Glomus Etunicatum Research Articles

Arbuscular mycorrhiza confers Pb tolerance in Calopogonium mucunoides

Heavy metals (HMs) are environmental pollutants of great concern to humans because of their high potential toxicity. Lead is a HM that is present in the soil in very small amounts, but anthropogenic activities have increased its content in some locations, which can make these areas unproductive or inappropriate for crop production. However, there are some plants that can grow in contaminated soils and, thus, can be useful for the removal or stabilisation of such contaminants. In addition, plants that are not able to tolerate high concentrations of HMs in the soil can become tolerant or increase their performance when associated with arbuscular mycorrhizal (AM) fungi. Accordingly, this study was carried out to verify whether the inoculation of Glomus etunicatum, an AM fungus species, in Calopogonium mucunoides would influence plant tolerance to increasing concentrations of Pb in the soil. The experimental design was completely randomised, in a 2 × 4 factorial design, and the treatments consisted of inoculation (or not) with the AM fungus, G. etunicatum, and the addition of four Pb concentrations (0, 250, 500 or 1,000 mg kg−1) to the soil. The results showed that the association of C. mucunoides with G. etunicatum promoted biomass production, and nutrient uptake (P, S and Fe) was also positively influenced by mycorrhization. The malondialdehyde content was higher in non-mycorrhizal leaves, suggesting a reduction in the damage to membranes by lipid peroxidation in plants associated with mycorrhizae. However, the Pb concentration in the shoots did not differ between the mycorrhizal and non-mycorrhizal plants. The results of our study suggest that the AM symbiosis can be considered very effective in contributing to the tolerance of C. mucunoides to Pb.

Acclimatization of Tapeinochilos ananassae plantlets in association with arbuscular mycorrhizal fungi

The objective of this work was to assess the potential of three isolates of arbuscular mycorrhizal fungi to promote growth of micropropagated plantlets of Tapeinochilos ananassae during acclimatization. The experiment was carried out in greenhouse, in a completely randomized block design, with four inoculation treatments: non‑inoculated control and plants inoculated with Glomus etunicatum, Acaulospora longula or Gigaspora albida, with ten replicates. After 90 days, the following parameters were evaluated: survival rate, height, leaf and tiller number, leaf area, fresh and dry biomass, contents of macro‑ and micronutrients in the root and shoot, glomerospore number, and mycorrhizal colonization. The survival percentage was 100%, except for plants inoculated with G. albida (80%). The isolate G. etunicatum is more suitable for plant development, since it improves survival, growth, dry matter production, nutritional status, and vigor of T. ananassae micropropagated plants.

On-site growth response of a desert ephemeral plant, Plantago minuta, to indigenous arbuscular mycorrhizal fungi in a central Asia desert

Desert ephemeral plants play a key role in desert ecosystem stability and environmental conservation. To determine the effect of indigenous arbuscular mycorrhizal (AM) fungi on the growth and P uptake of the desert ephemeral Plantago minuta, we conducted two on-site experiments in the Gurbantunggut Desert. The co-development of a pre-isolated indigenous AM fungus, Glomus etunicatum, with the ephemeral was also investigated. The results showed that both the single fungus and the indigenous AM fungal community enhanced the growth and P uptake of P. minuta. The phenological phases of P. minuta were highly consistent with the phases of the indigenous AM fungus, G. etunicatum, indicating that both symbiotic partners seem to be able to sense the changes in local weather, which might be an important trait for the survival of both plant and fungus in desert environments. The development of host plant and indigenous AM fungi were interdependent in the desert.

