In search for the ecological and toxicological relevance of sediment re-mobilisation and transport during flood events

In response to increasing concerns about the potential toxicological impacts of (extreme) flood events, scientists from several disciplines have joined to form the interdisciplinary research project named FLOODSEARCH. FLOODSEARCH is one of the recent Pathfinder Projects supported by the German Excellence Initiative via the Exploratory Research Space at RWTH Aachen (ERS). FLOODSEARCH aims to combine methodologies of hydraulic engineering and ecotoxicology in a new interdisciplinary approach to assess the risks associated with the re-mobilisation of particulate bound contaminants often observed after severe flood events. Impacts of extreme flood events and aspects of re-mobilisation of sediment-bound toxic compounds will be characterised and evaluated in controlled experiments fusing flood simulation technologies with biological effects assessment. The overall goal is to establish a novel and more realistic approach towards flood event testing that can be applied to a number of different questions and species. Specifically, model aquatic species such as rainbow trout (Onchorhynchus mykiss) will be exposed to particle-bound contaminants in flood-like conditions in a specifically designed annular flume that permits monitoring of both physical/chemical and biological parameter. Ultimately, this approach will assist to further our understanding of the potential biological risks associated with increasingly frequent extreme flood events, e.g., as a consequence of climate change, by bridging the gap between the physical (re-)mobilisation of contaminants and resulting toxicological impacts on aquatic organisms. Thus, it is the objective of the project to derive relationships between the hydrodynamic parameters such as velocities and turbulences, the parameters associated to sediment transport such as sediment concentration and grain sizes and the biological parameters.     

Cultivar variability of patatin biochemical characteristics: table versus processing potatoes (Solanum tuberosum L.)

Biochemical characteristics of patatin proteins purified by ion-exchange and affinity chromatography from tubers of 20 potato cultivars were studied to evaluate their genotype differences with respect to utility groups, table potato cultivars (TPCs) and processing potato cultivars (PPCs). Both groups of cultivars showed similar values of protein content in dry matter (3.98-7.39%) and of patatin relative abundance (5.40-35.40%). Three mass levels (～40.6, 41.8, and 42.9 kDa) of purified patatins were found by MALDI-TOF MS within all cultivars. Differences among mass levels corresponding with the mass of sugar antenna (～1.2 kDa) confirmed the previous concept of different glycosylation extentsin patatin proteins. It was showed that the individual types of patatin varying in their masses occur in the patatin family in a ratio specific for each of the cultivars, with the lowest mass type being the major one. Electrophoretic analyses demonstrated wide cultivar variability in number of patatin forms. Especially 2D-PAGE showed 17-23 detected protein spots independently on the utility group. Specific lipid acyl hydrolase (LAH) activity of purified patatins from the individual tested cultivars varied between 0.92 and 5.46 μmol/(min mg). Patatin samples within most of the TPCs exhibited higher values of specific LAH activity than samples of PPCs. It may be supposed that individual patatin forms do not have similar physiological roles.     

Morphological characteristics of some accessions of grass pea (<Emphasis Type="Italic">Lathyrus sativus</Emphasis> L.) grown in Europe and nutritional traits of their seeds

Thirty-one European accessions of grass pea (Lathyrus sativus L.) originating from Italy, Spain, Northern France, Germany and Poland grown in the same soil-climatic conditions in Poland were investigated. The morphological traits as well as the seed morphology and nutrient contents were studied. Substantial differentiation in some morphological characteristics was noticed. The plants could be assigned to two groups: one group comprising the lines from the Mediterranean basin (Italy and Spain) and the other group containing the accessions from West-central Europe (Northern France, Germany and Poland). The grass pea plants produced from the seeds obtained from West-central Europe appeared to be about 10 cm taller than the Mediterranean accessions and had predominantly white flowers. Their seeds were more than two times smaller than seeds of the accessions of Italian or Spanish origin. There were not noted any considerable differences in nutrient contents or antinutritional factors in seeds between these two groups of Lathyrus accessions. A negative correlation between β-ODAP and tannin contents (r = −0.379, P ≤ 0.05) and a positive correlation (r = 0.843, P ≤ 0.01) between a tannin content and flower color intensity were found. A white or crème colour was associated with a low tannin level in the seeds, while the colourful blooming accessions had higher tannin contents.     

