Royer, M., Stien, D., Beauchene, J., Herbette, G., McLean, J. P., Thibaut, A., et al. (2010). Extractives of the tropical wood wallaba (Eperua falcata Aubl.) as natural anti-swelling agents. Holzforschung, 64(2), 211–215.
Abstract: Wallaba (Eperua falcata) is a tropical wood that is known to have naturally high moisture related dimensional stability. Samples of wallaba heartwood were subjected to differential solvent extraction. Wood pieces that were extracted with methanol showed significantly greater swelling following rehydration from oven dry to 96% relative humidity than non- extracted samples and samples extracted with other solvents. Methanol soluble wallaba heartwood extract was purified by HPLC and the compounds present were characterized by NMR spectroscopy. The structure of 13 compounds in methanol extract was identified. The relative proportion of polar compounds in methanol extract was found to be high. The compounds identified are proposed to bind to the polymeric cell wall by means of multiple hydrogen bonds restricting the association of water and therefore act as natural anti-swelling agents.
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Gond, V., & Guitet, S. (2009). Remote Sensing in Post-Logging Diagnoses for Forest Management in French Guiana. Bois For. Trop., 63(299), 5–13.
Abstract: This study is part of the activities carried out to monitor tow-impact logging operations in humid tropical forests. The sustainability of these activities is highly dependent on the scale of logging damage, and managers therefore need to carry out effective checks on the quality of forestry work. In this study, remote sensing was used to track the extension of logging operations and to assess damage, through images acquired during and after logging in each parcel. Analysis of the high-resolution images (10 m) clearly identifies logged-over clearings and some skidding tracks, allowing assessments of gaps opening up in the canopy. Several parcels were monitored in this French Guiana study. A simple diagnostic procedure was established for each parcel to assess logging intensity and identify new logging tracks and timber losses. The remote sensing toot thus helps to make more accurate assessments of logging quality and to draw relevant conclusions for the logging company. The study has demonstrated the usefulness of remote sensing to identify damage after logging. The quality of restitution of the damage was validated by means of a database on the logging terrain and through field missions. This post-logging inspection tool can now be automated for fully operational use by forest managers.
Keywords: selective logging; logging impact inspections; French Guiana; remote sensing; forest management
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Cochard, H., Coste, S., Chanson, B., Guehl, J. M., & Nicolini, E. (2005). Hydraulic architecture correlates with bud organogenesis and primary shoot growth in beech (Fagus sylvatica). Tree Physiol., 25(12), 1545–1552.
Abstract: In beech (Fagus sylvatica L.), the number of leaf primordia preformed in the buds determines the length and the type (long versus short) of annual growth units, and thus, branch growth and architecture. We analyzed the correlation between the number of leaf primordia and the hydraulic conductance of the vascular system connected to the buds. Terminal buds of short growth units and axillary buds of long growth units on lower branches of mature trees were examined. Buds with less than four and more than five leaf primordia formed short and long growth units, respectively. Irrespective of the type of growth unit the bud was formed on, the occurrence of a large number of leaf primordia was associated with high xylem hydraulic conductance. Xylem conductance was correlated to the area of the outermost annual ring. These results suggest that organogenesis and primary growth in buds correlates with secondary growth of the growth units and thus with their hydraulic architecture. Possible causal relationships between the variables are discussed.
Keywords: development; hydraulic conductance; leaf primordia; meristem; xylem
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Marti, G., Eparvier, V., Litaudon, M., Grellier, P., & Gueritte, F. (2010). A New Xanthone from the Bark Extract of Rheedia acuminata and Antiplasmodial Activity of Its Major Compounds. Molecules, 15(10), 7106–7114.
Abstract: Bioassay-guided fractionation of the ethyl acetate bark extract of Rheedia acuminata led to the isolation of the new compound 1,5,6-trihydroxy-3-methoxy-7-geranyl-xanthone (1), together with four known compounds 2-5. These compounds were tested in vitro for their antiplasmodial activity on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) and for their cytotoxicity against the human diploid embryonic lung cell line MRC-5.
Keywords: Rheedia acuminata, Clusiaceae; xanthones; antiplasmodial activity; cytotoxicity
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Millet, J., Pascal, J. P., & Kiet, L. C. (2010). Effects of Disturbance Over 60 Years on a Lowland Forest in Southern Vietnam. J. Trop. For. Sci., 22(3), 237–246.