The impact of biological pesticides on arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi have a key role for plant nutrition in organic farming systems where crop protection relies on biopesticides. Although these are considered safe, their effects on non-target organisms, such as AM fungi, are not known and should be evaluated. A pot and a field experiment were employed to investigate the impact of biological pesticides (azadirachtin, spinosad, pyrethrum and terpens) on exogenous AM fungal inoculum (pots) and on indigenous AM fungi (field). The synthetic fungicide carbendazim and non-pesticide treated controls with or without mycorrhizal inoculation were also included. Plant growth and root colonization were measured 20 and 40 days post inoculation (dpi) in the pot experiment, or 40 and 90 dpi in the field study. Pesticide effects on the structure of the intraradical AM fungal community were determined via DGGE and cloning. Spinosad, pyrethrum and terpenes did not affect the colonization ability and the structure of the AM fungal community. On the contrary, pot application of azadirachtin resulted in a selective inhibition of the Glomus etunicatum strain of the inoculum. DGGE analysis showed that the field application of azadirachtin induced significant and persistent shifts in the AM fungal community. Carbendazim completely hampered mycorrhizal colonization in pots, compared to its field application which had a transitory effect on the colonization ability and the community structure of indigenous AM fungi. Our study provides first evidence for the effects of biological pesticides on the diversity of AM fungi.

Tolerância e potencial fitorremediador de Stizolobium aterrimum associada ao fungo micorrízico arbuscular Glomus etunicatum em solo contaminado por chumbo

A poluição do solo com metais pesados tem aumentado significativamente nos últimos anos, devido à ação antrópica. Diversas técnicas podem ser utilizadas para reverter ou minimizar a condição de contaminação do solo, porém muitas delas são prejudiciais ao solo. Uma alternativa é a utilização da fitorremediação, já que as plantas possuem a capacidade de absorver elementos do solo e, dessa maneira, promover sua descontaminação com teores excessivos de metais e outros elementos potencialmente tóxicos. A associação de plantas com fungos micorrízicos arbusculares (FMAs) pode influenciar a absorção desses elementos. Com o objetivo de avaliar o potencial fitorremediador de plantas de Stizolobium aterrimum associadas ou não a FMAs em solos com concentrações crescentes de Pb, realizou-se um experimento sob condições de casa de vegetação, em esquema fatorial 4 x 2. Os tratamentos consistiram na adição de quatro doses de Pb (0, 250, 500 e 1.000 mg dm-3) e da inoculação ou não de FMA. Os resultados mostraram que a planta foi tolerante ao Pb nas doses utilizadas. A associação com FMA não influenciou a absorção de Pb pela planta. No entanto, a micorrização influenciou a fixação biológica de N2, observando-se maior atividade da enzima nitrogenase em plantas micorrizadas. Apesar dos bons resultados obtidos com relação à tolerância dessa planta ao Pb, mais estudos precisam ser realizados acerca da absorção desse elemento, principalmente em solo multicontaminado, que é a realidade encontrada em sistemas poluídos.

Performa Fungi Mikoriza Arbuskula dan Pueraria phaseoloides yang Dipupuk Tepung Tulang dengan Ukuran dan Dosis Berbeda

Bone meal is a natural source of calcium and phosphorus required for plant growth, but phosphorus can cause problems if they occur in high concentrations particularly will inhibit growth of mycorrhizal fungi. The aim of this study was to find the best diameter size and dosage of bone meal for increasing growth of forage legume Pueraria phaseoloides and for producing arbuscular mycorrhizal fungi (AMF) Glomus etunicatum inoculant. A glass house experiment was laid out in a randomized block design consisted of 13 treatments (control and 12 combination of different diameter size and weight of bone meal) and replicated three times. Bone meal and artificial fertilizer resulted the same effect (P>0.05) on dry matter of P. phaseoloides. Application of 25–40 mg with <250 µm diameter significantly (P<0.05) increased dry matter production. Bone meal reduced significantly (P<0.05) root colonization but increased significantly number of spores compared to that of artificial fertilizer. Reducing bone meal diameter significantly increased root colonization and number of spores of AMF G. etunicatum.