Sensory and chemical changes in tomato sauces during storage

The present work aimed to identify the key odorants of tomato sauces responsible for the flavor change during storage. Products made from paste or canned tomatoes were stored at 25 and 40 degrees C. Sensory properties and quantification of the key odorants were measured and correlated. Significant sensory changes appeared after 1 and 3 months at 25 degrees C in the respective dice and paste sauces (p < 0.01). The dice sauce was characterized by a steep loss of the sensory quality during the early storage and then by identical changes within the same time span at 25 and 40 degrees C. In the paste sauce the sensory deterioration was slower than for the dice sauce and occurred more extensively at 40 degrees C than at 25 degrees C. Correlation between sensory and instrumental data revealed that the source of sensory changes should be (E,E)-deca-2,4-dienal in the dice sauce. The sensory change in the paste sauce could be due to acetaldehyde, methylpropanal, 3-methylbutanal, oct-1-en-3-one, 3-methylbutanoic acid, deca-2,4-dienal, 2-methoxyphenol, and beta-damascenone.     

Air Pollution and Lichen Physiology. Physiological Responses of Different Lichens in a Transplant Experiment Following an SO2-Gradient

Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.)Ach., and Bryoria fuscescens (Gyelnik) Brodo andHawksworth were exposed during autumn and winter at differentsites of the Erzgebirge (Ore Mountains), the Fichtelgebirge andcontrol sites. All lichens tested became visibly damaged withtime. Thallus bleaching started from the edges and went on tothe centre of the thallus. Sites of facilitated gas exchangelike the soralia of P. sulcata and the pseudocyphelles ofC. islandica became preferentially bleached. The sulfateconcentration increased with exposure time reaching 200% ofunpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and otherintracellular metabolites were leached from the thalli due tomembrane damage. The changes in the K-concentration proved tobe an excellent measure for membrane leakiness; it wascorrelated with time of exposure and with SO₂ concentrations at the different sites. Photosynthetic capacityand respiration were also strongly affected. Depending on theSO₂-dose, the Bryoria species were unable tophotosynthesize as early as 4–8 weeks after exposure, whereasCetraria and Hypogymnia showed clear reduction intheir ability to photoreduce CO₂ within 8–10 weeks ofexposure in the field. Parmelia sulcata was found to bethe most tolerant species. After 3–4 months, photosynthesis wasreduced by only 30%. The bioindicative value of theseobservations is discussed.     

Enzyme activities and microbial biomass in topsoil layer during spontaneous succession in spoil heaps after brown coal mining

Changes in the activity of extracellular enzymes (cellobiohydrolase, β-glucosidase, β-xylosidase, chitinase, arylsulfatase and phosphatases) and the changes in microbial community and abiotic properties in the topsoil layer, as well as soil abiotic properties during primary succession were investigated in a brown coal mine deposit area near Sokolov, Czech Republic. The study considered the chronosequence of 4 post-mining plots, 4-, 12-, 21- and 45-year old. The 4-year old site had no vegetation cover. Herbs and grasses (mainly Calamagrostis epigeios) were present on the 12-year old plot, shrubs (Salix caprea) occurred on the 21-year old plot and tree cover (Betula spp. and Populus tremuloides) developed on the 45-year old plot. Soil pH gradually decreased with site age, while the content of P, K, C and N peaked in the 21-year old site, being significantly lower in the 45-year old site and much lower in the 4- and 12-year old sites. Phosphatase activities were strongly affected by seasonality while the activities of all the other enzymes measured were more influenced by the effects of succession age and soil layer than by seasonality. Succession age was also the most important factor affecting the total and bacterial PLFA contents, followed by the effects of soil layer and season while for the fungal biomass content-related properties (ergosterol, fungal PLFA and the fungal/bacterial PLFA ratio), season was the most important. Activities of individual enzymes in the topsoil (0–5 cm depth) were significantly affected by both site age and season. Cellobiohydrolase and β-xylosidase were more affected by site age while chitinase and phosphatases were more affected by season. Enzyme activity increased with succession age. Comparison of the effect of site and season on enzyme activity showed that season played a principal role in the enzyme activity of the entire 0–5 cm component of topsoil, as well the soil layers when evaluated separately.     

