Arbuscular mycorrhizal fungi associated with the babassu palm (Attalea speciosa) in the eastern periphery of Amazonia, Brazil / Fungos micorrízicos arbusculares associados com a palmeira babaçu (Attalea speciosa) na periferia leste da Amazônia, Brasil

Babassu, Attalea speciosa (Arecaceae) is a ruderal palm native to Amazonia, which turned dominant in frequently burned lands throughout the arc of deforestation and other degraded lands, in extreme cases attaining complete dominance. This study investigated arbuscular mycorrhizal fungi (AMF) as one possible explanation for the outstanding ecological success of this exceptional palm. We explored the relationships between the babassu palm and native arbuscular mycorrhizal fungi and babassu effects on the AMF richness and mycorrhizal inoculum potential (MIP) in the eastern periphery of Amazonia. For this purpose, we sampled topsoil (0-20 cm) at the onset of the rainy season from a 5-year-old secondary forest regrowth (SEC) area with three levels of babassu dominance (sites with 10, 50 and 70% babassu biomass shares), and at three distances (0, 2.5 and 4 m) from isolated babassu patches within a degraded pasture (PAS), both with five replications per treatment. Glomerospore density varied from 100 to 302 per gram of soil, 56% higher in SEC than PAS. We identified a total of 16 AMF species, with dominance of Acaulospora (six species) followed by Glomus (three species). AMF richness increased with babassu dominance in SEC sites, and reduced with distance from babassu patches within the PAS. The colonization rate of babassu roots was higher in SEC than in PAS, whereas MIP was similar in both areas and without treatment differences. Our study points to strong mycorrhizal association of the babassu palm as a potential mechanism for its outstanding ecological success in degraded lands.

Babaçu, Attalea speciosa (Arecaceae) é uma palmeira ruderal nativa da Amazônia, dominante em terras frequentemente queimadas ao longo do arco de desmatamento e outras áreas degradadas, em casos extremos atingindo domínio completo. Este estudo investigou os fungos micorrízicos arbusculares (FMA) como possível explicação do sucesso ecológico desta palmeira. Nós exploramos as relações entre o babaçu e glomerosporos, efeitos do babaçu na riqueza destes fungos e o potencial do inóculo micorrízico (PIM) na periferia oriental da Amazônia. Amostras de solo (0-20 cm) foram coletadas no início da estação chuvosa em uma área de floresta secundária (SEC) de cinco anos de idade e três níveis de dominância do babaçu (10, 50 e 70% de biomassa de babaçu) e a três distâncias (0; 2,5 e 4 m) de ilhas de babaçu isoladas em uma pastagem degradada (PAS), ambas com cinco repetições por tratamento. A densidade de esporos de FMA variou de 100 a 302 por grama de solo, sendo 56% maior em SEC do que em PAS. Dezesseis espécies de FMA foram identificadas, com predominância de Acaulospora (seis espécies) seguidos do gênero Glomus (três espécies). A riqueza destes fungos aumentou com o domínio da palmeira em SEC e reduziu com a distância das ilhas de babaçu em PAS. A taxa de colonização das raízes de babaçu foi superior nas áreas de SEC enquanto o PIM não apresentou diferenças entre os tratamentos. Nosso estudo aponta a uma forte associação micorrhízica da palmeira babaçu, um possível mecanismo central no seu sucesso ecológico em áreas degradadas.

Diversity and growth-effects of ectomycorrhizal fungi of a Nothofagus pumilio forest in the Andes of Southern Chile / (Diversidad y efectos de crecimiento de hongos ectomicorrízicos en un bosque de Nothofagus pumilio en los andes del sur de Chile

Chilean temperate rainforests have unique climatic, edaphic and biotic conditions, constituting pre-industrial blueprint ecosystems. Mycorrhizal associations play a central role in the biogeochemical processes of these ecosystems´ functioning. Baseline forest ecology studies are necessary in order to better understand diversity patterns, specifically regarding mycorrhizal symbiosis. Therefore, here we describe the vegetation characteristics and the mycorrhizal relationships of vascular plants in a Nothofagus pumilio forest. We also describe, via morphological methods, the ectomycorrhizal diversity present in this forest. Additionally, we determined whether ectomycorrhizal inoculation confers positive growth effects on N. pumilio seedlings. We found that from 46 vascular plant species identified in this study, 42 (91%) were mycorrhizal and of these 33 (72%) were associated with arbuscular mycorrhizae (AM), two (the dominant trees N. pumilio and N. dombeyi) were forming ectomycorrhizae (EM), five were associated with ericoid mycorrhizae, two with orchid mycorrhizae, and four were nonmycorrhizal. Additionally, 26 EM species were detected of which 15 belong to Cortinarius. Finally, there were clear differences in the growth of N. pumilio seedlings inoculated with the ectomycorrhizal fungus Laccaria laccata compared to noninoculated plants. We suggest that mycorrhizal fungi play a key role in seedling colonization of harsh environments such as the Andean treeline.

