Search results for "EED"
showing 10 items of 5952 documents
Transition to conservation agriculture : changes in cropping practices and responses of weed communities
2020
Conservation agriculture is a farming system based on the continuous and simultaneous application of three principles: minimal soil disturbance, continuous residue cover on the soil surface and diverse crop rotations. Adoption of this form of sustainable agriculture in France since the 2000s has been hampered by a number of constraints, including the development and management of weed populations. From an agronomic point of view, the adoption of conservation agriculture and associated abandonment of tillage results in a significant loss of weed management practices for farmers. From an ecological point of view, its application can modify all the assembly processes that act on weed communiti…
Effect of growing area on tocopherols, carotenoids and fatty acid composition ofPistacia lentiscusedible oil
2014
International audience; In this investigation, we aim to study, for the first time, the effect of the growing area on tocopherols, carotenoids and fatty acid content of Pistacia lentiscus fixed oil. Fruits were harvested from eight different sites located in the north and the centre of Tunisia. Tocopherols, carotenoids and fatty acid content of the fixed oils were determined. The highest carotenoid content was exhibited by Feija oil (10.57 mg/kg of oil). Oueslatia and Tabarka oils displayed the highest alpha-tocopherol content (96.79 and 92.79 mg/kg of oil, respectively). Three major fatty acids were determined: oleic, palmitic and linoleic acids. Oleic acid was the main fatty acid presenti…
Étude de la biologie d'une messicole en régression: le bleuet (Centaurea cyanus L.)
2011
Agroecosystems are currently experiencing high biodiversity loss, in particular among the plant species specifically adapted to this habitat. This decline results from cropping systems that have been intensified in Western Europe since the 1950s. The cornflower (Centaurea cyanus L.), considered as emblem of the flora associated with traditional cereals, appears as a species that may be at risk and should be monitored. Indeed, cornflower can serve as a host to predators of crop pests and is strongly attractive for the pollinators. This study examines the biological factors that could potentially cause the decline of this species: spatial distribution, potential for growth, population's genet…
Contribution des pollinisateurs dans la production de colza et de tournesol en zone atelier « Plaine et Val de Sèvre »
2018
Insect pollination is essential for over 70% of crops around the world. However, the contribution of pollinators to crop production and the insects involved in crop pollination have rarely been studied. Moreover, assessments of pollinator contributions have mostly been conducted on a small scale or under simplified conditions, which do not represent the real contributions at the field scale and do not take into account possible interactions between pollinators and farming practices. The aim of this study is to quantify directly under field conditions, the contribution of pollinators in two crops frequently cultivated in Europe: oilseed rape and sunflower. Estimations are realized both at th…
Etude dynamique et structurale de biomolécules par microscopie à force atomique HS-AFM : application à une petite protéine de choc thermique sHsp
2012
The atomic force microscopy (AFM) gives access to the topography of organic and inorganic samplesat the atomic scale. The latest innovations offer the possiblity to understand the sample nano-mechanicalproperties (elasticity, adhesion...). Its feature set allows overcoming the demands of nanotechnology,both in the fields of physics, chemistry and biology.However, understanding biological processes require faster acquisitions for the atomic forcemicroscopy, less than a second per frame. As conventional equipment does not offer the possibility toovercome the constraint of time for dynamical studies, a prototype of high-speed atomic forcemicroscope (HS-AFM) was developed in partnership with Pr…
Modeling and energy optimization of the operative parts of an air assisted drill
2016
In the context of sustainable farming, the optimization of the energy costs of agricultural operations allows shorter working times and high quality of the agricultural operations. This question relates particularly to the seeding. This operation one is decisive for the quality of the future harvest. The modern high capacity seed drills must be compatible with all the constraints. The main goal of this PhD thesis is thus to develop an innovative methodology, integrating the modeling tools, in order to reduce the energy consumption of the heavy seeding equipment. Thus, we explored four key aspects concerning air seed drill design: maneuverability of poly-articulated seed drills; establishmen…
Résistance aux inhibiteurs de l'ALS: gare aux dicots ! Après le coquelicot et les matricaires, la stellaire fait de la résistance
2012
SPE GEAPSI
Le rôle écologique des bonobos : service écologique de dispersion de graine en forêt du Congo
2012
Bonobos (Pan paniscus) are threatened with extinction. They are the largest primates, and the only apes (except human), of the southern bank of the Congo Basin. Along with chimpanzees, they are our closest living relatives and are studied by anthropologists to include/understand our hominid origins; but what about their functional role in the forest? Would their disappearance have serious consequences for forest ecology? Answering this question is the aim of this new project, with several years of observations of a free-ranging habituated group of bonobos on the LuiKotale research station (DR Congo). In this tropical rainforest, the very great majority of plants need animals to reproduce an…
The spatial and temporal distribution of carabid and weed seed predation in winter wheat: a comparison between conventional and conservation agricult…
2013
Carabids can be key players in weed seed predation within arable crops under temperate climate. Field management options, because they affect carabid communities, may represent potential levers to increase weed seed predation levels within fields. Among these options, Conservation Agriculture is often presented as a promising management option for carabids but its effect on weed seed predation levels is less clear. In this study, carabids and weed seed predation were monitored using a grid sampling from April till September 2011 in two adjacent winter-wheat fields in North-eastern France, one conducted as no-till with cover crop for 5 years (conservation agriculture) and the other as conven…
Impact of endopolyploidy on seed coat development and cell expansion in Medicago truncatula
2013
Growth of the seed coat is regulated by genetic interactions between maternal and filial tissues that ultimately establish seed size. However, endopolyploidy is one of the welldocumented factors controlling organ size. During seed development, the arrest of cell division at 4 DAP in the expanding seed coat is compensated for by cell elongation. Thus, the ploidy status of seed coat nuclei was assessed in order to determine if there is any correlation of endopolyploidy with cell elongation. In 10 DAP seed sections, the DAPI-integrated fluorescence, which correlates to DNA quantity, was measured in the seed coat parenchyma nuclei using the diploid embryo nuclei as internal control. Significant…