Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Food Res Int ; 192: 114768, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39147496

RESUMO

In the context of biorefinery, researchers have been looking for lignocellulosic biomasses and ideal treatments to produce economically viable biofuels. In this scenario, the bamboo culm appears as a plant matrix of great potential, given the high cellulose content of low crystallinity. Thus, the objective and differential of this work was to determine the best conditions for enzymatic hydrolysis of cellulose extracted from bamboo culm and to evaluate its potential application in the production of bioethanol through Separate Hydrolysis and Fermentation (SHF) and Saccharification and Simultaneous Fermentation (SSF) by Saccharomyces cerevisiae modified via CRISPR/Cas9. The average cellulose extraction yield was 41.87 % with an extraction efficiency of 86.76 %. In general, as the hydrolysis time increased, an increase in glucose production was observed in almost all assays, with higher hydrolysis efficiency values at 72 h. The results ranged from 2.09 to 19.8 g/L of glucose obtained with efficiency values of 10.47 to 99 %. The best conditions were found in test 5 (temperature of 36 °C and pH 5.0, with only 10 FPU/g of substrate Cellic Ctec2 Novozymes ® cocktail). It is observed that for all hydrolysis times the independent variables pH and temperature were significant under the hydrolysis efficiency, showing a negative effect, indicating that higher values of the same promote lower values of the response variable. For bioethanol production, a maximum concentration of 7.84 g/L was observed for the SSH process after 4 h of fermentation, while for the SSF process it was 12.6 g/L after 24 h of fermentation, indicating the large potential of the simultaneous process together with the application of bamboo culm biomass for high production of biofuel.


Assuntos
Biocombustíveis , Sistemas CRISPR-Cas , Celulose , Etanol , Fermentação , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Hidrólise , Celulose/metabolismo , Etanol/metabolismo , Celulase/metabolismo , Sasa , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Biomassa
2.
Meat Sci ; 216: 109588, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38964226

RESUMO

This study examined the effects of replacing alkaline phosphate (AP) with bamboo fiber (BF), isolated pea protein (PP), and mushroom powder (MP) on the nutritional, technological, oxidative, and sensory characteristics of low-sodium mortadellas. Results indicated that this reformulation maintained the nutritional quality of the products. Natural substitutes were more effective than AP in reducing water and fat exudation. This led to decreased texture profile analysis (TPA) values such as hardness, cohesiveness, gumminess, and chewiness. The reformulation reduced the L* values and increased the b* values, leading to color modifications rated from noticeable to appreciable according to the National Bureau of Standards (NBS) index. Despite minor changes in oxidative stability indicated by increased values in TBARS (from 0.19 to 0.33 mg MDA/kg), carbonyls (from 2.1 to 4.4 nmol carbonyl/mg protein), and the volatile compound profile, the sensory profile revealed a beneficial increase in salty taste, especially due to the inclusion of MP, which was enhanced by the synergy with BF and PP. In summary, the results confirmed the potential of natural alternatives to replace chemical additives in meat products. Incorporating natural antioxidants into future formulations could address the minor oxidation issues observed and enhance the applicability of this reformulation strategy.


Assuntos
Agaricales , Fibras na Dieta , Produtos da Carne , Valor Nutritivo , Proteínas de Ervilha , Paladar , Proteínas de Ervilha/química , Animais , Produtos da Carne/análise , Fibras na Dieta/análise , Agaricales/química , Humanos , Antioxidantes , Pós , Manipulação de Alimentos/métodos , Masculino , Fosfatos , Cor , Oxirredução , Suínos , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Feminino , Sasa/química
3.
Environ Monit Assess ; 196(5): 423, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38570374

