Chemical characterization of an aqueous extract and the essential oil of Tithonia diversifolia and their biocontrol activity against seed-borne pathogens of rice     

Dongmo  Albert Nanfack  Nguefack  Julienne  Dongmo  Joseph Blaise Lekagne  Fouelefack  François Romain  Azah  Rene Udom  Nkengfack  Ephrem Augustin  Stefani  Emilio 《植物病害和植物保护杂志》2021,128(3):703-713

Journal of Plant Diseases and Protection - The high cost of chemical pesticides and their negative impact on the environment prompted the search for natural pesticides from plants. The objective of...  相似文献   

Changes in the nutrient composition of potatoes during home preparation: I. Proximate composition     

R. B. Toma  J. Augustin  P. H. Orr  R. H. True  J. M. Hogan  R. L. Shaw 《American Journal of Potato Research》1978,55(11):639-645

The effects of various home cooking methods on the proximate composition of four potato varieties were investigated. The results revealed significant increases in the dry matter content of tubers during oven-baking and microwave cooking. With one exception, cooking unpeeled tubers in boiling water did not significantly alter their proximate composition. Boiling peeled tubers resulted in a significant decrease in the total ash content. Except for one variety, there was a significant decrease in crude fiber in boiled peeled and oven-baked potatoes. Changes in protein values were erratic.  相似文献   

Changes in the nutrient composition of potatoes during home preparation: II. Vitamins     

Augustin  Jorg  Johnson  S. R.  Teitzel  C.  True  R. H.  Hogan  J. M.  Toma  R. B.  Shaw  R. L.  Deutsch  R. M. 《American Journal of Potato Research》1978,55(12):653-662

American Journal of Potato Research - The retention of water-soluble vitamins by several potato varieties using various home preparation methods was investigated. Retention values in general...  相似文献   

Plant rhizodeposition — an important source for carbon turnover in soils     

Birgit W. Hütsch  Jürgen Augustin  Wolfgang Merbach 《植物养料与土壤学杂志》2002,165(4):397-407

The soil organic matter plays a key role in ecological soil functions, and has to be considered as an important CO₂ sink on a global scale. Apart from crop residues (shoots and roots), left over on the field after harvest, carbon and nitrogen compounds are also released by plant roots into the soil during vegetation, and undergo several transformation processes. Up to now the knowledge about amount, composition, and turnover of these root‐borne compounds is still very limited. So far it could be demonstrated with different plant species, that up to 20 % of photosynthetically fixed C are released into the soil during vegetation period. These C amounts are ecological relevant. Depending on assimilate sink strength during ontogenesis, the C release varies with plant age. A large percentage of these root‐borne substances were rapidly respired by microorganisms (64—86 %). About 2—5 % of net C assimilation was kept in soil. The root exudates of maize were mainly water‐soluble (79 %), and in this fraction about 64 % carbohydrates, 22 % amino acids/amides and 14 % organic acids could be identified. Plant species and in some cases also plant cultivars varied strongly in their root exudation pattern. Under non‐sterile conditions the exuded compounds were rapidly stabilized in water‐insoluble forms and bound preferably to the soil clay fraction. The binding of root exudates to soil particles also improved soil structure by increasing aggregate stability. Future research should focus on quantification and characterization of root‐borne C compounds during the whole plant ontogenesis. Apart from pot experiments with ¹⁴CO₂ labeling, it is necessary to conduct model field experiments with ¹³CO₂ labeling in order to be able to distinguish between CO₂ originating from the soil C pool and rhizosphere respiration, originating from plant assimilates. Such a separation is necessary to assess if soils are sources or sinks of CO₂. The incorporation of root‐borne C (¹⁴C, ¹³C) into soil organic matter of different stability is also of particular interest.  相似文献   

The desorption solution — an alternative approach to measure water soluble ions in soils     

Mario S. Blattner  Sabine Augustin  Helmer Schack‐Kirchner  Ernst E. Hildebrand 《植物养料与土壤学杂志》2000,163(6):583-587

Although the composition of the soil solution has important ecological information, there is no general consensus for obtaining and analyzing of the soil solution. This study presents an alternative procedure to obtain the soil solution and determine all relevant anions and cations. The soil samples are taken with an auger. 10—20 g of field moist soil are desorbed in a pressure chamber at 170 kPa (pF 3.2), with a cellulose acetate membrane filter (∅︁ < 0.45 μm) as capillar bridge between the interior and exterior of the chamber. The desorption procedure is performed at 4°C for 24 hours and yields up to 1.0 ml soil solution, depending on the actual water potential. If more soil solution is needed, the soil may be replaced by another aliquot of the same sample. 0.15 ml of soil solution is sufficient for analysing all cations and anions, which account quantitatively for the ion balance with a capillary electrophoresis. Compared with suction cups, ion concentrations in desorption solutions are, although generally lower, in the same order of magnitude. The advantage of this method is that no field equipment is needed, apart from the auger. Even in heterogeneous forest soils, water soluble ions can be monitored with a high spatial resolution and without any dilution effects, which are common in the most laboratory methods. The problem of lacking spatial representativity in stationary lysimeter stations is also overcome. Additionally it is possible to obtain and analyze soil solutions in a suction range where suction cups fail.  相似文献   

