Fungal Difference in Symbiosis with Arbuscular Mycorrhizal Fungi in Tomato Plug Seedlings.

Abstract

Influence of inoculation with arbuscular mycorrhizal (AM) fungi [Gigaspora margarita (GM), Glomus fasciculatum (GF), Glomussp. R10 (GR) ] for the production of tomato (Licopercicon esculentumMill., cv. Momotaro-T93) as plug seedlings was investigated. Twenty eight days after inoculation, in GM plots, dry weights of shoots and roots were heaviest among the plots irrespective of the 3 phosphorus levels (5, 25 and 50 ppm KH2PO4in liquid fertilizer), and became maximum in 25 ppm P. As for root ball formation, the percentage of complete root ball formation reached 100% in all the P levels only in GM plots. AM fungal infection level in a root system showed highest values in GM plots among the fungi, irrespective of the P levels. GM plots gave greater P concentration in shoots and roots than did noninoculated ones except 50 ppm P ; in GF and GR, no increase in P concentration occurred among almost of the treatments. Tomato seedlings raised in 25 ppm P, infected with GM, continued to grow rapidly after being transplanted to a new bed soil. These results suggest that AM fungus inoculation is essential for obtaining vigorous tomato seedlings and for enhancing the initial growth of transplants in a plug seedling system, though the effects differed with fungal species.