Fruit and seed production in a natural population of a dioecious plant: Piliostigma reticulatum HOSCHT (Caesalpinioïdeae)

Plant fruit/seed production is a central subject of many questions in plant evolutionary and conservation biology. In the Sudano-Sahelian forest of Burkina Faso, fruit and seed production of a common dioecious shrub, Piliostigma reticulatum, were assessed by considering plant size, fruiting success and distance between male and female individuals. The results showed that P. reticulatum has a low production of fruits and seeds (17.63 g ± 3.33 SE of fruit per plant and 0.1045 g ± 0.0018 SE per seed). A large percentage of the seeds aborted (40%) and were damaged by herbivory (10%). The fruiting success ranged from 0.1 to 0.4. The percentage of seeds attacked by insects was negatively correlated with the mean diameter of the canopy and the height of trees. When the female of P. reticulatum was more than 10 meters from the male, fruit and seed productions were greater. The conclusion was that losses of flowers and fruits were important and suggested further information on pollination limitation or genetic studies to identify the cause of the insufficient quality and quantity of fruit and seed productions of P. reticulatum.Keywords: Piliostigma reticulatum, dioecious, fruiting success, soudanian forest, Burkina Fas

Flowering phenology and floral visitors of Piliostigma reticulatum in a tropical dry forest, Burkina Faso

Piliostigma reticulatum is a dioecious species that provides food, fodder and the revenues from the sale of its pods constituted an important resource for sahelian population. During the flowering, flowers are abundant but the fruit set remained very low in spite of a large number of insect visitors. The aim of this work was to study flowering phenology, to identify potential pollinators and visitors, to determine the visitation rate and the synchronism between floral phenology and the insect visitors. The natural population studied is located at Budtenga in the North Sudanian area of Burkina Faso. The phenological study was carried out from July 2009 to December 2009 on 500 inflorescences randomly sampled from inflorescences of 40 male and female individuals. Potentials pollinators were determined using their physical ability to carry pollen in their body and the reference based diets. Our results showed that many orders of insects visit the flowers of P. reticulatum. Nymphalidae (Lepidoptera), Syrphidae (Diptera), Apidae (Hymenoptera) and Sphecidae (Hymenoptera) were regarded as main potential pollinators of P. reticulatum. Apidae (Apis mellifera) was the most abundant and frequent visitor. We found that August was the peak flowering period for both male and female individuals and the peak emergence of potential pollinators. Therefore, the emergence of potential pollinators responsible for pollen dispersal might be punctuated by flowering phenology.Keywords: Caesalpinioideae, P. reticulatum, phenology, visitors, Sudanian fores

Amélioration de la valeur nutritionnelle des gousses de Piliostigma reticulatum (D. C.) Hochst dans l’alimentation du bétail en période de soudure

Dans la zone nord soudanienne du Burkina Faso, les gousses de Piliostigma reticulatum sont intensément utilisées pendant la saison sèche comme aliment d’appoint pour le bétail. L’objectif de cette étudeest d’améliorer la qualité nutritionnelle de ces gousses pour optimiser leur apport. Neuf rations comprenant chacune des gousses de P. reticulatum (70 p.100) et du foin de Pennisetum pedicellatum (30 p.100) distribuéesà raison de 50 g MS/kg p0,75 ont été testées sur des ovins de race Djallonké. Les gousses ont subi différents traitements physiques (concassage, mouture) suivis ou non de traitement à l’urée auxquelles est associé dans certains cas du charbon de bambou à des doses de 0,25 ou 0,50 g/kg PV dans le but d’influencer l’action des tanins. L’utilisation de l’urée a entraîné, quelle que soit la forme de distribution, une amélioration de la digestibilité, surtout celle des matières azotées en raison de l’augmentation significative de leur teneur. L’adjonction du charbon de bambou n’a amélioré la digestibilité des gousses non traitées à l’urée qu’à la dose de 0,50 g/kg PV. Par contre, sur des gousses traitées à l’urée, il a permis une amélioration significative (

Grazing Behaviour and Selection of Browse Species by Cattle, Sheep and Goats on Natural Pasture in the Sahelian Zone of Burkina Faso

