Tolérance à la dessiccation des graines d’Uapaca bojeri, Euphorbiaceae

Uapaca bojeri, espèce endémique à usages multiples du versant occidental des hauts plateaux de Madagascar, présente des graines difficiles à conserver. Cette étude a pour objectif de connaître la tolérance à la dessiccation de ces graines afin de pouvoir les conserver convenablement. La germination des graines d’Uapaca bojeri séchées à l’ombre d’une part et entreposées sous différents degrés d’humidité relative d’autre part a été étudiée au SNGF. Les résultats ont donné un taux de germination compris entre 45 et 95%, avec une teneur en eau entre 20 et 30%, que ce soit après 10 à 15 jours de séchage à l’ombre ou sous une humidité relative allant de 60 à 84% pendant 26 jours. Il est ainsi conclu que les graines d’U. bojeri sont récalcitrantes et ne tolèrent pas une dessiccation en dessous de 20% de teneur en eau

Global to local genetic diversity indicators of evolutionary potential in tree species within and outside forests

There is a general trend of biodiversity loss at global, regional, national and local levels. To monitor this trend, international policy processes have created a wealth of indicators over the last two decades. However, genetic diversity indicators are regrettably absent from comprehensive bio-monitoring schemes. Here, we provide a review and an assessment of the different attempts made to provide such indicators for tree genetic diversity from the global level down to the level of the management unit. So far, no generally accepted indicators have been provided as international standards, nor tested for their possible use in practice. We suggest that indicators for monitoring genetic diversity and dynamics should be based on ecological and demographic surrogates of adaptive diversity as well as genetic markers capable of identifying genetic erosion and gene flow. A comparison of past and present genecological distributions (patterns of genetic variation of key adaptive traits in the ecological space) of selected species is a realistic way of assessing the trend of intra-specific variation, and thus provides a state indicator of tree genetic diversity also able to reflect possible pressures threatening genetic diversity. Revealing benefits of genetic diversity related to ecosystem services is complex, but current trends in plantation performance offer the possibility of an indicator of benefit. Response indicators are generally much easier to define, because recognition and even quantification of, e.g., research, education, breeding, conservation, and regulation actions and programs are relatively straightforward. Only state indicators can reveal genetic patterns and processes, which are fundamental for maintaining genetic diversity. Indirect indicators of pressure, benefit, or response should therefore not be used independently of state indicators. A coherent set of indicators covering diversity–productivity–knowledge–management based on the genecological approach is proposed for application on appropriate groups of tree species in the wild and in cultivation worldwide. These indicators realistically reflect the state, trends and potentials of the world’s tree genetic resources to support sustainable growth. The state of the genetic diversity will be based on trends in population distributions and diversity patterns for selected species. The productivity of the genetic resource of trees in current use will reflect the possible potential of mobilizing the resource further. Trends in knowledge will underpin the potential capacity for development of the resource and current management of the genetic resource itself will reveal how well we are actually doing and where improvements are required

A proposal for ethical research conduct in Madagascar

This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. The attached file is the published version of the article

Description of the male of Erromyrma Bolton & Fisher, 2016 (Hymenoptera, Formicidae)

The male of the myrmicine genus Erromyrma is described for the first time on the basis of two specimens of Erromyrma latinodis (Mayr, 1872) collected in northern Madagascar. We used COI barcoding to confirm the identification of the male specimens as conspecific with Erromyrma latinodis. We provide an illustrated male-based key to the four Myrmicinae tribes (Attini, Crematogastrini, Solenopsidini, Stenammini) and to the Solenopsidini genera (Adelomyrmex, Erromyrma, Solenopsis, Syllophopsis and Monomorium) for the Malagasy region

2009. Small effect of fragmentation on the genetic diversity of Dalbergia monticola, an endangered tree species of the eastern forest of Madagascar, detected by chloroplast and nuclear microsatellites. Annals of Botany 104

