Effect of Arbuscular Mycorrhizal Fungus Inoculation on Growth of Sandersonia.

The means of inoculation with arbuscular mycorrhizal (AM) fungi [Gigaspora margarita (GM), Glomus aggregatum (ga), Glomus fasciculatum (gf), Glomus mosseae (gm)] were investigated in sandersonia (Sandersonia aurantiaca Hook.).Fifteen weeks after inoculation, AM fungal infection with the four fungal species occurred in all the inoculated plants. The infection level in a root system reached 51.6% in GM, 45.9% in gf, 39.4% in ga and 30.2% in gm. Shoot growth, plant height, no. of leaves and no. of flowers in AM fungus-inoculated plants were superior to those in noninoculated ones, the effect being relatively greater in GM and gf than in ga and gm. As for daughter tuber growth, both the length and maximum diameter of daughter tubers showed higher values in almost all AM fungus-inoculated plants than in noninoculated ones, the effect being more pronounced in GM and gm than in ga and gf. Dry weights of both shoots and daughter tubers were superior in AM fungus-inoculated plants. Formation of marble-shaped daughter tubers occurred in all the treatments, and the rate of such formation was higher in AM fungus-inoculated plants. An increase in P concentrations occurred in the shoots of AM fungus-inoculated plants, the effect being more pronounced in ga and gf than in GM and gm. On the other hand, in daughter tubers, no major difference appeared in P concentration among the treatments.It was clarified that AM fungus infection and plant growth promotion through symbiosis occurred in sandersonia, and that AM fungus inoculation is effective in stimulating tuberization.