Le projet "Dahomey Gap": une contribution à l'histoire de la végétation au Sud-Bénin et Sud-ouest du Nigéria

La coupure que l'on constate dans les forêts denses africaines au niveau du Togo et du Bénin soulève de nombreuses questions sur les rapports forêt/savane au cours des derniers millénaires. Le projet Dahomey Gap vise à y répondre, par une approche pluridisciplinaire intégrant botanique et histoire de la végétation dans le Sud-Bénin et le Sud-Ouest du Nigéria. A partir de travaux déjà avancés sur la végétation du Bénin et des premières prospections palynologiques, quelques aspects du projet sont exposés ici: tels la caractérisation des différentes formations forestières du Bénin, les premiers résultats sur l'histoire holocène de la végétation du Sud-Bénin (mangroves, forêts, savanes) enregistrée depuis près de 7000 ans dans les lagunes

Etude Phytochimique Et De Cytotoxicité De Quelques Plantes Utilisées Dans Le Traitement De La Stérilité Féminine Au Sud-Bénin

The most cited plant drugs during an ethnobotanical survey conducted for traditional healers and resource persons in southern Benin, used in the treatment of female infertility, were the subject of a phytochemical screening. It aims to determine the chemical substances that are conferred on the plants. These chemical substances are the pharmacological properties that are used for the treat of ailment recognized as being the origin of this disease. As a result, we studied the cytotoxicity of each herbal drug. In total, the organs of 17 plant species involved in this study are Aframomum melegueta, Allium cepa, Anchomanes deformants, Baphia nitida, Carissa spinarum, Elaeis guineensis, Garcinia cola, Kigelia africana, Monodora myristica, Morinda lucida, Musa sapientum, Olax subscorpioidea, Piper guineense, Pterocarpus erinaceus, Pupalia lappacea, Tetrapleura tetraptera, Xylopia aethiopica. The results obtained indicate that the richness in phytochemical element is a function of the species. Thus, Aframomum melegueta, Garcinia kola, Monodora myristica, Tetrapleura tetraptera, Xylopia aethiopica, and Anchomanes difformis are rich in catechin and/or gallic tannins, mucilages, reducing compounds, anthocyanins and/or leucoanthocyanins. On the other hand, no drugs is at same time rich in free anthracenics, steroids and / or terpernoids, alkaloids, saponosides, and quinone derivatives. The calculated CL50 values for each of the plant organs are all greater than 0.1 mg / ml. None of them is toxic. However, the non-toxicity of an herbal drug does not mean the same with the multispecies recipe in which it is used. Pharmacological tests of the various recipes used are also of significant importance

Diversité floristique et caractérisation structurale de la réserve forestière de Ouoghi en zone soudanoguinéenne (Centre-Bénin)

Objective: The objective of this study is to identify the plant species and to characterize the vegetation of the Ouoghi forest reserve in the commune of Savè (Center-Benin). Method and results: Floristic and forest inventories were carried out through 144 relevés in according to the Braun-Blanquet method. A total of 246 plant species were identified. They belong to 178 genera and 63 families. Multivariate analyzes with the Community Analysis Package (CAP) software made it possible to individualize 3 vegetation formations comprising 8 plant groups. This is the shrub savannah with Prosopis africana and Pennisetum polystachion, the tree savannah with Hymenocardia acida and Pennisetum polystachion, the tree savannah to Vitellaria paradoxa and Pennisetum polystachion, the tree savannah to Pterocarpus erinaceus and Hyptis suaveolens, the woodland savannah with Daniellia Oliveri and Chromolaena odorata, the woodland savannah at Isoberlinia doka and Pennisetum polystachion, the woodland savannah at Daniellia oliveri and Andropogon tectorum and the tree flood savannah to Daniellia oliveri and Leersia hexandra. The floristic and structural parameters change from one group to another. Thus, the specific richness varies from 49 to 153 species and the diversity of families is between 22 and 49 with a predominance of Leguminosae. The density varies from 95 to 275 stems / ha, basal area from 2.35 to 8.44 m² / ha. Conclusion and application of results: The study evaluated the floristic diversity of the Ouoghi reserve. In addition, it indicated the need for its integral protection for its dynamics towards dry dense forest vegetation. Sustainable management of this site needs implication of local population

