total PCDDs/Fs, while the PCDFs accounted for 22–41%. The pattern of PCDD/F congeners in the sediments was dominated by OCDD. However, the second-most prevalent constituents were OCDF and ∑HpCDFs in the low TOC sediment (< 10 g TOC kg^?1), but HpCDD in the rich TOC samples (> 10 g TOC kg^?1). PCDD/F concentrations in the sediment samples were 2- to 38-fold higher than the sediment quality guidelines limit, indicating high ecological risk potential. Although a considerable proportion of PCDDs/Fs in the bottom sediments from the Rybnik Reservoir were derived from combustion processes, they were also obtained via transport, wastewater discharge, high-temperature processes and thermal electricity generation. The PCDD/F concentrations were significantly correlated with all fractions of organic matter; however, the strongest correlation coefficients were found between PCDDs/Fs and humic substances. Besides organic matter, the proportions of silt/clay fractions within sediments played an important role in the transport of PCDDs/Fs in bottom sediments.

Conclusions

The silt/clay fraction of the bottom sediments plays a dominant role in the movement of PCDDs/Fs, while the organic matter fraction affects their sorption. The results indicate that the environmental behaviour of PCDDs/Fs is affected by the quantity and quality of organic matter and the texture of sediments.

     

Soil properties and not high CO2 affect CH4 production and uptake in periodically waterlogged arable soils

Journal of Soils and Sediments - Several studies related to CH4 cycling focus on the effect of elevated atmospheric CO2 levels on soil methanogenesis and methanotrophy. However, periodically...