Diversity of Arbuscular Mycorrhizal Fungi Associated with Plants Growing in Fly Ash Pond and Their Potential Role in Ecological Restoration

Root colonization and diversity of arbuscular mycorrhizal fungi (AMF) were analyzed in plants growing in fly ash pond. Eight species could be separated morphologically, while phylogenetic analyses after PCR amplification of the ITS region followed by RFLP and sequencing revealed seven different AM fungal sequence types. Phylogenetic analysis showed that these sequences cluster into four discrete groups, belonging to the genus Glomus and Archaeospora. Inoculation of plants with spores of AM fungal consortia (Glomus etunicatum, Glomus heterogama, Glomus maculosum, Glomus magnicaule, Glomus multicaule, Glomus rosea, Scutellospora heterogama, and Scutellospora nigra) along with colonized root pieces increased the growth (84.9%), chlorophyll (54%), and total P content (44.3%) of Eucalyptus tereticornis seedlings grown on fly ash compared to non-inoculated seedlings. The growth improvement was the consequence of increased P nutrition and decreased Al, Fe, Zn, and Cu accumulations. These observations suggested that the inoculation of tree seedlings with stress adapted AM fungi aid in the reclamation of fly ash ponds.

Arbuscular mycorrhizal fungi and biological control of Verticillium-wilted cotton plants

The interaction of arbuscular mycorrhizal fungi (Glomus etunicatum, Glomus intraradices, and Glomus versiforme) with a wilt-causing soil-borne pathogen, Verticillium dahliae, was studied in cotton. It was found that establishment by arbuscular mycorrhizal fungi reduced disease index. In diseased cotton plants colonised by G. etunicatum, the disease index was less than other diseased mycorrhizal and non-mycorrhizal ones. In diseased cotton plants, chlorophyll content was lower than others. Three Glomus species significantly increased content of sugar and protein in shoot and root. Pathogen-infected plants had higher proline concentration in shoot and root than healthy plants. On the other hand, the increased content of proline as stress sensor showed that Verticillium accelerates senescence and reduces yield. These results suggest that the beneficial effects of mycorrhiza can alleviate the pathogenesis effects of V. dahliae partly, and also there is a competitive interaction between the pathogenic and symbiotic fungi.

EXPLOITATION OF PHOSPHORUS PATCHES WITH DIFFERENT PHOSPHORUS ENRICHMENT BY THREE ARBUSCULAR MYCORRHIZAL FUNGI

The effect of three arbuscular mycorrhizal (AM) fungi on phosphorus (P) nutrient activation and acquisition by maize from spatially heterogeneous sand was investigated using dual-mesh packages enriched with different P concentrations and compared with non-mycorrhizal cotrols. As would be expected the AM fungi significantly enhanced leaf photosynthetic rate and the biomass and P concentrations in shoots and roots. All three fungi (Glomus intraradices, Glomus mosseae and Glomus etunicatum) displayed the capacity to dissolve inorganic P and promoted P nutrient availability in the packages (P patches). G. etunicatum showed the largest effect comparing with Glomus intraradices and Glomus mosseae, particularly in packages with high concentrations of P. Possible mechanisms involved include the acidification of the P patches by the AM fungi, promotion of the dissolution of the P, and more marked effects of the three fungal isolates with increasing enrichment of P in the patches. Inoculation with G. etunicatum resulted in greater acidification compared to the other two fungi. We conclude that AM fungi can promote P availability by acidifying the soil and consequently exploiting the P in nutrient patches and by facilitating the growth and development of the host plants.

Effects of arbuscular mycorrhizal fungus on photosynthesis and water status of maize under high temperature stress

The purpose of this study was to investigate the effects of arbuscular mycorrhizal (AM) symbiosis on gas exchange, chlorophyll fluorescence, pigment concentration and water status of maize plants in pot culture under high temperature stress. Zea mays L. genotype Zhengdan 958 were cultivated in soil at 26/22°C for 6 weeks, and later subjected to 25, 35 and 40°C for 1 week. The plants inoculated with the AM fungus Glomus etunicatum were compared with the non-inoculated plants. The results showed that high temperature stress decreased the biomass of the maize plants. AM symbiosis markedly enhanced the net photosynthetic rate, stomatal conductance and transpiration rate in the maize leaves. Compared with the non-mycorrhizal plants, mycorrhizal plants had lower intercellular CO2 concentration under 40°C stress. The maximal fluorescence, maximum quantum efficiency of PSII photochemistry and potential photochemical efficiency of mycorrhizal plants were significantly higher than corresponding non-mycorrhizal plants under high temperature stress. AM-inoculated plants had higher concentrations of chlorophyll a, chlorophyll b and carotenoid than non-inoculated plants. Furthermore, AM colonization increased water use efficiency, water holding capacity and relative water content. In conclusion, maize roots inoculated with AM fungus may protect the plants against high temperature stress by improving photosynthesis and water status.

