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When exotic species spread over novel environments, their phenotype will depend on a combination of different processes, including phenotypic plasticity (PP), local adaptation (LA), environmental maternal effects (EME) and genetic drift (GD). Few attempts have been made to simultaneously address the importance of those processes in plant invasion. The present study uses the well-documented invasion history of Senecio inaequidens (Asteraceae) in southern France, where it was introduced at a single wool-processing site. It gradually invaded the Mediterranean coast and the Pyrenean Mountains, which have noticeably different climates. We used seeds from Pyrenean and Mediterranean populations, as well as populations from the first introduction area, to explore the phenotypic variation related to climatic variation. A reciprocal sowing experiment was performed with gardens under Mediterranean and Pyrenean climates. We analyzed climatic phenotypic variation in germination, growth, reproduction, leaf physiology and survival. Genetic structure in the studied invasion area was characterized using AFLP. We found consistent genetic differentiation in growth traits but no home-site advantage, so weak support for LA to climate. In contrast, genetic differentiation showed a relationship with colonization history. PP in response to climate was observed for most traits, and it played an important role in leaf trait variation. EME mediated by seed mass influenced all but leaf traits in a Pyrenean climate. Heavier, earlier-germinating seeds produced larger individuals that produced more flower heads throughout the growing season. However, in the Mediterranean garden, seed mass only influenced the germination rate. The results show that phenotypic variation in response to climate depends on various ecological and evolutionary processes associated with geographical zone and life history traits. Seeing the relative importance of EME and GD, we argue that a "local adaptation vs. phenotypic plasticity" approach is therefore not sufficient to fully understand what shapes phenotypic variation and genetic architecture of invasive populations. [ABSTRACT FROM AUTHOR]

Mining activities generate spoils and effluents with extremely high metal concentrations of heavy metals that might have adverse effects on ecosystems and human health. Therefore, information on soil and plant metal concentrations is needed to assess the severity of the pollution and develop a strategy for soil reclamation such as phytoremediation. Here, we studied soils and vegetation in three heavily contaminated sites with potential toxic metals and metalloids (Zn, Pb, Cd, As, TI) in the mining district of Les Malines in the Languedoc region (southern France). Extremely high concentrations were found at different places such as the Les Aviniéres tailing basins (up to 160,000 mg kg Zn, 90,000 mg kg Pb, 9,700 mg kg of As and 245 mg kg of Tl) near a former furnace. Metal contamination extended several kilometres away from the mine sites probably because of the transport of toxic mining residues by wind and water. Spontaneous vegetation growing on the three mine sites was highly diversified and included 116 plant species. The vegetation cover consisted of species also found in non-contaminated soils, some of which have been shown to be metal-tolerant ecotypes ( Festuca arvernensis, Koeleria vallesiana and Armeria arenaria) and several Zn, Cd and Tl hyperaccumulators such as Anthyllis vulneraria, Thlaspi caerulescens, Iberis intermedia and Silene latifolia. This latter species was highlighted as a new thallium hyperaccumulator, accumulating nearly 1,500 mg kg. These species represent a patrimonial interest for their potential use for the phytoremediation of toxic metal-polluted areas. [ABSTRACT FROM AUTHOR]

Studies the effects of time since abandonment and date of flowering on the number and biomass of seeds of Rumex acetosella at monthly intervals near Paris, France. Observation of decrease in filled-seed production per plant with successional age in summer; Differences between the populations in the mean weight of seeds; Absence of any correlation between the number and biomass of seeds when pooling of all populations.

Monitors the changes in sex ratio in experimental populations of dioecious perennial plant, Rumex acetosella in Paris, France. Outnumbered female ramets by male ramets during third year of growth; Balanced sex ratios during first year of growth; Greater clonal growth of ramets.