Effet du Manganèse sur la Croissance de la Patate Douce (Ipomoea batatas L.) au Gabon

Soil contamination in the mining town of Moanda, in southwestern of Gabon, is characterized by high concentrations of Manganese. This work aims to analyze the impact of various manganese concentrations in soils on sweet potato growth and development. The plant's seeds were obtained on the local market. The stems were grown in greenhouses in 5 media, 4 of which were enriched with manganese and 1 not enriched. The manganiferous effect was assessed by measuring biochemical and physico-chemical parameters (total chlorophyll, dry matter, total sugars). The effects of the 5 treatments were compared on the Statistica 7.2. software from an Anova. The results show that high concentrations (25%, 50%, 75% and 100%) affect the morphometric characteristics of the sweet potato. Concentrations at 25% Mn increase the parameters and decrease them to 50% and 75% Mn, compared to the control. The 100% Mn concentrations totally inhibit the growth and development of the sweet potato. La contamination des sols de la ville miniere de Moanda, au Sud-Est du Gabon est caracterisee par de fortes concentrations de manganese. De ce fait, ce travail vise a analyser l’impact de diverses concentrations de manganese dans les sols sur la croissance et le developpement de la patate douce. Les semences de la plante ont ete obtenues sur le marche local. Les tiges ont ete cultivees en serre sur 5 milieux dont 4 enrichis en manganese et 1 non enrichi. L’effet manganifere a ete evalue par la mesure des parametres biochimiques et physico-chimiques (chlorophylle totale, matiere seche, sucres totaux). Les effets des 5 traitements ont ete compares sur le logiciel Statistica 7.2. a partir d’une Anova. Les resultats montrent que les fortes concentrations (25% ,50%, 75% et 100%) affectent les caracteristiques morphometriques de la patate douce. Les concentrations a 25% de Mn entrainent une augmentation des parametres et une diminution de ces derniers a 50% et 75% de Mn, par rapport au temoin. Les concentrations a 100% de Mn inhibent totalement la croissance et le developpement de la patate douce.