Éditeur(s) : INRA : Institut National de la Recherche Agronomique Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : In the new context of the agro-ecological transition, present agricultural systems will have to produce more and better in a more constraint world. Mixed crop livestock systems (MCLS) represent sound alternative ways to progressively achieve these goals through crop-livestock integration (CLI). CLI exploits the synergies between cropping and livestock systems through organic fertilization with manure or plant association, use of crop residues to feed livestock, .... It offers many opportunities to improve productivity, as well as to increase resource use efficiency and improve the resilience of the whole farming system. In the scientific literature, authors advocate the interest of MLCS and CLI, based on theoretical considerations, modelling and empirical evidence from local case studies. But these studies do not clearly identify the respective roles of diversity of activities and CLI management practices in improving performances at the level of the whole farming system. Our aim was thus to assess CLI at farm scale in a range of MCLS and to explain farm performances by analyzing the combination of activities and the level of integration. We conducted our analyses in Guadeloupe, (French West Indies), where MCLS and CLI are complex but important challenges for local agricultural. In order to analyze CLI in a holistic and systemic way, we applied a method traditionally used in ecology, ecological network analysis, to study the structure, functioning and performance of agrosystems. This method was implemented on a range of Guadeloupian MCLS where CLI practices where identified. Nitrogen was retained to conduct the analysis due to its central role for both animal and vegetal productions. The ENA method allows an estimation of productivity, resilience, efficiency, productivity and self- sufficiency of the flows network. Our results show that 1/ efficiency and resilience appear correlated to the complexity and intensity of the network of flows; 2/ efficiency and resiliency are positively correlated when we consider them in terms of N flows; 3/ in the Guadeloupian context, CLI concerns mainly specific practices, as feeding pigs with a wide range of crop residues and organic fertilization of small market gardens and plots used to grow tubers. But at whole system level, CLI remains rare and mainly depends on conventional management practices as mineral fertilization and animal complementation of some farming activities as sugar cane, cattle breeding and banana. Moreover, the combination of productions implemented determines the potential of CLI and related performances linked to relative N efficiency of each production. Consequently, performance and especially efficiency and self-sufficiency depend more on the nature of the activity than on CLI management practices. There is still a gap between theoretical studies and CLI in practice, even though CLI is more complicated than simple flows and provides other services and functions. Dans le nouveau contexte de la transition agro-écologique, les systèmes agricoles actuels devront produire plus et les améliorer dans plus de monde de contrainte. Les systèmes mélangés de bétail de culture (MCLS) représentent des manières alternatives saines d'atteindre progressivement ces buts par l'intégration de culture-bétail (CLI). Le CLI exploite les synergies entre l'emblavage et les systèmes de bétail par la fertilisation organique avec l'association d'engrais ou d'usine, utilisation des résidus de culture d'alimenter le bétail,?. Il donne beaucoup d'occasions d'améliorer la productivité, aussi bien que d'augmenter l'efficacité d'utilisation de ressource et d'améliorer la résilience du système d'exploitation agricole entier. Dans la littérature scientifique, les auteurs préconisent l'intérêt de MLCS et de CLI, basé sur des considérations théoriques, modeler et des preuves empiriques des études de cas locales. Mais ces études n'identifient pas clairement les rôles respectifs de la diversité des activités et des pratiques de gestion de CLI en améliorant des interprétations au niveau du système d'exploitation agricole entier. Notre but était ainsi d'évaluer le CLI à l'échelle de ferme dans une gamme de MCLS et d'expliquer des interprétations de ferme en analysant la combinaison des activités et du niveau de l'intégration. Nous avons réalisé nos analyses en Guadeloupe, (des Antilles françaises), où MCLS et le CLI sont des défis complexes mais importants pour agricole local. Afin d'analyser le CLI d'une manière holistique et systémique, nous avons appliqué une méthode traditionnellement employée en écologie, analyse réseau écologique, pour étudier la structure, le fonctionnement et l'interprétation des agrosystems. Cette méthode a été appliquée sur une chaîne de Guadeloupian MCLS où des pratiques en matière de CLI où identifiée. L'azote a été maintenu pour réaliser l'analyse due à son rôle central pour les productions animales et végétales. La méthode d'ENA permet une évaluation de la productivité, de la résilience, de l'efficacité, de la productivité et de l'autosuffisance du réseau d'écoulements. Nos résultats prouvent que 1 efficacités et résiliences semblent corrélées avec la complexité et l'intensité du réseau des écoulements ; 2 efficacité et élasticité sont franchement corrélés quand nous les considérons en termes d'écoulements de N ; 3 dans le contexte de Guadeloupian, CLI concerne principalement des pratiques spécifiques, en tant que les porcs de alimentation par un large éventail de résidus de culture et de fertilisation organique de petits jardins du marché et complots employés pour cultiver des tubercules. Mais à au niveau système entier, le CLI demeure rare et dépend principalement des pratiques de gestion conventionnelles en tant que complémentation minérale de fertilisation et d'animal de quelques activités agricoles comme canne à sucre, élevage et banane. D'ailleurs, la combinaison des productions mises en application détermine le potentiel du CLI et des interprétations relatives liés à l'efficacité relative de N de chaque production. En conséquence, l'interprétation et particulièrement l'efficacité et l'autosuffisance dépendent davantage de la nature de l'activité que sur des pratiques de gestion de CLI. Il y a toujours un espace entre les études et le CLI théoriques dans la pratique, quoique le CLI soit plus compliqué que des écoulements simples et fournisse d'autres services et fonctions.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16247
V16247

