Ricardo Bemfica Steffen

Mycorrhizal morphotyping and molecular characterization of Chondrogaster angustisporus Giachini, Castellano, Trappe & Oliveira, an ectomycorrhizal fungus from Eucalyptus

Chondrogaster angustisporus is a hypogeous ectomycorrhizal fungus described from fruiting bodies collected under Eucalyptus spp. in Brazil, Uruguay, and Australia. Due to its efficiency in promoting plant growth, we decided to characterize this fungus through mycorrhizal morphotyping and internal transcribed spacer (ITS) (rRNA) sequencing. DNA extracted from mycelium was amplified and sequenced using specific primers. Mycorrhizas were obtained aseptically and analyzed in terms of macroscopic and microscopic characteristics. When compared with other fungal DNA sequences available in the NBCI GenBank, the C. angustisporus sequence presented the highest similarity to an uncultured ectomycorrhizal fungus from the Seychelles. It also shows significant similarities to Gomphus, Ramaria, and Hysterangium species supporting the classification of Chondrogaster in the subclass Phallomycetidae in the gomphoid–phalloid group. The mycorrhizas were characterized by a narrow mantle with a single tissue layer densely arranged and organized as a net synenchyma with elongated hyphae. Interhyphal spaces were seen only in the external region where hyphae were more loosely organized. Bottle-shaped cystidia with bent necks were observed on the surface of the mantle. Emanating hyphae were larger than those in the mantle and presented a granular content. At regular intervals the hyphae were divided by septa with clamp connections. The Hartig net was of the common type, with typical palmetti and single hyphal rows and limited to the epidermal layer. The mycorrhizal description and the ITS sequence obtained are useful tools to identify this ectomycorrhizal fungus in culture and in association with Eucalyptus roots.

Copper resistance of different ectomycorrhizal fungi such as Pisolithus microcarpus, Pisolithus sp., Scleroderma sp. and Suillus sp.

Environments contaminated with heavy metals negatively impact the living organisms. Ectomycorrhizal fungi have shown important role in these impacted sites. Thus, this study aimed to evaluate the copper-resistance of ectomycorrhizal fungi isolates Pisolithus microcarpus - UFSC-Pt116; Pisolithus sp. - UFSC-PT24, Suillus sp. - UFSM RA 2.8 and Scleroderma sp. - UFSC-Sc124 to different copper doses in solid and liquid media. The copper doses tested were: 0.00, 0.25, 0.5, 0.75, 1.0 and 1.25 mmol L−1 in the solid medium and 0.00, 0.32, 0.64 and 0.96 mmol L−1 in the liquid medium. Copper was amended as copper sulphate in order to supplement the culture medium MNM at pH 4.8, with seven replicates to each fungus-dose combination. The fungal isolates were incubated for 30 days at 28 °C. UFSC-Pt116 showed high copper-resistance such as accessed by CL50 determinations (concentration to reduce 50% of the growth) as while as UFSC-PT24 displayed copper-resistance mechanism at 0.50 mmol L−1 in solid medium. The UFSC-PT24 and UFSC-Sc124 isolates have increased copper-resistance in liquid medium. The higher production of extracellular pigment was detected in UFSC-Pt116 cultures. The UFSC-Pt116 and UFSC-PT24 isolates showed higher resistance for copper and produced higher mycelium biomass than the other isolates. In this way, the isolates UFSG-Pt116 and UFSC-PT24 can be important candidates to survive in copper-contaminated areas, and can show important role in plants symbiosis in these contaminated sites.

ÓLEO ESSENCIAL DE Eucalyptus grandis Hill ex Maiden NO ESTÍMULO À MICORRIZAÇÃO DE MUDAS DE SIBIPIRUNA (Caesalpinia peltophoroides Benth.)