Los bosques templados lluviosos de Chile tienen condiciones climáticas, edáficas y bióticas únicas, constituyendo ecosistemas preindustriales modelo. Las asociaciones micorrízicas juegan un rol central en los procesos biogeoquímicos del funcionamiento de estos ecosistemas. Por lo tanto, en este estudio describimos las características de la vegetación y las relaciones micorrízicas de las plantas vasculares de un bosque de Nothofagus pumilio. También describimos, vía métodos morfológicos, la diversidad ectomicorrízica presente en este bosque. Adicionalmente, determinamos si inoculaciones ectomicorrízicas confieren efectos de crecimiento positivos a semilleros de N. pumilio. Encontramos que, de 46 especies de plantas vasculares identificadas en este estudio, 42 (91%) son micorrízicas, y de estas, 33 (72%) están formando micorrizas arbusculares (AM), dos (los árboles dominantes N. pumilio y N. dombeyi) están asociados con ectomicorrizas (EM), cinco están asociadas con micorrizas ericoides, dos con micorrizas orquioides, y cuatro fueron nomicorrizadas. Adicionalmente, 26 especies de EM fueron detectadas, de las cuales 15 pertenecen a Cortinarius. Finalmente, hubo claras diferencias en el crecimiento de los semilleros de N. pumilio inoculados con el hongo ectomicorrízico Laccaria laccata, comparados a plantas no inoculadas. Sugerimos que los hongos micorrízicos juegan un rol clave en la colonización de ambientes severos por juveniles, como en el límite altitudinal andino.

Crescimento de Ruta graveolens l. Inoculada com micorrizas sob doses de fósforo / Growth of Ruta graveolens l. Inoculated with arbuscular mycorrhizal fungi under levels of phosphorus / Crecimiento del Ruta graveolens l. Inoculada con micorrizas bajo dosis de fósforo

Os fungos micorrízicos arbusculares (FMAs) são micro-organismos que fazem simbiose com raízes da maioria das plantas. O objetivo deste trabalho foi avaliar a influência dos FMAs Rhizophagus clarus e Claroideoglomus etunicatum em substrato sob baixa e ou alta dose de fósforo (P), na produção de biomassa e na acumulação de P na arruda (Ruta graveolens L.). O experimento foi conduzido no laboratório de botânica da Universidade Paranaense - UNIPAR, município de Umuarama - PR. O delineamento experimental foi inteiramente ao acaso, em fatorial 3x2, sendo os fatores: FMAs (sem FMA, com R. clarus e ou com C. etunicatum); duas doses de P (20 e 200 mg kg-1) com 8 repetições por tratamento, num total de 48 unidades experimentais (vasos de 3 L). Avaliou-se a produção de massa seca das raízes (MSR), massa seca da parte aérea (MSPA), massa seca total (MST) e o acúmulo de P na parte aérea da planta (PPA). A produção de MSR, MSPA e MST pela planta não foram significativamente afetadas apenas pela adição de P ao substrato, porém sim, pela inoculação com o FMA C. etunicatum, sob baixo e ou alto P. O acúmulo de P na parte aérea da planta foi aumentado significativamente no tratamento sem a inoculação com FMAs. Conclui-se que a inoculação com C. etunicatum é indicada para aumentar a produtividade da arruda.(AU)

Arbuscular mycorrhizal fungi (AMF) are microorganisms that present symbiosis with the roots of most plants. The purpose of this work was to evaluate the influence of AMF Rhizophagus clarus and Claroideoglomus etunicatum on low and high doses of phosphorus (P) on plant biomass and P accumulation in rue (Ruta graveolens L.). The experiment was performed in the botanical laboratory at Universidade Paranaense ­ UNIPAR in the city of Umuarama, in the state of Paraná, Brazil. It used a completely randomized 3x2 experimental design, being: AMFs (without AMF, with R. clarus and/or with C. etunicatum); two levels of P (20 and 200 mg kg-1) with 8 repetitions per treatment, totaling 48 experimental units (3 L pots). Root dry matter (RDM), shoot dry matter (SDM), total dry matter (TDM) and P accumulation in the aerial part of the plant were evaluated. The production of RDM, SDM and TDM by the plant was not significantly affected by the addition of P to the substrate, but by the inoculation with AMF C. etunicatum under low and/or high P. The accumulation of P in the aerial part of the plant significantly increased in the treatment without AMF inoculation. It was concluded that inoculation with C. etunicatum is indicated to increase the productivity of rue.(AU)

Los hongos micorrícicos arbusculares (HMA) son microorganismos que forman simbiosis con las raíces de la mayoría de las plantas. El objetivo de este estudio fue evaluar la influencia del HMA Rhizophagus clarus y Claroideoglomus etunicatum en substrato so baja y/o alta dosis de fósforo (P), en la producción de biomasa y en la acumulación de P en la ruda (Ruta graveolens L.). El experimento se llevó a cabo en el laboratorio de botánica de la Universidad Paranaense - Unipar, municipio de Umuarama - PR. El diseño experimental fue completamente al azar, en un 3x2 factorial, con los factores: HMA (Sin HMA, con R. clarus y C. etunicatum); dos dosis de P (20 y 200 mg kg-1) con 8 repeticiones por tratamiento de un total de 48 unidades experimentales (vasos de 3 L). Se evaluó la producción de materia seca de las raíces (MSR), materia seca de la parte aérea (MSPA), materia seca total (MST) y la acumulación de P en la parte aérea de la planta (PPA). La producción de MSR, MSPA y MST por la planta no se vieron afectados significativamente sólo mediante la adición de P al sustrato, sino por inoculación con HMA C. etunicatum so bajo y/o alto P. El acúmulo de P en parte aérea de la planta se incrementó significativamente en el tratamiento sin inoculación con HMA. Se concluye que la inoculación con C. etunicatum está indicada para aumentar la productividad de la ruda.(AU)

Production of native arbuscular mycorrhizal fungi inoculum under different environmental conditions

Abstract In order to obtain an arbuscular mycorrhizal fungi (AMF) native inoculum from Sierra de Moa and determine the most appropriate conditions for its big scale production, four light and temperature combinations were tested in three plant species (Calophyllum antillanum, Talipariti elatum and Paspalum notatum). Growth and development parameters, as well as the mycorrhizal functioning of the seedlings were evaluated. The natural light treatment under high temperatures (L-H) was the most suitable for the growth and development of the three plant species, showing the highest total biomass values, mainly of root, and a positive root-shoot ratio balance. This treatment also promoted higher values of root mycorrhizal colonization, external mycelium and AMF spore density. A total of 38 AMF species were identified among the plants and environmental conditions tested. Archaeospora sp.1, Glomus sp.5, Glomus brohultii and G. glomerulatum were observed in all the treatments. The L-H condition can be recommended for native inoculum production, as it promotes a better expression of the AM symbiosis and an elevated production of mycorrhizal propagules.

Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd. ) Poir from Brazilian semi-arid

Abstract Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a) during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b) soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites.

Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil

Abstract High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis) and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM), height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels.

Functionality of arbuscular mycorrhizal fungi in three plant communities in the Managed Floristic Reserve San Ubaldo-Sabanalamar, Cuba / Funcionalidad de hongos micorrízicos arbusculares en tres comunidades vegetales de la Reserva Florística Manejada de San Ubaldo-Sabanalamar, Cuba

Despite the ubiquity and importance of indigenous arbuscular mycorrhizal fungi (AMF) for plant ecosystems; functioning of indigenus mycorrhizal symbiosis (IMS) and related environmental factors at coastal Caribbean ecosystems remains still scarce. In order to determine functionality of IMS under contrasting land uses and wet seasons from Cuba, the influence of the water stress on some AMF functionality parameters from a semi-natural savannah (NS), a recovered savannah (RS) and an agro-ecosystem (AG) from the Managed Floristic Reserve San Ubaldo-Sabanalamar, Pinar del Rio, Cuba were assessed during two-years. Soil and root samples were collected in April and October, during the dry and wet seasons, respectively, in 2008 and 2010. Four plots in each ecosystem were selected, and five soil sub-samples were randomly collected, bulked, mixed homogeneously and used as the composite sample per plot. The host plant root biomass, arbuscular mycorrhizal colonization of the host plant, density of the intraradical and extraradical AMF mycelia, fungal endophyte biomass and AMF spore density were assessed. The host plant root biomass increased in the NS environment during the dry season, and approximately 12.85g root/dm³ dry soil was recorded. The colonization degree were significantly higher in all environments during the wet season of the second year, with means ranging from 79% to 89%. The extraradical mycelia were significantly more abundant in the dry season of the second year in all environments, with a maximum of 279mg/dm³ in the RS ecosystem. The density of AMF spores was highest in the dry season of the second year for the three studied ecosystems. The RS ecosystem hosted 5 670 spores/100g dry soil. In general, the influence of rainfall seasonality on the function of AMF was stronger than the influence of ecosystem management. The root biomass and extraradical mycelia were high in the dry seasons, suggesting strategies to increase the volume of soil for the mutual benefit of the symbionts. The increase in spore density during the dry seasons appears as an adaptation allowing AMF to survive period of water shortage. This study improves our understanding of the adaptative responses of arbuscular mycorrhizal symbiosis to seasonal variations in soil water availability. Rev. Biol. Trop. 63 (2): 341-356. Epub 2015 June 01.

En el presente estudio se evaluó, durante dos años, la influencia de los períodos seco y lluvioso sobre el funcionamiento de hongos formadores de micorrizas arbusculares (HFMA) simbiontes de plantas nativas de una sabana semi natural, una sabana recuperada de la actividad agrícola y un agroecosistema, ubicados en la Reserva Florística Manejada San Ubaldo-Sabanalamar, Pinar del Río, Cuba. Se recolectaron muestras de suelo en abril y octubre (período seco y húmedo de 2008 y 2010, respectivamente). Dentro de cada ecosistema se seleccionaron cuatro parcelas y se recolectaron cinco submuestras al azar, las que fueron homogeneizadas para formar una muestra compuesta por parcela. Se cuantificó la biomasa de raicillas, la colonización micorrízica de las plantas hospedadoras en el campo, el micelio extrarradical, el micelio endófito y la densidad de esporas. La biomasa de raicillas en la sabana semi natural incrementó durante los períodos secos, la cual alcanzó hasta 12.85 g/dm3 de suelo. En todos los ecosistemas, la mayor colonización micorrízica ocurrió en la época lluviosa del segundo año con valores que oscilaron entre 79 y 89 %. Las mayores biomasas de micelio externo fueron registradas en los tres ecosistemas durante el período seco del segundo año, con un valor máximo de 279 mg/dm3 de suelo en la sabana recuperada. La mayor densidad de esporas de HFMA fue determinada en el periodo seco del segundo año para los tres ecosistemas estudiados, con el valor más alto en la sabana recuperada con 5 670 esporas/100 g de suelo seco. De manera general, se evidenció un efecto de la estacionalidad de la lluvia más que del manejo de ecosistema sobre el funcionamiento de los HFMA. La mayor actividad colonizadora se evidenció en períodos húmedos, mientras que mayor biomasa de raicillas y micelio externo durante los períodos secos, lo que sugiere estrategias de incremento del volumen del suelo explorado por parte de los HFMA como de las plantas hospedadoras. La proliferación de esporas evidenció la formación de estructuras de resistencia de los HFMA ante condiciones adversas. Los resultados obtenidos pondrían en evidencia la plasticidad de la simbiosis micorrízica ante variaciones en la disponibilidad de agua.

