Thinning Partially Mitigates the Impact of Atlantic Forest Replacement by Pine Monocultures on the Soil Microbiome.

Forest replacement by exotic plantations drive important changes at the level of the overstory, understory and forest floor. In the Atlantic Forest of northern Argentina, large areas have been replaced by loblolly pine (Pinus taeda L.) monocultures. Plant and litter transformation, together with harvesting operations, change microclimatic conditions and edaphic properties. Management practices such as thinning promote the development of native understory vegetation and could counterbalance negative effects of forest replacement on soil. Here, the effects of pine plantations and thinning on physical, chemical and microbiological soil properties were assessed. Bacterial, archaeal, and fungal community structure were analyzed using a metabarcoding approach targeting ribosomal markers. Forest replacement and, to a lesser extent, thinning practices in the pine plantations induced significant changes in soil physico-chemical properties and associated shifts in bacterial and fungal communities. Most measured physical and chemical properties were altered due to forest replacement, but a few of these properties reached values similar to natural forests under the thinning operation. Fungal alpha diversity decreased in pine plantations, whereas bacterial alpha diversity tended to increase but with little statistical support. Shifts in community composition were observed for both fungal and bacterial domains, and were mostly related to changes in plant understory composition, soil carbon, organic matter, water content, pH and bulk density. Among several other changes, highly abundant phyla such as Proteobacteria (driven by many genera) and Mortierellomycota (mainly driven by Mortierella) decreased in relative abundance in the plantations, whereas Acidobacteria (mainly driven by Acidothermus and Candidatus Koribacter) and Basidiomycota (mainly driven by the ectomycorrhiza Russula) showed the opposite response. Taken together, these results provide insights into the effects of forest replacement on belowground properties and elucidate the potentially beneficial effect of thinning practices in intensive plantation systems through promoting the understory development. Although thinning did not entirely counterbalance the effects of forest replacement on physical, chemical and biological soil properties, the strategy helped mitigating the effects and might promote resilience of these properties by the end of the rotation cycle, if subsequent management practices compatible with the development of a native understory vegetation are applied.

Evaluation of laccase production by Ganoderma lucidum in submerged and solid-state fermentation using different inducers.

Laccases are multicopper oxidases with high potential for industrial applications. Several basidiomycete fungi are natural producers of this enzyme; however, the optimization of production and selection of inducers for increased productivity coupled with low costs is necessary. Lignocellulosic residues are important lignin sources and potential inducers for laccase production. Pinus taeda, a dominant source of wood-based products, has not been investigated for this purpose yet. The aim of this study was to evaluate the production of laccase by the basidiomycete fungus Ganoderma lucidum in the presence of different inducers in submerged and solid-state fermentation. The results of submerged fermentation in presence of 5 µM CuSO 4 , 2 mM ferulic acid, 0.1 g/L P. taeda sawdust, or 0.05 g/L Kraft lignin indicated that although all the tested inducers promoted increase in laccase activity in specific periods of time, the presence of 2 mM ferulic acid resulted in the highest value of laccase activity (49 U/L). Considering the submerged fermentation, experimental design following the Plackett-Burman method showed that the concentrations of ferulic acid and P. taeda sawdust had a significant influence on the laccase activity. The highest value of 785 U/L of laccase activity on submerged fermentation was obtained on the seventh day of cultivation. Finally, solid-state fermentation cultures in P. taeda using ferulic acid or CuSO 4 as inducers resulted in enzymatic activities of 144.62 and 149.89 U/g, respectively, confirming the potential of this approach for laccase production by G. lucidum.

Use of n-alkanes to trace erosion and main sources of sediments in a watershed in southern Brazil.