Os metabolitos secundarios extraidos de especies florestais formadoras de ectomicorrizas podem estimular a simbiose entre fungos ectomicorrizicos e especies florestais nativas do Rio Grande do Sul. O objetivo deste trabalho foi determinar o efeito do oleo essencial de eucalipto na formacao de associacao ectomicorrizica e no crescimento de mudas de sibipiruna, em condicoes de casa de vegetacao. Plântulas de sibipiruna foram submetidas a quatro tratamentos constituidos pela presenca e ausencia do inoculo ectomicorrizico Pisolithus microcarpus (Cooke & Massee) e aplicacao ou nao do oleo essencial de eucalipto. O oleo essencial foi solubilizado e aplicado com pulverizador manual nos periodos de 0, 7 e 14 dias a contar da data de transplante das plântulas. Utilizou-se o delineamento inteiramente casualizado com sete repeticoes. Decorridos 90 dias de crescimento, as mudas foram coletadas e avaliou-se altura, diâmetro do colo, comprimento de raizes, massa seca da parte aerea e porcentagem de colonizacao micorrizica. A aplicacao do oleo essencial de eucalipto favoreceu a ocorrencia de associacao ectomicorrizica, com Pisolithus microcarpus em mudas de sibipiruna, proporcionando aumento significativo no desenvolvimento da parte aerea das mudas.

Crescimento e qualidade de mudas de Timbó e Dedaleiro cultivadas em solo contaminado por cobre

The mining and viticulture activities in the State of Rio Grande do Sul, Brazil have contributed to soil contamination by copper. The aim of this study was to evaluate the effect of copper doses on growth and quality of Ateleia glazioviana and Lafoensia pacari seedlings. The experimental design was completely randomized in a factorial scheme (2 x 4) with five replications. The experiment involved two forest species and three copper doses (64, 128 and 192 mg kg-1). The plant height, stem diameter, root and shoot dry-mass, length and specific superficial area of roots, as well as seedlings quality index: relationship between shoot height and stem diameter, shoot height and dry-mass of shoots were evaluated. In addition, Dicksons quality index was estimated. The results showed that the tested copper doses reduce the quality of seedlings of Ateleia glazioviana; however, the Lafoensia pacari quality was better with Cu dose of 128 mg kg-1. Dose of copper influenced the growth of Ateleia glazioviana seedlings, but increased significantly the length and specific surface area of the Lafoensia pacari up to Cu dose of 128 mg kg-1. Lafoensia pacari seedlings are more tolerant to soil contamination than Ateleia glazioviana and display better quality of seedlings at high copper doses.

Doses de dejeto líquido de suínos na comunidade da fauna edáfica em sistema plantio direto e cultivo mínimo

The high production of liquid pig slurry makes the soil, the main alternative to its use as an organic fertilizer. However, the addition of organic residues in soil management systems is a factor that may influence the soil biota. The aim of this study was to evaluate the influence of dose application of liquid swine manure on soil biota in different cropping systems. The study was conducted in the experimental area located in the Taquarucu do Sul. The design was a randomized block factorial arrangement (2x5), two soil management (minimum and no tillage) and five doses (0, 20, 40, 80m3 ha-1 of liquid swine slurry and chemical fertilizer - ROLAS) with four replications. Sampling of soil biota was carried out with PROVID traps in plots of 22.5m2. It was evaluated the total group, springtails, mites, abundance, richness, Simpson’s index, Shannon’s diversity and Pielou’s index. The results indicate that no tillage system associated with 40 and 80m3 ha-1 resulted in a greater abundance of organisms, caused by the greater number of springtails. The mite population is larger in minimum tillage compared to no tillage at a rate of 80m3 ha-1. In no-tillage increases the dominance of Simpson and Shannon diversity decreases with increasing levels of liquid swine manure.

Influência da aplicação de calcário na população da meso e macrofauna do solo sob sistema plantio direto

No presente estudo avaliou-se o efeito de diferentes doses e modos de aplicacao de calcario em plantio direto em campo nativo sobre a fauna edafica, apos cinco anos da aplicacao. Organismos da fauna epiedafica foram coletados com armadilhas tipo Provid e macrorganismos euedaficos utilizando monolitos de solos em duas epocas de amostragem: inverno e verao. Os organismos foram identificados ao nivel de classe e ordem. Foram identificados 17 grupos taxonomicos, com ocorrencia de cinco classes: Arachnida, Diplopoda, Crustacea, Oligochaeta e Insecta. A abundância de organismos apresentou maior variacao em funcao das diferentes epocas de coleta e nao sofreu influencia das diferentes doses e modos de aplicacao de calcario avaliados.