Effect of three Greek arbuscular mycorrhizal fungi in improving the growth, nutrient concentration, and production of essential oils of oregano and mint plants

Arbuscular mycorrhizal fungi have been widely used in agriculture to improve the cultivation of many crops. One of the aims of this study was the isolation and molecular identification of arbuscular mycorrhizal fungi isolated from mountain areas of Northern Greece (Ritini Pieria, Elatochori Pieria, Ambelakia Ossa). Only three isolates were obtained; two of Glomus etunicatum and one of G. lamellosum. The second objective of this study was to investigate the effect of these arbuscular mycorrhizal fungi on the concentration of macro- and micronutrients in tissues, the quantity and quality of essential oils and the growth of oregano and mint plants (two widely used aromatic plants in Greece). It was found that mycorrhizal oregano and mint plants had a higher content of essential oils and nutrient elements, and grew better than non-mycorrhizal plants. In addition, the composition of the essential oil in mycorrhizal plants differed from the oil of non-mycorrhizal plants. These results suggest that the use of mycorrhizal fungi may allow plant growth in low fertility soils, reduce fertilizer inputs and increase aromatic plant production of essential oils, They also indicate that it may be possible to use mycorrhizae to affect the quality of the essential oil produced.

Incremento no desenvolvimento do porta-enxerto de pessegueiro 'Okinawa', promovido por fungos micorrízicos arbusculares autóctones

Fungos micorrízicos arbusculares (FMA) são organismos comuns da rizosfera, que se associam às raízes das plantas, incrementando a absorção nutricional e estimulando o seu crescimento. Objetivou-se avaliar a influência de três espécies de FMA (Gigaspora margarita, Glomus clarum e Glomus etunicatum), isolados de pomares de pessegueiros, no crescimento vegetativo, absorção de nutrientes e acúmulo de substâncias de reserva, de plantas do porta-enxerto de pessegueiro cv. Okinawa (Prunus persica (L.) Batsch). O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições por tratamento e 15 plantas por parcela. As plantas que foram inoculadas com G. etunicatum apresentaram maior altura, diâmetro de caule, área foliar, biomassa fresca e seca da parte aérea, total de nutrientes absorvidos e substâncias de reserva acumuladas, enquanto as inoculadas com G. clarum apresentaram crescimento intermediário, superior às inoculadas com G. margarita, que apresentaram resultados semelhantes às plantas não inoculadas. O desempenho foi relacionado com as taxas de colonização das raízes que, nas plantas inoculadas com G. etunicatum e G. clarum, foram de 93 e 91%, respectivamente, enquanto, nas com G. margarita foi somente de 37%.

Selection of arbuscular mycorrhizal fungi for citrus growth promotion and Phytophthora suppression

