The SAHGA model to calculate the Spatial Ammoniacal Heterogeneity at the soil surface after fertiliser Granule Application     

Edith?Le?CadreEmail author  Sophie?Génermont  Farooq?Azam  Sylvie?Recous 《Biology and Fertility of Soils》2004,40(3):178-180

After dissolution of fertiliser granules, a high nitrogen concentration is recovered in the immediate vicinity of granules, which may enhance damaging processes like nitrite accumulation or ammonia volatilisation. Based on the diffusion equations of Cranck, the granule-soil microsite was modelled to obtain the actual fertilised surface plot and the effective rate of N application on this surface. Parameterisation of the diffusion coefficient of solutes consisted of a temperature and soil texture correction. The model was tested against an experimental data set obtained from soil incubations at two soil water contents (21.2% m³ m^–3 and 28.3% m³ m^–3) and two temperatures (4°C and 25°C) by comparing NH₄⁺ recovery at various distances from the granules. The simulated radius of the granule-soil microsite was more affected by the water content than by the temperature. The model is very accurate because 95–100% of total NH₄⁺ applied was recovered in the modelled surface depending on the experimental conditions (temperature and water content). The model was simple enough to be easily integrated into larger models dealing with surface-applied granule fertilisers.  相似文献   

Physical,Compositional, and Wet‐Milling Characteristics of Mexican Blue Maize (Zea mays L.) Landrace     

Perla Marysol Uriarte‐Aceves  Edith Oliva Cuevas‐Rodríguez  Roberto Gutirrez‐Dorado  Saraid Mora‐Rochín  Cuauhtmoc Reyes‐Moreno  Sirima Puangpraphant  Jorge Miln‐Carrillo 《Cereal Chemistry》2015,92(5):491-496

Mexico has the largest diversity of genetic resources for maize in the world, with about 59 different landraces. However, little is known about their wet‐milling characteristics. The aim of this study was to determine whether 15 Mexican blue maize (Zea mays L.) genotypes of Elotero de Sinaloa landrace collected in the northwestern region of Mexico have suitable wet‐milling properties. Great variability of physical, compositional, and wet‐milling characteristics among these blue maize genotypes was observed. The FAUAS‐457 and FAUAS‐488 maize genotypes had similar starch yield and starch recovery as reported for the wet‐milling industry, which indicated that they may be useful as a source of extractable starch. Residual protein levels in the starch fractions were in the range of 0.39–0.68%, and total solids recovery exhibited a mean value of 98.8%, indicating acceptable efficacy of the wet‐milling process. This process afforded starches from blue maize genotypes with low protein contents. Wet‐milling fractions correlated with the physical and chemical properties of the kernels. Our results indicate that Mexican blue maize genotypes contain characteristics that make them appropriate and utilizable at the industrial level, and they can also be valuable for improving wet‐milling characteristics of maize through breeding programs.  相似文献   

Mikrobiologische Beurteilung biologischer Bodendekontaminationsverfahren im Modellversuch     

Ellen Kandeler  Christine Pennerstorfer  Edith Bauer  Rudolf Braun 《植物养料与土壤学杂志》1994,157(5):345-350

Microbiological control of the biological decontamination of soils Five agricultural soils which were contaminated with n-tetradecane, 5-methyl-3-heptanone and naphthalene were used to follow the biological clean-up process of these soils. The hydrocarbon content, the microbial biomass (substrate-induced respiration), dehydrogenase activity and N-mineralisation were monitored for 20 weeks in the contaminated and control soils. Dehydrogenase activity followed similar patterns within various soils, the values being lowest at the beginning of the experiment and highest during the following weeks. N-mineralisation of four contaminated soils was reduced at the start of the experiment, but was increased afterwards. The influence of contamination on microbial activities was detected even after elimination of the hydrocarbons. The addition of compost of bark and pieces of bark increased the biological cleanup process of the Calcic Chernozem contaminated with 3,8% (w/w) fuel oil. The addition of both organic materials reduced the decontamination rate of the Haplic Chernozem. The ratio of N-mineralisation to microbial biomass of the Calcic Chernozem increased with the addition of compost of bark and pieces of bark, but decreased with the same treatment of the. Haplic Chernozem. The results of this study suggest that microorganisms immobilize nitrogen in the Haplic Chernozem ammended with pieces of bark to a great extent during the whole experiment. The high N-immobilization and the adsorption of hydrocarbons to the added organic material may be the main cause of the slow decontamination of the Haplic Chernozem.  相似文献   

To what extent can multifractal measures provide an accurate model of the porosity of soils?     