Interaction of Rhizobium and Pseudomonas with Wheat (Triticum Aestivum L.) in Potted Soil with or Without P2O5

The effect of inoculation of Rhizobium or Pseudomonas, or both, in the presence and absence of phosphorus pentoxide (P₂O₅) fertilizer on wheat yield was tested. The experiment was conducted outdoors in potted soil during two consecutive years under natural conditions. Rhizobial strain (Thal 8-chickpea nodulating bacteria) and Pseudomonas strain (54RB), both indigenous P solubilizers were applied in broth culture at seedling stage. Fertilizer in the form of P₂O₅ was an additional treatment applied at sowing time. Results revealed that inoculation of Pseudomonas strain in presence of phosphorus (P) fertilizer increased yield up to 41.8% when it was compared with only P fertilizer applied. Co-inoculation of Rhizobium and Pseudomonas strains with the P₂O₅ treatment however resulted in increased grains yield by 10% over the P₂O₅ treatment alone. It is inferred that inoculation with Rhizobium and Pseudomonas combined with P₂O₅ is not only environmentally beneficial but also economically sound and productive, with wheat yield increases of 10% to 42%.     

Impact of Heat Treatment on Wheat Flour Solvent Retention Capacity (SRC) Profiles

The impact of heat treating wheat flour (for 2 or 5 h at 80 or 100°C) on its functional properties was studied with solvent retention capacity (SRC) tests and related to changes in individual groups of flour constituents. Heat treatments increased the overall water retention capacity (from 55.6% for control flour to 62.4% for flour heated 5 h at 100°C) as well as sucrose SRC (from 85.0 to 113.5%), although no changes were observed in sodium carbonate SRC. The decrease in lactic acid SRC values (from 113.1 to 97.4%) indicated that heat treatment restricted swelling of the protein network. As deduced from a decrease in both the level of proteins extractable in sodium dodecyl sulfate–containing medium and the level of free sulfhydryl groups, the restricted swelling was related to protein cross‐linking within the flour particles. Such upfront polymerization prevented proper hydration and gluten network formation during mixing. Starch (swelling) properties were also affected by heat treatment. Finally, the impact of heat treatment on flour SRC profiles was comparable to that noted when chlorinating wheat flour.     

EFFECT OF NITROGEN AND SULFUR FERTILIZATION ON YIELD COMPONENTS,SEED AND OIL YIELDS OF CANOLA

Field experiments were conducted to evaluate the effects of nitrogen (N) and sulfur (S) levels and their methods of application on canola. Branches plant^?1, pods plant^?1 and biological yield significantly increased with increase in nitrogen level and no significant increase in seed pod^?1 and seed and oil yields occurred beyond 120 kg N ha^?1. However, thousand seed weight consistently decreased with increasing level of nitrogen. Pods plant^?1 and biological yield continually increased with increase in sulfur level. Alternatively, significant increase in branches plant^?1, seed pod^?1, seed weight, seed and oil yields was noted with increase in sulfur level up to 40 kg ha^?1. Applications of sulfur and nitrogen in split significantly decreased seed yield as compared to sole applications. It is concluded that sulfur and nitrogen application as sole at the rate of 40 and 120 kg ha^?1, respectively performed better than the rest of their levels and method of application.