RESUMO

Mobile herbicides have a high potential for groundwater contamination. An alternative to decrease the mobility of herbicides is to apply materials with high sorbent capacity to the soil, such as biochars. The objective of this research was to evaluate the effect of eucalyptus, rice hull, and native bamboo biochar amendments on sorption and desorption of hexazinone, metribuzin, and quinclorac in a tropical soil. The sorption-desorption was evaluated using the batch equilibrium method at five concentrations of hexazinone, metribuzin, and quinclorac. Soil was amended with eucalyptus, rice hull, and native bamboo biochar at a rate of 0 (control-unamended) and 1% (w w-1), corresponding to 0 and 12 t ha-1, respectively. The amount of sorbed herbicides in the unamended soil followed the decreasing order: quinclorac (65.9%) > metribuzin (21.4%) > hexazinone (16.0%). Native bamboo biochar provided the highest sorption compared to rice hull and eucalyptus biochar-amended soils for the three herbicides. The amount of desorbed herbicides in the unamended soil followed the decreasing order: metribuzin (18.35%) > hexazinone (15.9%) > quinclorac (15.1%). Addition of native bamboo biochar provided the lowest desorption among the biochar amendments for the three herbicides. In conclusion, the biochars differently affect the sorption and desorption of hexazinone, metribuzin, and quinclorac mobile herbicides in a tropical soil. The addition of eucalyptus, rice hull, and native bamboo biochars is a good alternative to increase the sorption of hexazinone, metribuzin, and quinclorac, thus, reducing mobility and availability of these herbicides to nontarget organisms in soil.


Assuntos
Eucalyptus , Herbicidas , Oryza , Quinolinas , Sasa , Poluentes do Solo , Triazinas , Carvão Vegetal , Solo , Adsorção , Monitoramento Ambiental , Herbicidas/análise , Poluentes do Solo/análise
4.
J Colloid Interface Sci ; 587: 767-779, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33309243

RESUMO

Commercialization of novel adsorbents technology for providing safe drinking water must consider scale-up methodological approaches to bridge the gap between laboratory and industrial applications. These imply complex matrix analysis and large-scale experiment designs. Arsenic concentrations up to 200-fold higher (2000 µg/L) than the WHO safe drinking limit (10 µg/L) have been reported in Latin American drinking waters. In this work, biochar was developed from a single, readily available, and taxonomically identified woody bamboo species, Guadua chacoensis. Raw biochar (BC) from slow pyrolysis (700 °C for 1 h) and its analog containing chemically precipitated Fe3O4 nanoparticles (BC-Fe) were produced. BC-Fe performed well in fixed-bed column sorption. Predicted model capacities ranged from 8.2 to 7.5 mg/g and were not affected by pH 5-9 shift. The effect of competing matrix chemicals including sulfate, phosphate, nitrate, chloride, acetate, dichromate, carbonate, fluoride, selenate, and molybdate ions (each at 0.01 mM, 0.1 mM and 1 mM) was evaluated. Fe3O4 enhanced the adsorption of arsenate as well as phosphate, molybdate, dichromate and selenate. With the exception of nitrate, individually competing ions at low concentration (0.01 mM) did not significantly inhibit As(V) sorption onto BC-Fe. The presence of ten different ions in low concentrations (0.01 mM) did not exert much influence and BC-Fe's preference for arsenate, and removal remained above 90%. The batch and column BC and BC-Fe adsorption capacities and their ability to provide safe drinking water were evaluated using a naturally contaminated tap water (165 ± 5 µg/L As). A 960 mL volume (203.8 Bed Volumes) of As-free drinking water was collected from a 1 g BC-Fe fixed bed. Adsorbent regeneration was attempted with (NH4)2SO4, KOH, or K3PO4 (1 M) strippers. Potassium phosphate performed the best for BC-Fe regeneration. Safe disposal options for the exhausted adsorbents are proposed. Adsorbents and their As-laden analogues (from single and multi-component mixtures) were characterized using high resolution XPS and possible competitive interactions and adsorption pathways and attractive interactions were proposed including electrostatic attractions, hydrogen bonding and weak chemisorption to BC phenolics. Stoichiometric precipitation of metal (Mg, Ca and Fe) oxyanion (phosphate, molybdate, selenate and chromate) insoluble compounds is considered. The use of a packed BC-Fe cartridge to provide As-free drinking water is presented for potential commercial use. BC-Fe is an environmentally friendly and potentially cost-effective adsorbent to provide arsenic-free household water.


