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Balanites aegyptiaca (L.) is an important tree in the semi-arid ecosystem with beneficial attributes. However, very little information is available in its reproductive biology. In order to better control the reproduction system of B. aegyptiaca , three experimental approaches are used: floral morpholgy, fluorochromatic procedure and hand pollination. The floral morphology shows that B. aegyptiaca flowers are hermaphrodite and gathered in several types of inflorescence (clusters, fascicles or glomerules). They blossomed asynchronically and nectar is exuded by the flowers. Top ovary holds five anatropous ovules. The second approach consisting in fluorochromatic procedure reveals a pollen with 3 apertures and a viability rate of 92%. This viability decrease down to 50% after a storage at -5°C for 7 days. Finally, the hand pollination proves that B. aegyptiaca is a partially auto-compatible plant and the main vectors of pollination are Halictidae (Hymenopterae) and Dipterae. Key Words: Balanites aegyptiaca , fluorochromatic test, pollen, pollination, auto-compatible. African Journal of Biotechnology Vol.3(1) 2004: 30-46

International audience; Transient auxin treatment for in vitro rooting of microcuttings of Acacia tortilis subsp. raddiana. An auxin in vitro pretreatment (IBA or NAA at 10 to 20 mg L$^{-1}$) combined with a low concentration of Kinetin (0.01 mg L$^{-1}$) during 10 or 20 days allowed to improve the rooting (number and root length) of Acacia tortilis raddiana microcuttings after transfer on Lloyd and Mc Cown medium (WPM) without hormone. After microcuttings transfer in expression medium, 56% are rooted and the rooting frequency can reach 80% after pretreatment with IBA at 10 mg L$^{-1}$. Measurements made after 28 days show that the auxin type used for inducing rhizogenesis has a significant effect, both on rooting percentage and rooting system morphology. For 80% of plantlets, the number of roots is low with NAA (1 to 5) but roots are strong and orthotropic (4.5 to 5 cm on average) when with IBA roots are numerous (10 to 15), but thin and plagiotropic (3 to 3.7 cm) for 68% of rooted plantlets.; Chez Acacia tortilis raddiana, l'application transitoire d'auxine (acide indol butyrique (AIB) ou acide naphtalène acétique (ANA) à 10 ou 20 mg L$^{-1}$) combinée ou non avec une cytokinine (kinétine à 0,01 mg L$^{-1}$) pendant 10 ou 20 jours a permis d'améliorer l'enracinement (nombre et longueur moyenne des racines) après le transfert des microboutures sur un milieu Lloyd et McCown (WPM) dépourvu d'hormone. Le pourcentage des microboutures enracinées sur milieu d'expression est de 56 % en moyenne et atteint 80 % avec un traitement inductif à 10 mg L$^{-1}$ d'AIB. Les mesures effectuées après 28 jours de culture ont montré que la nature de l'auxine utilisée pour induire la rhizogenèse a une influence significative aussi bien sur la fréquence de l'enracinement que sur la morphologie du système racinaire qui se met en place. Avec l'ANA les racines sont peu nombreuses (1 à 5 racines par bouture) et robustes et orthotropes (4,5 à 5 cm en moyenne) dans 80 % des cas et avec l'AIB, elles sont très nombreuses (10 à 15 racines par bouture) et fines et plagiotropes (3 à 3,7 cm) dans 68 % des cas.

Transgenic Hibiscus sabdariffa plants have been produced by a tissue culture independent method using Agrobacterium tumefasciens transformation procedure. Embryo axes of mature seeds with one cotyledon excised were infected by immersion in a suspension of Agrobacterium LBA 4404 strain culture that carries pBal plasmid with β-glucuronidase p35SGUSINT and plant selectable marker Neomycin Phospho-Transferase gene ( npt II). Following a 24 h co-cultivation with Agrobacterium strain and decontamination with cefotaxime, embryos were grown on soil rite containing MS medium added with a killer concentration of kanamycin (100 μg/ml) during 4 weeks at room conditions and thereafter transferred to greenhouse. 54.3% of the seedlings grew well on the selective medium; 68% of the explants excised from putative transformed plants were found to be GUS positive. After 60 days evaluation point, the assessment of the transformation by PCR revealed that H. sabdariffa line tested, carried the npt II gene. Key Words: Hibiscus sabdariffa; genetic transformation. African Journal of Biotechnology Vol. 3 (4), 2004: 226-228

