The influence of dietary sunflower honey, propolis, and a flavonoid extract of propolis was examined on drug-metabolizing enzyme activities in rat liver and on microsome-mediated binding of benzo[a]pyrene to DNA. Characterization of flavonoids present in sunflower honey and propolis was achieved in order to assess the relative effects of different components of honey and propolis. Honey and propolis contained the same major flavonoids, pinocembrin, chrysin, galangin, and pinobanksin. The concentration of flavonoids was higher in propolis. Sunflower honey produced no significant changes on phase I and phase II enzyme activities and no modification of in vitro binding of benzo[a]pyrene to DNA. Propolis treatment produced an increase of ethoxyresorufin deethylase, pentoxyresorufin depentylase, ethoxycoumarin deethylase, glutathione transferase, and epoxide hydrolase activities. A flavonoid extract from propolis slightly enhanced only few enzyme activities, ethoxycoumarin deethylase and epoxide hydrolase. The induction pattern was similar to that observed with pinocembrin (a major flavonoid of propolis) administered solely. Binding of benzo[a]pyrene to DNA by microsomes from rats fed with propolis or a flavonoid extract from propolis was not significantly modified. These results contribute to identification of food or foodstuffs that can modify drug-metabolizing enzymes and binding of carcinogens to DNA. Keywords: Sunflower honey; propolis; flavonoids; drug-metabolizing enzymes; benzo[a]pyrene−DNA binding

The flavonoids of sunflower honey were isolated and analyzed by different methods: RP-TLC, RP-HPLC/UV-Vis (diode array detection) using post-column derivatization, GC/SM. Five main compounds were identified as pinocembrin (5,7-dihydroxyflavanone), pinobanksin (3,5,7-trihydroxyflavanone), chrysin (5,7-dihydroxyflavone), galangin (3,5,7-trihydroxyflavone) and quercetin (3,5,7,3',4'-pentahydroxy flavone). Two minor flavonoids were also detected: tectochrysin (5 hydroxy-7-methoxyflavone) and kaempferol (3,.5,7,4'-tetrahydroxy flavone). All these compounds had been previously reported in propolis, another hive product. Honey is a source of flavonoids in the human diet. Flavonoid structures may provide an index of floral origin with further study.

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Differences between the distributions of the numbers of preformed and neoformed organs may be explained by alluding to the duration of differentiation and extension for each of these groups of organs. The deconvolution of distributions is a useful tool for the analysis of neoformation and shoot structure in trees.

-Growth pattern and polycyclism were studied for three French populations of Cedrus atlantica, and ten populations of Cedrus libani (seven Turkish and three Lebanese populations). The polycyclism rate and the length of annual shoots and growth units were recorded at two sites in France. There were significant variations in polycyclism rate and annual growth between the Turkish and Lebanese populations. Polycyclism appeared to be linked to the climatic conditions of the current growth year for French and Turkish populations, unlike the Lebanese populations. The Turkish populations have exhibited a greater stability as well at the between-station as at the between-year levels. Polycyclism appears as an adaptive trait of trees to difficult growth conditions. The construction of a dendrogram based on polycyclism and annual shoot length revealed two distinct main clusters corresponding to the different geographical origins. Polycyclism could be used in breeding and genetic improvement programmes of these species.

Leaf area and leaf dry biomass are key parameters linked to plant production and they are used in functional–structural plant models to simulate plant growth, but they are difficult to ascertain. Measuring leaf dimensions (length and width) to estimate them provides a non-destructive and rapid approach that can be used in the field. This was tested on teak (Tectona grandis) in Togo. Leaves were sampled to maximize variability in sizes along two categories of axes and at different ranks on the growth units. Two different equations were determined to estimate leaf area and dry biomass from leaf dimensions. The relation between leaf area (A) and the product of length (L) × width (Wi) was defined by the linear equation A = 0.60 × L × Wi whereas dry biomass (We) was predicted by a power law We = 0.004 × (L × Wi)1.11. This method could also be tested and applied to other species

International audienceIn agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently, on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for the intercrops. These results are discussed in terms of agroforestry system management