Mycorrhizal fungi isolated from native terrestrial orchids of pristine regions in Córdoba (Argentina) / Hongos micorrízicos aislados de orquídeas terrestres nativas de regiones pristinas en Córdoba (Argentina)

Orchidaceae is a highly dependent group on the Rhizoctonia complex that includes Ceratorhiza, Moniliopsis, Epulorhiza and Rhizoctonia, for seed germination and the development of new orchid plants. Thus, the isolation and identification of orchid mycorrhizal fungi are important to understand the orchid-fungus relationship, which can lead to the development of efficient conservation strategies by in vivo germination of seeds from endangered orchid plants. The aim of our work was to isolate and characterize the different mycorrhizal fungi found in roots of terrestrial orchids from Córdoba (Argentina), and, to learn about the natural habit and fungal associations in the Chaco Serrano woodland pristine region. In this study, bloomed orchid root and rhizosphere soil samples were obtained in two times from Valle de Punilla during spring of 2007; samples were kept in plastic bags until processed within 48 hours, and mycorrhizal condition confirmed assessing peloton presence. A total of 23 isolates of the orchideous mycorrhizal Rhizoctonia complex were obtained. The isolates were studied based on morphological characters and ITS-rDNA sequences. Morphological characteristics as color of colonies, texture, growth rate, hyphal diameter and length and presence of sclerotia were observed on culture media. To define the number of nuclei per cell, the isolates were grown in Petri dishes containing water-agar (WA) for three days at 25°C and stained with Safranine-O solution. The mycorrhizal fungi were grouped into binucleate (MSGib, 10 isolates) and multinucleate (MSGim, 13 isolates) based on morphological characteristics of the colonies. We obtained the ITS1-5.8s-ITS4 region that was amplified using primers ITS1 and ITS4. Based on DNA sequencing, isolates Q23 and Q29 were found to be related to species of Ceratobasidium. Isolates Q24 and Q4 were related to the binucleated anastomosis group AG-C of Rhizoctonia sp. The rest of the isolates grouped in the Ceratobasidium clade without grouping. From our knowledge this is the first report of the association of the AG-C testers with terrestrial orchids. A high specificity was observed in the symbiotic relationship. As the mycorrhizal fungal isolates were obtained from native orchids, they could be incorporated in conservation programes of endangered orchids in Argentina.

La Familia Orchidaceae se encuentra estrechamente relacionada con hongos micorrízicos que pertenecen al complejo Rhizoctonia, e incluyen los géneros Ceratorhiza, Moniliopsis, Epulorhiza y Rhizoctonia. Esta asociación es esencial para el desarrollo de nuevas plantas ya que favorecen el proceso de germinación de las semillas. Por lo tanto, el conocimiento de la naturaleza de esta interacción es importante para que los resultados de los programas de conservación de orquídeas sean efectivos. La fragmentación del bosque Chaqueño Serrano en el centro de Argentina, ha alcanzado un punto crítico en los últimos años, afectando el funcionamiento del ecosistema. El objetivo de este trabajo fue: a) aislar y caracterizar hongos micorrízicos presentes en orquídeas terrestres de la provincia de Córdoba (Argentina) y b) conocer el hábitat natural y las asociaciones fúngicas que se establecen en esta región prístina. A partir de las raíces de orquídeas terrestres, se obtuvieron 23 aislamientos de hongos micorrízicos que pertenecen al complejo Rhizoctonia. Estos aislamientos fueron caracterizados con base en caracteres morfológicos y moleculares. Las características morfológicas (color y textura de las colonias, cinética de crecimiento, diámetro y largo de la hifa y presencia de esclerocios) fueron observados en PDA y MEA a 25ºC. El número de núcleos por célula se observó en cultivos crecidos en AA (agar-agua) y teñidos con una solución de Safranine-O. La región ITS se amplificó usando los primers ITS1 e ITS4. Con base en las características morfológicas de la colonia, los aislamientos fueron agrupados en binucleados (MSGib) y multinucleados (MSGim). De acuerdo al cladograma obtenido con las secuencias de ADN, los aislamientos Q23 y Q29 están relacionados a especies de Ceratobasidium, aisladas de raíces de orquídeas. Los aislamientos Q24 y Q4 se asocian con el grupo de anastomosis de Rhizoctonia AG-C. Finalmente, se observó una alta variabilidad en el grado de especificidad existente en la simbiosis que se establece entre las raíces de estas orquídeas terrestres y los aislamientos obtenidos a partir de ellas. Este es el primer reporte de la asociación entre el grupo de anastomosis AG-C y orquídeas terrestres. Dado que estos aislamientos se obtuvieron de orquídeas terrestres nativas, podrían ser incorporados como nuevos patrones para micorrizas de orquídeas terrestres en Argentina. Este trabajo contribuye al conocimiento de la relación simbiótica que se establece entre orquídeas y hongos micorrízicos, así como también al desarrollo de estrategias de conservación de orquídeas terrestres nativas del bosque Chaco Serrano.

Optimization of the production of mycorrhizal inoculum on substrate with organic fertilizer

The system for production of inoculum of arbuscular mycorrhizal fungi (AMF) using sand and vermiculite irrigated with nutrient solution is promising. However, organic amendments added to the substrate can stimulate sporulation of AMF and replace the nutrient solution. The aim of this study was to maximize the production of AMF (Acaulospora longula, Claroideoglomus etunicatum, Dentiscutata heterogama and Gigaspora albida) using selected organic substrates (vermicompost, coir dust and Tropstrato) together with sand and vermiculite. The production of spores varied among the tested AMF and according to the organic source added to the substrate. The vermicompost promoted higher sporulation of A. longula in relation to the other AMF and substrates. The Tropstrato® inhibited the sporulation of D. heterogama while the reproduction of C. etunicatum was not affected by the organic compounds. The inoculum of A. longula also showed a high number of infective propagules and promoted biomass accumulation in maize plants. The system of inoculum production using sand and vermiculite + 10% vermicompost favors the production of infective inoculum of A. longula with the fungus benefiting growth of corn plants.

