Arbuscular mycorrhizal fungi on adjacent semi-natural grasslands with different vegetation in Japan

Arbuscular mycorrhizal (AM) fungi on Japanese semi-natural grasslands were investigated at three adjacent sites with different vegetation. The predominant grasses at the three sites were 1) Pleioblastus chino, 2) Miscanthus sinensis and Arundinella hirta (M. sinensis/A. hirta), and 3) Zoysia japonica, respectively. The degree of colonization was higher in M. sinensis/A. hirta than in P. chino and Z. japonica. AM fungi were recovered by spore extraction and by pot cultures started from soil inoculum or from transplanting of field plants. Total spore number obtained by the spore extraction method was highest in the rhizosphere of M. sinensis/A. hirta and lowest in that of P. chino. A Glomus sp. resembling G. geosporum predominated in association with M. sinensis/A. hirta and P. chino. From Z. japonica, three species, Acaulospora gerdemannii, Glomus leptotichum, and a species resembling G. clarum, were isolated by pot culture from soil and two species, A. Iongula and Scutellospora cerradensis, by pot culture from transplanting of Z. japonica. From M. sinensis/A. hirta, one species, A. Iongula, was found by pot culture from soil. From P. chino, no AM fungus was detected by either method. Single-spore culture confirmed that G. leptotichum and A. gerdemanniiare conspecific.