Éditeur(s) : CARDI : Caribbean Agricultural Rechearch and Development Institute Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : Banana and plantain (Musa spp) are important foreign exchange earners in Guyana and the Windward Islands of the Caribbean. Black Sigatoka Disease (BSD) also referred to as black leaf streak disease is one of the most destructive diseases of banana and plantain and is present within the region. In Guyana within two years following its introduction in 2008, the industry was totally decimated, recording a 100% decline, turning the country to a net banana importer. Also, from 2009 ? 2012 the disease spread in the Windward Islands causing as much as 100% decrease in the export of banana. The disease is caused by the ascomycete fungus, Mycosphaerella fijiensis (anamorph Pseudocercospora fijiensis) and is aggressive, challenging to control and results in enormous crop damage if left uncontrolled. In an effort to develop an integrated management approach to the disease the Caribbean Agricultural Research and Development Institute (CARDI) with financial assistance from the Caribbean Development Bank (CDB) is evaluating five FHIA banana and plantain accessions and eight IITA plantain accessions for tolerance to BSD. The evaluation is presently conducted in four Caribbean countries, Dominica, Guyana, St Lucia and St Vincent and the Grenadines. In each country, four distinct agro- ecological zones were selected for the trial evaluation blocks and using a randomized block design, four blocks were established in each country. Five FHIA accessions: FHIA-01, FHIA-03, FHIA-18, FHIA-21 and FHIA-23 are being evaluated in Dominica, St Lucia and St Vincent and the Grenadines whereas, plantain accessions: PITA-17, PITA-21, PITA-22, PITA-23, PITA-24 and PITA-26 are to be evaluated in Guyana for tolerance to the disease. Cavendish are used as regional controls and as borders rows to increase disease pressure. The disease parameters evaluated are youngest leaf spotted (YLS), disease development time (DDT), leaf emission rate (LER), disease severity at 6 months, bunch emergence and harvest, and index of standing leaves. Agronomic data; days from planting to flowering, bunch weight, number of hands in bunch, average weight of hands and average number of fingers per hand and bunch, as well as organoleptic characteristics of both cooked and ripe fruits are also evaluated. The early data collection, of the FHIA only accessions, show trends in the disease tolerance and agronomic performance as well as their adaptability in the different agro-ecological zone. The trends indicate better disease tolerance of FHIA varieties with higher leaf counts before, at bunching and at harvest. The organoleptic test shows a preference to FHIA 03 and FHIA 21. La banane et le plantain (espèces de Musa) sont les acquéreurs de devises étrangères importants en Guyane et en Îles du Vent des Caraïbe. La maladie noire de Sigatoka (schéma) également désignée sous le nom de la maladie noire de filet de feuille est l'une des maladies les plus destructives de la banane et du plantain et est présente dans la région. En Guyane dans un délai de deux ans après son introduction en 2008, l'industrie a été totalement décimée, enregistrant une baisse de 100%, tournant le pays à un importateur net de banane. En outre, à partir de 2009-2012 la propagation de maladie en Îles du Vent causant pas moins de la diminution de 100% de l'exportation de la banane. La maladie est provoquée par le champignon d'ascomycète, fijiensis de Mycosphaerella (fijiensis anamorph de Pseudocercospora) et est agressive, contestant pour commander et les résultats dans l'énorme culture endommagent si laissé incontrôlé. Dans un effort de développer une approche intégrée de gestion à la maladie l'institut agricole des Caraïbes de recherche et développement (CARDI) avec l'aide financière de la banque de développement des Caraïbes (BDC) évalue des adhésions de banane et de plantain de cinq FHIA et huit adhésions de plantain d'IITA pour la tolérance au schéma. L'évaluation est actuellement effectuée quatre pays des Caraïbes, Dominique, Guyane, St Lucia et Saint-Vincent-et-les Grenadines. Dans chaque pays, quatre agro zones écologiques distinctes ont été sélectionnées pour les blocs d'essai d'évaluation et employant une conception de bloc randomisé, quatre blocs ont été établis dans chaque pays. Cinq adhésions de FHIA : FHIA-01, FHIA-03, FHIA-18, FHIA-21 et FHIA-23 sont évalués en Dominique, au St Lucia et au Saint-Vincent-et-les Grenadines tandis que, des adhésions de plantain : PITA-17, PITA-21, PITA-22, PITA-23, PITA-24 et PITA-26 doivent être évalués en Guyane pour la tolérance à la maladie. Cavendish sont employés en tant que contrôles régionaux et comme rangées de frontières pour augmenter la pression de la maladie. Les paramètres de la maladie évalués sont la plus jeune feuille repérée (YLS), le temps d'élaboration de la maladie (DDT), le taux d'émission de feuille (LER), la sévérité de la maladie à 6 mois, émergences et récoltes de groupe, et index des feuilles debout. Données agronomiques ; des jours de la plantation à la floraison, du poids de groupe, nombre de mains dans le poids de groupe et moyen des mains et du nombre moyen de doigts par main et groupe, aussi bien que les caractéristiques organoleptiques des fruits cuits et mûrs sont également évalués. La collecte de données tôt, des adhésions de FHIA seulement, exposition tend dans la tolérance de maladie et la représentation agronomique aussi bien que leur adaptabilité dans la zone agro-écologique différente. Les tendances indiquent qu'une meilleure tolérance de maladie des variétés de FHIA avec une plus haute feuille compte avant, à se rassembler et à la récolte. L'essai organoleptique montre une préférence à FHIA 03 et à FHIA 21.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16266
V16266

