Abstract

Through inoculating Amorpha fruiticosa with arbuscular mycorrhizal (AM) fungi and without, the seedlings’ growth indexes, dynamic characteristics of plant endogenous hormone levels, soluble sugar contents in roots and in leaves respectively, and physiological characteristics of seedlings utilizing nitrogen (N), phosphorous (P), were systematically studied. The results showed that both the two tested AM fungi strains, Glomus mosseaeand Glomus intraradices, could colonize the A. fruiticosa roots forming mycorrhizal complexes, and G. mosseae found to be the best AM fungus for A. fruiticosa had a better colonization compatibility than G. intraradices on A. fruiticosa roots with colonization percentage up to 88.5% that of the highest. On the one hand, inoculation with AM fungi could obviously elevate seedling heights, root collar diameter and dry biomass which were 1.94, 1.56 and 1.68 times that of control seedlings when A. fruiticosa seedlings inoculated with G. mosseae at the last stage of seedling growth (110 days). On the other hand, the soluble sugar contents in roots and leaves of seedlings inoculated with AM fungi were significantly higher than control treatments, having a positive correlation with colonization percentage. In addition, AM fungi dramatically increased the contents of auxin (IAA), gibberellin (GA) and zeatin (ZR) in roots, but had little impact on abscisic acid (ABA). Furthermore, AM fungi inoculation not only improved per seedling total N, P contents, but also significantly increased the soluble N, P concentration of rhizosphere soil.

Key words: Arbuscular mycorrhizal fungi, Amorpha fruiticosa, soluble sugar, endogenous hormone, N, P element.