Erosive processes can transport sediments containing nutrients, heavy metals and contaminants of organic and inorganic origin into bodies of water, therefore affecting the local ecosystem and the population that benefits from the water sources. In order to better understand the origin of sediment sources and establish mitigation measures, the use of the sediment fingerprinting technique has been highlighted. Thus, the present work had as objective to apply n-alkanes in order to trace and understand the main sources of organic matter in sediments and associate the results with land and soil occupation. The study area is located in the municipality of Rio Negrinho - Brazil, in the Saci river basin. Soil samples were collected and classified according to their use and occupation, as well as and samples of local vegetation to be used as reference. The distribution of n-alkanes in the sediments was compared with the distribution found in the vegetation and soil. Previously, a distribution pattern of n-alkanes had been identified in all major vegetation used to trace the source of organic matter and hence the soil. The concentrations of total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and granulometry were also analyzed in the soil and sediment samples. Indexes between n-alkanes were used and applied to assess the source together with statistical analysis (PCA). In sum, the results showed that the sediments are mainly composed of Pinus taeda reforestation soils, as well as soil from the abandoned roads used to transport the cut trees, while the contribution of autochthonous sediments was found to be minimal. In this way, the fingerprint technique served as an auxiliary tool in order to establish measures for the good management of a river basin, bringing important information about the contributing sources of sediment to water bodies.

Characterization and Structural Performance in Bending of CLT Panels Made from Small-Diameter Logs of Loblolly/Slash Pine.

The main objective of this work was to study the structural viability of using small-diameter logs of Uruguayan Loblolly/Slash pine, mainly from thinning operations, to design cross-laminated timber (CLT) panels. A visual grade named "CTH" (coniferous thinning) was proposed, and 45 specimens of sawn timber boards were tested, resulting in 51% lower bending strength than that of the minimum strength class C14. Subsequently, 20 CLT panels were manufactured and experimentally tested, the results showed that the bending strength of the CLT panels was 43% above that of the individual layers. Additionally, the structural performance of the CLT panels for use in floors was calculated, and the thickness-span relationship depending on strength class and imposed load are presented. Results showed than the use of CTH timber to design CLT floors implies a volume (m³/m²) 17% higher than that using C24 timber.

Rapid increase in growth and productivity can aid invasions by a non-native tree.

Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human-mediated ecological and evolutionary processes in population-level dynamics is key to understanding the ability of non-native species to invade.

Molecular and morphological analyses confirm Rhizopogon verii as a widely distributed ectomycorrhizal false truffle in Europe, and its presence in South America.

The genus Rhizopogon includes species with hypogeous or subepigeus habit, forming ectomycorrhizae with naturally occurring or planted pines (Pinaceae). Species of the genus Rhizopogon can be distinguished easily from the other hypogeous basidiomycetes by their lacunose gleba without columella and their smooth elliptical spores; however, the limit between species is not always easy to establish. Rhizopogon luteolus, the type species of the genus, has been considered one of the species that are more abundant in Europe, as well as it has been cited in pine plantation of North and South America, different parts of Africa, Australia, and New Zealand. However, in this study, based on molecular analyses of the ITS nuclear ribosomal DNA (nrDNA) sequences (19 new sequences; 37 sequences from GenBank/UNITE, including those from type specimens), we prove that many GenBank sequences under R. luteolus were misidentified and correspond to Rhizopogon verii, a species described from Tunisia. Also, we confirm that basidiomes and ectomycorrhizae recently collected in Germany under Pinus sylvestris, as well as specimens from South of Brazil under Pinus taeda belong to R. verii. Thanks to the numerous ectomycorrhizal tips collected in Germany, a complete description of R. verii/P. sylvestris ectomycorrhiza is provided. Moreover, since in this paper the presence of R. verii in South America is here reported for the first time, a short description of basidiomes collected in Brazil, compared with collections located in different European herbaria, is included.

Loci under selection during multiple range expansions of an invasive plant are mostly population specific, but patterns are associated with climate.

Identifying the genes underlying rapid evolutionary changes, describing their function and ascertaining the environmental pressures that determine fitness are the central elements needed for understanding of evolutionary processes and phenotypic changes that improve the fitness of populations. It has been hypothesized that rapid adaptive changes in new environments may contribute to the rapid spread and success of invasive plants and animals. As yet, studies of adaptation during invasion are scarce, as is knowledge of the genes underlying adaptation, especially in multiple replicated invasions. Here, we quantified how genotype frequencies change during invasions, resulting in rapid evolution of naturalized populations. We used six fully replicated common garden experiments in Brazil where Pinus taeda (loblolly pine) was introduced at the same time, in the same numbers, from the same seed sources, and has formed naturalized populations expanding outward from the plantations. We used a combination of nonparametric, population genetics and multivariate statistics to detect changes in genotype frequencies along each of the six naturalization gradients and their association with climate as well as shifts in allele frequencies compared to the source populations. Results show 25 genes with significant shifts in genotype frequencies. Six genes had shifts in more than one population. Climate explained 25% of the variation in the groups of genes under selection across all locations, but specific genes under strong selection during invasions did not show climate-related convergence. In conclusion, we detected rapid evolutionary changes during invasive range expansions, but the particular gene-level patterns of evolution may be population specific.