Abstract: MILLET J, PASCAL JP & MET LC. 2010. Effects of disturbance over 60 years on a lowland forest in southern Vietnam. Tropical lowland forests are some of the most threatened in the world and this is particularly the case in Vietnam. This study aimed to identify changes in species composition and forest structure in the Tan Phu lowland forest resulting from disturbance over a 60 year period. Analysis of forest composition and structure rely on data from 25 plots of 0.5-ha size established in a lowland secondary forest. The five forest stands described differed greatly from the three forest stand types described in 1943. Some long-lived shade-tolerant species had been replaced by pioneer species, such as Cratoxylon formosum and Shorea roxburghii. In addition to altering composition, forest disturbances had resulted in large changes in forest structure. While in the past, forest stands had a large number of exploitable trees, current forest stands have few trees in the diameter class > 50 cm and sometimes no trees in the diameter class > 80 cm. This paper provides notable results on forest tree ecology, forest dynamics and on the state of secondary forests in Vietnam. This is particularly important as future goods and services will increasingly have to come from such forests.
Keywords: Lowland tropical forest; disturbance impact; floristic composition; forest structure; Tan Phu forest
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Marti, G., Eparvier, V., Moretti, C., Prado, S., Grellier, P., Hue, N., et al. (2010). Antiplasmodial benzophenone derivatives from the root barks of Symphonia globulifera (Clusiaceae). Phytochemistry, 71(8-9), 964–974.
Abstract: In an effort to find antimalarial drugs, a systematic in vitro evaluation on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) was undertaken on sixty plant extracts collected in French Guiana. The ethyl acetate extract obtained from the root barks of Symphonia globulifera exhibited a strong antiplasmodial activity (97% at 10 μg/ml). The phytochemical investigation of this extract led to the isolation of nine polycyclic polyprenylated acylphloroglucinol (PPAPs) compounds and two oxidized derivatives. All compounds showed antiplasmodial activity with IC(50)s ranged from 2.1 to 10.1 μM. A LC/ESI-MSn study performed on polyprenylated benzophenones previously isolated from Moronobea coccinea provided a reliable method for their detection in the extract and structural elucidation. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords: Symphonia globulifera; Clusiaceae; Benzophenone; Symphonone; Antiplasmodial; LC/ESI-MS
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Sobotnik, J., Sillam-Dusses, D., Weyda, F., Dejean, A., Roisin, Y., Hanus, R., et al. (2010). The frontal gland in workers of Neotropical soldierless termites. Naturwissenschaften, 97(5), 495–503.
Abstract: The presence of the frontal gland is well established in termite soldiers of Rhinotermitidae, Serritermitidae, and Termitidae. It is one of their main defensive adaptations or even an exclusive weapon. The gland was also occasionally reported in alate imagoes, but never in the worker caste. Here, we report the first observation of a frontal gland in workers of several Neotropical and one African species of Apicotermitinae. The ultrastructure of Aparatermes cingulatus and Anoplotermes nr. subterraneus is described in detail. In these two species, the gland is well-developed, functional and consists of class 1 secretory cells. The presence of envelope cells, wrapping the gland, is an unusual feature, as well as the presence of several zonulae adherens, connecting neighbouring glandular cells. The frontal gland of workers is homologous to this organ in soldiers and imagoes, as evidenced by the same position in the head and its connection to the same muscle. However, the defensive role of the frontal gland in workers remains to be confirmed.
Keywords: Frontal gland; Workers; Soldierless termites; Apicotermitinae; Anoplotermes; Aparatermes
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Petillon, J., Lambeets, K., Montaigne, W., Maelfait, J. P., & Bonte, D. (2010). Habitat structure modified by an invasive grass enhances inundation withstanding in a salt-marsh wolf spider. Biological Invasions, 12(9), 3219–3226.
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Petillon, J., Montaigne, W., & Renault, D. (2009). Hypoxic coma as a strategy to survive inundation in a salt-marsh inhabiting spider. Biol. Lett., 5(4), 442–445.
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Orivel, J., & Leroy, C. (2011). The diversity and ecology of ant gardens (Hymenoptera: Formicidae; Spermatophyta: Angiospermae). Myrmecol. News, 14, 73–85.
Abstract: Mutualistic interactions between ants and plants are important features of many ecosystems, and they can be divided into three main categories: dispersal and protective mutualisms and myrmecotrophy. In both the Neotropics and the Southeastern Asian Paleotropics, ant gardens (AGs), a particular type of ant-plant interaction, are frequent. To initiate AGs, ants integrate the seeds of certain epiphyte species into the carton of their nest. The development of the plants leads to the formation of a cluster of epiphytes rooted in the carton. They have been defined as one of the most complex associations between ants and plants known because of the plurispecific, but also specialized nature of the association involving several phylogenetically-distant ant and plant species. The aim of this review is to provide a synthesis of the diversity and ecology of AGs, including the outcomes experienced by the partners in the interaction and the direct and indirect impacts ant-garden ants have on the plant and arthropod communities.
Keywords: Ant-plant interactions; epiphytes; mutualisms; Neotropics; Paleotropics; phytotelm; parabiosis; seed dispersal; review
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