Dissolved and colloidal phosphorus fluxes in forest ecosystems—an almost blind spot in ecosystem research

Understanding and quantification of phosphorus (P) fluxes are key requirements for predictions of future forest ecosystems changes as well as for transferring lessons learned from natural ecosystems to croplands and plantations. This review summarizes and evaluates the recent knowledge on mechanisms, magnitude, and relevance by which dissolved and colloidal inorganic and organic P forms can be translocated within or exported from forest ecosystems. Attention is paid to hydrological pathways of P losses at the soil profile and landscape scales, and the subsequent influence of P on aquatic ecosystems. New (unpublished) data from the German Priority Program 1685 “Ecosystem Nutrition: Forest Strategies for limited Phosphorus Resources” were added to provide up‐to‐date flux‐based information. Nitrogen (N) additions increase the release of water‐transportable P forms. Most P found in percolates and pore waters belongs to the so‐called dissolved organic P (DOP) fractions, rich in orthophosphate‐monoesters and also containing some orthophosphate‐diesters. Total solution P concentrations range from ca. 1 to 400 µg P L^?1, with large variations among forest stands. Recent sophisticated analyses revealed that large portions of the DOP in forest stream water can comprise natural nanoparticles and fine colloids which under extreme conditions may account for 40–100% of the P losses. Their translocation within preferential flow passes may be rapid, mediated by storm events. The potential total P loss through leaching into subsoils and with streams was found to be less than 50 mg P m^?2 a^?1, suggesting effects on ecosystems at centennial to millennium scale. All current data are based on selected snapshots only. Quantitative measurements of P fluxes in temperate forest systems are nearly absent in the literature, probably due to main research focus on the C and N cycles. Therefore, we lack complete ecosystem‐based assessments of dissolved and colloidal P fluxes within and from temperate forest systems.     

Influence of lignification and feruloylation of maize cell walls on the adsorption of heterocyclic aromatic amines

Both epidemiological and experimental data indicate that a diet rich in fiber may reduce cancer risk. One possible mechanism is by adsorbing carcinogens and transporting them out of the body without metabolic activation. We investigated the role of fiber lignification and feruloylation on the adsorption of four of the most relevant heterocyclic aromatic amines in food: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and 2-amino-9H-pyrido[2,3-b]indole (AalphaC). Adsorption experiments, under conditions mimicking the small intestine, were carried out using nonlignified and artificially lignified primary maize walls with defined lignin and ferulate/diferulate concentrations and defined lignin compositions. Lignin concentration and composition both influenced the adsorption of heterocyclic aromatic amines, especially the more hydrophobic types. Heterocyclic aromatic amine adsorption increased with lignin concentration. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and 2-amino-9H-pyrido[2,3-b]indole were better adsorbed by guaiacyl-rich lignins, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by syringyl-rich lignins, whereas the adsorption of 2-amino-3-methylimidazo[4,5-f]quinoline was not clearly influenced by lignin composition. Nonlignified cell walls adsorbed lesser amounts of heterocyclic aromatic amines. Variations in cell wall feruloylation had no effect on heterocyclic aromatic amine adsorption.     

Annual survival probabilities of juvenile loggerhead sea turtles indicate high anthropogenic impact on Mediterranean populations

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Climate Change, Risk and Grain Yields in China

Adopting Just and Pope (1978, 1979) style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. We find that changes in climate will affect grain production in North and South China differently. Specifically, it emerges that a 1℃ increase in annual average temperature could reduce national grain output by 1.45% (1.74% reduction in North China and 1.19% reduction in South China), while an increase in total annual precipitation of around 100 mm could increase national grain output by 1.31% (3.0% increase in North China and 0.59% reduction in South China).     

Stilbene levels in grape cane of different cultivars in southern Chile: determination by HPLC-DAD-MS/MS method

Health benefits of trans-resveratrol and other stilbenes in grapes, must, and wine have been pointed out by numerous authors. Less attention has been paid to the presence of stilbene derivatives in viticultural residues, such as grape canes. The present work reports the first results of a systematic study of stilbene levels in different grape varieties and cultivation areas in Chile, to evaluate their potential as an alternative source of bioactive stilbenes. In all cane samples, the predominant stilbene is trans-resveratrol, followed by ε-viniferin and piceatannol. In canes of Pinot noir up to 5590 ± 172 mg kg(-1) of trans-resveratrol and up to 6915 ± 175 mg kg(-1) of total stilbenes were detected. The observed concentrations of stilbenes in canes of Pinot noir from southern Chile until now are higher than those reported previously for this red variety. However, the highest concentration of total stilbenes observed in the analyzed samples was in the canes of white variety Gewürztraminer with 7857 ± 498 mg kg(-1). Preliminary results indicate that these levels can evolve if canes are left for some months on the vineyard after pruning, observing an increase during the first 2 months and a decrease after this period.     

