C4 plants are plants with modified photosynthetic metabolism, allowing overproduction of organic matter, compared to other so-called C3 plants. It is for this reason that C4 plants are used primarily in the nutritional and nutritional formulations of infants. Current data on these plants are only limited to Western work done on a limited sample. This work has been done to identify the C4 food plants found on the Gabonese market. A collection of food plants was thus carried out on the central market of Franceville, and the samples studied in the laboratory. The determination technique was based on anatomical identification of perivascular sheaths at the level of cellular cross sections. The results obtained showed that out of 32 species analyzed, only 5 plants belonging to 2 families were of C4 typology. These are local lemongrass (Cymbopogon cytratus, Poaceae), maize (Zea mays, Poaceae), sugar cane (Saccharum officinarum, Poaceae), Chinese lemongrass (Cymbopogon sp., Poaceae) and folon / amaranth (Amaranthus sp. Amaranthaceae). The presence of C4 plants on the Gabonese market seems relatively weak.

Coconut fiber is the substrate of choice for the production of plants in vegetable nursery above ground Gabon. However, procurement and production costs of the material remain high. This study conducted in the experimental area of the company Horta Gabon, located in the town of Akanda north of Libreville in Gabon, with the aims to test the possibility of substituting coconut fiber imported by coffee husks produced locally. Thus, through monitoring of the germination and vegetative behavior of Tomato seedlings (Lycopersicon esculentum) subject to various disinfection treatments, which have focused on the nature of disinfectant and the volumes applied, have showed that plants of tomato products on coffee husks disinfected 1.5 L of Metam Sodium (MS) and washed have better returns in terms of germination and development of tomato seedlings. These results indicate that the coffee husk could be an alternative substrate of coconut fiber without causing major imbalances.