Éditeur(s) : Elsevier
Résumé : Herbivorous (20% vegetable protein, 40% carbohydrate) and carnivorous diets (40% marine animal protein, 20% carbohydrate) were experimentally tested to assess their effect on the energy balance and energetic substrates utilized by postlarvae (PL's /15 days) and juvenile shrimp (3-6 g) of Litopenaeus vannamei. Postlarval stage 60 (PL60, early juveniles) shrimps fed HeD and CaD diets, then late juveniles (3-6 g) acclimated to the same diets were tested for their respective energy partitioning potential. No significant differences (p>0.05) on growth were obtained in early juveniles (mean final wet weight of 0.19 g). However in late juvenile stages a significant difference (p<0.05) in growth rate was observed. In terms of energy partitioning, both early and late juveniles seem to spend more energy in respiratory metabolism than in the elimination of excretion products. A change in feed composition based on quality protein sources induced some modifications on shrimp's activity measured by heat increment. Shrimps fed with an herbivorous diet showed a higher heat increment. Interestingly, the early stages of L vannamei display a remarkable capacity to assimilate a plant protein-based and a high carbohydrate level diet. Such capacity with a stimulation of genes would lead to a good adaptation of juveniles receiving all-plant diets to sustain growth performances up to a marketable size. The implications of these findings for the shrimp farming feeding costs are briefly discussed. (C) 2009 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2009-11 , Vol. 296 , N. 1-2 , P. 123-128

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-7402.pdf
DOI:10.1016/j.aquaculture.2009.08.007
http://archimer.ifremer.fr/doc/00000/7402/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Aim of the study: A knowledge attitude and practice study centred on leishmaniasis and its treatment was performed among the Chayahuita, an Amazonian Peruvian ethnic group living in an endemic area. This study documents traditional Chayahuita plant's use and disease concepts. Also, activty of some medicinal plants used by the Chayahuita is highlighted and discussed. Materials and methods: Ninety-three Chayahuita people were interviewed, following a semi-structured questionnaire focussed on disease knowledge and perception, personal attitude and healing practices. Simultaneously, a collection of plants was performed in different ecotopes, in order to make an extensive inventory of the pharmacopoeia. Results: For the Chayahuita, cutaneous (CL) and muco-cutaneous leishmaniasis (MCL) are considered as diseases of their own, with specific names, aetiologies, mode of transmission. Regarding CL, Chayahuita people consider that the humid characteristic of the skin ulcer is a discriminative fact orienting the diagnostic forTa'ta' (leishmaniasis). Forty-six different species were designated useful against LC and /or MCL (29 species by means of the questionnaire and 27 species when collecting in different ecotopes). Thirty-seven extracts corresponding to 31 species used medicinally were screened in vitro against Leishmania amnzonensis axenic amastigotes, assessing their viability by the reduction of tetrazolium salt (MTT). Six species displayed a good activity ( 10 μg/ml < IC50 < 20 μg/ml): an undetermined hemi-epiphytic Clusiaceae, Cyhianthus anthuriophyllus Pipoly (Myrsinaceae), two Piper, Piper sanguineispicum Trel., and Piper loretoanum Trel. (Piperaceae), Desmodium axillare Sw. DC. (Fabaceae), and Clibadium sylvestre (Aubl.) Baill. (Asteraceae). Conclusion: Perception of leishmaniasis, attitude, treatments and diet prohibitions still largely reflects traditional Chayahuita cosmovision, even if some tentative of bio-medical re-interpretation is arising.
ISSN: 0378-8741

hal-01087667
https://hal-agroparistech.archives-ouvertes.fr/hal-01087667
DOI : 10.1016/j.jep.2009.07.015

Éditeur(s) : HAL CCSD Wiley
Résumé : A standardized rapid inventory method providing information on both tree species diversity and aboveground carbon stocks in tropical forests will be an important tool for evaluating efforts to conserve biodiversity and to estimate the carbon emissions that result from deforestation and degradation (REDD). Herein, we contrast five common plot methods differing in shape, size, and effort requirements to estimate tree diversity and aboveground tree biomass (AGB). We simulated the methods across six Neotropical forest sites that represent a broad gradient in forest structure, tree species richness, and floristic composition, and we assessed the relative performance of methods by evaluating the bias and precision of their estimates of AGB and tree diversity. For a given sample of forest area, a several small' (<1ha) sampling strategy led to a smaller coefficient of variation (CV) in the estimate of AGB than a few large' one. The effort (person-days) required to achieve an accurate AGB estimate (<10% CV), however, was greater for the smallest plots (0.1ha) than for a compromise approach using 0.5ha modified Gentry plots, which proved to be the most efficient method to estimate AGB across all forest types. Gentry plots were also the most efficient at providing accurate estimates of tree diversity (<10% CV of Hill number). We recommend the use of the 0.5ha modified Gentry plot method in future rapid inventories, and we discuss a set of criteria that should inform any choice of inventory method.
ISSN: 0006-3606

hal-01032408
https://hal.archives-ouvertes.fr/hal-01032408
DOI : 10.1111/btp.12006

Éditeur(s) : INRA : Institut National de la Recherche Agronomique Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : In the Global South, improvement of agricultural outputs is eagerly awaited. While by 2050, its population will double areas devoted to agriculture will decrease exacerbating undernutrition of the poor. Unfortunately, the demand for fresh locally-produced meat products is not satisfied yet in the tropics. So, efficiency in animal productions is essential to allow coverage of protein nutritional needs of people, both in quality and quantity. In the Caribbean territories mixed farming systems are the most common farming systems (about 80%) and can constitute a solution to reach food sovereignty in such limited and isolated spaces. Lessons to be learned from these systems involve improving animal performance while respecting the natural balance with environment and maintaining the multi-functionality of plants and animals. Firstly, the natural (or selected) comfort zone of animal and plants must fit with the farm conditions, insuring thereby animal survival and welfare. Enhancement of adaptation to stresses (biotic, abiotic and socio- economic) in species or animal genotypes is a key element implying their equilibrium with the farm environment. This approach underpins for the farmer an integrated management of animal health, nutrition, genetics, reproduction, in close relationship with other compartments of the farming system. Secondly, animal adaptation may be completed by resilience ability within systems. Animals have to produce although facing stresses. Finally, the animal must be efficient that is to say must reconcile physiological functions of production, reproduction with adaptation functions. This optimization leads to decreased inputs and to overall efficiency of mixed farming systems at the end. The aim of the breeder is to choose the animal producing the best balance between output-reproduction-adaptation, at the individual or the flock scale combining genetic and physiological diversity. The underlying idea is to give to humans and animals their right place in the food chain taking into account the farmers? skills and wills. This idea is included in the agroecological approach and may give guidelines for food sovereignty worldwide.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16318
V16318

