Navarro Elisabeth auteur aut IRD Gauthier Daniel auteur aut IRD Lesage G. auteur aut IRD Simonet P. auteur aut IRD Jaffré Tanguy auteur aut IRD Rinaudo Gérard auteur aut IRD text conferencePaper eng text/pdf reformatted digital access The native region of Casuarinaceae family (actinorhizal plants) is Oceania (Australia and Indo-Pacific islands). In New Caledonia, in spite of the reduced area, a great number of endemic Casuarinaceae are present. In fact, 8 species of Gymnostoma out of the 18 which make up this genus and 1 species of Casuarina are originated from New Caledonia. The two genera, except 1 species, occur in soils derivated from ultramafic rock and are adapted to poor and toxic soils. Furthermore, actinorhizal plants can establish nitrogen-fixing symbioses with the slow growing actinomycete Frankia. Because of their ecological characteristics, actinorhizal plants frequently occur as pioneer vegetation and are used in the rehabilitation of degraded sites. This work was a first study of the ecology of the symbiosis Casuarinaceae-Frankia in New Caledonia. It was focused on two major topics. The first part will be concerned with the symbiosis, particularly with cross-inoculation trials using crushed nodule suspension as inoculum. The biodiversity of the microsymbiot Frankia, in relation to plants species and soil, will be analysed in the second part. The results obtained show that this symbiosis is characterized by a great biodiversity. Inside the Gymnostoma group, no host specificity was observed. These results were obtained by cross-inoculation tests and molecular characterization of Frankia. Furthermore, no correlation was shown between site or soil and the diversity of Frankia strains. (Résumé d'auteur) specialized SYMBIOSE FIXATION BIOLOGIQUE DE L'AZOTE INOCULATION BIODIVERSITE NOUVELLE CALEDONIE 084SYMBIO02 Ecologie des Milieux Serpentiniques : Conférence Internationale = Serpentine Ecology : International Conference, 2., Nouméa (NCL), 1995/07/31; 1995/08/05 35 Nouméa ORSTOM 1995 https://www.documentation.ird.fr/hor/fdi:010005648 [F A010005638] https://www.documentation.ird.fr/hor/fdi:010005648 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers10-09/010005648.pdf IRD - Base Horizon / Pleins textes 1996-06-12 2013-02-24 fdi:010005648 fre