Intra-varietal genetic diversity of the grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) cultivar ‘Nero d’Avola’ as revealed by microsatellite markers

The Sicilian grape cultivar ‘Nero d’Avola’ is among the oldest and most cultivated in the island, taking part in the production of several red wines exported worldwide, including DOC wines (Etna Rosso and Cerasuolo di Vittoria). Due to the ancient origin and repeated clonally propagation of the cultivar, phenotypic variability has been observed. Clone identification in this important cultivar has so far relied on phenotypic and chemical traits analyses, often affected by environmental conditions. Genetic markers, such as microsatellites, are particularly useful for cultivar identification, parentage testing, pedigree reconstruction and population structure studies. In the present paper, microsatellites were used to analyze the intra-varietal genetic diversity among 118 plants of ‘Nero d’Avola’, collected in 30 vineyards displaced in different areas of Sicily. Out of 22 microsatellites, 11 showed polymorphism among samples and 15 different phylogenetic groups were identified. Results show that ‘Nero d’Avola’ actually comprises different genetic profiles, although most of clones share a common origin.     

Evaluation of non-chemical seed treatment methods for the control of Alternaria dauci and A. radicina on carrot seeds

The current study was initiated to evaluate the efficacy of physical methods (hot water, aerated steam, electron treatment) and agents of natural origin (resistance inducers, plant derived products, micro-organisms) as seed treatments of carrots for control of Alternaria dauci and A. radicina. Control of both Alternaria species by seed treatment with the resistance inducers was generally poor. Results were also not satisfactory with most of the formulated commercial micro-organism preparations. Based on the average of five field trials, one of these, BA 2552 (Pseudomonas chlororaphis), provided a low but significant increase in plant stand. Among the experimental micro-organisms, the best results were obtained with Pseudomonas sp. strain MF 416 and Clonostachys rosea strain IK726. A similar level of efficacy was provided by seed treatment with an emulsion (1%) of thyme oil in water. Good and consistent control was generally achieved with the physical methods aerated steam, hot water and electron treatment. Aerated steam treatment was, apart from the thiram-containing chemical standard, the best single treatment, and its performance may at least partially be due to extensive pre-testing, resulting in dosages optimally adapted to the respective seed lot. In some of the experiments the effect of the hot water treatment, which was tested at a fixed, not specifically adapted dosage, was significantly improved when combined with a Pseudomonas sp. MF 416 or C. rosea IK726 treatment. The results are discussed in relation to the outcome of experiments in which the same seed treatment methods and agents were tested in other seed-borne vegetable pathosystems.     

The herbicide binding niche of photosystem II-a model

The Q_B binding niche of photosystem II is also the binding site for many different herbicides. In order to understand the mode of binding of the herbicides, a 3-dimensional model of the binding niche was constructed. The model was based upon a comparison of the known structure of the Q_B binding niche in purple bacteria with sequence and mutant data of the D-1 protein of photosystem II. Plastoquinone builds up hydrogen bonds to phenylalanine 265 backbone amide nitrogen, to serine 264 hydroxyl, and to histidine 215 delta-1 nitrogen. In addition to these hydrogen bond donors and acceptors, herbicides can build up hydrogen bonds to backbone carbonyl of alamine 263 and to serine 268 hydroxyl. This is supported by binding data of inhibitors in Chlamydomonas reinhardtii chloroplasts of wild type and of five D-1 protein mutants (Ser264 Ala, Ala251 Val, Phe255Tyr, Val2191le, Leu275Phe).     

Female reproductive success in a species with an age‐inversed hierarchy

In most group‐living mammals, reproductive success declines with increasing age and increases with increasing rank. Such effects have mainly been studied in matrilineal and in “age positive” hierarchies, which are stable and in which high ranking females often outperform low ranking ones. These relationships are less well‐understood in age‐inversed dominance hierarchies, in which a female's rank changes over time. We analyzed demographic data of 2 wild, unprovisioned groups of gray langurs (Semnopithecus schistaceus) near Ramnagar, Nepal covering periods of 5 years each. Female rank was unstable and age‐inversed. We measured reproductive success via birth rates (57 births), infant survival (proportion of infants surviving to 2 years) and number of offspring surviving to 2 years of age (successful births) for 3 age and 3 rank classes. We found that old females performed significantly worse than expected (birth rate P = 0.04; successful births P = 0.03). The same was true for low ranking females (P = 0.04, and P < 0.01, respectively). Infant survival was highest for young and middle‐aged as well as for high and middle ranking females. Overall, the results for these unstable hierarchies were rather similar to those for stable hierarchies of other mammals, particularly several nonhuman primates. Compared to a provisioned population of a closely related species, the wild and unprovisioned population examined (i) showed stronger age effects, while (ii) female reproductive success was equally affected by rank. Future comparative studies are needed to examine whether captive or provisioned populations deviate predictably from wild populations.