Introduction. RNA isolation is a prerequisite to studying gene expression in banana and to understanding changes occurring in response to the environment. Standard extraction methods do not efficiently extract RNA from plants such as banana, with high levels of phenolics, carbohydrates, or other compounds that bind to and/or coprecipitate with RNA. Materials and methods. Five to seven RNA extraction methods were compared. Four crown-tissue storage methods were also compared. cDNA-AFLP was used to ensure that the obtained RNA was of sufficient quality for molecular applications and that RNA expression was unaltered by in situ storage. Results and discussion. The modified hot-borate method proved to be the best RNA extraction method, allowing high yields of good quality, undegraded RNA from the crown, fruit peel and pulp at all stages of ripening. The RNA obtained by this method was of sufficient quality for molecular applications such as cDNA-AFLP that give highly reproducible results. Freeze-drying of fresh tissues and tissue conservation in hot-borate buffer, two original storage methods, appear appropriate for preserving RNA in situ without ultra-low temperature. The RNA obtained was of high quality, undegraded, and useful for all downstream applications. The genome expression profile obtained by cDNA-AFLP analysis was unaltered by these methods for storing collected tissues. Conclusion. By applying all the suggested procedures in this work, it is possible to store and study gene expression in any banana fruit tissue, whatever the maturity stage, without affecting the RNA expression level.

Introduction. Fruit ripening is the process resulting in changes in color, taste and texture, which make the fruit acceptable for consumption. Since a wide spectrum of physiological, biochemical and organoleptic changes are involved in the development of a soft, edible, ripe fruit, we studied theses changes in an underutilized fruit, khirni [Manilkara hexandra (Roxb.) Dubard]. Materials and methods. The changes in biochemical composition, which includes chlorophylls, carotenoids, anthocyanins, sugars, starch, free amino acids, phenols and proteins, and the specific activity of enzymes such as amylase, invertase, catalase, peroxidase, pectinmethylesterase, polygalacturanase and cellulase were analyzed in the fruit of Manilkara hexandra at five sequential developmental stages (young, premature, mature, preripened and ripened fruit stages). Results and discussion. The pulp of khirni fruit tastes sour during its growth period, but turns sweet when it ripens. A decreasing trend in chlorophylls occurs simultaneously with an increase in the quantity of total carotenoids and anthocyanins. Further, an increase in the quantity of sugars, proteins and phenols occurs towards the ripened stage, but starch and total free amino acids show a decrease in their quantities. Also, khirni fruit exhibits climacteric behavior with its increased rate of respiration and ethylene production. The moderate to significant changes in the activity of enzymes such as amylase, invertase, catalase and peroxidase involved in a number of catabolic and anabolic reactions indicate that these enzymes also have an active role in the process of khirni fruit growth and ripening.

Introduction. Les aliments dits de disette, dont la plupart sont des fruits, sont identifiés un peu partout dans le monde tel qu’en Australie au Soudan, au Sénégal, en Amérique, au Sahel et au Tchad. Les travaux réalisés sur ces fruits portent souvent sur leurs valeurs nutritives. Au Sénégal, Maerua pseudopetalosa (Gil & Gil-Ben) De Wolf, espèce de la famille des capparidacées, fournit des fruits consommables aux populations autochtones pendant la période de soudure. Aucune étude scientifique n’a encore fait mention de la composition nutritive et de l’apport énergétique du fruit de cette espèce. Nos travaux ont permis d’évaluer l’apport en éléments nutritifs de son fruit. Matériel et méthodes. Des fruits de M. pseudopetalosa ont été récoltés à maturité au mois de juin 2007 et mai 2008 aux alentours des villages de Kéniéba et de Koussane, dans la région de Tambacounda au Sénégal. Les amandes ont été séchées et broyées pour les besoins des différents dosages. Les cendres, protéine, sucres, matières grasses, et sels minéraux ont été déterminés par des méthodes d’analyse classiques normalisées. Résultats et discussions. Nos résultats ont montré que le fruit de M. pseudopetalosa était riche en fer (26,8–45,9 mg·kg–1), en potassium (1098–1342 mg·100 g–1) et en protéine (19,26–22,06%). Cependant, le profil d’acides aminés témoigne d’une médiocre qualité nutritionnelle de sa protéine. Conclusion. Il ressort de cette analyse que le fruit de M. pseudopetalosa constitue malgré tout une excellente source de nutriments et peut valablement combler certaines carences, surtout en période de disette.