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Functional traits are posited to explain interspecific differences in performance, but these relationships are difficult to describe for long-lived organisms such as trees, which exhibit strong ontogenetic changes in demographic rates. Here, we use a size-dependent model of tree growth to test the extent to which of 17 functional traits related to leaf and stem economics, adult stature and seed size predict the ontogenetic trajectory of tree growth.[br/] 2. We used a Bayesian modelling framework to parameterize and contrast three size-dependent diameter growth models using 16 years of census data from 5524 individuals of 50 rain forest tree species: a size-dependent model, a size-dependent model with species-specific parameters and a size-dependent model based on functional traits.[br/] 3. Most species showed clear hump-shaped ontogenetic growth trajectories and, across species, maximum growth rate varied nearly tenfold, from 0.58 to 5.51 mm year(-1). Most species attained their maximum growth at 60% of their maximum size, whereas the magnitude of ontogenetic changes in growth rate varied widely among species.[br/] 4. The Trait-Model provided the best compromise between explained variance and model parsimony and needed considerably fewer parameters than the model with species terms.[br/] 5. Stem economics and adult stature largely explained interspecific differences in growth strategy. Maximum absolute diameter growth rates increased with increasing adult stature and leaf delta(13)C and decreased with increasing wood density. Species with light wood had the greatest potential to modulate their growth, resulting in hump-shaped ontogenetic growth curves. Seed size and leaf economics, generally thought to be of paramount importance for plant performance, had no significant relationships with the growth parameters.[br/] 6. Synthesis. Our modelling approach offers a promising way to link demographic parameters to their functional determinants and hence to predict growth trajectories in species-rich communities with little parameter inflation, bridging the gap between functional ecology and population demography.
ISSN: 0022-0477

hal-01032387
https://hal.archives-ouvertes.fr/hal-01032387
DOI : 10.1111/j.1365-2745.2011.01883.x

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
1. Despite considerable interest in the application of plant functional traits to questions of community assembly and ecosystem structure and function, there is no consensus on the appropriateness of sampling designs to obtain plot-level estimates in diverse plant communities. 2. We measured 10 plant functional traits describing leaf and stem morphology and ecophysiology for all trees in nine 1-ha plots in terra firme lowland tropical rain forests of French Guiana (N = 4709). 3.We calculated, by simulation, the mean and variance in trait values for each plot and each trait expected under seven sampling methods and a range of sampling intensities. Simulated sampling methods included a variety of spatial designs, as well as the application of existing data base values to all individuals of a given species. 4. For each trait in each plot, we defined a performance index for each sampling design as the proportion of resampling events that resulted in observed means within 5% of the true plot mean, and observed variance within 20%of the true plot variance. 5. The relative performance of sampling designs was consistent for estimations of means and variances. Data base use had consistently poor performance for most traits across all plots, whereas sampling one individual per species per plot resulted in relatively high performance. We found few differences among different spatial sampling strategies; however, for a given strategy, increased intensity of sampling resulted in markedly improved accuracy in estimates of trait mean and variance. 6. We also calculated the financial cost of each sampling design based on data from our 'every individual per plot' strategy and estimated the sampling and botanical effort required. The relative performance of designs was strongly positively correlated with relative financial cost, suggesting that sampling investment returns are relatively constant. 7. Our results suggest that trait sampling for many objectives in species-rich plant communities may require the considerable effort of sampling at least one individual of each species in each plot, and that investment in complete sampling, though great, may be worthwhile for at least some traits.
ISSN: 0269-8463

hal-00594009
https://hal.archives-ouvertes.fr/hal-00594009

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Ethnopharmacological relevancePsidium acutangulum Mart. ex DC is a small tree used by the Wayana Amerindians from the Upper-Maroni in French Guiana for the treatment of malaria.Aim of the studyIn a previous study, we highlighted the in vitro antiplasmodial, antioxidant and anti-inflammatory potential of the traditional decoction of P. acutangulum aerial parts. Our goal was then to investigate on the origin of the biological activity of the traditional remedy, and eventually characterize active constituents.Materials and methodsLiquid-liquid extractions were performed on the decoction, and the antiplasmodial activity evaluated against chloroquine-resistant FcB1 ([3H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains, and on a chloroquine sensitive NF54 ([3H]-hypoxanthine bioassay) P. falciparum strain. The ethyl acetate fraction (D) was active and underwent bioguided fractionation. All the isolated compounds were tested on P. falciparum FcB1 strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) of the ethyl acetate fraction and of an anti-Plasmodium active compound, was concurrently assessed on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the fractions and pure compounds was measured on VERO cells, L6 mammalian cells, PBMCs, and RAW cells.ResultsFractionation of the ethyl acetate soluble fraction (IC50 ranging from 3.4 to <1 µg/mL depending on the parasite strain) led to the isolation of six pure compounds: catechin and five glycosylated quercetin derivatives. These compounds have never been isolated from this plant species. Two of these compounds (wayanin and guaijaverin) were found to be moderately active against P. falciparum FcB1 in vitro (IC50 5.5 and 6.9 µM respectively). We proposed the name wayanin during public meetings organized in June 2015 in the Upper-Maroni villages, in homage to the medicinal knowledge of the Wayana population. At 50 µg/mL, the ethyl acetate fraction (D) significantly inhibited IL-1β secretion (−46%) and NO production (−21%), as previously observed for the decoction. The effects of D and guiajaverin (4) on the secretion of other cytokines or NO production were not significant.ConclusionsThe confirmed antiplasmodial activity of the ethyl acetate soluble fraction of the decoction and of the isolated compounds support the previous results obtained on the P. acutangulum decoction. The antiplasmodial activity might be due to a mixture of moderately active non-toxic flavonoids. The anti-inflammatory activities were less marked for ethyl acetate fraction (D) than for the decoction.
ISSN: 0378-8741

