The knowledge of the functioning of our forest ecosystems protected is an issue of the maintenance of the planetary balance as regards its biodiversity and its climate. Its floristic dynamic apprehended by the mortality of trees, has formed the base of this study in the site of Isekelende at the biosphere reserve of Yangambi (Tshopo, D.R. Congo). Collected in a device of 6 ha, the results arising from this study have shown that the rate of tree mortality is more than 4 times higher than the tropical average. The causes differ according to the type of mortality. For the mortality on foot, the aging and the Fungal pathologies are the causes mainly observed while for the Chablis, we cannot say with statistical certainty that the frequencies and the wind speeds which are the main causes. A spatial distribution of dead trees identified highlights a relief of specific gaps. This mosaic is positively correlated to the direction of the prevailing wind of Yangambi.

As for hybridization, the Violet forms were more compatible with the foreign varieties Roma and Makis than the Red forms. The local varieties were also compatible among themselves. The success rate of crossing was on average 50%.The genetic disjunctive generation analysis F2 shows that all characters with discontinuous variation (qualitative: color and shape of the fruit) follow a simple Mendelian genetic determinism. Moreover, heritability (in the broad sense) of some quantitative characters (size, number of flowers, number of fruits and weight of fruits) by the variance decomposition method can reach relatively high values (0.8 to 0.95) for some groups of crossings. The same holds good for heritability in the restricted sense (0.56 to 0.98) for some characters and groups.

The objective of this work is to determine the phenotypic characterization of enterobacteria with a view to identifying them, extracting aromatic oils, and preparing ethereal, chloroformic extracts of foods, in order to test the antibacterial activity of four foods, among other Allium sativum, Allium schoenoprasum, Allium cepa and Allium porrum.The aqueous, ethereal and chloroform extracts were obtained by hydro-distillation and by the extraction method using ether and chloroform respectively.As a result, the strains observed are Gram negative bacteria; their morphological and biochemical characterization made it possible to identify three germs including Citrobacter sp, Proteus mirabilis and Escherichia coli.The study of the sensitivity of these strains to hydro-distillation, to the ethereal and chloroform extract of Allium sativum, Allium schoenoprasum, Allium cepa and Allium porum by the method of diffusion in agar medium led to the following results: strains S8, S13 and S16 inhibited on hydro distillation (8; 15; 16mm of inhibition diameters); the ethereal extract of these same drugs inhibited the S14 strains for garlic (with 8mm inhibition diameter; S13 and S16 for chives (with 10mm inhibition diameter) and finally, the S16 strain for onion (with 16mm inhibition diameter), on the other hand, the chloroformic extract presented the zones of inhibition to strains S15 and S16 (14 and 12mm inhibition diameter) for Allium sativum (garlic); to strains S6 and S16 (9 and 13mm inhibition diameters) for Allium schoenoprasum (chives) and finally, strain S16 (17mm inhibition diameter) for Allium cepa (onion).Further in-depth research should be encouraged in order to make available to society effective and less expensive products which fight against antibiotic-resistant enterobacteria in the Kisangani region.