Assuntos
Arsênio , Sasa , Poluentes Químicos da Água , Purificação da Água , Adsorção , Arsênio/análise , Carvão Vegetal , Compostos Férricos , Ferro , Cinética , Transferência de Tecnologia , Poluentes Químicos da Água/análise
5.
Acta Trop ; 205: 105352, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31981495

RESUMO

Despite the importance of Aedes, Haemagogus and Sabethes in the transmission of yellow fever virus (YFV) and the public health impacts of recent YFV epidemics in the Americas, relatively little has been reported on the biology and ecology of these vectors. Many Aedes, Haemagogus and Sabethes spp. in the American tropics inhabit and develop in the forest canopy and are difficult to sample with conventional entomological surveillance methods. We tested the utility of two previously developed phytotelmata-style oviposition traps (bamboo Guadua angustifolia) and (monkey-pot Lecythis minor), for collecting immature forms of these mosquitoes in a forest near the community of Aruza Abajo, Darién Province, Panama. Our results showed distribution of mosquito species emerging from the two types of traps was found to be significantly different (X2 = 210.23; df = 14; P < 0.001), with significantly greater numbers of Sabethes (Peytonulus) aurescens (Lutz) and Sabethes (Peytonulus) undosus (Coquillett) emerging from the bamboo traps. More females of Sabethes (Sabethes) cyaneus (Fabricius) were captured in the monkey-pot traps, although the difference was not significant. No differences were observed in the average time to emergence for the two traps. These results suggest that various phytotelmata-style traps, including monkey-pot and bamboo, could be used to improve entomological surveillance of YFV vectors in the American tropic.


Assuntos
Controle de Mosquitos/métodos , Mosquitos Vetores , Febre Amarela/transmissão , Aedes/fisiologia , Aedes/virologia , Animais , Feminino , Masculino , Mosquitos Vetores/virologia , Sasa
6.
Sci Total Environ ; 706: 135943, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31862592

RESUMO

Discarded bamboo culms of Guadua chacoensis were used for biochar remediation of aqueous As(V). Raw biochar (BC), activated biochar (BCA), raw Fe3O4 nanoparticle-covered biochar (BC-Fe), and activated biochar covered with Fe3O4 nanoparticles (BCA-Fe) were prepared, characterized and tested for As(V) aqueous adsorption. The goal is to develop an economic, viable, and sustainable adsorbent to provide safe arsenic-free water. Adsorbents were characterized using scanning electron microscopy (SEM) and energy dispersive analysis by X-ray (SEM-EDX), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (TEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), Brunauer-Emmett-Teller surface area measurements (SBET), point of zero charge determinations (PZC), and elemental analysis. Activation with KOH increased the O/C ratio and the surface area of BC from 6.7 m2/g to 1239.7 m2/g (BCA). As(V) sorption equilibrium was achieved within <2 h for all four adsorbents and kinetics followed the pseudo-second-order model. At a 10 mg/L initial As(V) concentration, BC-Fe achieved a 100% removal (5 mg/g) over a pH 5 to 9 window. Sorption was endothermic on all four adsorbents and the capacities rose with the increasing temperature. Langmuir capacities at 40 °C for BC, BCA, BC-Fe, and BCA-Fe were 256, 217, 457, and 868 mg/g, respectively, and capacities were compared with other sorbents. Breakthrough fixed-bed column sorption was carried out for BC and BC-Fe producing 6.6 mg/g and 13.9 mg/g bed capacities, respectively. Potassium phosphate was a better As stripping agent than sodium bicarbonate. Performance of the adsorbents in an As(V)-spiked natural water and a naturally As(V)-contaminated domestic water were assessed. Robust arsenate sequestration occurred generating As-safe water (As <0.01 mg/L), despite the presence of competing ions. Stoichiometric precipitation of iron-arsenate complexes triggered by iron dissolution was also established.