Eucalyptus grandis Hill ex Maiden inoculated with Pisolithus microcarpus (UFSC-Pt116) in land subject to the sandy process in southern Brazil

Eucalypts is one of the main species used for commercial reforestation in the state of Rio Grande do Sul, Brazil. This study aimed to evaluate the survival and early growth of eucalyptus trees in an area subject to sandy process after three years of growth. The Eucalyptus grandis seedlings were grown in a greenhouse, innoculated or not with the isolated ectomycorrhizal Pisolithus microcarpus (UFSC-Pt116), produced in peat or Entisol. After 120 days, the seedlings were transplanted to an area subject to the sandy process, in the city of São Francisco de Assis, RS. The plants have been evaluated regarding survival, height, stem diameter, nitrogen, phosphorus and potassium levels and total phosphorus, inorganic phosphorus, organic phosphorus and wood production on different days after planting. The seedlings grown on the Entisol which was inoculated with the isolated UFSC-Pt116 presented higher survival rates, height, stem diameter, nitrogen concentration and wood production compared to the non-inoculated seedlings. Inoculation with ectomycorrhizal fungi enhanced the production of E. grandis seedlings in survival rates, height, stem diameter.

Early changes in arbuscular mycorrhiza development in sugarcane under two harvest management systems

Sugarcane (Saccharum spp.) is grown on over 8 million ha in Brazil and is used to produce ethanol and sugar. Some sugarcane fields are burned to facilitate harvesting, which can affect the soil microbial community. However, whether sugarcane pre-harvest burning affects the community of arbuscular mycorrhizal fungi (AMF) and symbioses development is not known. In this study, we investigated the early impacts of harvest management on AMF spore communities and root colonization in three sugarcane varieties, under two harvest management systems (no-burning and pre-harvest burning). Soil and root samples were collected in the field after the first harvest of sugarcane varieties SP813250, SP801842, and RB72454, and AMF species were identified based on spore morphology. Diversity indices were determined based on spore populations and root colonization determined as an indicator of symbioses development. Based on the diversity indices, spore number and species occurrence in soil, no significant differences were observed among the AMF communities, regardless of harvest management type, sugarcane variety or interactions between harvest management type and sugarcane variety. However, mycorrhiza development was stimulated in sugarcane under the no-burning management system. Our data suggest that the sugarcane harvest management system may cause early changes in arbuscular mycorrhiza development.

Fungos micorrízicos arbusculares, biomassa e atividade microbiana de solo sob banana, braquiária e degradado / Abuscular mycorrhizal fungi, microbial soil biomass and activity under banana, brachiaria and degraded soil / Hongos micorrízicos arbusculares, actividad y biomasa microbiana en suelo cultivado con banana, brachiaria y degradado

O uso e manejo adequado do solo podem ser medidos por meio de bio-indicadores de qualidade do solo. Os objetivos deste trabalho foram determinar a densidade de esporos de fungos micorrízicos arbusculares (FMAs), carbono da biomassa microbiana do solo (C-BMS), respiração basal do solo (RBS) e quociente metabólico (qCO2) de áreas com cultivo orgânico com banana e com braquiária sem pastejo, comparativamente com uma área próxima degradada com palmeiras imperiais em Umuarama, PR. O solo foi coletado na profundidade de 0-10 cm com 4 repetições em cada área e analisadas em duplicata no laboratório. Os resultados foram submetidos à análise de variância (ANOVA) e teste de Tukey (p ? 0,05), usando o programa SPSS v.16. A densidade de esporos de FMAs foi significantemente menor na área degrada. O C-BMS foi significantemente maior na área com braquiária, comparativamente com o solo cultivado com banana e degradado. Na área com banana o C-BMS foi maior que na área degradada. A análise química do solo revelou na área degradada apresentou baixo teor de fósforo, carbono, cálcio e potássio, o que pode ter contribuído para o baixo C-BMS, devido ao estresse elevado neste solo. Não houve diferença significativa na RBS entre as áreas, mas o qCO2 foi significantemente maior no solo degradado, indicando novamente um nível de estresse elevado neste solo. Manejo e uso adequado do solo como o cultivo orgânico de bananas e/ou braquiária aumentou a densidade de esporos de FMAs e C-BMS, além disso, diminuiu o qCO2 comparado com a área degradada.(AU)

The sustainable use and management of soil can be measured using soil quality bioindicators. The objectives of this study were to determine arbuscular mycorrhizal fungi (AMF) spore density, carbon in soil microbial biomass (MB-C), soil basal respiration (SBR) and metabolic quotient (qCO2) in different areas under organic cultivation of banana and brachiaria without grazing compared to nearby degraded area growing imperial palms in the city of Umuarama, in the state of Parana. Soil samples were collected at 0-10 cm depth with four repetitions in each area and analyzed in duplicate. All the results were submitted to the analysis of variance (ANOVA) and Tukey?s test (p ? 0.05), utilizing the statistical program SPSS, version 16.0 for Windows. The results showed that AMF spore density was significantly lower in the degraded area. MB-C was significantly higher in the area cultivated with brachiaria in comparison with banana and degraded areas. However, in the banana area, the MB-C was higher than that in the degraded area. Soil chemical analysis showed that the degraded area had low soil phosphorus, carbon, calcium and potassium content, which could have contributed to the decrease in MB-C, due to a high stress condition in this soil. No significant differences were found for SBR among the analyzed areas. However, qCO2 increased significantly in the degraded area, indicating high stress under this condition. Soil use and management under organic cultivation with banana and/or brachiaria increased AMF spore density and MB-C, as well as decreasing qCO2 when compared to the degraded area.(AU)

