Statut mycorhizien de la rhizosphère des plants du cultivar blanc de macabo (Xanthosoma sagittifolium L. Schott) dans la région du Centre

Abstract

Cocoyam (Xanthosoma sagittifolium L. Schott) is an herbaceous plant that belongs to the Araceae family which is cultivated for its edible tubers and leaves. This work aimed to evaluate the mycorrhizal status of cocoyam in Cameroon Centre Region. The experiment was carried out in plants and rhizosphere of cocoyam white cultivar from four localities of the Centre (Ahala, Nkolbisson, Soa and Ngoa-Ekele). Roots and leaves were subjected to an assessment of mycorrhizal status and biochemical analysis respectively. The pH of the different rhizosphere, the mycorrhizal parameters were determined as well as the amount of some biochemical compounds. The results showed a variation of the pH of the rhizosphere showed between sites 8.25; 4.89; 8.05 and 8.36 for Ahala, Nkolbisson, Soa and Nga-Ekele respectively. The highest percentage of mycorrhization was observed in Ahala (75%) while 57%, 47.3%, 47% were observed for Soa, Ngoa-ekelé and Nkolbisson sites respectively. In addition, the intensity of mycorrhization was significantly high in Ahala (330%) compared to the others sites 16.15%; 14.01% and 11.21% for Nkolbisson, Ngoa-Ekele and Soa respectively. Histological analysis showed structures characteristic of endomycorrhizae. No structures characteristic of ectomycorrhizas was observed. Mycorrhization has no significant effect on total chlorophyll content. Furthermore a significant effect of mycorhization on total amino acids, proline and phenols content was observed in the site of high mycorhization especially Ahala. Cocoyam white cultivar can be classed in the group of plant with high mycorrhizal dependence type endomycorrhizae. This work can be apply in intensive biological agriculture by the use of biofertilizers containing arbuscular mycorrhizal fungi