Assuntos
Sasa , Purificação da Água , Adsorção , Arsênio , Carvão Vegetal , Compostos Férricos , Cinética , Nanopartículas Metálicas , Poluentes Químicos da Água
7.
Int J Biometeorol ; 62(11): 1955-1962, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30121896

RESUMO

Bamboo has an important role in international commerce due to its diverse uses, but few studies have been conducted to evaluate its climatic adaptability. Thus, the objective of this study was to construct an agricultural zoning for climate risk (ZARC) for bamboo using meteorological elements spatialized by neural networks. Climate data included air temperature (TAIR, °C) and rainfall (P) from 4947 meteorological stations in Brazil from the years 1950 to 2016. Regions were considered climatically apt for bamboo cultivation when TAIR varied between 18 and 35 °C, and P was between 500 and 2800 mm year-1, or PWINTER was between 90 and 180 mm year-1. The remainder of the areas was considered marginal or inapt for bamboo cultivation. A multilayer perceptron (MLP) neural network with a multilayered "backpropagation" training algorithm was used to spatialize the territorial variability of each climatic element for the whole area of Brazil. Using the overlapping of the TAIR, P, and PWINTER maps prepared by MLP, and the established climatic criteria of bamboo, we established the agricultural zoning for bamboo. Brazil demonstrates high seasonal climatic variability with TAIR varying between 14 and 30 °C, and P varying between < 400 and 4000 mm year-1. The ZARC showed that 87% of Brazil is climatically apt for bamboo cultivation. The states that were classified as apt in 100% of their territories were Mato Grosso do Sul, Goiás, Tocantins, Rio de Janeiro, Espírito Santo, Sergipe, Alagoas, Ceará, Piauí, Maranhão, Rondônia, and Acre. The regions that have restrictions due to low TAIR represent just 11% of Brazilian territory. This agroclimatic zoning allowed for the classification of regions based on aptitude of climate for bamboo cultivation and showed that 71% of the total national territory is considered to be apt for bamboo cultivation. The regions that have restrictions are part of southern Brazil due to low values of TAIR and portions of the northern region that have high levels of P which is favorable for the development of diseases.


Assuntos
Agricultura , Meteorologia , Sasa/crescimento & desenvolvimento , Brasil , Planejamento de Cidades
8.
Int J Biol Macromol ; 107(Pt A): 371-382, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28888543

RESUMO

In this study, films based on two different polysaccharides (chitosan and cassava starch) were produced by casting technique and nanostructured by montmorillonite (MMTNPs) or bamboo nanofibers (BNFs) at two different concentrations: 0.5g/100g and 1.0g/100g of polymer, using glycerol as plasticizer at concentration of 30g/100g of polymer. The particle size and surface charge of the MMTNPs and BNFs nanoparticles were 315±14nm and 60±3nm and -31.78mV and -20.77mV, respectively. In relation to the mechanical properties, the nanofibers increased the tensile strength in 50% of starch films, while the elongation at break shows a similar increase (66%) for both types of nanoparticles at concentration of 1.0g/100g. Cassava starch films showed a better response to nanostructure process, noticed through by the mechanical properties. XRD analyses showed good interaction between the polymer matrix and bamboo nanofibers.


Assuntos
Bentonita/química , Quitosana/química , Embalagem de Alimentos , Amido/química , Celulose/química , Quitosana/síntese química , Manihot/química , Nanocompostos/química , Nanofibras/química , Sasa/química , Amido/síntese química , Resistência à Tração
9.
Braz. j. biol ; Braz. j. biol;76(4): 834-844, Oct.-Dec. 2016. tab, graf
Artigo em Inglês | LILACS | ID: biblio-828103

