Optimisation of inoculation of Leucaena leucocephala and Acacia mangium with rhizobium under greenhouse conditions

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 10 9 to 10 10 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 other hand, for Leucaena leucocephala, this method of inoculation and the coating of seeds with a bacterial culture mixed with arabic gum improved significantly the growth of the seedlings. Results obtained in our study can be useful for the partners from developing countries involved in the large scale production of tree seedlings.Acacia mangium / Leucaena leucocephala / rhizobium / size of inoculum / symbiosis Résumé -Optimisation de l'inoculation de Leucaena leucocephala et de Acacia mangium avec rhizobium en conditions de serre. Nos travaux ont porté sur l'optimisation de l'inoculation de 2 espèces agroforestières de légumineuses ligneuses : Leucaena leucocephala et Acacia mangium avec différentes souches de rhizobium. Tout d'abord, nous avons montré que le stade physiologique de la culture bactérienne n'a aucune influence sur la nodulation et la croissance des plants d'Acacia mangium inoculés et cultivés in vitro pendant 4 mois. Pour Leucaena leucocephala, le nombre de nodules est significativement supérieur pour les plants inoculés avec une culture bactérienne en phase plateau. En revanche, quelle que soit l'espèce, aucune différence significative n'est notée en ce qui concerne le poids sec des parties aériennes. L'effet de la taille de l'inoculum sur la nodulation et la croissance des plants de L. leucocephala a été étudié après 5 mois de culture en serre. Nos résultats ont montré qu'une inoculation avec des cutures bactériennes contenant 10 10 à 10 9 bactéries par millilitre sont les conditions optimales pour avoir une nodulation et une croissance maximale des plants. Les 2 espèces de légumineuses montrent des différences significatives en ce qui concerne l'effet de la méthode d'inoculation sur la nodulation et la croissance d...

Relations between rhizobial nodulation and root colonization of Acacia crassicarpa provenances by an arbuscular mycorrhizal fungus, Glomus intraradices Schenk and Smith or an ectomycorrhizal fungus, Pisolithus tinctorius Coker & Couch

“…After 1-week culture, the young seedlings were inoculated by 5 mL of the Bradyrhizobium sp. suspension (10 9 bacterial cells) or 5 mL of the culture medium without bacteria for the control treatments as it was suggested by Diouf et al (2003) [6] for the inoculation of Acacia mangium. The pots were arranged in a randomised complete block design with nine replicates per treatment.…”

“…As most of Australian native plants (Eucalyptus, Casuarina, etc. ), Acacia may form mycorrhizal associations with arbuscular mycorrhizas (AM) and ectomycorrhizas (EM) [1,6,12]. More recently, it has been established that each morphological types of mycorrhizas could greatly interact within the same root system [15].…”

Inoculation with arbuscular mycorrhizal fungi improves seedlings growth of two sahelian date palm cultivars (<i>Phoenix dactylifera</i> L., cv. Nakhla hamra and cv. Tijib) under salinity stresses

“…These pots were filled to 4/5 of the volume of soil from Sangalkam. The soil of Sangalkam is sandy (94.9% sand content, clay 3.6%, silt 0.8%), poor in minerals, especially nitrogen (0.02%) and phosphorus (4.8 mg•kg) [12]. The soil was watered to field capacity 48 hours before the transfer of plants.…”

Bio-Revegetation Impact on the Physicochemical Characteristics of a Sandy Quarry Soil in Terga Beach Region in Algeria

“…Each 5 ml of a pure culture of rhizobia containing approximately 30X10 8 bacteria/ml was used in the soil at the collar when transplanting. One week after the seedlings, plantlets received a second inoculation (Diouf et al, 2003;Mansouri, 2011).…”