Influence de l'état d'ameublissement et de la rugosité du sol des parcelles agricoles sur l'exactitude de l'altitude des points de contrôle positionnés au GPS

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 33-44

Our goal in this study is to estimate through ranges of variation, the impact of agricultural parcels soil’s tilth and roughness, due to cultivation techniques, on the exactness of ground control points ... [more ▼]

Our goal in this study is to estimate through ranges of variation, the impact of agricultural parcels soil’s tilth and roughness, due to cultivation techniques, on the exactness of ground control points elevation surveyed by RTK (Real Time Kinematic) GPS (Global Positioning System). So, 16 point’s elevations which were located each 100 mm on a transect have been surveyed first by using a total station (TS), and then a RTK GPS in 2 parcels (3 transects per parcel). Cultivation techniques on those parcels were different. The parcel 1 was tilled, and the soil of parcel 2 was prepared for cereal cropping. Then, the analysis of variance has been applied on the differences of TS and RTK GPS elevations data to estimate the confidence interval of ground control points elevation due (i) to soil tilth, whereas the times series statistical method have been applied on elevation data to estimate the confidence interval due (ii) to soil roughness. The confidence intervals of points elevation are estimated being (i) [51 mm; 57 mm], (ii) [-4 mm; 4 mm] for parcel 1, and (i) [97 mm; 113 mm], (ii) [-35 mm; 23 mm], for parcel 2. Results show that ground control point’s elevations exactness is influenced by soil tilth and soil roughness. In conclusion, we can admit that soil tilth and soil roughness have significant impact on the exactness of ground control points located on agricultural parcels. This impact must be considered in DEM errors evaluation of agricultural watershed. [less ▲]

The Status of the Medium-Sized Ungulate Populations in 2010, Nazinga Game Ranch, Burkina Faso (Western Africa)

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3),

The present study consists of analyzing the raw data collected from the annual line-transect foot count of medium-sized ungulates, carried out at the Nazinga Game Ranch (NGR), Burkina Faso (Western Africa ... [more ▼]

The present study consists of analyzing the raw data collected from the annual line-transect foot count of medium-sized ungulates, carried out at the Nazinga Game Ranch (NGR), Burkina Faso (Western Africa), in both 2001 and 2010. The annual census focused on the seven main medium-sized ungulates, namely (in alphabetical order), the Bushbuck (Tragelaphus scriptus), the Common Warthog (Phacochoerus africanus), the Defassa Waterbuck (Kobus ellipsiprymnus), the Grimm’s Duiker (Sylvicapra grimmia), the Oribi (Ourebia ourebi), the Roan Antelope (Hippotragus equinus) and the Western Hartebeest (Alcelaphus buselaphus). The census also focused on illegal anthropogenic activities. The wildlife populations were quantitatively analyzed through an estimation of their absolute density via the distance sampling method and through their evolution over the last decade using two relative density indexes, namely the Kilometric Abundance Index (KAI) and a spatial distribution index. These indexes were also used to measure the evolution of illegal activities over the same period. Both the wildlife observations and the anthropogenic observations were mapped using the Kernel method. Following an increasing trend in their population between 2001 and 2010, both the Roan Antelope and the Western Hartebeest reached an estimated density of 4.7 individuals per km², while the Defassa Waterbuck reached 2.4 individuals per km². Following an inverse trend over the same period, the Bushbuck, the Grimm’s Duiker and the Oribi reached an estimated density of 0.4 individuals per km². As for the Common Warthog, its estimated density of 2.5 individuals per km² seemed to remain unchanged during that decade. A comparison between wildlife observations and anthropogenic observations reveals a high decrease in animal densities in the north, east and west peripheral borders of the NGR and a flagrant extension of the proportion of the ranch being subjected to illegal activities (poaching, cattle herding, etc.). [less ▲]

Development and application of a microplate method to evaluate the efficacy of essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens of fruits

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 325-336

A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two ... [more ▼]

A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two 96-well ELISA plates was used as a reproducible and standardized design to identify the in vitro effectiveness of these essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. M.A. Curtis) Arx, three postharvest fungal pathogens, on fruits. Growth of mycelium was monitored by measuring optical density (492 nm). Cinnamomum zeylanicum, Cinnamomum verum and Eugenia caryophyllus were found to be still active against all the three pathogens even at 100 ppm. Compared to other methods, this microbioassay proved to be a rapid, reproducible, and efficient method for testing the efficacy of essential oils that inhibit spore germination in P. italicum, P. digitatum and C. musea. The assay requires relatively small amounts of essential oils. [less ▲]

Les crèmes végétales : une alternative aux crèmes laitières

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 344-359

Structure, properties and obtention routes of flaxseed lignan secoisolariciresinol

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 115-124

Following a brief description of the structure and nomenclature of the lignan family, this review focuses on the flaxseed lignan secoisolariciresinol (SECO). The main properties, the analysis methods and ... [more ▼]

Following a brief description of the structure and nomenclature of the lignan family, this review focuses on the flaxseed lignan secoisolariciresinol (SECO). The main properties, the analysis methods and two routes for the preparation of SECO, i.e. extraction from renewable raw material and (hemi)-synthesis, are reviewed. Green methods recently developed for the first route and chemical syntheses inspired from biosyntheses for the second one are the main subjects of this paper. [less ▲]

Caractérisation des plantations privées de teck (Tectona grandis L.f.) du département de l'Atlantique au Sud-Bénin

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 441-451

Teak plantations are an undeniable asset, representing socio-economic and environmental importance in South Benin. Plantation owners see teak as an asset, enabling them to supplement their income through ... [more ▼]