hal-01313006
http://hal.upmc.fr/hal-01313006
http://hal.upmc.fr/hal-01313006/document
http://hal.upmc.fr/hal-01313006/file/Houel_Wayanin_and.pdf
DOI : 10.1016/j.jep.2016.04.053

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Sugarcane yellow leaf virus, the causal agent of yellow leaf, is transmitted from plant to plant by aphids. Understanding and evaluating the epidemic risks due to spread of yellow leaf by aphids is an important feature for sugarcane production. Four distinct sugarcane trials were set up with disease-free plants to study the relationship between spread of yellow leaf, the vector dynamics and environmental conditions that may favour yellow leaf epidemics. The study was performed by surveys of vector populations and determination of plant infections. Sugarcane cultivar SP71-6163, highly susceptible to yellow leaf, was analyzed spatially at different dates in all four trials and compared to commercial cultivars in two of the four trials. These surveys allowed us to identify a correlation between the aphid dynamics in the field and yellow leaf progress. Additionally, a negative correlation was found between rainfall during the first weeks after transferring sugarcane plants to the field and aphid dispersal within the field. This later result revealed an impact of rainfall on aphid invasion and subsequent plant infection by SCYLV. If aphids are the key factor for disease spread, plant response varied also according to cultivar resistance with high variation depending on rain conditions.
ISSN: 0929-1873

hal-00684227
https://hal.archives-ouvertes.fr/hal-00684227

Éditeur(s) : HAL CCSD Maney Publishing
Résumé : International audience
The strict environmental legislations and increasing ecological awareness among scientists have led to the development of “green” alternatives to mitigate corrosion. In the present work, literature on green corrosion inhibitors has been reviewed, and the salient features of our work on green corrosion inhibitors have been highlighted. Among the studied leaves, extract Andrographis paniculata showed better inhibition performance (98%) than the other leaves extract. Strychnos nuxvomica showed better inhibition (98%) than the other seed extracts. Moringa oleifera is reflected as a good corrosion inhibitor of mild steel in 1 M HCl with 98% inhibition efficiency among the studied fruits extract. Bacopa monnieri showed its maximum inhibition performance to be 95% at 600 ppm among the investigated stem extracts. All the reported plant extracts were found to inhibit the corrosion of mild steel in acid media.
ISSN: 1478-422X

hal-01097106
https://hal-agroparistech.archives-ouvertes.fr/hal-01097106
DOI : 10.1016/j.corsci.2010.10.006

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Estrogen receptors (ER) α and β are found in both women and men in many tissues, where they have different functions, including having roles in cell proliferation and differentiation of the reproductive tract. In addition to estradiol (E2), a natural hormone, numerous compounds are able to bind ERs and modulate their activities. Among these compounds, phytoestrogens such as isoflavones, which are found in plants, are promising therapeutics for several pathologies. Glyceollins are second metabolites of isoflavones that are mainly produced in soybean in response to an elicitor. They have potentially therapeutic actions in breast cancer by reducing the proliferation of cancer cells. However, the molecular mechanisms driving these effects remain elusive. METHODS: First, to determine the proliferative or anti-proliferative effects of glyceollins, in vivo and in vitro approaches were used. The length of epithelial duct in mammary gland as well as uterotrophy after treatment by E2 and glyceollins and their effect on proliferation of different breast cell line were assessed. Secondly, the ability of glyceollin to activate ER was assessed by luciferase assay. Finally, to unravel molecular mechanisms involved by glyceollins, transcriptomic analysis was performed on MCF-7 breast cancer cells. RESULTS: In this study, we show that synthetic versions of glyceollin I and II exert anti-proliferative effects in vivo in mouse mammary glands and in vitro in different ER-positive and ER-negative breast cell lines. Using transcriptomic analysis, we produce for the first time an integrated view of gene regulation in response to glyceollins and reveal that these phytochemicals act through at least two major pathways. One pathway involving FOXM1 and ERα is directly linked to proliferation. The other involves the HIF family and reveals that stress is a potential factor in the anti-proliferative effects of glyceollins due to its role in increasing the expression of REDD1, an mTORC1 inhibitor. CONCLUSION: Overall, our study clearly shows that glyceollins exert anti-proliferative effects by reducing the expression of genes encoding cell cycle and mitosis-associated factors and biomarkers overexpressed in cancers and by increasing the expression of growth arrest-related genes. These results reinforce the therapeutic potential of glyceollins for breast cancer.
ISSN: 1478-811X

hal-01560288
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560288
DOI : 10.1186/s12964-017-0182-1
PUBMED : 28666461