Alelopatia de acículas de pínus na germinação e desenvolvimento de plântulas de milho, picão preto e alface / Allelopathy of pine needles on the germination and development of corn, lettuce and beggartick

Os sistemas agrosilvipastoris estão ampliando os espaços ocupados e ganhando novos adeptos, tendo em vista ampliações produtivas nas mesmas áreas. Porém algumas questões, como efeitos alelopáticos de algumas culturas, nesse caso o pinus, ainda são pouco conhecidas. Objetivou-se com esse trabalho avaliar o efeito alelopático do extrato aquoso de acículas de Pinus taeda na germinação e no desenvolvimento de plântulas de alface, picão-preto e milho. O experimento foi conduzido no delineamento inteiramente casualizado, com os tratamentos distribuídos em um bifatorial (2x5), onde: condições das acículas (verdes e secas) x concentrações dos extratos (0, 25, 50, 75 e 100%), em quatro repetições sob condições de temperatura, umidade e luminosidade controladas. As avaliações foram realizadas no tempo em intervalos regulares de 24 horas, de 0 a 144 horas. Avaliou-se a germinação, velocidade média da germinação, comprimento das radículas e epicótilos da alface, picão-preto e milho. Extratos a base de acícula verde afetou significativamente as variáveis, onde o efeito aumentava conforme aumentava a concentração, sendo o efeito mais perceptível no picão-preto. Já no extrato a base de acículas seca de pínus, houve resultados mínimos quando comparados a testemunha.

Agrosilvipastoris systems are expanding the spaces occupied and gaining new adherents in order expansions productive in the same areas. But some issues, such as allelopathic effects of some cultures, in which case the pine, are still poorly known. This research aimed to evaluate the allelopathic effect of aqueous extract from the pine needles on the germination and development of lettuce, corn and beggarticks seedlings. The experiment was carried in a completely randomized design with treatments arranged in a factorial (2x5), where: conditions of the needles (green and dry) x extracts concentrations (0, 25, 50, 75 and 100%) in four replications, under temperature, humidity and light controlled. Evaluations were carried out time intervals of 24 hours, from 0 to 144 hours. It was evaluated the germination, average speed of germination, the length of the primary roots of lettuce and the length from the seedlings roots of lettuce, beggarticks and corn. Extracts the base of green needles affected the variables, where the effect increased with increase in concentration, the effect being more marked in beggarticks. In the statement the basis of dry pine needles, there were minimal results when compared to control.

Differential dry mass accumulation in eucalypt and pine exposed to glyphosate / Acúmulo diferencial de massa seca em eucalipto e pinus expostos a glyphosate

The weed control onto planting line by using glyphosate is commonly used in forestry areas of eucalyptus and pine; however it can expose the crop of interest to herbicide drift and cause impact on the initial growth of plantlets. The objective was to evaluate comparatively the dry mass of eucalyptus and pine plants exposed to doses of glyphosate and to verify the occurrence of hormesis. In early transplanted plants, glyphosate herbicide was sprayed at doses varying from 0 up to 720 g ae ha-1, and the dry mass of stem, leaves, and shoot were evaluated at 30 days after spraying. Pine showed less susceptibility for dry mass of stem (occurring hormesis), while eucalyptus showed less susceptibility for dry mass of leaves (occurring hormesis). Hormesis occurred in pine and eucalyptus shoots at doses of 8 g ae ha-1 (4.1%) and 11 g ae ha-1 (4.8%), respectively; the dose required to reduce shoot dry mass by 50% was 75 g ae ha-1 and 108 ae ha-1, and the reduction of shoot dry mass was 57% and 69% (with plant death) when plants were exposed to glyphosate at 720 g ae ha-1, respectively for pine and eucalyptus. Pine is more susceptible to glyphosate than eucalyptus.(AU)