Teak plantations are an undeniable asset, representing socio-economic and environmental importance in South Benin. Plantation owners see teak as an asset, enabling them to supplement their income through timber production and sales. Sustainable management of teak plantations requires a high level of knowledge and understanding of the resource by plantation owners. The snowball sampling method was used in order to reach private teak plantations owners. This is a chain sampling method, which uses information from the first informant (plantation owner) to trace the others in the sample. Data were collected on the socio-economic status of plantation owners, and on both the geographical location and the size of the plantations. Dendrometrical parameters were measured through strip sampling. Factor analysis followed by hierarchical classification and stepwise discriminant analysis were performed in order to build a profile of the owners. We have identified 2,431 owners and 2,624 plantations. Young plantations (up to 5 years old) represent 16.4% of the total plantation area, high forests 12.7% and coppices 70.9%. Overall, these plantations were small in size (average = 0.44 ha). The number of trees per ha was found to be high, regardless of the forest system (respectively 3,371 trees/ha for young plantations, 3006 trees/ha for high forests and 6305 trees/ha for coppice). These high numbers reflect the fact that the trees represent farm-grown timber. Four groups of owners were distinguished: smallholder farmers seeking income (group 1), small city dweller planters and those motivated by securing their properties (group 2), city dweller planters with medium size plantations (group 3); and owners with large-scale plantations (group 4). All groups were willing to secure their land or be involved in the timber trade. The specific characteristics of each group need to be taken into account in considering the sustainable management of private teak plantations in South Benin. [less ▲]

Les entérocoques : avantages et inconvénients en biotechnologie (synthèse bibliographique)

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 67-76

Silk moths in Madagascar: Biology, uses and challenges related to Borocera cajani (Boisduval, 1833) (Lepidoptera – Lasiocampidae)

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 269-276

Borocera cajani (Lepidoptera, Lasiocampidae), also named Landibe, is main wild silk moth currently used to produce silk textiles in Madagascar. Silk production involve many member of the local population ... [more ▼]

Borocera cajani (Lepidoptera, Lasiocampidae), also named Landibe, is main wild silk moth currently used to produce silk textiles in Madagascar. Silk production involve many member of the local population, from the wild silk harvesters, to the spinners, traders, dyers, weavers and the artisans who transform the silk into clothing, accessories and decorative items. Uapaca bojeri (Tapia) forests are the last remnants of highland primary forest, which are threatened by human destruction through bush fires, firewood collection and charcoal production. Uapaca bojeri forest in the highland shelters wild Malagasy silkworms Borocera cajani and is the main host plant of this Lepidoptera species. Both this tree and Borocera cajani are endemic of Madagascar. Due to other-harvest of pupae and destruction of nature forest, wild silk production in those early sites has largely disappeared. Studing Borocera cajani’s biology and revitalize its silk constitute a way to conserve them [less ▲]

PAMPs, MAMPs, DAMPs and others: An update on the diversity of plant immunity elicitors [PAMPs, MAMPs, DAMPs et autres: Mise à jour de la diversité des éliciteurs de l'immunité des plantes]

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 257-268

Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition ... [more ▼]

Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition. Specifically, there are compounds derived from these organisms and called elicitors that are perceived by the plant to induce a locally or systemically expressed resistance. The understanding of the physiological and biological basis of these induced immunity mechanisms have greatly advanced over the past years but a deeper investigation of the mechanisms underlying the perception of elicitors is essential to develop novel strategies for pest control. The application of chemical and biological stimulators of plant immune defenses in conventional agriculture is expected to increase within the next years. Because of their organic origin and as they provide means for conferring plant protection in a non-transgenic manner, elicitors of plant immunity have a huge potential as biocontrol products. Through this review, we want to illustrate the diversity of compounds identified as stimulators of the plant immune system and describe the mechanisms by which they could be recognized at the plasma membrane level. [less ▲]

Identité et écologie des espèces forestières commerciales d'Afrique Centrale: le cas de Milicia spp.

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16

Le terme iroko regroupe les deux espèces du genre africain Milicia et désigne le bois qui en est dérivé. Malgré une importance économique reconnue depuis plus de deux siècles et une diminution sensible ... [more ▼]

Le terme iroko regroupe les deux espèces du genre africain Milicia et désigne le bois qui en est dérivé. Malgré une importance économique reconnue depuis plus de deux siècles et une diminution sensible des densités de population du fait de l'exploitation, les connaissances scientifiques utiles à la gestion durable de l'iroko font défaut, particulièrement en Afrique Centrale. L'existence même d'une spéciation au sein du genre Milicia mérite d'être revérifiée: les caractères utilisés pour séparer les deux taxons M. excelsa (Welw.) C.C. Berg et M. regia (A. Chev.) C.C. Berg sont peu consistants et une révision de ces traits distinctifs permettrait de réétudier le niveau de vulnérabilité des populations de Milicia spp., et donc de revoir les stratégies de gestion de ce groupe taxonomique. M. regia n'a fait l'objet que de rares études écologiques tandis que M. excelsa, plus largement distribuée, a retenu l'attention scientifique en Afrique de l'Ouest, dans une certaine mesure. Dans tous les cas, les traits d'histoire de vie conditionnant la diversité génétique et le taux de régénération naturelle méritent d'être identifiés ou mieux décrits. En particulier, les connaissances existantes sur les populations reproductrices, les facteurs régulant la floraison, les patrons de fructification et de dispersion des diaspores, ainsi que d'autres caractères qui amènent à décrire l'iroko comme un arbre pionnier (besoins en lumière, dormance des graines) devraient être mieux documentés. Enfin, la dynamique même des populations naturelles de juvéniles devra également être mieux caractérisée. En l'absence de données fines en écologie, la durabilité de nombreuses ressources ligneuses commerciales est tributaire d'actions sylvicoles, lesquelles peuvent être coûteuses et ne pas être garanties sur le long terme. [less ▲]