Introduction. Investigation of pollen performance is essential in breeding experiments or artificial pollination procedures, especially in a crop such as chestnut, some genotypes of which are characterized by male sterility. Our study was carried out to determine the pollen germination rate and the pollen tube growth of some European chestnut genotypes. Materials and methods. Seven Turkish advanced chestnut selections (SE3-12, SE18-2, SE21-2, SE21-9, 552-8, 552-10 and 554-14), and a cultivar (Sariaslama), growing in two different locations, were studied in the central Black Sea region of Turkey in 2006. For this purpose, in vitro pollen germination tests were performed on media with four different concentrations of sucrose [(0, 5, 10 and 15)%]. Results and discussion. The pollen germination rates of the eight genotypes studied were significantly different due to the sucrose concentrations. The best pollen germination rate was found in the 554-14 chestnut genotype (35.80%). The best sucrose concentration for a high germination rate and pollen tube growth was 10%. For the same genotype, the results varied due to the two different study locations (Terme and Fatsa). A linear relationship between the sucrose concentrations and pollen tube length was found to be significant in most genotypes. The longest pollen tube length was found in the 554-14 genotype (74 mm).

Introduction. Little is known about the impact of organic manure on andosol. Materials and methods. Two varieties of Solanum lycopersicum L. (cvs. ‘Rio grande’ and ‘Rossol VFN’) were grown under tropical andosol. The soil was silty, acidic and very poor in Bray P (3 mg·kg–1) with a strong imbalance in the (Ca:Mg:K) ratio of (74.0:25.0:0.7). Five fertilization treatments were used: (i) control with no fertilizer, (ii) minerals, with a (Ca:Mg:K) ratio of (76:18:6) and 75 mg P·kg–1 of soil; (iii) poultry manure with a (Ca:Mg:K) ratio of (68:24:7) and 450 mg P·kg–1 of soil; (iv) a combination of (ii) and (iii), and (v) mineral fertilization as applied by local farmers, with a (Ca:Mg:K) ratio of (73:25:1) and 54 mg P·kg–1 of soil. Results. All cation-balanced treatments (organic, mineral or a combination of both) significantly improved plant growth, the number of trusses and fruits per plant, the marketable fruit yield and fruit P, K, Ca and Na contents of both tomato varieties considered. The ‘Rio grande’ variety was the most productive (32–44 t·ha–1) compared with the ‘Rossol’ variety (20–22 t·ha–1). There was no major difference between the organic fertilizer and the cation-balanced mineral fertilizer. There was no effect of mineral fertilizer with an unbalanced cation composition on tomato plant growth and production as compared with unfertilized control. Conclusion. In tropical andosol poor in potassium and phosphorous and with excess of Mg, application of poultry manure in adequate dosage and at the right time is capable of sustaining tomato fruit production, as well as the application of calculated inorganic fertilizer.

Introduction. Hibiscus sabdariffa L. est une plante herbacée, vivace, localisée dans les zones tropicales et subtropicales des deux hémisphères. L’espèce est exploitée pour sa fibre et principalement pour ses calices qui sont de trois types : vert, rouge et rouge foncé. Composition. Les calices de type rouge sont les plus utilisés et se caractérisent par leur concentration élevée en anthocyanes qui peut atteindre 1,5 g·kg–1. La delphinidine 3-sambubioside et la cyanidine 3-sambubioside sont les anthocyanes majoritaires avec, respectivement, (71 et 29) % des anthocyanes totaux. Les acides organiques, minéraux et acides aminés sont présents dans les calices, feuilles et graines d’H. sabdariffa à des teneurs variables suivant la variété et la zone géographique. Utilisations. Les utilisations des différentes parties de l’H. sabdariffa sont nombreuses et variées aussi bien dans l’alimentation que dans la médecine traditionnelle. Les calices, du fait de leur concentration élevée en acides, vitamine C et surtout en anthocyanes, constituent la partie de la plante la plus valorisée. Ils sont surtout utilisés pour la production de boissons désaltérantes et tonifiantes sans alcool. Les graines d’H. sabdariffa de par leur richesse en protéine (26 %), lipides (20 %) et sucres totaux (40 %) sont très utilisées dans l’alimentation dans de nombreux pays africains. Les feuilles constituent une bonne source de nutriments et sont utilisées en Afrique pour la préparation de sauces.