El uso y manejo adecuado del suelo pueden ser medidos mediante indicadores biológicos de calidad del suelo. Los objetivos de este estudio fueron determinar la densidad de esporas de hongos micorrízicos arbusculares (HMA), carbono de la biomasa microbiana del suelo (C-BMS), respiración basal del suelo (RBS) y cociente metabólico (qCO2) en áreas con cultivo orgánico de banana, brachiaria sin pastoreo, comparativamente con una zona cercana degradada con palmeras imperiales en Umuarama, PR. Se ha recogido suelo a una profundidad de 0-10 cm con 4 repeticiones en cada área y analizados por duplicado en el laboratorio. Los resultados han sido sometidos a análisis de varianza (ANOVA) y la prueba de Tukey (p ? 0,05), utilizando el programa SPSS v.16. La densidad de esporas de HMA fue significativamente menor en el área degradada. El C-BMS fue significativamente mayor en el área con brachiaria en comparación con el suelo cultivado con banana y degradado. En el área con banana C-BMS fue mayor que en el área degradada. El análisis químico del suelo reveló en el área degradada bajo tenor en fósforo, carbono, calcio y potasio, lo que puede haber contribuido a la baja C-BMS, debido al estrés elevado en el suelo. No hubo diferencia significativa en RBS entre las áreas, pero el qCO2 fue significativamente mayor en el suelo degradado, indicando nuevamente alto nivel de estrés en ese suelo. Manejo y uso adecuado del suelo como el cultivo de bananas y/o brachiaria aumentaron la densidad de esporas de HMAs y C-BMS, además disminuyó el qCO2 en comparación con el área degradada.(AU)

Molecular approach to characterize ectomycorrhizae fungi from Mediterranean pine stands in Portugal

Stone pine (Pinus pinea L.), like other conifers, forms ectomycorrhizas (ECM), which have beneficial impact on plant growth in natural environments and forest ecosystems. An in vitro co-culture of stone pine microshoots with pure mycelia of isolated ECM sporocarps was used to overcome the root growth cessation not only in vitro but also to improve root development during acclimation phase. Pisolithus arhizus (Scop.) Rauschert and Lactarius deliciosus (L. ex Fr.) S.F. Gray fungi, were collected, pure cultured and used in in vitro co-culture with stone pine microshoots. Samples of P. arhizus and L. deliciosus for the in vitro co-cultures were collected from the pine stands southwest Portugal. The in situ characterization was based on their morphotypes. To confirm the identity of the collected material, ITS amplification was applied using the pure cultures derived from the sporocarps. Additionally, a molecular profile using PCR based genomic fingerprinting comparison was executed with other genera of Basidiomycetes and Ascomycetes. Our results showed the effectiveness of the techniques used to amplify DNA polymorphic sequences, which enhances the ­characte­rization of the genetic profile of ECM fungi and also provides an option to verify the fungus identity at any stage of plant mycorrhization.

Screening of efficient arbuscular mycorrhizal fungi for Azadirachta indica under nursery condition: a step towards afforestation of semi-arid region of western India

To optimize nursery practices for efficient plant production procedures and to keep up to the ever growing demand of seedlings, identification of the most suitable species of arbuscular mycorrhizal fungi (AMF), specific for a given tree species, is clearly a necessary task. Sixty days old seedlings of Neem (Azadirachta indica A. Juss) raised in root trainers were inoculated with six species of AMF and a mixed inoculum (consortia) and kept in green house. Performances of the treatments on this tree species were evaluated in terms of growth parameters like plant height shoot collar diameter, biomass and phosphorous uptake capabilities. Significant and varied increase in the growth parameters and phosphorous uptake was observed for most of the AMF species against control. Consortia culture was found to be the best suited AMF treatment for A.indica, while Glomus intraradices and Glomus mosseae were the best performing single species cultures. It is the first time in the state of Gujarat that a wide variety of AMF species, isolated from the typical semi-arid region of western India, were tested for the best growth performance with one of the most important tree species for the concerned region.

Evaluación de un sistema para la micorrización in vitro en plantas demora de castilla (Rubus glaucus, Benth) / Evaluation of an in vitro mycorrhization system of blackberry plants (Rubus glaucus, Benth) / Avaliação de um sistema para micorrização in vitro em plantas de amora-preta (Rubus glaucus, Benth)

