Inoculum production of arbuscular mycorrhizal fungi native to soils under different forest covers

Abstract

The low natural fertility of Brazilian soils requires the use of inoculants that facilitate the absorption of nutrients by plants. Arbuscular mycorrhizal fungi such as obligatory biotrophics of active roots perform this function, but access to this resource is limited by the difficulty in producing inoculants. The objective of this study was to investigate the production of AMF inoculants native of soils under different forest covers in Vitória da Conquista, BA, by means of spore quantification, colonization rate and species identification. For this purpose, soils were collected from sites under Mata Nativa (native forest) and plantations of Madeira Nova (Pterogyne nitens) and Eucalyptus, placed into separate 500 mL disposable cups with seeds of Brachiaria sp. and cultivated for five months. Spores were quantified and the AMF species identified in the control soil (without brachiaria) and in the cups cultivated with brachiaria at each month. From the first month, the colonization rate of brachiaria roots was evaluated. The inoculants produced showed differences in the number of spores and species, in the AMF species identified, and in the root colonization rate as a function of the forest cover. Thus, considering the increase in the number of spores, species and colonization over time, the inoculant produced from the soil under native forest was more promising for utilization. Produção de inóculos de fungos micorrízicos arbusculares nativos de solos sob diferentes coberturas florestaisA baixa fertilidade natural dos solos brasileiros requer o uso de inoculantes que facilitem a absorção de nutrientes pelas plantas. Os fungos micorrízicos arbusculares como biotróficos obrigatórios de raízes ativas desempenham esta função, porém o acesso a este recurso é limitado pela dificuldade na produção de inoculantes. Com isso, o objetivo deste trabalho foi avaliar a produção de inoculantes de FMAs nativos de solos sob diferentes coberturas florestais em Vitória da Conquista -BA, através da quantificação de esporos, taxa de colonização e identificação de espécies. Para isso, foram coletados solos nas coberturas florestais de Mata Nativa e em plantios de Madeira Nova e Eucalipto, colocados separadamente em vasos com braquiária e cultivados por cinco meses. No solo testemunha e a cada mês foram quantificados os esporos e identificadas as espécies de FMAs e, a partir do primeiro mês, avaliou-se a taxa de colonização das raízes da braquiária. Os inoculantes produzidos apresentaram diferenças no número de esporos e espécies, nas espécies de FMAs identificadas e na taxa de colonização das raízes, dependendo da cobertura florestal. Assim, considerando o aumento no número de esporos, espécies e colonização ao longo do tempo, o inoculante produzido a partir do solo da Mata Nativa apresentou-se mais promissor para o uso.Palavras-chave: simbionte; vaso armadilha; recuperação florestal. 198Renata Soares dos Santos et al.

Native Arbuscular Mycorrhizal Fungi and Agro-Industries in Arid Lands: Productions, Applications Strategies and Challenges

“…In comparison with the commercial inoculant, it has a low cost, higher taxonomic diversity, and the use of locally adapted species [25,26], which increases the chances of positive effects on the plant and avoid the introduction of exotic species [27]. The use of AMF inoculant produced from the forest soil is the most reliable and recommended method because of its high species diversity, the potential to accelerate the ecological restoration of the soil environment and to promote the germination and growth of the plants [9,[25][26][27].…”

“…Furthermore, mycorrhizal fungi bio-fertilizers are divided on two types depending on the fungus itself; there are bio-fertilizers based on ectomycorrhizal fungi and bio-fertilizers based on arbuscular mycorrhizal fungi. Arbuscular mycorrhizal fungi (AMF) promote a significant increase of the area of root absorption of plants colonized, maximizing the use of water and nutrients [8,9]. These symbiotic fungi enhance plant resistance to water stress, to high temperatures, improve resistance to conditions of toxicity and acidity of soil and to divers' type of pathogens [8].…”

“…These symbiotic fungi enhance plant resistance to water stress, to high temperatures, improve resistance to conditions of toxicity and acidity of soil and to divers' type of pathogens [8]. In addition to soil stabilization in the form of aggregates [9]. AMF are known for their positive effects on phosphorus assimilation by the mineralization of organic phosphorus and solubilization of insoluble phosphorus [10].…”

“…AMF are known for their positive effects on phosphorus assimilation by the mineralization of organic phosphorus and solubilization of insoluble phosphorus [10]. In spite of their potential and benefits, the large-scale use of AMFs is still restricted, mainly due to the deficiency of availability of inoculant in high quantities, low cost and high quality, besides the lack of practicality of inoculation in the field [9,11]. Their efficiency is also questioned by some authors [12,13], who claim that AMF indigenous community promotes greater root colonization than the addition of commercial inoculants.…”

Mycorrhizas in South American Anthropic Environments

“…In this chapter, we examine the major developments and advances on mycorrhizal fungi based on recent research from South American countries. New reports on the occurrence of mycorrhizas in Amazonian dark earth, as well as the inoculum production of arbuscular mycorrhizal fungi native of soils under native forest covers (dos Santos et al 2017), have resulted in a more detailed understanding of the soil biology from South America.…”