Genetic Adaptability of Sarotherodon Melanotheron to Polycyclic Aromatic Hydrocarbons (PAHs) in Some Senegal Hydrosystems

The objective of this study is to evaluate the level of Polycyclic Aromatic Hydrocarbons (PAH) contamination at the Sine-Saloum (Foundiougne, Kaolack and Missirah), Hann Bay and Niayes (1 and 2) sites in Sénégal and genetic ecotoxicology of Sarotherodon melanotheron specimens from these sites.The genes of the specimens were studied by the enzymatic electrophoresis technique. Seven enzymatic systems (ADH, AAT, IDHP, MDH, PGM, GPI and EST) were analyzed. The analysis of the PAHs was carried out by gas chromatography coupled to mass spectrometry (GCMS). Populations of Sarotherodon melanotheron and sediments used for PAH measurements were sampled in 2009. Chemical characterization of the sampling sites revealed a high concentration of PAHs at Foundiougne and Hann Bay. The high pollution of environment is characterized by PAH napht (Foundiougne (14 378 ng/g) ; Hann Bay (5856 ng/g). The analysis of allelic variability showed the existence of an adaptive polymorphism at the PGM locus in S. melanotheron. The particularly low frequencies of the PGM * 105 allele in populations of disturbed environment (Foundiougne, Kaolack, Hann Bay, Niayes 1 and Niayes 2) suggest its involvement in the response to environmental stress. A negative correlation was observed between the PGM, IDHP and MDH-1 locus and PAH. The presence of PAHs in the environmentcauses to a decrease in the frequency of the PGM * 105 alleleatS. melanotheronspecimens

Effets du Précédent Cultural de L’arachide (Arachis Hypogaea L.) et de la Fumure Minérale sur la Production du Coton (Gossypium Hirsutum L.)

Pour restaurer et améliorer la fertilité des sols en culture de coton, l’arachide (Arachis hypogaea L) a été utilisée comme précédent cultural. L’expérimentation a été faite suivant un dispositif en blocs de Fisher avec quatre (4) répétitions et cinq (5) traitements, sur deux années (2018 et 2019). Les résultats ont montré que l’arrière effet de l’arachide (la biomasse et l’azote résiduel issue de la symbiose entre la légumineuse et les bactéries) a amélioré la croissance et le développement végétatif des plants de cotonnier. L’impact de cet apport organique s’est traduit par des plants de cotonniers statistiquement plus grand, (hauteur supérieur à 100 cm) pour le traitement T5 (précédent arachide + dose complet d’engrais). Le traitement T4 (précédent arachide + ½ dose d’engrais) quant à lui a généré un nombre moyen de capsules supérieur à 8 à la seconde campagne. Il ressort également que le précédent arachide associé à la dose complète et à la demi dose de fumure minérale améliore mieux le rendement du coton-graine. Des gains de 3 à 14 % à la 1ère campagne et 19 à 58 % à la deuxième campagne ont été enregistrés. Ainsi, la rotation arachide/coton est une bonne pratique, à encourager. To restore and improve soil fertility in cotton cultivation, peanut (Arachis hypogaea L) was used as a previous crop. The experimentation was done in a Fisher block design with four (4) replications and five (5) treatments, over two years (2018 and 2019). The results showed that the after-effect of the peanut (biomass and residual nitrogen from the symbiosis between the legume and the bacteria) improved the growth and vegetative development of the cotton plants. The impact of this organic fertilizer resulted in statistically larger cotton plants (height greater than 100 cm) for treatment T5 (previous groundnut + full dose of fertilizer). Treatment T4 (previous groundnut + ½ dose of fertilizer) generated an average number of bolls greater than 8 in the second season. It also appears that the groundnut precedent associated with different doses of mineral fertilizer improves seed cotton yields. Gains of 3 to 14% in the first season and 19 to 58% in the second season were recorded. Thus, the groundnut/cotton rotation is a good practice that should be encouraged

Genetic ecotoxicology of Sarotherodon melanotheron from some Sénégal hydrosystems related to level of contamination by some micropollutants