Pastures in semi-arid countries, are subject to seasonal variability. Browse species that are less dependent on rainfall, are highly valued. Goats are browsers, while cattle and sheep are grazers. However, faced with a scarcity of feed resources, especially in the late dry season, all animal species fall back on browse species. The objective of this study was to estimate feeding behaviour and browse species utilisation by cattle, sheep and goats on natural pasture in different seasons, and concurrently appreciate the indigenous knowledge on browse species in the study area

Fourrages ligneux des savanes du Tchad : Etat actuel des peuplements et utilisation pastorale

Résumé L’objectif de l’étude a été de diagnostiquer l’état des peuplements ligneux sur la base de l’analyse de leur distribution et de leur structure. Les méthodes utilisées ont été celles de relevés phytosociologiques et de sondage systématique. En raison de leur intérêt pastoral, six espèces ligneuses ont fait l’objet de mesures de dendrométrie et d’observations phénologiques. Leurs potentialités de régénération ont été aussi appréciées par un inventaire quantitatif et une analyse des caractéristiques démographiques de la strate juvénile. Les relevés ont montré une flore ligneuse riche de 165 espèces regroupées en 69 genres et 35 familles, totalisant 4205 individus. La densité moyenne des ligneux a été de 1248 individus adulte à l’hectare. Les espèces les plus représentées sont Anogeissus leiocarpus, Combretum collinum et Pterocarpus erinaceus. L’inventaire de la strate ligneuse juvénile a permis de dénombrer 588 jeunes individus à l’hectare représentant 31 espèces regroupées en 27 genres et 16 familles. L’étude de la structure démographique a montré une bonne régénération mais le peuplement n’est pas en équilibre. L’étude de la phénologie des ligneux montre une grande variabilité dans les cycles des espèces. Une meilleure méthode d’aménagement et de gestion des ligneux fourragers en vue de leur utilisation optimale a été proposée. Mots clés : Ligneux fourragers - Relevés phytosociologiques - Mesures dendrométriques - Régénération - Zone soudanienne – Tchad Browse trees of Chad Savannas: Present state of populations and pasture use Summary The objective of this study was to diagnose the state of woody populations based on their spatial distribution and structure analysis. Two methods were used: phytosociological surveys and systematic sampling. Based on their pasture interest, six woody species have been the subject of measurements and phenological observations. Their potential regeneration was also assessed by a quantitative inventory and analysis of the demographic characteristics of the juvenile stratum. Floristic sampling has shown a richness of 165 woody species distributed into 69 genera and 35 families, totalizing 4205 individuals. The average woodland density was 1248 adult individuals per hectare. Anogeissus leiocarpus, Combretum collinum and Pterocarpus erinaceus was most represented. The inventory of woody stratum juvenile enumerates 588 young people per hectare representing 31 species grouped in 27 genera and 16 families. The study of population class distribution showed a non-equilibrium state. The study of woody species phenology showed high variability in the species cycles. The management methods of best use of these browse plants were proposed. Keywords: Woody forage - Phytosociological methods – Dendrometric statement - Regeneration – Sudanian zone – Chad  &#160

Hermaphrodisme morphologique et dioécie physiologique dans une population de Piliostigma reticulatum (D.C.) HOSCHT (Caesalpinioideae)