Diversité Des Loranthaceae Et Leur Impact Sur Vitellaria Paradoxa C.F.Gaertn.: Un Fruitier À Grande Valeur Socio-Économique Au Nord-Bénin

Shea butter: Vitellaria paradoxa C. F. Gaertn (Sapotaceae) is a fruit tree in the Sudano-Sahelian region where it is a major economic source. Unfortunately, in Benin, the species has been revealed in recent decades, the target of parasitic vascular plants of Loranthaceae family that threaten its conservation. The present study, carried out in northern Benin, evaluated the impact of these parasitic plants on the shea of two phytogeographical zones. The botanical inventory identified three species of Loranthaceae in fields and protected areas. The rate of infestation and parasite density were assessed and their variation on shea was assessed. The results show that shea is parasitized by three species of Loranthaceae in varying proportions: Agelanthus dodoneifolius (DC.) Polh. and Wiens (191.75 tufts / ha), Tapinanthus globiferus (A. Rich.) Van Tieghem (70.57 tufts / ha) and T. Ophiodes (Sprague) (2 tufts / ha). The impact of Loranthaceae on shea productivity varies significantly between fields and protected areas with infestation rates of 87% versus 42% and average densities per shea foot of 14.76 tufts versus 3.62 tufts. These results are data to be taken into account in the control programs against Loranthaceae which parasitize shea

Phytochimiques des plantes médicinales utilisées dans la prise en charge des maladies infantiles au SudBénin

In southern Benin, medicinal plants are used for the health care of children aged 0 to 12 years. The present study aims to highlight some medicinal plants used in southern Benin to treat childhood diseases including malaria, candidiasis, teething disorders, infant colic and diarrhea. The phytochemical screening of the leafy stems of the selected plants revealed the presence of alkaloids, tannins (gallic and catechic), coumarins, anthocyanins and leuco-anthocyans, quinone derivatives, triterpenoids, steroids, saponosides and reducing sugars. These various metabolites possess various therapeutic properties involved in the treatment of the indicated disorders. This would confirm the therapeutic uses reported by the populations surveyed. However, the evaluation of antimalarial, antibacterial, anti-inflammatory and analgesic activities as well as the toxicity test of the aqueous extract of these plants would be necessary

Genetic Divergence in Northern Benin Sorghum ( Sorghum bicolor

Sorghum [Sorghum bicolor (L.) Moench] is an important staple food crop in northern Benin. In order to assess its diversity in Benin, 142 accessions of landraces collected from Northern Benin were grown in Central Benin and characterised using 10 qualitative and 14 quantitative agromorphological traits. High variability among both qualitative and quantitative traits was observed. Grain yield (0.72–10.57 tons/ha), panicle weight (15–215.95 g), days to 50% flowering (57–200 days), and plant height (153.27–636.5 cm) were among traits that exhibited broader variability. Correlations between quantitative traits were determined. Grain yield for instance exhibited highly positive association with panicle weight (r=0.901, P=0.000) and 100 seed weight (r=0.247, P=0.000). UPGMA cluster analysis classified the 142 accessions into 89 morphotypes. Based on multivariate analysis, twenty promising sorghum genotypes were selected. Among them, AT41, AT14, and AT29 showed early maturity (57 to 66 days to 50% flowering), high grain yields (4.85 to 7.85 tons/ha), and shorter plant height (153.27 to 180.37 cm). The results obtained will help enhancing sorghum production and diversity and developing new varieties that will be better adapted to the current soil and climate conditions in Benin

Importance Du Couplage De L’inventaire Des Plantes Mellifères Et De L’analyse Pollinique Des Miels De La Saison Des Pluies En Zone Ouest Soudanienne Au Nord-Bénin

The melliferous plants vary from one area to another according to biotic, climatic and ecological factors. This study was realized in the Sudanese region of Benin, in order to inventorize honey plants visited by the honeybee Apis mellifera adansonii Latreille. Pollen analysis of 34 samples of honey from three apiaries in the northwest of the country, combined with direct observations around each apiary within 1000 m radius were realized per month. In total 129 species were censised including 109 species inventorized on the field and 73 taxa identified through pollen analysis. Among these taxa, 43 are identified until species level. The contribution of pollen analysis to the knowledge of melliferous plants is 15.50%. The pollen analysis of honeys and visual inventory of honey plants field are two complementary methods of studying the honey flora