EFEITO DO COBRE SOBRE O CRESCIMENTO E QUALIDADE DE MUDAS DE Stryphnodendron polyphyllum Mart. E Cassia multijuga Rich.

Soil contamination with copper has become common in the mining and agricultural regions by the use of copper-based-fungicide and application of liquid swine slurry to the soil, causing a reduction in plant productivity. Therefore, a study was undertaken to determine the effect of copper doses in growth and quality of Barbatimao (Stryphnodendron polyphyllum Mart.) and Cassia (Cassia multijugaRich.) seedlings. The experimental design was completely randomized in a factorial (2 x 4) being the two forest species and four doses of copper: 0, 150, 300 and 450 mg kg-1, with 10 repetitions. It was evaluated plant height, stem diameter, dry weight of shoot and root length and specific root surface area, and the quality indexes of seedlings: relationship between shoot height and diameter of the collar; height and shoot dry weight of shoots and Dickson Quality Index. The results revealed that the copper doses tested does not change the quality of seedlings of Cassia and that Barbatimao maintains the quality of seedlings up to 300 mg kg-1 of copper added to soil. Barbatimao presents greater growth and quality than Cassia seedlings in soil contaminated with copper.

MICORRIZAÇÃO DAS MUDAS DE EUCALYPTUS GRANDIS HILL EX MAIDEN COMERCIALIZADAS NO MUNICÍPIO DE SANTA MARIA, RS

For the formation of eucalyptus are used substrates of differentcompositions, which often have no mycorrhizal inoculum. The presenceof mycorrhizal fungi in the substrate can assist in the development ofseedlings and the establishment and maintenance of these aftertransplantation. The objective of this study was to evaluate the populationand diversity of arbuscular mycorrhizal fungi and ectomycorrhizal seedlingsin the market in the municipality of Santa Maria, RS. The results concludingthat there is occurrence of spores of mycorrhizal fungi on substrates ofeucalyptus seedlings, but the association with the plants was low. Noformation was observed in ectomycorrhizal seedlings of eucalyptus assessed.

CARACTERIZAÇÃO BIOQUÍMICA DO NEMATÓIDE DAS GALHAS (MELOIDOGYNE SPP.) EM LAVOURAS DE ARROZ IRRIGADO NA REGIÃO CENTRAL DO RIO GRANDE DO SUL

Twenty one populations of the root-knot nematode (Meloidogynespp.) from eight site located in districts of the Central area of Rio Grandedo Sul State, were biochemical characterized through the esteraseisoenzyme. Sampling was performed in areas with chlorotic plants,exhibiting deformated radicular systems typical symptoms of root-knotnematode attack. Esterase isoenzyme, identified in all the sites sampledthe phenotype esterase VS1 (Rm 0,70), typical of M. graminicola.

Fauna edáfica influenciada pelo uso de culturas e consórcios de cobertura do solo

The edaphic fauna is considered sensitive and responds relatively fast to the impact of different types of production systems, thereby enabling its use as an active component for evaluating soil quality. This study was conducted to determine the influence of black oat, turnip, vetch and the intercropping of turnip/black oat and vetch/turnip/black oat in the structure and composition of the edaphic fauna. The experimental design was randomized blocks, in a 6x4 factorial scheme, consisting of six soil cover crops (black oat, turnip and vetch, the intercropping of turnip/black oat and vetch/turnip /black oat and fallow ground) and four sampling times (0, 50, 100 and 150 days after sowing), with four replications. After collecting the soil fauna, the abundance of individuals, Collembola number, Margalef richness, Shannon diversity index, Pielou equitability and Simpson dominance were determined. The intercropping of turnip/black oat and vetch/turnip/black oat favored the abundance of individuals and the Collembola number, within the first 50 days. The intercropping of vetch/turnip/black oat reduced the Shannon diversity index by increasing the Collembola population. The highest species diversity was observed at 100 days after the crops implantation. The edphic fauna was influenced by the vegetative stage and soil cover crop types.