Plant Ageing, a Counteracting Agent to Xenobiotic Stress

International audienc

Nemesia Root Hair Response to Paper Pulp Substrate for Micropropagation

Agar substrates for in vitro culture are well adapted to plant micropropagation, but not to plant rooting and acclimatization. Conversely, paper-pulp-based substrates appear as potentially well adapted for in vitro culture and functional root production. To reinforce this hypothesis, this study compares in vitro development of nemesia on several substrates. Strong differences between nemesia roots growing in agar or in paper-pulp substrates were evidenced through scanning electron microscopy. Roots developed in agar have shorter hairs, larger rhizodermal cells, and less organized root caps than those growing on paper pulp. In conclusion, it should be noted that in this study, in vitro microporous substrates such as paper pulp lead to the production of similar root hairs to those found in greenhouse peat substrates. Consequently, if agar could be used for micropropagation, rooting, and plant acclimatization, enhancement could be achieved if rooting stage was performed on micro-porous substrates such as paper pulp

Selaginella bifida sp. nov. (Selaginellaceae: Pteridophyta) from Rodrigues Island, Mauritius

International audienceSelaginella bifida D. Delmail, a new species of the Selaginellaceae from Rodrigues Island, (Mascarene archipelago, Mauritius) is described and illustrated. The new species is related to S. rodrigueziana Baker in phenotypic appearance, but differs by having ciliate lateral leaf margins and bifid microsporophyll apices

Validation of Muhlenbergia fasciculata (Poaceae) endemic to Myanmar

International audienceMuhlenbergia fasciculata T. P. I. Phan, originally described in 1994, was an invalidly published name, because two collections (one flowering, one fruiting) were designated as the type. The name is validated here, with the flowering specimen designated as the holotype

Risk management of European inland waters using macrophyte biomonitoring

International audienceInland waters are extremely sensitive to inputs of contaminants. Increasing human activities lead to a rise in organic and inorganic pollutants leading to acidification or eutrophication problems. Many aquatic organisms are affected by these contaminants and significant modifications of their community composition have been recorded. As part of the European Water Framework Directive, macrophyte biomonitoring has been developed to assess the quality of waters and their ecological status. The purpose of such studies was to establish the macrophyte-community composition as an indicator of the pollution level using multivariate approaches. As the various macrophyte indices evolve in concordance with European environmental policy needs, spatial and temporal comparisons between aquatic environments from different regions or countries would be possible

Muhlenbergia fasciculata T.P.I. Phan (Poaceae) - a new angiospermic record for India

International audienc

Heavy-Metal Attack on Freshwater Side: Physiological Defense Strategies of Macrophytes and Ecotoxicological Ops

International audienceFor many years, strong anthropogenic pollutions like heavy metals induce deep changes in all ecosphere compartments especially in streams where deleterious effects on aquatic plants are noted. Indeed, ionic interactions on whole plant surface and permanent replacement of metal pool lead to ecophysiological disruptions among freshwater macrophytes. To prevent from irreversible alterations, macrophytes develop a typical antioxidant systems (e.g., proteins, secondary metabolites, metabolic pathways) to protect intracellular components from reactive oxygen species and to preserve major biosynthesis pathways like photosynthesis. These macrophytes also accumulate solutes to cope with increasing external metal toxicity. Moreover, new anatomical features reducing water stress and leading to cell homeostasis can appear in leaves, as a double endodermis. Tolerance to heavy metals is an interesting feature of freshwater plants for understanding any adaptation and acclimation processes to highly ionic concentrated environments at the genetic level. Indeed, specific genes involved in the synthesis of molecular chaperones might be related to heavy-metal tolerance in macrophytes. Due to their metal sensitivity and bioaccumulation capabilities, these organisms appear essential in ecotoxicological studies like biomonitoring to manage natural habitats

Note - Potentiels d’utilisation des macrophytes pour réduire l’impact des industries sur les milieux aquatiques européens

Les macrophytes sont de plus en plus exploités pour atteindre les bons états chimique et écologique recommandés des masses d’eau européennes. Mais quelles sont les particularités des macrophytes en tant qu’outil de bio-surveillance ? Et quelles nouvelles informations sont apportées par la recherche quant à leur potentiel de réduction d’écotoxicité

First description of Oidium neolycopersici (Erysiphaceae) in France, on a new host plant extinct in the wild

International audienceThe first description of Oidium neolycopersici (Erysiphaceae) discovered on a Madeiran plant now extinct in the wild, Normania triphylla (Solanaceae), is provided. The pathogen was collected from the National Botanical Conservatory of Brest in western France