Arbuscular mycorrhizal fungi (AMF) establishing efficient symbiosis with plants play an important role on ecosystem sustainability and can be useful for revegetation of degraded lands. Symbiotic efficiency is related to AMF genotypes and plant species, as well as to environmental conditions that may affect the expression of symbiotic relationships. Thus, the first step to an efficient AMF symbiosis management is to study fungal variability regarding the efficiency with different host species. In this study root colonization and efficiency of several AMF isolates, obtained from bauxite minespoil areas from two distinct environments ("serra" and "campo"), were evaluated for seedling growth of pioneer species [aroeira (Schinus terebenthifolius) and trema (Trema micrantha)], and secondary species [açoita-cavalo (Luehea grandiflora) and sesbânia (Sesbania virgata)], in a low fertility soil. The experiment was carried out under greenhouse conditions, for 120 days. Each plant species, was treated with ten AMF inoculation types (AMF isolates or their mixtures): Acaulospora longula, Paraglomus occultum, Glomus sp., Gigaspora sp., Acaulospora spinosa, and the mixture of all "campo" species; Acaulospora scrobiculata, Paraglomus occultum, Glomus sp. and the mixture of all "serra" species. For a comparison two additional treatments were included: one inoculated with efficient Glomus etunicatum, as reference, and an uninoculated treatment, as control. The growth of all plant species was lower in the absence of AMF whereas AMF inoculation enhanced plant growth. Benefits varied according to isolates and plant species. All tested isolates or their mixtures were efficient in sesbânia, while only one Glomus sp. was inefficient for trema and aroeira and both Glomus sp. isolates were inefficient for açoita-cavalo. It was found that no isolate from bauxite mine spoil was more efficient than Glomus etunicatum. However, several isolates from campo (Gigaspora sp., Paraglomus occultum and Acaulospora spinosa) were as efficient as G. etunicatum for all hosts. These results show that degraded land, i.e., bauxite mine spoils can have efficient AMF populations which may contribute to land rehabilitation.
inoculation; mycorrhizae; root symbiosis; soil fungi