International audienceOn the purpose to study the genetic ecotoxicology of Sarotherodon melanotheron, the degree of contamination due to two micropollutants (Polychlorinated biphenyls (PCBs) and Polybrominateddiphenyl ethers (PBDE)) on seven sites (Foundiougne, Kaolack, Missirah, Koular, HannBay and Niayes (1 and 2) was evaluated. Seven systems (ADH, AAT, IDHP, MDH, PGM, GPI and EST) were analyzed through the technical of enzymatic electrophoresis. The specimens and sediments used for the proportioning pollutants were sampled into 2009.The analysis of indicator PCBs was carried out by gaseous chromatography coupled to a detector with capture of electrons (GC-DCE).-The analysis of the PBDE, was done by gaseous chromatography coupled to mass spectrometry high resolution (GC-MSHR). Highest concentrations of pollutants PCBs (19 ng/g) and PBDE (5 ng/g) were observed in Hann Bay. The analysis of allelic variability revealed an adaptive polymorphism at locus EST-14 and PGM at S. m. heudelotii; PGM at S. m. paludinosus. The presence of allele EST-14*110 in Hann Bay and weakest frequencies particularly of allele PGM*105 in populations of disturbed zones suggest her implication in the response to the undergone environmental stress. A negative correlation was observed between locus EST-14 and PBDE. The fast alleles from this locus (EST-14*110) could be selected against in populations living in contaminated environment

Amélioration De L’état Physique Et De La Fertilité Chimique Des Sols Par La Rotation Légumineuse Alimentaire Arachide (Arachis Hypogaea L.) / Cotonnier (Gossypium Hirsutum L.)

Les sols sous cotonnier connaissent de fortes dégradations physiques et chimiques qui nécessitent d’être corrigés pour la variabilité et la durabilité des exploitations. Pour restaurer l’état physique et la fertilité chimique des sols dans ces systèmes de culture à base de cotonnier (Gossypium hirsutum L.), en vue d’augmenter le rendement du coton-graine, l’arachide (Arachis hypogaea L) a été utilisée comme précédent cultural. L’effet de précédent a été évalué suivant un dispositif en blocs de Fisher avec quatre (4) répétitions et cinq (5) traitements. Suite à la culture de l’arachide, les propriétés physiques et chimiques du sol ont été améliorées avec une faible densité apparente (1,56), une humidité pondérale élevée (2,25 p.c.) et une faible résistance du sol à la pénétration des racines (2,71 kg/cm2). La teneur en matière organique a augmenté de plus de 7 p.c. L’azote a connu une hausse de teneur de l’ordre de 14 p.c. La teneur en phosphore assimilable a augmenté de plus de 90 p.c. La CEC, également sous précédent arachide, a connu une forte augmentation. Elle est passée de 5,2 à 26 cmolc/kg en fin de culture. Le pHeau a été amélioré de 0,5 unités de plus. Les rendements en coton-graine ont été améliorés avec des gains allant de 3,78 à 14,39 p.c. Il ressort donc que la rotation arachide/coton est une pratique à encourager. Elle permet de restaurer l’état physique et la fertilité chimique des sols

Phytoplankton Composition and trophic state of Guessabo lake (Upstream in Buyo lake, Ivory Coast)

Objectives: The trophic quality of Guessabo Lake (Ivory Coast) under the influence of fishing and agriculture was analysed starting according from the phytoplankton composition. Methodology and results: Sampling spatio-temporal in pelagic zone were made from a plankton net and supplemented with an integrated sampler. A total of three hundred and forty six species were identified. The groups, by orders of prevalence are, Chlorophyta with 164 species (48 %), Euglenophyta with 64 species (19 %), Cyanobacteria represented by 53 species (16 %), Bacillariophyta with 50 species (15 %) and, the other groups (Pyrrophyta, Chrysophyta and Xanthophyta) represented by 15 species (4 %). On the level of sampling stations of Guessabo Lake, 239 species were identified in Guemon sector against 231 and 257 species respectively in bed of the lake and Haut Sassandra sector. Concerning Guemon sector, 181 species were recorded at station G1 and 192 at station G5. In bed of lake (Channel), 154 species were listed at station G2, whereas 157 and 168 species were observed respectively at stations G4 and G6. For Haut Sassandra, stations G3 and G7 respectively presents 208 and 211 species. During this study, 103 species constant were listed against 66 species additional and 170 species accidental. In the floristic list, 73 species are common to all sampling stations. Sorensen index showed a similarity between the sectors and sampling stations. Trophic index based on Phytoplankton composition indicated that lake is from mesotrophy to eutrophy state. Key words: Phytoplankton, lake, mesotrophy, eutrophy; Ivory Coast