O controle de plantas daninhas na linha de plantio com o uso de glyphosate é comum em áreas de florestamento de eucalipto e pinus, mas pode expor a cultura de interesse à deriva do herbicida e causar impacto sobre o crescimento inicial das mudas. O objetivo foi avaliar, comparativamente, a massa seca de plantas de pinus e eucalipto sob doses de glyphosate e verificar a ocorrência de hormese. Em plantas recém transplantadas, o herbicida glyphosate foi aplicado em doses variando de 0 a 720 g e.a. ha-1 e foi avaliada a massa seca do caule, das folhas e da parte aérea aos 30 dias após a aplicação. Pinus apresentou menor susceptibilidade para massa seca do caule (com ocorrência de hormese), enquanto eucalipto, para massa seca de folhas (com ocorrência de hormese). Pinus e eucalipto, respectivamente, apresentaram hormese de 4,1% e 4,8% para massa seca da parte aérea em doses de 8 g e.a. ha-1 e 11 g e.a. ha-1; a dose requerida para reduzir a massa seca em 50% foi de 75 g e.a. ha-1 e 108 g e.a. ha-1 e a redução da massa seca foi de 57% e 69% (com morte das plantas) quando expostas a dose de 720 g e.a. ha-1, respectivamente para pinus e eucalipto. Pinus é mais susceptível ao glyphosate que eucalipto.(AU)

Differential dry mass accumulation in eucalypt and pine exposed to glyphosate / Acúmulo diferencial de massa seca em eucalipto e pinus expostos a glyphosate

The weed control onto planting line by using glyphosate is commonly used in forestry areas of eucalyptus and pine; however it can expose the crop of interest to herbicide drift and cause impact on the initial growth of plantlets. The objective was to evaluate comparatively the dry mass of eucalyptus and pine plants exposed to doses of glyphosate and to verify the occurrence of hormesis. In early transplanted plants, glyphosate herbicide was sprayed at doses varying from 0 up to 720 g ae ha-1, and the dry mass of stem, leaves, and shoot were evaluated at 30 days after spraying. Pine showed less susceptibility for dry mass of stem (occurring hormesis), while eucalyptus showed less susceptibility for dry mass of leaves (occurring hormesis). Hormesis occurred in pine and eucalyptus shoots at doses of 8 g ae ha-1 (4.1%) and 11 g ae ha-1 (4.8%), respectively; the dose required to reduce shoot dry mass by 50% was 75 g ae ha-1 and 108 ae ha-1, and the reduction of shoot dry mass was 57% and 69% (with plant death) when plants were exposed to glyphosate at 720 g ae ha-1, respectively for pine and eucalyptus. Pine is more susceptible to glyphosate than eucalyptus.

O controle de plantas daninhas na linha de plantio com o uso de glyphosate é comum em áreas de florestamento de eucalipto e pinus, mas pode expor a cultura de interesse à deriva do herbicida e causar impacto sobre o crescimento inicial das mudas. O objetivo foi avaliar, comparativamente, a massa seca de plantas de pinus e eucalipto sob doses de glyphosate e verificar a ocorrência de hormese. Em plantas recém transplantadas, o herbicida glyphosate foi aplicado em doses variando de 0 a 720 g e.a. ha-1 e foi avaliada a massa seca do caule, das folhas e da parte aérea aos 30 dias após a aplicação. Pinus apresentou menor susceptibilidade para massa seca do caule (com ocorrência de hormese), enquanto eucalipto, para massa seca de folhas (com ocorrência de hormese). Pinus e eucalipto, respectivamente, apresentaram hormese de 4,1% e 4,8% para massa seca da parte aérea em doses de 8 g e.a. ha-1 e 11 g e.a. ha-1; a dose requerida para reduzir a massa seca em 50% foi de 75 g e.a. ha-1 e 108 g e.a. ha-1 e a redução da massa seca foi de 57% e 69% (com morte das plantas) quando expostas a dose de 720 g e.a. ha-1, respectivamente para pinus e eucalipto. Pinus é mais susceptível ao glyphosate que eucalipto.