In order to reduce unnecessary amount of P-fertilizer and severity of Phytophthora root rot in citrus orchards, the experiment was set up. Thirteen indigenous arbuscular mycorrhiza (AM) fungi species were isolated from rhizosphere soil of citrus orchards in Thailand and were then propagated into three host plants [sorghum ( Sorghum bicolor), maize ( Zea mays), and leek ( Allium cepa)] by trap culture. We also tested whether indigenous AMF species (13 different species) could colonize into three cultivars of citrus scions and rootstocks (Shogun: Citrus reticulata Blanco cv. Shogun; Tangerine: C. reticulata; and C-35 citrange: Citrus sinensis × Poncirus trifoliata). With root colonization rates, the results indicated that Acaulospora tuberculata and Glomus etunicatum provided the best colonization in all citrus cultivars. We selected, therefore, those AMF species to verify their influences on citrus growth and Phytophthora root rot resistance. Three cultivars of citrus scions and rootstocks, Shogun, Tangerine and C-35 citrange, were inoculated with two effective indigenous AMF species, G. etunicatum or A. tuberculata in order to determine the influences on citrus growth. The plants were investigated to determine the mycorrhizal efficiency index (MEI), AM colonization, P content, and other parameters. Co-inoculation of AMF species ( G. etunicatum or A. tuberculata) with Phytophthora nicotianae was also carried out in Shogun scion/C-35 citrange rootstocks. The results of citrus growth revealed that Shogun and Tangerine inoculated with G. etunicatum produced the highest MEI. Tangerine and C-35 citrange amended with fertilizers and G. etunicatum showed the highest P content in leaves. This indicated that G. etunicatum has an influence on citrus growth and P uptake, suggesting it to be the highly effective strain. Shogun scion/C-35 citrange rootstock combinations that were inoculated by both P. nicotianae and different AM fungi ( G. etunicatum or A. tuberculata) showed root injury at low level of root rot symptom. However, the part of Shogun scions grafted on rootstocks showed severe symptom of shoot die back in treatment inoculated with P. nicotianae alone, while treatment inoculated with different AM species ( G. etunicatum or A. tuberculata) and P. nicotianae rendered lower shoot die back symptoms than that of Phytophthora treatment. The low level of shoot die back symptom was shown at first, then healthy young shoot was restored. Our results indicated the facts that different host plants and different AMF species produced different outcomes of growth and pathogen resistance. The application of both AM isolates, therefore, has an enormous potential to be produced the inoculum for citrus orchards.

Spatio-temporal dynamics of an indigenous arbuscular mycorrhizal fungal community in an intensively managed maize agroecosystem in North China

The temporal and spatial dynamics of arbuscular mycorrhizal fungal (AMF) spore communities and biomass were studied in an intensively managed maize agroecosystem located in the North China Plain, one of the most important regions for cereal production in China. Maize roots and soils from three depths (0–30, 30–60 and 60–90 cm) were sampled in conventional agricultural management (CAM) and recommended agricultural management (RAM) systems at V6 (six leaf collar), V12 (twelve leaf collar), R1 (silking) and R6 (physiological maturity) stage of maize. The dynamics of percent root colonization by AMF, extra-radical hyphal length density (HLD), AMF fatty acid biomarkers (C16:1w5 and C18:1w7) and spore density were analyzed. AMF spore species were identified according to their morphological characteristics. Maize roots were rapidly and heavily colonized by arbuscular mycorrhizal (AM) fungi even under intensive agricultural management. The abundance of arbuscules and hyphal coils within maize roots peaked during early reproductive growth suggesting a period of high P demand by maize. This was preceded by increased concentration of the AMF biomarker C16:1w5 in the soil at the V12 growth stage, and led to a peak in soil HLD at R1. Twenty seven AMF species belonging to five genera were isolated in total, and dominant species such as Glomus aggregatum, Glomus claroideum, Glomus etunicatum, Glomus geosporum and Glomus mosseae occurred widely across growth stage, soil depth and management system. Rare species occurred mainly at a particular growth stage or soil depth. The effects of growth stage, soil depth and management system on spore relative abundance differed among AMF species. The highest species richness and diversity occurred at the R1 stage and may stem from increased C supply to the fungus during peak arbuscular development within the roots. The AMF community and biomass were mainly affected by soil depth and growth stage rather than agroecosystem management. The abundance of AMF biomass and species found deep in the soil profile highlights the potential for P uptake by AMF from lower soil depths under intensive maize management.