Edith Perrier  Philippe C. Baveye  Patricia Garnier 《European Journal of Soil Science》2021,72(2):510-526

Over the last decades, several authors have suggested that multifractal measures, that is, self-similar measures defined on fractal or non-fractal objects, could be useful to describe soil properties, to model soil processes, and to deal with their extreme microscale heterogeneity. In this context, a key question relates to the extent to which multifractal measures can indeed fulfill all the expectations they have generated. To address this question, we discuss the possibility of generating a synthetic soil image exhibiting multifractal porosity. To this end, a simple geometrical multifractal model in 2D is developed, which helps us to better understand the concept of multifractality and to generate images. We show that it is possible to generate synthetic binary images over a limited range of scales, but that a pure multifractal model for the distribution of the solid or pore mass cannot be developed due to physical constraints. Moreover, in the generated images mimicking multifractal solid space, a higher degree of multifractality corresponds to a larger porosity, rendering it difficult to tune model parameters to match actual soil properties. In addition, simple statistics relying on power-law fits appear insufficient to characterize soil architecture even if they may capture some key multiscale indicators of observed spatial heterogeneity. We argue that the same conclusions would be reached in a three-dimensional space, as well as for grey-scales images.  相似文献   

AIDS. Promote HIV chemoprophylaxis research, don't prevent it     

Grant RM  Buchbinder S  Cates W  Clarke E  Coates T  Cohen MS  Delaney M  Flores G  Goicochea P  Gonsalves G  Harrington M  Lama JR  MacQueen KM  Moore JP  Peterson L  Sanchez J  Thompson M  Wainberg MA 《Science (New York, N.Y.)》2005,309(5744):2170-2171

  相似文献   

Expanding the genetic code of Escherichia coli with phosphoserine     

Park HS  Hohn MJ  Umehara T  Guo LT  Osborne EM  Benner J  Noren CJ  Rinehart J  Söll D 《Science (New York, N.Y.)》2011,333(6046):1151-1154

O-Phosphoserine (Sep), the most abundant phosphoamino acid in the eukaryotic phosphoproteome, is not encoded in the genetic code, but synthesized posttranslationally. Here, we present an engineered system for specific cotranslational Sep incorporation (directed by UAG) into any desired position in a protein by an Escherichia coli strain that harbors a Sep-accepting transfer RNA (tRNA(Sep)), its cognate Sep-tRNA synthetase (SepRS), and an engineered EF-Tu (EF-Sep). Expanding the genetic code rested on reengineering EF-Tu to relax its quality-control function and permit Sep-tRNA(Sep) binding. To test our system, we synthesized the activated form of human mitogen-activated ERK activating kinase 1 (MEK1) with either one or two Sep residues cotranslationally inserted in their canonical positions (Sep(218), Sep(222)). This system has general utility in protein engineering, molecular biology, and disease research.  相似文献   

Salt tolerance variability amongst Argentine Andean potatoes (Solanum tuberosum L. subsp.andigena)     

Berta Velásquez  Mónica Balzarini  Edith Taleisnik 《Potato Research》2005,48(1-2):59-67

Summary Salt tolerance in Andean potatoes can be a source for this trait in cultivated potatoes or be exploited to expand potato cultivation to more marginal areas. The purpose of this study was to determine salt tolerance in twelve Argentine Andean potato varieties through the response of nodal segments cultured in vitro and to evaluate whether changes in Na⁺, K⁺ or proline accumulation associate with salt tolerance. Genotypes Bianca, Airampia, Sisa Sani and Cuarentilla were the most tolerant. The most susceptible varieties were Balcacha, Runa Rosada, Collareja, Overa, Bianca Redonda and Papa Baya, while Cuarentona and Colorado Ml comprised an intermediate group. These results indicate that variability for salt tolerance exists in this germplasm, and highlights its potential use in breeding programmes. No association was found between the salt tolerance rating and changes in K⁺, Na⁺ and proline accumulation in a salt gradient, thus precluding the use of these parameters as predictors for salt tolerance of these species in in vitro studies.  相似文献   