Estandarización de marcadores moleculares microsatélites para su uso en la industria forestal de Misiones, Argentina / Standarization of microsatellite molecular markers for Misiones (Argentina) forest industry

Provincia de Misiones posee actualmente una actividad forestal en pujante crecimiento ubicóndose entre las primeras del pais. Este marco de desarrollo productivo permite predecir un ámbito de crecimiento favorecido por las nuevas condiciones del mercado internacional. Por otro lado a pesar del avance de la tecnologi­a industrial, no se ha alcanzado el nivel de desarrollo biotecnológico óptimo que conjugue la calidad genética con caracterí­sticas fenotópicas de excelencia en las especies maderables de mayor demanda en la Provincia basó¡ndose la selección en criterios netamente fenotópicos y en la experiencia del productor, sin contarse con métodos moleculares desarrollados en la región. Este trabajo presenta los resultados del Proyecto Federal de Innovacíon Productiva (PFIP Mi09) cuyo objetivo principal fue estandarizar y transferir al sector productivo un conjunto de marcadores moleculares microsalites para ser aplicado al análisis de poblaciones y forestaciones de Araucaria angustifolia y Pinus taeda provenientes de la Provincia de Misiones (Argentina). Esto permitirá conocer el perfil genético de plantaciones y poblaciones de estas especies forestales, pudiendo aplicarse a la certificación de calidad en la producción forestal o a la selección de ejemplares de especies nativas.

Misiones Province currently has the first intensive forestry activity of Argentine. This framework of productive development allows predict an area of growth favored by the new conditions of the international market. On the other side despite the progress of industrial technology, has not been reached the optimal level of biotechnological development that combining quality with genomic and phenotypic characteristics of forest species. This work presents the results of Federal Project of Productive Innovation (PFIP Mi09) whose main objective was standardize and transfer to the productive sector a set of microsatellites molecular markers to be applied to the populations analysis of Araucaria angustifolia and Pinus taeda forestation from the Misiones (Argentine). This will reveal the plantations and forest genetic profile and may be applied to genetic certification of forest production quality.

Viability and infectivity of an ectomycorrhizal inoculum produced in an airlift bioreactor and immobilized in calcium alginate

The viability and infectivity of an ectomycorrhizal inoculum (isolate UFSC-Rh90, Rhizopogon nigrescens), produced by submerged cultivation in an airlift bioreactor and immobilized in beads of calcium alginate gel, was studied. Inoculum remained 100% viable after 18 months in a 0.85% NaCl solution at 8 ± 1ºC. Mycelium grew from the beads after 48 h when they were placed on a solid culture medium at 25 ± 1ºC. Viability of pellets of non-immobilized mycelium stored under the same conditions decreased gradually after the third month of storage, reaching 0% by the 12th month. These pellets presented a gradual darkening, which was more intense in those located near the surface of the NaCl solution. In culture medium, these dark pellets showed no viability. Gel immobilization helps to maintain mycelium viability during storage and offers a physical protection when the inoculum is applied to the planting substrate. After eight months refrigeration, the immobilized inoculum was still able to infect Pinus taeda seedlings, colonizing an average of 37% of the root tips when inoculated in the plant growth substrate under greenhouse conditions. This inoculum presents a commercial potential to be produced and applied in forest nurseries.

Estudou-se a viabilidade e a infectividade de inoculante fúngico ectomicorrízico (isolado UFSC-Rh90, Rhizopogon nigrescens), produzido através de cultivo submerso em biorreator airlift e encapsulado em gel de alginato de cálcio. O inoculante permaneceu viável após 18 meses em solução de NaCl (0,85%) a 8 ± 1ºC. O micélio emergiu dessas cápsulas após 48 h de incubação a 25 ± 1ºC em meio de cultura sólido. A viabilidade dos pellets de micélio não imobilizado, armazenados sob as mesmas condições, reduziu-se gradualmente após três meses de armazenamento e atingiu 0% aos 12 meses. Esses pellets apresentaram um escurecimento gradual que foi mais intenso naqueles localizados próximos à superfície da solução de NaCl. Em meio de cultura, os pellets escurecidos mostraram-se inviáveis. A imobilização em gel mantém a viabilidade do micélio durante o armazenamento, além de oferecer uma barreira física quando aplicado ao substrato de plantio. Após oito meses de armazenamento sob refrigeração, o inoculante imobilizado colonizou uma média de 37% das raízes curtas de mudas de Pinustaeda, quando aplicado ao substrato de plantio sob condições de casa-de-vegetação. Esse inoculante apresenta potencial para produção comercial e aplicação nos viveiros florestais.