Piliostigma reticulatum (Caesalpiniaceae) est une espèce dont les gousses sont fourragères et font l’objet d’un important commerce au Sahel. L’étude porte sur la morphologie et l’évolution florales dans le peuplement de Budtenga en zone nord soudanienne du Burkina Faso. Suite aux observations préliminaires, 5 individus à fleurs dites femelles et 5 autres à fleurs dites mâles ont été choisies. Sur chaque arbre 300 fleurs reparties entre le sommet, le milieu et la base du houppier ont été échantillonnées. L’observation a concerné la morphologie florale, l’anatomie des organes sexuels sous une loupe binoculaire. Ensuite, un comptage du nombre d’ovules et une étude de la viabilité in vitro des grains de pollens après coloration à la fushine ont été réalisés. Nos résultats montrent que la population étudiée est morphologiquement hermaphrodite mais fonctionnellement dioïque. Les individus à fleurs dites femelles montrent un ovaire bien développé contenant en moyenne 49 ovules. Le stigmate est globuleux et change de coloration du vert jaune au brun après l’épanouissement des fleurs. Leurs étamines sont atrophiées sous forme de staminodes et dépourvues de grains de pollen viables in vitro. Les individus à fleurs dites mâles montrent un pistil avec un ovaire réduit, un stigmate allongé qui ne change pas de coloration et des étamines bien développées avec des anthères contenant des grains de pollen viables invitro. La taille des fleurs dites mâles n’est pas significativement différente de celle des fleurs dites femelles. La dioécie fonctionnelle mise en évidence pourrait être le début d’une évolution vers un hermaphrodisme ou vers une dioécie stricte en fonction de l’intensité des pressions anthropiques.Mots clés : Caesalpinioideae; Piliostigma reticulatum; Morphologie florale; Hermaphrodisme ; DioéciePiliostigma reticulatum (Caesalpiniaceae) is a fodder species because of its pods which are subject of a major trade in the Sahel. The morphology and floral development in the population of Budtenga at north Sudanian zone of Burkina Faso have been carried out. After preliminary investigations, we chose 5 trees which bear female flowers and 5 others which bear male flowers were selected for studies. 300 flowers were collected from the top, the middle and the base of the crown on each tree. We observed floral morphology, anatomy of sexual organs in a binocular magnifying glass. Then we counted the number of ovules and the viability of pollen grains from female and male flowers after colored with the  fushine has been tested in vitro. Our results showed that the species was morphologically hermaphroditic but functionally dioecious. Female flowers showed a well developed ovary containing an average of 49 ovules. The stigma was globular and changed color from green-yellow to brown after the opened flowering stage. The stamens were atrophied and devoid of viable pollen  grains in vitro. Male flowers showed a pistil with a reduced ovary a stigma that did not change in color. The stamens were well developed and the anthers contained viable pollen grains in vitro. The size of the male flowers was not significantly different from that of female flowers. The functional dioecy highlighted could be the beginning of an evolution to either hermaphrodism or strict dioecy according to the intensity of anthropogenic pressure.Key words: Caesalpinioideae; Piliostigma reticulatum; Floral morphology; Hermaphrodism; Dioec

TDF and quantitative ultrasound bone quality in African patients on second line ART, ANRS 12169 2LADY sub-study.

Bone demineralization, which leads to osteoporosis and increased fracture risk, is a common metabolic disorder in HIV-infected individuals. In this study, we aimed to assess the change in bone quality using quantitative ultrasound (QUS) over 96 weeks of follow-up after initiation of second-line treatment, and to identify factors associated with change in bone quality.In a randomized trial (ANRS 12169), TDF and PI-naïve participants failing standard first-line treatment, from Burkina Faso, Cameroon, and Senegal were randomized to receive either TDF/FTC/LPVr, ABC/ddI/LPVr or TDF/FTC/DRVr. Their bone quality was assessed using calcaneal QUS at baseline and every 24 weeks until week 96. Stiffness index (SI) was used to measure bone quality. Out of 228 participants, 168 (74%) were women. At baseline, median age was 37 years (IQR: 33-46 years) and median T-CD4 count was 199 cells/μl (IQR: 113-319 cells/μl). The median duration of first-line antiretroviral treatment (ART) was 52 months (IQR: 36-72 months) and the median baseline SI was 101 (IQR: 87-116). In multivariable analysis, factors associated with baseline SI were sex (β = -10.8 [-18.1,-3.5] for women), age (β = -8.7 [-12.4,-5.1] per 10 years), body mass index (BMI) (β = +0.8 [0.1,1.5] per unit of BMI), and study site (β = +12.8 [6.5,19.1] for Cameroon). After 96 weeks of second-line therapy, a reduction of 7.1% in mean SI was observed, as compared with baseline. Factors associated with SI during the follow-up were similar to those found at baseline. Exposure to TDF was not associated with a greater loss of bone quality over time.Bone quality decreased after second-line ART initiation in African patients independently of TDF exposure. Factors associated with bone quality include age, sex, baseline BMI, study site, and duration of follow-up