Abstract:

【Objective】 Research on the characteristics of ammonium, nitrate and organic nitrogen utilization by ericoid mycorrhizal fungi and impacts on growth in vitro of Rhododendron fortunei was carried out to determine the suitable nitrogen sources in ericoid mycorrhizal (ERM) fungal cultivation and test the effects of ERM on host plant growth in substrate with different nitrogen sources. 【Method】 Mycelial dry weight of ERM fungal strain in the different nitrogen source media was used as the index to assess nitrogen utilization. These ERM fungal strains were also inoculated on seedlings of Rhododendron fortunei on different nitrogen source substrates, and the effect of ERM fungi on the host plant was evaluated by dry weight of the seedlings. 【Result】 Nitrogen sources had a significant effect on fungus biomass. Fungal growth was the best on ammonium and nitrate, moderate on arginine and Bovine Serum Albumin (BSA), and poor on medium without nitrogen. Inoculated plants grew better than non-inoculated plants regardless of nitrogen sources, and grew best on BSA. 【Conclusion】 Ammonium and nitrate were suitable N source for the growth of the ERM strains. Inoculation with these ERM fungi increased the capacity of Rhododendron fortunei to utilize nitrogen source, especially nitrate and BSA nitrogen.

Key words: Rhododendron fortunei, ericoid mycorrhiza, organic nitrogen, nitrate nitrogen, inoculation effect