PROMOTION OF ROOTING AND THE INCREASE IN LEAF GABA CONTENT OF MYCORRHIZAL TEA PLANTS

Cuttings of tea (Camellia sinensis cv. ‘Yabukita’) plants were inoculated with 5 species of arbuscular mycorrhizal fungi (AMF) to investigate the colonization and the rooting and growth enhancement through symbiosis, including changes in free amino acid content in leaves. Three months after inoculation, AMF plots raised in autoclaved field soil showed higher values than in non-AMF plots in the items of rooting rate, plant height, leafing rate, leaf area and dry weight of shoots and roots. Glomus fasciculatum and Gigaspora margarita became highest among the fungi especially in rooting and leafing rate; Gl. fasciculatum was highest in leafing rate. On the other hand, Gl. mosseae became lowest in rooting and leafing rate among the species. T/R ratio in plants was lower in most of the AMF plots than in non-AMF, because of the greater development of root system in mycorrhizal plants. AMF colonization level differed with the species, and Gl. fasciculatum and Gi. margarita showed higher levels among the fungi. No correlation was recognized between AMF colonization level and the increase in dry weight of plants. As for free amino acid content in leaves, total free amino acid content differs little between AMF and non- AMF plots. However, GABA (gamma-amino butyric acid) content became higher in Gl. fasciculatum plot than in non-AMF one. These findings suggest that Gl. fasciculatum has high affinity with the tea plants, resulted in improving the rooting of cuttings and the nursery raising period by growth promotion, and inducing the increase in GABA content in leaves which leads to high quality.