Symbiotic compatibility of arbuscular mycorrhizal fungi with tropical tree species

Revegetation with tree species is an appropriate strategy for the rehabilitation of degraded areas. However, the establishment and growth of these species in low nutrient soils depends upon several factors, such as the ability of the species to form and benefit from mycorrhizae. In this study, conducted in pots under greenhouse conditions at the Federal University of Lavras in Minas Gerais, Brazil, aspects of host-fungus relationship in tree species found in Southeastern Brazil were evaluated. The following arbuscular mycorrhiza (AM) fungal species were studied: Scutellospora pellucida, Acaulospora scrobiculata, Entrophospora colombiana, Gigaspora gigantea, Gigaspora margarita, Glomus etunicatum, Scutellospora gregaria, Glomus clarum, and fungi isolated from agrosystems and native forest. All these fungi were inoculated on the following sixteen plant species: Luehea grandiflora, Cecropia pachystachya, Schinus terebinthifoliu, Machaerium nyctitans, Senna macranthera, Senna spectabilis, Solanum. granuloso-leprosum, Caesalpinea ferrea, Tabebuia serratifolia, Madura tinctoria, Guazuma ulmifolia, Acacia polyphylla, Mimosa caesalpiniaefolia, Enterolobium contortisiliquum, Trema micrantha, and Cedrela fissilis. These species presented differentiated susceptibility and growth response under inoculation with AM fungi. Within the substantially wide range of symbiotic efficiency Gl. clarum, E. colombiana, S. pellucid,a and Gl. etunicatum. presented the highest amplitudes, being efficient for over 80 % of all studied species, whereas A. scrobiculata was the fungus with the most restricted range of hosts. A compatibility analysis of the host-fungus relationships indicated the existence of a differential selectivity among them, resulting in varied symbiotic efficiency for the host plants. The importance of these results for the revegetation of degraded areas is discussed.