Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"Optimisation of inoculation of Leucaena leucocephala and Acacia mangium with rhizobium under greenhouse conditions" | Ann. For. Sci. 60 2003 379-384 INRA EDP Sciences 2003 DOI forest 2003029 379 Original article Optimisation of inoculation of Leucaena leucocephala and Acacia mangium with rhizobium under greenhouse conditions Diégane DIOUFa Sylvain FORESTIERb Marc Neyrac and Didier LESUEURb a Université . Diop Département de Biologie Végétale Laboratoire de Microbiologie des Sols IRD BP 1386 Dakar Sénégal b Programme Arbres et Plantations du CIRAD-Forêt Laboratoire de Microbiologie des Sols IRD BP 1386 Dakar Sénégal c Unité de Recherche Symbioses Tropicales et Méditerranéennes de l IRD Laboratoire de Microbiologie des Sols IRD BP 1386 Dakar Sénégal Received 10 December 2001 accepted 13 August 2002 Abstract - Our work concerned the optimization of inoculation of two agroforestry species of woody leguminous plants Leucaena leucocephala and Acacia mangium with various strains of rhizobium. First we showed that the physiological stage of the bacterial culture had no effect on nodulation and growth of the seedlings of Acacia mangium inoculated and cultivated in vitro for four months. For Leucaena leucocephala the number of nodules was significantly higher when the seedlings were inoculated with a bacterial culture in stationary phase. On the other hand whatever the species no significant difference was noted with regards to the dry weight of the shoots. The effect of the size of inoculum on the nodulation and growth of the seedlings was studied in L. leucocephala after five months in a greenhouse. Our result show that an inoculation with bacterial cultures containing 109 to 1010 bacteria per milliliter are the optimal conditions to have a maximum nodulation and growth of the seedlings. The two legume plant species showed significant differences with regard to the effect of the method of inoculation on nodulation and growth of the seedlings. For Acacia mangium inoculation with a liquid culture one week after sowing was more favourable for the growth of the seedlings. On the .