ABSTRACT
Currently, southern Minas Gerais (MG) state is an important producer of different olive tree (Olea europaea L.) cultivars because, in this region, the plants can differentiate the buds to produce flowers and fruit. To stimulate the rooting of cuttings, the synthetic hormone indole-3-butyric acid (IBA) at a concentration of 3 g L−1 is used commercially. However, few studies have investigated arbuscular mycorrhizal fungi (AMF), isolated or combined with rhizobacteria, as a biotechnological tool to produce hormones that function in the rooting of olive tree cuttings. The aim of this study was to evaluate the capacity of different AMF species (Rhizophagus clarus, Gigaspora rosea, or Acaulospora scrobiculata), combined or not with IBA or rhizobacteria, to promote the rooting of three olive tree cuttings (Arbequina, Grappolo 541, and Maria da Fé) with potential for cultivation in this region. For this, three experiments were conducted at the Experimental Farm of EPAMIG in Maria da Fé (MG), and the rooting potential of the olive tree cuttings inoculated with I) AMF, II) AMF combined with increasing doses of IBA, and III) AMF combined with three isolates of rhizobacteria was evaluated. The inoculation of olive tree cuttings of cultivars Arbequina, Grappolo 541, and Maria da Fé with Rhizophagus clarus, Gigaspora rosea, or Acaulospora scrobiculata combined or not with IBA or rhizobacteria did not significantly promote rooting. Alternative forms of rooting olive tree cuttings are still a challenge, and further studies for standardizing methodologies and experimental conditions are required.
Subject(s)
Plant Roots , Mycorrhizae , OleaABSTRACT
RESUMO A clínica hospitalar se depara diariamente com desafios terapêuticos advindos da presença de bactérias multirresistentes a antibióticos. Todavia, considerando que há evidência de bactérias multirresistentes nos ambientes solo e água, o presente estudo objetivou avaliar os aspectos microbiológicos de fontes de águas naturais potenciais para consumo no município de Itajubá (MG), incluindo a determinação do perfil de resistência de bactérias heterotróficas a antimicrobianos, não exigida nos critérios atuais de potabilidade. Para isso, foram realizadas análises das características microbiológicas em 11 fontes canalizadas durante a estação chuvosa e 9 fontes durante a estação seca, incluindo coliformes totais, Escherichia coli, densidade de bactérias heterotróficas e teste de resistência de bactérias heterotróficas a agentes antimicrobianos, além de características físicas e químicas. Os resultados obtidos evidenciaram elevadas porcentagens de resistência de bactérias heterotróficas aos antimicrobianos, sem relação com a época de amostragem. Entretanto, não se verificou relação entre resistência bacteriana e densidades de bactérias heterotróficas e coliformes totais, o que pode levar à falsa ideia de ausência de risco nas águas naturais estudadas que apresentem baixa contaminação.
ABSTRACT The hospital clinic daily faces therapeutic challenges arising from the presence of multidrug-resistant bacteria to antibiotics. However, considering there is evidence of multi-resistant bacteria in soil and water environments, this study aimed to evaluate the microbiological aspects of potential natural water sources for consumption in the city of Itajubá (MG, Brazil), including the determination of the resistance profile of heterotrophic bacteria to antimicrobials, which is not required in the current potability criteria. Thus, we performed analyzes of the microbiological characteristics in 11 channeled sources during the rainy season and nine sources during the dry season, including total coliforms, Escherichia coli, density of heterotrophic bacteria and resistance testing of heterotrophic bacteria to antimicrobial agents, besides physical and chemical characteristics. The results showed high resistance percentages of heterotrophic bacteria to antimicrobials, unrelated to the sampling time. However, there was no relationship between bacterial resistance and density of heterotrophic bacteria and total coliforms, which can lead to the false idea of the absence of risk in the natural studied waters presenting low contamination.