Distribution of assimilated carbon in the system <Emphasis Type="Italic">Phragmites australis</Emphasis>-waterlogged peat soil after carbon-14 pulse labelling     

M. Richert  S. Saarnio  S. Juutinen  J. Silvola  J. Augustin  W. Merbach 《Biology and Fertility of Soils》2000,32(1):1-7

 Short-term (3–6 days) and long-term (27 days) laboratory experiments were carried out to determine the distribution of assimilated C in the system Phragmites australis (common reed)-waterlogged fen soil after ¹⁴C pulse labelling. The investigated system of fen plants and anaerobic organic soil showed different patterns of assimilated ¹⁴C distribution when compared to systems with cultivated plants and aerobic mineral soil. Between 90% and 95% of the ¹⁴C in the system was found in the reed plants. A maximum of 2% of the assimilated plant ¹⁴C was released from the fen soil as CO₂ and about 5–9% remained in the soil. The ¹⁴C remaining in the waterlogged fen soil of the reed plant had the same amount as that of a cultivated plant in mineral soil, despite lower ¹⁴C-release (i.e. rhizodeposition and root respiration) from reed roots. Assuming that root respiration of fen plants is low, this indicates that microbial C turnover in waterlogged fen soil is much slower than in mineral soil. The estimated quantity of the assimilated C remaining in the soil was of an ecologically relevant order of magnitude. Received: 8 July 1999  相似文献   

Book Reviews/Buchbesprechung     

G. Pfeiffer  Sankt Augustin 《Zoonoses and public health》2000,47(5):399-399

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Do postlarval amphidromous fishes transport marine‐derived nutrients and pollutants to Caribbean streams?          下载免费PDF全文

Augustin C. Engman  Thomas J. Kwak  W. Gregory Cope 《Ecology of Freshwater Fish》2018,27(3):847-856

Diadromous fishes are known biotransport vectors that can move nutrients, energy and contaminants in an upstream direction in lotic ecosystems. This function has been demonstrated repeatedly in anadromous salmonids, but the role of other diadromous species, especially tropical taxa, as biotransport vectors is less studied. Amphidromous fish species exhibit potential to act as upstream vectors of nutrients and contaminants in their postlarval and juvenile stages, but this role is largely unknown because of limited understanding of larval growth habitats. Moreover, because some species are harvested in artisanal fisheries as postlarvae, and postlarvae are consumed by riverine and estuarine predators, heavy contaminant loads may present a human or wildlife health concern. This research incorporates stable isotope and contaminant analyses to infer larval habitats and contaminant accumulation of amphidromous fishes on the Caribbean island of Puerto Rico. The isotopic signatures of postlarval amphidromous fishes indicated marine basal sources and food web components, rather than those from riverine habitats. Additionally, postlarvae did not contain concentrations of anthropogenic pollutants that would be of ecological or human health concern. These findings are the first and strongest evidence that amphidromous fish postlarvae function as biotransport vectors of marine nutrients into and up river ecosystems without posing a health threat to the receiving food web or human consumers.  相似文献   

Using the truncated auto-Poisson model for spatially correlated counts of vegetation     

Nicole H. Augustin  Jim McNicol  Carol A. Marriott 《Journal of Agricultural, Biological & Environmental Statistics》2006,11(1):1-23

With vegetation data there are often physical reasons for believing that the response of neighbors has a direct influence on the response at a particular location. In terms of modeling such scenarios the family of auto-models or Markov random fields is a useful choice. If the observed responses are counts, the auto-Poisson model can be used. There are different ways to formulate the auto-Poisson model, depending on the biological context. A drawback of this model is that for positive autocorrelation the likelihood of the auto-Poisson model is not available in closed form. We investigate how this restriction can be avoided by right truncating the distribution. We review different parameter estimation techniques which apply to auto-models in general and compare them in a simulation study. Results suggest that the method which is most easily implemented via standard statistics software, maximum pseudo-likelihood, gives unbiased point estimates, but its variance estimates are biased. An alternative method, Monte Carlo maximum likelihood, works well but is computer-intensive and not available in standard software. We illustrate the methodology and techniques for model checking with clover leaf counts and seed count data from an agricultural experiment.  相似文献   

Databases on food phytochemicals and their health-promoting effects     

Scalbert A  Andres-Lacueva C  Arita M  Kroon P  Manach C  Urpi-Sarda M  Wishart D 《Journal of agricultural and food chemistry》2011,59(9):4331-4348

Considerable information on the chemistry and biological properties of dietary phytochemicals has accumulated over the past three decades. The scattering of the data in tens of thousands publications and the diversity of experimental approaches and reporting formats all make the exploitation of this information very difficult. Some of the data have been collected and stored in electronic databases so that they can be automatically updated and retrieved. These databases will be particularly important in the evaluation of the effects on health of phytochemicals and in facilitating the exploitation of nutrigenomic data. The content of over 50 databases on chemical structures, spectra, metabolic pathways in plants, occurrence and concentrations in foods, metabolism in humans and animals, biological properties, and effects on health or surrogate markers of health is reviewed. Limits of these databases are emphasized, and needs and recommendations for future developments are underscored. More investments in the construction of databases on phytochemicals and their effects on health are clearly needed. They should greatly contribute to the success of future research in this field.  相似文献