Objetivo. Obtener un sistema de micorrización in vitro en sistemas de cultivo autotrófico para plantas de mora de castilla (Rubusglaucus, Benth). Materiales y métodos. Se utilizaron esporas y fragmentos de raíces con vesículas del Hongo Formador de MicorrizaArbuscular (HFMA) Glomus sp. (GEV02). Se estableció un sistema de cultivo autotrófico para plántulas de mora, comparando dosmétodos de inoculación directa con el HFMA. Se cuantificó el número de esporas producidas, la longitud del micelio extraradical; asícomo el porcentaje de colonización del HFMA. Adicionalmente se midió la longitud aérea y radical, el peso fresco y seco de la partefoliar y radical para determinar el desarrollo de las plantas. Resultados. El sistema de cultivo autotrófico fue exitoso para plantas demora de castilla (Rubus glaucus, Benth); observándose un óptimo crecimiento de la parte aérea y radical de la planta. Adicionalmenteen este estudio se pudo obtener un sistema que permitió el desarrollo de Glomus sp (GEV02) bajo condiciones in vitro, con formaciónde estructuras típicas de la simbiosis como una buena colonización intraradical, con producción de arbúsculos y vesículas, así comoel desarrollo de micelio extraradical con hifas ramificadas y la formación de nuevas esporas. Conclusión. Las plantas de moramicropropagadas se asociaron con éxito, por primera vez, con un hongo formador de micorriza arbuscular bajo condiciones in vitro,permitiendo el desarrollo del sistema simbiótico HFMA Glomus sp., asociado a las raíces de plántulas de mora castilla micropropagadas...

Objective. Obtain an in vitromycorrhization system in autotrophic culture systems of blackberry plants (Rubus glaucus, Benth). Materials and methods. We usedspores and root fragments with vesicles of Arbuscular Mycorrhizal Fungus (AMF) Glomus sp (GEV02). We established an autotrophicculture system of blackberry plantlets comparing two methods of direct inoculation of the AMF. We measured the number of sporesproduced, the length of the extraradical mycelium as well as the percentage of colonization of the AMF. Additionally, we measuredthe shoot and root length, and the fresh and dry weight of the leaf and root parts to determine the plant development. Results. Theautotrophic culture system was successful for blackberry plants (Rubus glaucus, Benth; an optimal shoot and root growth was observed.Additionally, we obtained a system that allowed the development of Glomus sp. in in vitro conditions, with the formation of structurestypical of the symbiosis as well as a good intraradical colonization, with the production of arbuscules and vesicles, development ofextraradical mycelium with branched hyphae, and formation of new spores. Conclusion. For the first time, micropropagated blackberryplants associated successfully with an AMF under in vitro conditions, enabling the development of the symbiotic system AMF Glomussp. associated to roots of micropropagated blackberry plantlets...

Objetivo. Obter umsistema de micorrização in vitro em sistemas de cultura autotróficos para plantas de amora-preta (Rubus glaucus, Benth). Materiais emétodos. Foram usados esporos e fragmentos de raízes com vesículas do Fungo Formador Micorrízico Arbuscular (FFMA) Glomus sp.(GEV02). Foi estabelecido um sistema de cultivo autotrófico para mudas de amora-preta, comparando dois métodos de inoculação diretacom o FFMA. Foi quantificado o número de esporos produzidos, o comprimento do micélio extra radicular; bem como a porcentagemde colonização do FFMA. Além disso, foi medido o comprimento e o peso fresco e seco da parte folhar e radicular para determinar odesenvolvimento das plantas. Resultados. O sistema de cultivo autotrófico foi bem-sucedido para as plantas de amora-preta (Rubusglaucus, Benth), onde foi observado um crescimento ótimo da parte aérea e da raidicular da planta. Além disso, neste estudo foi obtido umsistema que permitiu o desenvolvimento de Glomus sp (GEV02) sob condições in vitro, com formação de estruturas típicas da simbiosecomo uma boa colonização intra radicular, com produção de arbúsculos e vesículas, assim como o desenvolvimento de micélio extraradicular com hifas ramificada e a formação de novos esporos. Conclusão. As plantas de amora-preta micropropagadas associaram-secom sucesso, pela primeira vez, com um fungo formador micorrízico arbuscular em condições in vitro, permitindo o desenvolvimentodo sistema simbiótico FFMA Glomus sp., associado às raízes das plântulas de amora-preta micropropagadas...

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

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.

Seasonality and host preference of arbuscular mycorrhizal fungi of five plant species in the inner Mongolia steppe, China

The seasonal change and host preference of arbuscular mycorrhizal (AM) colonization and community composition of five common plant species Agropyron cristatum, Anemarrhena asphodeloides, Cleistogenes squarrosa, Leymus chinensis, and Stipa grandis in the Inner Mongolia steppe were investigated. The AM root length colonization rates were different among the five plant species and were generally high in early (May and June) and late (September) growth seasons and low in August. A total of 18 AM fungal species representing five genera were isolated from rhizosphere soils of the five plant species, and most AM fungi had not host specificity, except that Acaulospora sp., Glomus constrictum, G. diaphanum and Glomus sp. showed a certain degree of host preference. Glomus albidum, G. etunicatum and G. geosporum were the dominant species and showed various sporulation patterns in the five plants during the growth seasons. The AM fungal spore densities and species richness increased from May to September and decreased in October and were different in the same month in the five plants. Multivariate analyses revealed that season and host significantly co-affected the AM fungal spore density, species richness, and Shannon-Wiener diversity index, and the season had higher influence than the host.

