Phenolic content and antioxidant activity of some wild plant teas of Masako

ABSTRACT Human body produces free radicals which can damage biomolecules and cause diseases. Phenolic compounds of foods can prevent those damages. The aim of this study is to identify some phenolic wild plant teas of Masako and evaluate the phenolic content and the antioxidant activity of their aqueous decoctions. Some wild plants consumed as teas were collected in Masako. Their chemical screening was done for identifying plants which contain phenolic compounds. Aqueous decoctions of phenolic plants were prepared and their phenolic content was determined by UV-Vis Spectrophotometry. In vitro antioxidant activity (Reducing and Scavenging power) of these decoctions was evaluated as well. Leaf aqueous decoctions of Alchornea cordifolia, Sabicea johnstonii, Hymenocardia ulmoides and Ipomoea involucrata contain polyphenolic compounds. These decoctions contain significant amount of polyphenolic compounds and show significant reducing and scavenging power. These aqueous decoctions are other potential sources of natural antioxidants which could prevent diseases associate to oxidative stress

Foliar and wood traits covary along a vertical gradient within the crown of long-lived light-demanding species of the Congo Basin semi-deciduous forest

Plant functional traits have shown to be relevant predictors of forest functional responses to climate change. However, the trait-based approach to study plant performances and ecological strategies has mostly been focused on trait comparisons at the interspecific and intraspecific levels. In this study, we analyzed traits variation and association at the individual level. We measured wood and leaf traits at different height locations within the crown of five individuals of Pericopsis data (Harms) Meeuwen (Fabaceae) from the northern tropical forest of the Democratic Republic of the Congo. All traits varied between and within individuals. The between-individual variation was more important for leaf traits (23%-48%) than for wood traits (similar to 10%) where the within-individual variation showed to be more important (33%-39%). The sample location height within the crown was found to be the driving factor of this within-individual variation. In a gradient from the base to the top of the crown, theoretical specific hydraulic conductivity and specific leaf area decreased while the stomatal density increased. We found significant relationships among traits and between wood and leaf traits. However, these relationships varied with the position within the crown. The relationship between vessel size and vessel density was negative at the bottom part of the crown but positive upward. Also, the negative relationship between stomatal density and stomatal size became stronger with increasing height within the crown. Finally, the positive relationship between specific leaf area and theoretical specific hydraulic conductivity became stronger in higher parts of the crown, suggesting that P. data constantly adapts its water use with respect to its water supply, more strongly at the top of the crown where the environment is more extreme and less buffered against environmental fluctuations

La photogrammétrie terrestre: approche non destructive pour modéliser la forme des troncs irréguliers d'arbres tropicaux

peer reviewed1. Irregularly shaped trees including trees with buttresses, flutes or stilt roots are frequent in tropical forests. The lack of an international standard tomeasure the diameter of such trees leads to high uncertainties in biomass estimation, tree growth and carbon budget monitoring. 2. In this study, we developed a new method based on terrestrial close-range photogrammetry for measuring andmodelling irregular stems. This approach is cheap and easy to implement in the field as it only requires a camera and a graduated rod. We validated the approach with destructive cross-sectionmeasurements along the stem of three buttressed trees. To demonstrate the broader utility of this method, we extended the validated approach to 43 additional trees belonging to two species: Celtis mildbraedii (Ulmaceae) and Entandophragma cylindricum (Meliaceae). Based on the three dimensional models, we computed shape indices for each tree, and we analysed the stem morphology of the two species. Finally, we analysed some standardized predictors for the estimation of above-ground biomass. 3. We found a high concordance between diameters derived from the photogrammetric process and destructive diameter measurements along the stem for the three calibration trees. We found that C. mildbraedii develop much stronger irregularities than E. cylindricum.We also identified a large intraspecific variation in trunk morphology for E. cylindricum. The basal area at 1 3 mheight (Darea130) seems to be amore robust predictor for biomass estimates (lowest Akaike information criterion and relative squared error) than diameter measured above buttresses (DAB) or diameter at breast height estimated from available taper model. Finally, Darea130 might be estimated with a good precision [root mean square error (RMSE) < 5%] with linear model based on the field measurements DABand the perimeter of the convex hull of the buttresses at 1 3 mheight (Dconvhull130). 4. In this study, we showed the high potential of the photogrammetry for measuring and modelling irregular stems. Photogrammetry could then be used as a non-destructivemeasurement tool to produce correction factors for standardizing the diameter of irregular stems at a reference height which is a key issue in tree growthmonitoring and biomass change estimation.DynaFfor, PreRED