INFLUENCE OF ARBUSCULAR MYCORRHIZAL FUNGI AND AMMONIUM:NITRATE RATIOS ON GROWTH AND PUNGENCY OF SPRING ONION PLANTS

A pot experiment was carried out to study the growth and pungency of Allium fisutulosum grown in Perlite as affected by colonization by the arbuscular mycorrhizal (AM) fungi Glomus etunicatum, Glomus vesiforme, and by ammonium (NH+ 4 ):nitrate (NO− 3 ) ratios of 5:95, 50:50, and 95:5 in 4 mM solutions. Plants were grown in a greenhouse for 20 weeks and then harvested. In general, NH+ 4 :NO− 3 ratio of 50:50 supplied resulted in the highest shoot dry weight regardless of non-mycorrhizal and mycorrhizal plants while the effect of inoculation treatment on plant biomass was not significant. The plant sulfur (S) concentrations were usually higher in mycorrhizal plants than controls irrespective of nitrogen ratio and therefore inoculation with G. etunicatum increased the enzyme produced pyruvic acid (EPY) while inoculation with G. versiforme decreased the EPY compared with the non-mycorrhizal plants. In general, shoot pungency was lowest when NH+ 4 :NO− 3 ratio of 95:5 supplied irrespective of mycorrhizal treatment. Colonization by both AM fungi made a substantial contribution to spring onion sulfur nutrient status but show different way on flavor characteristics of host plants.

Effect of nitrogen on the sporulation of arbuscular mycorrhizal fungi colonizing several gramineous plant species

We examined the effect of nitrogen on sporulation of arbuscular mycorrhizal (AM) fungi colonizing gramineous plant species growing in a volcanic deposit with a nitrogen deficit. Five gramineous species (Saccharum spontaneum, Rhynchelytrum repens, Miscanthus sinensis, Paspalum notatum, and Eragrostis curvula) growing in a volcanic deposit on Mount Fugendake, Japan, were inoculated with the AM fungus Glomus etunicatum with or without the application of nitrate nitrogen (20 mg N kg soil–1). The AM dependent species (M. sinensis and P. notatum) which showed growth response to the inoculation increased sporulation with nitrogen addition. However, the species that did not depend on AM for their growth (S. spontaneum and E. curvula) showed decreased or non-increased sporulation with nitrogen application. This trend was also found for Glomus etunicatum in a dual-inoculation experiment with Glomus etunicatum and Gigaspora margarita. These indicate that the effect of nitrogen on the sporulation of AM fungi differed among gramineous species and that in some species nitrogen may suppress the sporulation.

Infection by Mycorrhizal Fungi Increases Natural Enemy Abundance on Tobacco (Nicotiana rustica)

The presence of arbuscular mycorrhizal fungi (AMF) influences plant nutrient uptake, growth, and plant defensive chemistry, thereby directly influencing multi-trophic interactions. Different fungal isolates (genotypes of the same fungal species) have been shown to differ in nutrient uptake ability. Plants infected with different AMF genotypes may vary in foliar nutrient or defensive chemical levels, potentially influencing multi-trophic interactions. Using a completely randomized design, we compared the effect of two isolates of the mycorrhizal fungus Glomus etunicatum W. N. Becker & Gerdemann on silver leaf whitefly (Bemisia argentifolii Bellows & Perring) (Hemiptera: Aleyrodidae) and parasitic wasp (Eretmocerus eremicus Rose & Zolnerowich) (Hymenoptera: Aphelinidae) abundance. Whitefly populations were not influenced by AMF infection. Parasite populations were higher on plants infected with the isolate collected from Georgia, even after controlling for whitefly abundance and plant architecture. We propose that AMF indirectly influences parasite abundance and parasitism through a change in leaf surface chemicals that affect parasitic wasps. Because of the ubiquity of and genetic variation in AMF, multi-trophic interactions are likely to be strongly influenced by belowground processes.