Genetic variability for responses to short‐ and long‐term salt stress in vegetative sunflower plants     

Dolores Bustos  Leandro Ismael Ortega  Alicia Córdoba  Abelardo Vegetti  Edith Taleisnik 《植物养料与土壤学杂志》2012,175(6):882-890

Sunflower (Helianthus annuus L.) has been rated as moderately salt‐resistant, and variability for salt resistance has been detected within this crop. However, variability in salt‐resistance mechanisms has not been assessed. Osmotic tolerance, the relation of salt resistance with whole‐plant Na⁺ and K⁺ distribution and tissue Na⁺ tolerance were investigated in several sunflower inbred lines. Plants were grown under controlled conditions, in pots with sand and perlite irrigated with salinized (NaCl, –0.65 MPa) nutrient solution. Osmotic tolerance was assessed from the initial effects of the salt treatment on plant elongation in eleven sunflower lines. Long‐term salinity responses were evaluated in four of those lines, by assessing whole‐plant growth. A principal components analysis (PCA) was run on relative‐to‐control growth data, and this information was used to establish a relative resistance ranking, which indicated lines HAR2 > HAR1 > HA64 > HAR5. Osmotic tolerance was observed in HA64 and HAR2. The lines showed different degrees of Na⁺ accumulation, it was very low in some of them, but relative salt resistance was not associated to this trait. Tissue Na⁺ tolerance was deduced by comparing the percentage of dead leaves as a function of leaf blade Na⁺ accumulation, and it was higher in HAR1 than in the rest. These results indicate that variability for salt‐resistance mechanisms exists in sunflower. Osmotic tolerance and tissue Na⁺ tolerance were detected in different lines, highlighting that such variability may be exploited for increasing salt resistance in this crop.  相似文献   

Microalgae n-3 PUFAs Production and Use in Food and Feed Industries     

Marine Remize  Yves Brunel  Joana L. Silva  Jean-Yves Berthon  Edith Filaire 《Marine drugs》2021,19(2)

N-3 polyunsaturated fatty acids (n-3 PUFAs), and especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential compounds for human health. They have been proven to act positively on a panel of diseases and have interesting anti-oxidative, anti-inflammatory or anti-cancer properties. For these reasons, they are receiving more and more attention in recent years, especially future food or feed development. EPA and DHA come mainly from marine sources like fish or seaweed. Unfortunately, due to global warming, these compounds are becoming scarce for humans because of overfishing and stock reduction. Although increasing in recent years, aquaculture appears insufficient to meet the increasing requirements of these healthy molecules for humans. One alternative resides in the cultivation of microalgae, the initial producers of EPA and DHA. They are also rich in biochemicals with interesting properties. After defining macro and microalgae, this review synthesizes the current knowledge on n-3 PUFAs regarding health benefits and the challenges surrounding their supply within the environmental context. Microalgae n-3 PUFA production is examined and its synthesis pathways are discussed. Finally, the use of EPA and DHA in food and feed is investigated. This work aims to define better the issues surrounding n-3 PUFA production and supply and the potential of microalgae as a sustainable source of compounds to enhance the food and feed of the future.  相似文献   

Phytochemicals and Antioxidant Capacity of Tortillas Obtained after Lime-Cooking Extrusion Process of Whole Pigmented Mexican Maize   总被引：1，自引：1，他引：0  

Aguayo-Rojas J  Mora-Rochín S  Cuevas-Rodríguez EO  Serna-Saldivar SO  Gutierrez-Uribe JA  Reyes-Moreno C  Milán-Carrillo J 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(2):178-185

The lime-cooking extrusion represents an alternative technology for manufacturing pre-gelatinized flours for tortillas with the advantages of saving energy and generation of null effluents. The phytochemical profiles (total phenolics, anthocyanins) and antioxidant activity of four different types of whole pigmented Mexican maize [white (WM), yellow (YM), red (RM), blue maize (BM)] processed into tortillas were studied. The lime-cooking extrusion process caused a significant decrease (p?相似文献