We developed microsatellite to investigate genetic diversity of Oxytenanthera abyssinica (Bindura bamboo) a bamboo species endemic to Senegal. Using the microsatellite-enriched library method, we identified 14 primer pairs. The primers amplified 10 di-nucleotide repeats and 4 composite motifs, the number of alleles ranged from 5 to 28 with an average of 11.9. The results indicate that these primer pairs offer an appropriate amount of variation to address issues of germplasm characterization, patterns of gene flow and conservation studies. Cross amplification has been tested in other bamboo species.

La gomme sterculia est produite par Sterculia setigera Del. en Afrique. Ses proprietes physicochimiques changent suivant divers facteurs dont l’influence sur sa qualite a ete peu etudiee. C’est dans cette perspective que l’humidite, le pH, le pouvoir gonflant et la viscosite de cette gomme ont ete evalues au Senegal (Daoudi, Malem niani et Bala). Les resultats ont montre que son humidite varie en fonction du phenotype (ecorce claire ou foncee). Elle a ete plus elevee sur la gomme de la periode seche-chaude a Daoudi mais elle n’a pas change suivant le site apres un an de conservation. Son pH a varie en fonction de l’interaction periode de saignee- couleur de l’ecorce a Malem Niani alors qu’a Daoudi il a varie suivant la periode de saignee seulement. A Malem, son gonflement a aussi varie suivant l’interaction periode de saignee-couleur de l’ecorce. Apres un an de conservation (temperature ambiante), son pouvoir gonflant a diminue dans tous les sites. Sa viscosite a ete 3,5 fois plus elevee a Bala qu’a Daoudi et Malem Niani. Ces resultats ont permis d’acquerir de nouvelles connaissances et d’identifier Bala comme ayant la meilleure qualite de gomme par rapport aux deux autres sites. Mots cles : Acidite, Humidite, pouvoir de gonflement, Sterculia setigera Del., Tambacounda, viscosite

Phenology, flowering and fructification were studied in 5 natural populations of Faidherbia albida in a semi-arid zone in Senegal. In this species, the inflorescence acts as the reproductive unit; the basal flowers, opening first, have a low rate of fertilisation; the maximum rate of fertilisation (65%) was obtained in the apical flowers. Stigmatic receptivity, tested by esterasic reaction, was maximal immediately after anthesis. Stigmata of F. albida can bear simultaneously 2 or 3 polyads. Controlled pollination revealed that allogamy is the dominant reproductive system (ISI = 0.2) in natural populations of F. albida. Intra-specific variability in selfing (ISI ranging from 0 to 0.54) was also observed. Despite of the complete reproductive mechanism during flowering, only a small number of ripe pods (1.25%) is produced, and an average of 70% of the ovules per carpel are fertilized.

Des embryons somatiques de stade globulaire ont ete obtenus sur des cals issus d'embryons zygotiques immatures d'Acacia tortilis subsp. raddiana apres 90 a 100 jours de culture a l'obscurite sur des milieux VA enrichis de 2,4-D (acide 2,4-dichlorophenoxyacetique) (2, 4 et 8 mg/l) seul ou combine a la BAP (benzyl amino purine) (1 et 0,5 mg/l). La proliferation de ces embryons a ete optimisee en condition de photoperiode (16 h jour / 8 h obscurite), 30 jours apres le transfert des cals embryogenes sur un milieu MS/2 contenant 0,5 mg/l de BAP et 0,05 mg/l d'AIB (acide indol butyrique). Ces structures developpent un axe bipolaire sur un milieu MS enrichi en ABA (acide abscissique) (2,6 et 5,2 mg/l) ou en saccharose (50 g/l). Les embryons somatiques matures se sont developpes en vitroplants sur un milieu MS/2 sans hormone mais enrichi en saccharose (50 g/l).