Fungos micorrízicos arbusculares (FMA) em porta-enxertos micropropagados de videira

O uso de fungos micorrízicos na produção de mudas de videira é importante alternativa para acelerar o desenvolvimento inicial das plantas. Este trabalho teve por objetivo avaliar o comportamento de dois FMA sobre o crescimento vegetativo de três porta-enxertos (PE) de videira. Foram utilizados os FMA Glomus etunicatum e Scutellospora heterogama e os PE SO4, Paulsen 1103 e 043-43. Os PE, oriundos de micropropagação, foram transferidos e aclimatizados em copos plásticos de 300 mL e após 58 dias transplantados para sacos plásticos de 2 L de capacidade, contendo como substrato uma mistura de casca de arroz carbonizada e Plantmax® na proporção de 1:1 v/v. Utilizaram-se, como inóculo, 20 g de solo rizosférico mais fragmentos de raízes contendo as estruturas dos FMA, adicionados ao substrato na fase de aclimatização. Aos 135 dias após inoculação, foram avaliadas as massas de matéria fresca e seca das raízes e parte aérea, comprimento de raízes e parte aérea, diâmetro de colo e teores de nutrientes da parte aérea. Os FMA Glomus etunicatum e Scutellospora heterogama proporcionaram melhor nutrição e maior crescimento vegetativo dos porta-enxertos de videira, se comparadas as plantas testemunhas. Os benefícios oriundos da simbiose dependeram da combinação específica entre o isolado fúngico e a variedade de porta-enxerto utilizada, sendo o 043-43 beneficiado preponderantemente pelo FMA Glomus etunicatun e o SO4 e Paulsen 1103 por Glomus etunicatum e Scutellospora heterogama.

Inoculação micorrízica no crescimento de mudas de angico em solo de cerrado

O objetivo desse estudo foi avaliar o crescimento de mudas de Angico [Anadenanthera macrocarpa (Benth.) Brenan] sob o efeito da inoculação de fungos micorrízicos arbusculares (FMAs) em solo preservado e antropizado. O experimento foi desenvolvido em casa de vegetação, no período de janeiro a setembro de 2006. O arranjo experimental foi em delineamento inteiramente casualizado, em esquema fatorial de 2 x 4, sendo dois tipos de solo (preservado ou antropizado) em quatro tratamentos distintos de inoculação micorrízica sendo (1) Solo esterilizado submetido à inoculação com a mistura Glomus etunicatum + Paraglomus brasilianum; (2) Solo esterilizado submetido à inoculação com a mistura Glomus etunicatum + Gigaspora margarita; (3) Solo esterilizado não inoculado (controle) (4) Solo natural (não esterilizado e não inoculado), com cinco repetições. Foram avaliados o crescimento em altura a cada 15 dias e, aos 150 dias, a área foliar, matéria seca da parte aérea e das raízes, comprimento de raízes, teores de nutrientes da parte aérea e colonização micorrízica. Melhor crescimento das mudas de angico foi observado no tratamento com solo esterilizado e inoculado com a mistura de G. margarita e G. etunicatum, o qual refletiu em aumento da área foliar, matéria seca da parte aérea e das raízes, assim como maior comprimento de raízes e colonização micorrízica, tanto no solo da área preservada quanto no da antropizada.

Triple inoculation with Bradyrhizobium, Glomus and Paenibacillus on cowpea (Vigna unguiculata [L.] walp.) development.

The use of microorganisms to improve the availability of nutrients to plants is of great importance to agriculture. This study aimed to evaluate the effect of triple inoculation of cowpea with arbuscular mycorrhizal fungi (AMF), plant growth-promoting bacteria (PGPB) and rhizobia to maximize biological nitrogen fixation (BNF) and promote plant growth. The experiment was conducted in a greenhouse using cowpea plants (Vigna unguiculata L. Walp cv. IPA 206). The treatments included inoculation with strains of Bradyrhizobium sp. (BR 3267 and EI – 6) individually and as a mixture, an absolute control (AC) and mineral nitrogen control (NC), all combined with the presence or absence of native AMF (Glomus etunicatum) and PGPB (Paenibacillus brasilensis - 24) in a 5x2x2 factorial design. All treatments were replicated three times. Contrasts were performed to study the treatment of variables. Inoculation with Bradyrhizobium sp. (BR 3267 and EI – 6) and G. etunicatum favored nitrogen acquisition and phosphorus availability for the cowpea plants. Inoculation with P. brasilensis – 24 increased colonization by Bradyrhizobium sp. and G. etunicatum and promoted cowpea growth, while the nitrogen from symbiosis was sufficient to supply the plants nutritional needs.