Narrow genetic base in forest restoration with holm oak (Quercus ilex L.) in Sicily

In order to empirically assess the effect of actual seed sampling strategy on genetic diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the genetic composition of two seedling lots (nursery stock and plantation) and their known natural seed origin stand by means of six nuclear microsatellite loci. Significant reduction in genetic diversity and significant difference in genetic composition of the seedling lots compared to the seed origin stand were detected. The female and the total effective number of parents were quantified by means of maternity assignment of seedlings and temporal changes in allele frequencies. Extremely low effective maternity numbers were estimated (Nfe $\approx$ 2-4) and estimates accounting for both seed and pollen donors gave also low values (Ne $\approx$ 35-50). These values can be explained by an inappropriate forestry seed harvest strategy limited to a small number of spatially close trees

Experimental data on the animal pulmonary scrubling

Massé R., Méthivier H., Ducousso Roger. Données expérimentales sur l'épuration pulmonaire animale. In: Bulletin de l'Académie Vétérinaire de France tome 137 n°3, 1984. pp. 397-402

Reproduction and gene flow in the genus Quercus L

In this paper we review the characteristics of the floral biology, life cycle and breeding system in the genus Quercus. The species of this genus are self-incompatible and have very long life spans. The focus of our review is on the effects of gene flow on the structuration of genetic variation in these species. We have examined the influence of gene flow in 2 ways: 1) by measuring the physical dispersal of pollen, seed and vegetative organs; and 2) by using nuclear and cytoplasmic markers to estimate genetic parameters (Fis, Nm). These approaches have shown that nuclear (isozyme markers) as well as cytoplasmic (chloroplastic DNA) gene flow is usually high, so that very low interspecific differentiation occurs. However, intraspecific differentiation is higher for the cytoplasmic DNA than for the nuclear isozyme markers.Système de reproduction et flux de gènes chez les espèces du genre Quercus. Les caractéristiques de la biologie florale, du cycle de vie et du système de reproduction ont été analysées pour les espèces du genre Quercus. Ces espèces sont auto-incompatibles et à très longue durée de vie. Les effets des flux de gènes sur la structuration de la variabilité génétique ont aussi été étudiés de 2 manières. D'une part, grâce aux mesures de la dispersion du pollen, des graines et des organes végétatifs, et, d'autre part, en utilisant des paramètres génétiques (Fis, Nm) obtenus à partir des marqueurs nucléaires et cytoplasmiques. Il apparaît que les flux géniques nucléaires (isozymes) et cytoplasmiques (ADN chloroplastique) sont en général importants, d'où une faible différenciation interspécifique. Néanmoins la différenciation intraspécifique est plus forte lorsqu'elle est estimée à partir des marqueurs cytoplasmiques que lorsqu'elle l'est à partir des marqueurs nucléaires

Mycorrhizal fungi : use in sustainable agriculture and land restoration

Metal-rich soils, especially heavy metal-polluted soils and ultramafic soils, are generally toxic to non-adapted plants and microorganisms. The role of mycorrhizal fungi in the metal tolerance of adapted plant species has become clear in the last decade. This review aims to synthesize the findings of representative studies of the effects of mycorrhizas on the alleviation of heavy metal toxicity on plants and on the absorption/accumulation of heavy metals in their roots and shoots. The adaptation to heavy metals by mycorrhizal symbionts is associated with their efficiency in metal-rich soils. More than 80 % of the studies have indicated a positive role of mycorrhizal fungi in the adaptation of plants to heavy metals in these soils, but the relationships between plant tolerance to heavy metals and the absorption of metals are complex and depend on a range of biological, physical and chemical factors

Mesure du dépôt de plutonium 239 atmosphérique sur les feuilles de Casuarina equisetifolia : comparaison entre Mururoa et l'ensemble de la zone intertropicale

Le Casuarina equisetifolia possède un feuillage qui ressemble à celui des conifères. De ce fait, il présente un bon rendement de captation des aérosols atmosphériques. Il est très répandu dans la zone intertropicale. Nous avons pu ainsi comparer le plutonium 239 de l'atmosphère des sites expérimentaux de Mururoa et de Fangataufa à celui de l'atmosphère du reste de la Polynésie française et de différents autres points de la zone intertropicale. Aucune différence significative n'a pu être mise en évidence

New insights into the mycorrhizal status of Cyperaceae from ultramafic soils in New Caledonia

In New Caledonia, a hot spot of biodiversity, plants from the Cyperaceae family are mostly endemic and considered pioneers of the nickel-rich natural serpentine ecosystem. The aim of the study was to highlight the mycorrhizal status of these Cyperaceae and to bring new insights into the role of this symbiosis in plant tolerance to ultramafic soils. Nine Cyperaceae species were studied and presented evidence of root colonization by arbuscular mycorrhizas (AMs), with frequencies ranging from 8% to 57%. The highest level of AM colonization was observed in plants from the endemic dominant genus Costularia. Molecular evidence demonstrated the presence of Glomus sp. inside the roots. In a controlled greenhouse assay, AM inoculation of Costularia comosa grown under ultramafic conditions significantly enhanced plant growth, with an increase in biomass by up to 2.4-fold for shoots and 1.2-fold for roots, and also reduced nickel content in roots by 2.5-fold, as compared with the controls. All these data support our hypotheses (i) that a relationship exists between the mycorrhizal status of Cyperaceae and their habitat, and (ii) that AM have a positive role in plant tolerance to ultramafic soils (mineral nutrition and metal tolerance), suggesting the use of these pioneer plants with AM management as potential tools for nickel mine site rehabilitation in New Caledonia