INOCULATION OF LEUCAENA AND PROSOPIS SEEDLINGS WITH GLOMUS AND RHIZOBIUM SPECIES IN SALINE SOIL - RHIZOSPHERE RELATIONS AND SEEDLING GROWTH

Leaucaena leucocephala and Prosopis juliflora seedlings were grown in a sandy loam and loamy clay soil amended with three concentrations of NaCl with and without the mycorrhizal fungus Glomus fasciculatum and a Rhizobium isolate. After 16 weeks in glasshouse culture L. leucocepha la and P. juliflora plants inoculated with G. fasciculatum and Rhizobi um developed abundant vesicular-arbuscular mycorrhizae (VAM) and root nodules in the sandy loam soil without NaCl amendments. In contrast, r oot system colonization by both rhizosphere symbionts was reduced in t he loamy clay soil. In the absence of NaCl, plants inoculated with com binations of VAM and rhizobia had significantly greater total dry weig ht, tissue phosphorus concentration, and leaf area compared to seedlin gs colonized with individual symbionts in both soils. Although NaCl am endments greater than 40 and 80 mM decreased mycorrhizal colonization, number of chlamydospores, and root system nodulation by rhizobia, dry weight and tissue P concentration of plants colonized with VAM fungi and rhizobia were generally larger than those of seedlings colonized w ith only rhizobia. These data suggest that dual inoculation with VAM f ungi and rhizobia isolates may help Leucaena and Prosopis species miti gate the adverse effects of NaCl on juvenile growth and development.