Propagules of arbuscular mycorrhizal fungi in a secondary dry forest of Oaxaca, Mexico

Plant cover loss due to changes in land use promotes a decrease in spore diversity of arbuscular mycorrhizal fungi (AMF), viable mycelium and, therefore, in AMF colonization, this has an influence in community diversity and, as a consequence, in its recovery. To evaluate different AMF propagules, nine plots in a tropical dry forest with secondary vegetation were selected: 0, 1, 7, 10, 14, 18, 22, 25, and 27 years after abandonment in Nizanda, Oaxaca, Mexico. The secondary vegetation with different stages of development is a consequence of slash and burn agriculture, and posterior abandonment. Soil samples (six per plot) were collected and percentage of AMF field colonization, extrarradical mycelium, viable spore density, infectivity and most probable number (MPN) ofAMF propagules were quantified through a bioassay. Means for field colonization ranged between 40% and 70%, mean of total mycelium length was 15.7 +/- 1.88 mg(-1) dry soil, with significant differences between plots; however, more than 40% of extracted mycelium was not viable, between 60 and 456 spores in 100 g of dry soil were recorded, but more than 64% showed some kind of damage. Infectivity values fluctuated between 20% and 50%, while MPN showed a mean value of 85.42 +/- 44.17 propagules (100 g dry soil). We conclude that secondary communities generated by elimination of vegetation with agricultural purposes in a dry forest in Nizanda do not show elimination of propagules, probably as a consequence of the low input agriculture practices in this area, which may encourage natural regeneration.

La vegetación secundaria con diferentes grados de desarrollo es consecuencia de prácticas agrícolas de rozatumba- quema y su posterior abandono. La remoción de la vegetación por cambios de uso de suelo promueve una disminución en la diversidad de esporas, micelio viable y por lo tanto de la colonización de los hongos micorrizógenos arbusculares (HMA), lo cual repercute en la diversidad de la comunidad y como consecuencia en su regeneración. Para evaluar los propágulos de HMA se seleccionaron nueve parcelas con vegetación secundaria con diferentes edades de abandono: 0, 1, 7, 10, 14, 18, 22, 25, 27 años, en la región de Nizanda, Oaxaca, México. Se recolectaron muestras de suelo (seis por parcela) y se cuantificó la colonización de campo, el micelio extrarradical, la densidad de esporas viables, así como la infectividad y el número más probable de propágulos infectivos (NMP). Los promedios de la colonización de campo fueron de 40 a 70 %, el promedio de la longitud de micelio total alcanzó 15.7 ± 1.88 mg-1 suelo seco con diferencias significativas entre parcelas, pero más del 40 % del micelio extraído no fue viable. Se encontraron entre 60 y 456 esporas en 100 g de suelo pero más del 64 % presentaron algún tipo de daño. Los valores de infectividad se encontraron entre 20 % y 50 %, mientras que el NMP presentó un promedio de 85.42 ±44.17 (100 g de suelo seco). Concluimos que las comunidades secundarias generadas por la eliminación de la vegetación con fines agrícolas en la selva baja caducifolia en Nizanda o presentan eliminación de propágulos, probablemente por el bajo impacto de la agricultura, lo cual indica que la regeneración natural es posible.

Inoculo de hongos de micorrizasarbuscular en pasturas de Brachiaria decumbens(Poaceae) en zonas de loma y vega / Inoculum of Arbuscular Mycorrhizal Fungi on Brachiaria decumbens (Poaceae) Pastures in Valley and Hilly Terrain

Los factores que influyen en la distribución del inóculo de hongos micorrícicos arbusculares (micelio externo y esporas) son diversos. Entre ellos pueden mencionarse la especie vegetal predominante, el pH, la humedad del suelo, la conductividad, el contenido de fósforo, nutrientes y de metales pesados. Muchos de los reportes de la literatura son contradictorios y basados en estudios realizados en zonas templadas; en condiciones tropicales es difícil determinar los factores edáficos y ambientales que estimulan la producción de inóculo y la forma en que lo hacen. Brachiaria decumbens, como especie de pasto predominante en paisajes de loma y vega en el piedemonte amazónico colombiano, ha sido poco estudiada en su relación micorrícica. En este estudio se realizó la determinación de la densidad de esporas y micelio externo en 26 zonas cubiertas con B. decumbens, correspondientes a paisajes de loma y vega. Simultáneamente se valoraron el contenido de fósforo disponible (ppm), pH y humedad relativa del suelo (por ciento). Mediante correlaciones de Spearman (rangos) y análisis de varianza (ANDEVA) de una vía por KruscallWallis, se encontró que el inóculo se distribuye de forma diferente en loma y vega, siendo mayor la densidad de esporas en loma que en vega y más homogéneo en contenido de micelio externo en vega que en loma. No se encontró efecto del fósforo disponible, el pH y la humedad del suelo sobre la densidad de inóculo de HMA.

El tiempo de establecimiento de pasturas y su relacion con la micorriza arbuscular en paisajes de loma y vega / Time of Stablishment of Pastures and Their Relationship with Arbuscular Mycorrhiza in Hilly Terrain and Fertile Valley

El presente trabajo fue realizado para evaluar el efecto del tiempo (0-5 años, 5-10 años y más de 10 años) de establecimiento de pasturas de Brachiaria sp. sobre las poblaciones de hongos de micorriza arbuscular (HMA), su distribución de esporas, géneros, longitud de micelio extramatrical, colonización radical por HMA y otros hongos, en sistemas donde previamente existían bosques, en paisajes de loma y vega en Florencia, Caquetá, Colombia. Cualquiera que sea la edad de establecimiento de la pastura, predominan los géneros Glomus y Acaulospora; el cambio de la cobertura requiere de un periodo de más de diez años para que diferentes especies de HMA puedan recolonizar, adaptarse y diversificarse. En loma, la relación de Brachiaria sp. con los HMA disminuye con la edad, especialmente después de diez años; en vega se mantiene media y estable (21-50 por ciento), mientras la colonización radical por hongos diferentes a los HMA se incrementa, mostrando posiblemente un mecanismo de competencia por el espacio radical, o una acción conjunta. Finalmente, el micelio extramatrical y las esporas en loma y vega siguen tendencias variables (incremento, descenso o estabilidad) con la edad.