Éditeur(s) : HAL CCSD Wiley
Résumé :  
The symbiotic interactions between Frankia strains and their associated plants from the Casuarinaceae under controlled conditions are well documented but little is known about these interactions under natural conditions. We explored the symbiotic interactions between eight genotypically characterized Frankia strains and five Casuarinaceae species in long-term field trials. Characterization of strains was performed using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) for the nifD-nifK intergenic transcribed spacer (ITS) and 16S-23S ITS. Assessments of the symbiotic interactions were based on nodulation patterns using nodule dry weight and viability, and on actual N-2 fixation using the delta N-15 method. The PCR-RFLP patterns showed that the analyzed strains belonged to the same genotypic group (CeD group), regardless of the host species and environment of origin. The nodule viability index is introduced as a new tool to measure the viability of perennial nodules and to predict their effectiveness. The host Casuarinaceae species was a key factor influencing both the actual N-2-fixing activity of the associated Frankia strain and the viability of nodules within a location. This is the first study providing information on the symbiotic interactions between genotypically characterized Frankia strains and actinorhizal plants under natural conditions. The results revealed a way to improve a long-term management of the Casuarinaceae symbiosis.
ISSN: 0031-9317

hal-01032134
https://hal.archives-ouvertes.fr/hal-01032134
DOI : 10.1111/j.1399-3054.2007.00856.x

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé :  
1. Despite considerable interest in the application of plant functional traits to questions of community assembly and ecosystem structure and function, there is no consensus on the appropriateness of sampling designs to obtain plot-level estimates in diverse plant communities. 2. We measured 10 plant functional traits describing leaf and stem morphology and ecophysiology for all trees in nine 1-ha plots in terra firme lowland tropical rain forests of French Guiana (N = 4709). 3.We calculated, by simulation, the mean and variance in trait values for each plot and each trait expected under seven sampling methods and a range of sampling intensities. Simulated sampling methods included a variety of spatial designs, as well as the application of existing data base values to all individuals of a given species. 4. For each trait in each plot, we defined a performance index for each sampling design as the proportion of resampling events that resulted in observed means within 5% of the true plot mean, and observed variance within 20%of the true plot variance. 5. The relative performance of sampling designs was consistent for estimations of means and variances. Data base use had consistently poor performance for most traits across all plots, whereas sampling one individual per species per plot resulted in relatively high performance. We found few differences among different spatial sampling strategies; however, for a given strategy, increased intensity of sampling resulted in markedly improved accuracy in estimates of trait mean and variance. 6. We also calculated the financial cost of each sampling design based on data from our 'every individual per plot' strategy and estimated the sampling and botanical effort required. The relative performance of designs was strongly positively correlated with relative financial cost, suggesting that sampling investment returns are relatively constant. 7. Our results suggest that trait sampling for many objectives in species-rich plant communities may require the considerable effort of sampling at least one individual of each species in each plot, and that investment in complete sampling, though great, may be worthwhile for at least some traits.
Functional Ecology

hal-01032175
https://hal.archives-ouvertes.fr/hal-01032175
DOI : 10.1111/j.1365-2435.2009.01600.x

Éditeur(s) : HAL CCSD Wiley
Résumé : Decomposing litter provides critical nutrients for plants, particularly in nutrient-poor ecosystems such as tropical forests. We hypothesised that decomposing litter improves the performance of a variety of tropical tree seedlings, and that this litter effect varies depending on the species of litter present in litter mixtures. We addressed these hypotheses with a large pot experiment manipulating a range of different litter mixtures of contrasting quality and using seedlings of four tree species from the Amazonian forest of French Guiana. In contrast to our initial hypothesis, decomposing litter had either neutral or negative impacts on seedling growth, despite strongly different growth rates, biomass allocation patterns and leaf and root traits among tree species. Tree species varied in their responses to litter additions, which were further modified by species identity of the added litter. Our data show litter species-specific effects on growth, biomass allocation and leaf and root traits of tropical tree seedlings. These results suggest that a net nutrient release from decomposing litter does not necessarily improve tree seedling growth, even under nutrient-limiting conditions. In conclusion, litter layer composition may affect seedling establishment and recruitment success beyond litter-derived plant nutrient availability, which may contribute to tree species composition and dynamics in the studied tropical forest.
ISSN: 1435-8603

hal-01032421
https://hal.archives-ouvertes.fr/hal-01032421
DOI : 10.1111/j.1438-8677.2011.00534.x