Aims The oriental forest ecosystem in Madagascar has been seriously impacted by fragmentation. The pattern of genetic diversity was analysed on a tree species, Dalbergia monticola, which plays an important economic role in Madagascar and is one of the many endangered tree species in the eastern forest. † Methods Leaves from 546 individuals belonging to 18 small populations affected by different levels of fragmentation were genotyped using eight nuclear (nuc) and three chloroplast (cp) microsatellite markers. † Key Results For nuclear microsatellites, allelic richness (R) and heterozygosity (H e,nuc ) differed between types of forest: R ¼ 7 . 36 and R ¼ 9 . 55, H e,nuc ¼ 0 . 64 and H e,nuc ¼ 0 . 80 in fragmented and non-fragmented forest, respectively, but the differences were not significant. Only the mean number of alleles (N a,nuc ) and the fixation index F IS differed significantly: N a,nuc ¼ 9 . 41 and N a,nuc ¼ 13 . 18, F IS ¼ 0 . 06 and F IS ¼ 0 . 15 in fragmented and non-fragmented forests, respectively. For chloroplast microsatellites, estimated genetic diversity was higher in non-fragmented forest, but the difference was not significant. No recent bottleneck effect was detected for either population. Overall differentiation was low for nuclear microsatellites (F ST,nuc ¼ 0 . 08) and moderate for chloroplast microsatellites (F ST,cp ¼ 0 . 49). A clear relationship was observed between genetic and geographic distance (r ¼ 0 . 42 P , 0 . 01 and r ¼ 0 . 42 P ¼ 0 . 03 for nuclear and chloroplast microsatellites, respectively), suggesting a pattern of isolation by distance. Analysis of population structure using the neighbor-joining method or Bayesian models separated southern populations from central and northern populations with nuclear microsatellites, and grouped the population according to regions with chloroplast microsatellites, but did not separate the fragmented populations. † Conclusions Residual diversity and genetic structure of populations of D. monticola in Madagascar suggest a limited impact of fragmentation on molecular genetic parameters

Echec ou succès ? : la foresterie paysanne contractualisée dans ses paradoxes

Cette recherche effectuée par une équipe multidisciplinaire sur le thème de la GEstion LOcale SÉcurisée (Gelose) n’est pas circonscrite au Sud‑Ouest malgache, même si la majorité des études de cas se rapporte à cette région, ni à la seule stratégie de la gestion communautaire incluant une sécurisation foncière : les corridors forestiers d’Ankeniheny-Zahamena et de Fandriana‑Vondrozo comptent des dispositifs en Gestion Contractualisée des forêts (GCF). D’une façon générale, le thème ici traité..

A single editing event is a prerequisite for efficient processing of potato mitochondrial phenylalanine tRNA.

In bean, potato, and Oenothera plants, the C encoded at position 4 (C4) in the mitochondrial tRNA Phe GAA gene is converted into a U in the mature tRNA. This nucleotide change corrects a mismatched C4-A69 base pair which appears when the gene sequence is folded into the cloverleaf structure. C-to-U conversions constitute the most common editing events occurring in plant mitochondrial mRNAs. While most of these conversions introduce changes in the amino acids specified by the mRNA and appear to be essential for the synthesis of functional proteins in plant mitochondria, the putative role of mitochondrial tRNA editing has not yet been defined. Since the edited form of the tRNA has the correct secondary and tertiary structures compared with the nonedited form, the two main processes which might be affected by a nucleotide conversion are aminoacylation and maturation. To test these possibilities, we determined the aminoacylation properties of unedited and edited potato mitochondrial tRNAPhe in vitro transcripts, as well as the processing efficiency of in vitro-synthesized potato mitochondrial tRNAPhe precursors. Reverse transcription-PCR amplification of natural precursors followed by cDNA sequencing was also used to investigate the influence of editing on processing. Our results show that C-to-U conversion at position 4 in the potato mitochondrial tRNA Phe GAA is not required for aminoacylation with phenylalanine but is likely to he essential for efficient processing of this tRNA