Structures spatiales de la richesse spécifique dans quelques blocs forestiers du nord-est du Bassin congolais: Implication pour la diversité régionale et la conservation

The assessment of species diversity remains an indispensable tool in the development of biodiversity conservation strategies and ecosystem management. In tropical rainforest, richness and species diversity are almost always high but they vary spatially. Several studies have been conducted at the local level to assess the richness and floristic composition of the forests of the Congolese central basin. With a hundred of inventory plots we performed in four forest sites in northeastern Congo Basin, we have shown that tree stands have significant variations in species diversity and species composition. The northern sites in Ituri and Rubi-Tele are less diverse than those of Yoko and Uma around Kisangani.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Influence of spacing and seed trees on the growth of Pericopsis elata saplings during the first twenty months of a planting trial

Description of the subject. Pericopsis elata (Fabaceae) is a long-lived light-demanding tree from African rain forests that produces timber of high economic value. Natural populations suffer from overexploitation and a deficit of natural regeneration. Plantations could increase its production and limit the pressure on natural forests. However, we lack knowledge on the influence of spacing and seed tree origin on tree growth to optimize plantation protocols. Objectives. This study evaluated the impact of sapling density and seed tree origin on the growth in diameter and height of P. elata plants, 20 months after plantation. Method. Seeds were collected on 19 mother trees in a 400 ha natural stand near Kisangani (DRC). In October 2017, seedlings were transplanted in a Nelder design plantation with three replicates, to compare sapling growth at 10 contrasting plant densities under full sun. Diameter and height increments of 540 plants were analyzed according to local competition and maternal origin using generalized additive models. Results. Twenty months after planting, height growth peaked at an intermediate density of 47,000 stems.ha-1 (165.6 ± 39.2 cm. year-1), while diameter growth peaked at a lower density of 4,200 stems.ha-1 (24.6 ± 8.3 mm.year-1). The maternal origin of saplings affected their growth, the coefficients of variation among mother trees reaching 7.6% and 6.4% for diameter and height increments, respectively. The initial diameter affected positively diameter growth while the initial height did not influence height growth. Conclusions. The Nelder design proved useful to assess how plant growth depends both on spacing and genetic factors.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Influence de l’écartement et du semencier sur la croissance des plants de pericopsis elata durant les vingt premiers mois d’un essai de plantation

Description of the subject. Pericopsis elata (Fabaceae) is a long-lived light-demanding tree from African rain forests that produces timber of high economic value. Natural populations suffer from overexploitation and a deficit of natural regeneration. Plantations could increase its production and limit the pressure on natural forests. However, we lack knowledge on the influence of spacing and seed tree origin on tree growth to optimize plantation protocols. Objectives. This study evaluated the impact of sapling density and seed tree origin on the growth in diameter and height of P. elata plants, 20 months after plantation. Method. Seeds were collected on 19 mother trees in a 400 ha natural stand near Kisangani (DRC). In October 2017, seedlings were transplanted in a Nelder design plantation with three replicates, to compare sapling growth at 10 contrasting plant densities under full sun. Diameter and height increments of 540 plants were analyzed according to local competition and maternal origin using generalized additive models. Results. Twenty months after planting, height growth peaked at an intermediate density of 47,000 stems·ha-1 (165.6 ± 39.2 cm·year-1), while diameter growth peaked at a lower density of 4,200 stems·ha-1 (24.6 ± 8.3 mm·year-1). The maternal origin of saplings affected their growth, the coefficients of variation among mother trees reaching 7.6% and 6.4% for diameter and height increments, respectively. The initial diameter affected positively diameter growth while the initial height did not influence height growth. Conclusions. The Nelder design proved useful to assess how plant growth depends both on spacing and genetic factors