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : L’exploitation commerciale des produits forestiers non ligneux a animé et anime encore au plan international les débats sur la gestion durable des forêts, notamment par son apport en matière de conservation, d’amélioration des conditions d’existence des populations locales et de gestion participative. Cependant, l’exploitation commerciale des PFNL soulève la problématique de la durabilité tant au plan écologique, économique que sociopolitique. La présente recherche traite de cette problématique en prenant comme PFNL d’illustration le raphia dans la forêt marécageuse Hlanzoun. Elle vise à analyser la durabilité socio-économique et environnementale de l’exploitation du raphia dans la forêt marécageuse « Hlanzoun ». La méthodologie utilisée est une combinaison d’approches quantitatives et qualitatives. Les outils d’analyse de données utilisés sont entre autre, la statistique descriptive, l’analyse filière des revenus d’exploitation et des valeurs ajoutées et l’analyse du système socio-écologique. Nos résultats montrent que le raphia est une plante à usages multiples. Que ce soit les feuilles, les fibres, la sève ou le tronc, tout ou presque peut être valorisé sur le raphia. Au niveau des villages riverains du Hlanzoun l’exploitation de la sève du raphia et sa transformation en alcool alimentaire est de loin le type d’usage qui procure le plus de revenu malgré le fait que les autres types d’usages mobilisent un nombre plus important d’acteurs. L’exploitation commerciale de ce PFNL se déploie suivant une organisation relativement simple et avec des caractéristiques propres à la plupart des activités de la petite production marchande des économies sous-développées en crise. Cette exploitation est essentiellement articulée autour des coupeurs/collecteurs, des intermédiaires commerciaux, des agents de transformation/conditionnement et des consommateurs des produits finis. La contribution annuelle totale de la filière raphia au développement a été estimée à 192 429 633 Fr. CFA (environ 385 000 dollar) et les revenus d’exploitation de tous les acteurs ont un signe positif malgré le faible niveau de technologie et de formation. Le raphia apporte donc des revenus relativement importants aux divers acteurs en dépit des handicaps de la filière et du déficit d’équité dans la répartition des richesses produites. Au plan de la gouvernance, on note un déficit d’instances, de règles et de procédures, dont l’effectivité et la légitimité sont clairement établies. Cet état de chose laisse le parc à raphia dans un régime d’accès « libre » mais seulement pour les riverains ; nous nous retrouvons donc en présence d’un système de cueillette, caractérisé par l’exploitation de plants immatures et la surexploitation, mettant en péril la capacité de renouvellement de la ressource et même l’avenir de la filière. On note cependant un effort de contrôle de l’accès des non riverains et des tentatives d’adaptation des riverains. En effet, le nombre d’exploitants est passé de 148 à 92 entre 2008 et 2010 et le nombre de pieds de raphia saignés est passé de 15 452 à 8 832 durant la même période. Au total, l’exploitation du raphia dans le Hlanzoun s’inscrit dans un environnement défavorable par rapport aux exigences de développement durable d’une filière de PFNL. Mais les divers acteurs sont à présent conscients de la nécessité d’agir pour une meilleure réglementation de l’accès et de l’exploitation.
The commercial use of non woody forest products is a crucial issue in the international debate on the sustainable management of forests. These products are supposed to contribute to conservation by improving local populations’ livelihood and their involvement in forest management. This study lies within the scope of two South-South Cooperation projects (PSC 22P07 and PSC 03T08) implemented by the CEBEDES NGO with the financial support of the Kingdom of the Netherlands. It aims at analyzing the socioeconomic and environmental sustainability of the raffia stands management in the swamp forest "Hlanzoun ". This small forest is located in one of Benin southern Wetlands in the municipality of Zogbodomey.The methodology to assess raffia socioeconomic performances relies on the estimation of the values added within the raffia value chains. Stakeholders at every segment of the value chains have been surveyed on the incomes obtained out of raffia. The methodology to assess the sustainability of the management relies on a simple indicator measuring the ratio of younger to elder palms. Palms in stands have been counted according to their age group. The survey confirms that raffia is a multi-purpose plant used for its leaves, fibers, sap and trunk. In villages at the borders of the Hlanzoun forest, harvesting the raffia sap on standing palms and processing it into alcohol are a major income generating activity. Alcohol is then marketed through a network of collectors, wholesalers and petty traders up to the consumers. The contribution of raffia to local and regional development was estimated by the total incomes generated at 192.429.633 F CFA. All stakeholders earn positive and significant incomes in spite of the low level of technology and skills, but traders receive a large share of the wealth produced. As regard to governance, "free" access only concerns residents and efforts are made to control the access of non-residents. One notes a deficit of legitimated authorities, rules and procedures for a sustainable use: Restrictions on the harvest of immature palms are not anymore enforced and it endangers the renewal capacity of the resource. But at the same time, the number of operators seems to be decreasing (from 148 to 92 between 2008 and 2010, whereas the number of harvested raffia palms decreased from 15,452 to 8,832 during the same period). A self-regulation might occur, due to the fact that a livelihood of local people relies on a diversity of income generating activities. In total, the operation of Raffia in Hlazoun is in an unfavorable environment with the requirements of sustainable development in a sector of NTFF. But the various actors are now aware of the need for action to better regulate access and operation.
Bénin

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5556
http://journals.openedition.org/etudescaribeennes/5556

Résumé : Cette thèse concerne la modélisation des dynamiques de maladies foliaires de cultures pérennes tropicales à différentes échelles spatiales. Cette approche de modélisation est appliquée à la cercosporiose noire du bananier. Il s’agit d’explorer et de déterminer les paramètres environnementaux et de résistance de l’hôte ayant une influence significative sur la dynamique spatiotemporelle de la maladie et d’apporter des éléments associés au contrôle de la cercosporiose noire.Deux modèles ont été développés dans le cadre de cette thèse. La dynamique épidémiologique au niveau de la plante est décrite par un modèle mécaniste décomposé en un modèle de croissance de la plante et un module épidémiologique décrivant le cycle épidémique du pathogène. L’architecture du bananier est prise en compte par le biais de compartiments foliaires positionnés dans l’espace. Le modèle a été validé par un jeu de données indépendant. Les expérimentations numériques et l’analyse de sensibilité du modèle réalisées par les méthodes de Morris et de e-FAST ont permis de mieux comprendre le fonctionnement épidémique de cette maladie et d’identifier les paramètres influant le plus la dynamique épidémique en particulier la vitesse d’extension des lésions, la durée d’incubation et l’efficacité d’infection .L’approche bayésienne a permis de prendre en compte l’information a priori disponible pour ces trois paramètres sur lesquels a porté l’inférence statistique. L’analyse de sensibilité du modèle a également permis d’identifier l’influence de deux paramètres liés à la croissance de la plante : le nombre de feuilles sur une plante et le rythme d’émission foliaire Un modèle de dynamique spatio-temporelle de la cercosporiose noire a été développé à l’échelle d’un territoire à partir d’enquêtes effectuées enMartinique pendant la période d’invasion de cette maladie de septembre 2010 à mai 2012. Les données récoltées étant censurées, l’inférence des paramètres du modèle a été réalisée dans un cadre bayésien en utilisant un algorithme d’augmentation de données. Le modèle et l’inférence développés permettent de reconstruire la dynamique spatio-temporelle de l’invasion et de prédire la fin d’invasion sur le territoire.Les deux modèles de dynamiques spatio-temporelles développés à deux échelles spatiales différentes ont permis d’acquérir des informations importantes pour construire des outils de conception de méthode de contrôle de la cercosporiose noire des bananiers.
This thesis concerns the modeling of the dynamics of foliar diseases of tropical tree crops at different spatial scales. This modeling approach is applied to black Sigatoka of banana. It is to explore and determine the environmental parameters and host resistance has a significant influence on the spatiotemporal dynamics of the disease and to provide elements associated with the control of Sigatoka noire.Deux models were developed as part of this thesis. The epidemiological dynamics at the plant is described by a mechanistic model decomposed into a growth model of the plant and an epidemiological unit describing the pathogen epidemic cycle. The architecture of the banana is taken into account through foliar compartments positioned in space. The model was validated by an independent data set. Numerical experiments and model sensitivity analysis performed by the methods of Morris and e-FAST enabled to better understand the functioning of this epidemic disease and identify the parameters affecting the most dynamic epidemic especially speed extension of the lesions, the incubation period and efficiency of Bayesian .L'approche infection allowed to take into account prior information available for these three parameters that were the statistical inference. The model sensitivity analysis also identified the influence of two parameters related to plant growth: the number of leaves on a plant and rate of leaf emission A dynamic model of space-time Black Sigatoka has been developed at the scale of a territory from surveys enMartinique during the period of invasion of the disease from September 2010 to May 2012. The data collected being censored, inference of model parameters has was performed in a Bayesian framework, using a data augmentation algorithm. The model developed and inference possible to reconstruct the spatiotemporal dynamics of the invasion and predict the end of the invasion territoire.Les two spatio-temporal dynamics models developed at two different spatial scales has been gained important information for build tools design method of control of black Sigatoka of banana.

http://www.theses.fr/2015AGUY0835/document

Éditeur(s) : HAL CCSD Wiley
Résumé : Plant germination and development depend upon a seed's successful dispersal into a suitable habitat and its ability to grow and survive within the surrounding biotic and abiotic environment. The seeds of Aechmea mertensii, a tank-bromeliad species, are dispersed by either Camponotus femoratus or Neoponera goeldii, two ant species that initiate ant gardens (AGs). These two mutualistic ant species influence the vegetative and reproductive traits of the bromeliad through their divergent ecological preferences (i.e. light and substrate). We hypothesised that the seeds dispersed by these two ant species have underlying genetic differences affecting germination, growth and survival of A.mertensii seedlings in different ways. To test this, we used an experimental approach consisting of sowing seeds of A.mertensii: (i) taken from the two AG-ant associations (i.e. seed origin), (ii) in two contrasting light conditions, and (iii) on three different substrates. Light and substrate had significant effects on germination, survival and on eight key leaf traits reflecting plant performance. Seed origin had a significant effect only on germination and on two leaf traits (total dry mass and relative growth rate). Overall, this bromeliad performs better (i.e. high growth and survival rates) when growing both in the shade and in the carton nest developed by C.femoratus ants. These results suggest that the plasticity of the tank bromeliad A.mertensii is mainly due to environment but also to genetic differences related to seed origin, as some traits are heritable. Thus, these two ant species may play contrasting roles in shaping plant evolution and speciation.
ISSN: 1435-8603

hal-01606565
https://hal.archives-ouvertes.fr/hal-01606565
DOI : 10.1111/plb.12452
PRODINRA : 407514

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Microbial pollution in aquatic environments is one of the crucial issues with regard to the sanitary state of water bodies used for drinking water supply, recreational activities and harvesting seafood due to a potential contamination by pathogenic bacteria, protozoa or viruses. To address this risk, microbial contamination monitoring is usually assessed by turbidity measurements performed at drinking water plants. Some recent studies have shown significant correlations of microbial contamination with the risk of endemic gastroenteresis. However the relevance of turbidimetry may be limited since the presence of colloids in water creates interferences with the nephelometric response. Thus there is a need for a more relevant, simple and fast indicator for microbial contamination detection in water, especially in the perspective of climate change with the increase of heavy rainfall events. This review focuses on the one hand on sources, fate and behavior of microorganisms in water and factors influencing pathogens' presence, transportation and mobilization, and on the second hand, on the existing optical methods used for monitoring microbiological risks. Finally, this paper proposes new ways of research.
ISSN: 1660-4601

hal-01122209
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122209
PUBMED : 24747537
DOI : 10.3390/ijerph110404292
PUBMEDCENTRAL : PMC4025003

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Cross-species analyses of plant functional traits have shed light on factors contributing to differences in performance and distribution, but to date most studies have focused on either leaves or stems. We extend these tissue-specific analyses of functional strategy towards a whole-plant approach by integrating data on functional traits for 13 448 leaves and wood tissues from 4672 trees representing 668 species of Neotropical trees. Strong correlations amongst traits previously defined as the leaf economics spectrum reflect a tradeoff between investments in productive leaves with rapid turnover vs. costly physical leaf structure with a long revenue stream. A second axis of variation, the 'stem economics spectrum', defines a similar tradeoff at the stem level: dense wood vs. high wood water content and thick bark. Most importantly, these two axes are orthogonal, suggesting that tradeoffs operate independently at the leaf and at the stem levels. By simplifying the multivariate ecological strategies of tropical trees into positions along these two spectra, our results provide a basis to improve global vegetation models predicting responses of tropical forests to global change.
ISSN: 1461-023X

hal-00594040
https://hal.archives-ouvertes.fr/hal-00594040