RESUMO

Abstract Palms, bromeliads and bamboos are key elements of tropical forests and understanding the effects of climate, anthropogenic pressure and forest structure on these groups is crucial to forecast structural changes in tropical forests. Therefore, we investigated the effects of these factors on the abundance of these groups in 22 Atlantic forest fragments of Northeastern Brazil. Abundance of bromeliads and bamboos were assessed through indexes. Palms were counted within a radius of 20 m. We also obtained measures of vegetation structure, fragment size, annual precipitation, precipitation seasonality and human population density. We tested the effects of these predictors on plant groups using path analysis. Palm abundance was higher in taller forests with larger trees, closed canopy and sparse understory, which may be a result of the presence of seed dispersers and specific attributes of local palm species. Bromeliads were negatively affected by both annual precipitation and precipitation seasonality, what may reflect adaptations of these plants to use water efficiently, but also the need to capture water in a regular basis. Bamboos were not related to any predictor variable. As climate and forest structure affected the abundance of bromeliads and palms, human-induced climatic changes and disturbances in forest structure may modify the abundance of these groups. In addition, soil properties and direct measurements of human disturbance should be used in future studies in order to improve the predictability of models about plant groups in Northeastern Atlantic Forest.


Resumo Palmeiras, bromélias e bambus são importantes elementos das florestas tropicais e, entender os efeitos do clima, pressão antrópica e estrutura da floresta nesses grupos é crucial para prever alterações estruturais em florestas tropicais. Portanto, nós investigamos os efeitos desses fatores na abundância desses grupos vegetais em 22 fragmentos de Mata Atlântica no nordeste brasileiro. Abundâncias de bromélias e bambus foram registradas através de índices. Palmeiras foram contadas em um raio de 20 m. Nós também obtemos medidas da estrutura da vegetação, tamanho de fragmento, precipitação anual, sazonalidade na precipitação e densidade populacional humana. Nós testamos os efeitos desses preditores nos grupos vegetais através de análises de caminhos. A abundância de palmeiras foi maior em florestas mais altas, com árvores mais grossas, dossel fechado e sub-bosque aberto, o que deve refletir a presença de dispersores de sementes e atributos específicos das espécies de palmeiras locais. Bromélias foram negativamente afetadas pela precipitação anual e pela sazonalidade na precipitação, o que deve refletir adaptações dessas plantas para o uso eficiente da água, mas também a necessidade de captar água regularmente. Bambus não estiveram relacionados com nenhum dos preditores avaliados. Dado que clima e estrutura florestal afetaram a abundância de bromélias e palmeiras, as mudanças climáticas e distúrbios na estrutura das matas causados por ações antrópicas podem alterar a abundância desses grupos. Adicionalmente, propriedades do solo e medidas diretas de distúrbios antrópicos devem ser usadas em estudos futuros para melhorar o poder preditivo dos modelos sobre a abundância de plantas na Mata Atlântica do nordeste brasileiro.


Assuntos
Humanos , Florestas , Clima , Arecaceae/fisiologia , Bromeliaceae/fisiologia , Sasa/fisiologia , Solo/química , Árvores/fisiologia , Brasil , Densidade Demográfica , Atividades Humanas/estatística & dados numéricos
10.
Genet Mol Res ; 15(3)2016 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-27706589

RESUMO

Ty3-gypsy long-terminal repeat retroelements are ubiquitously found in many plant genomes. This study reports the occurrence of heterogeneous Ty3-gypsy retroelements in four representative bamboo species: Phyllostachys heterocycla (Carr.) Mitford cv. pubescens, P. heterocycla (Carr.) Mitford cv. heterocycla, Dendrocalamopsis oldhami, and Pleioblastus fortunei. Using degenerate oligonucleotide primers corresponding to the conserved domains of reverse transcriptase (rt) genes of Ty3-gypsy retroelements, 165 distinct sequences were amplified from genomic DNA. The length of the nucleotide sequences varied from 366 to 438 bp. The sequences demonstrated a high heterogeneity, with homology ranging from 52.2 to 99.8%. A phylogenetic tree was constructed, including Arabidopsis thaliana and Oryza sativa. Bamboo Ty3-gypsy sequences formed three distinct retroelement clusters (gypsy I-III). Further analysis indicated that there were not only nearly identical Ty3-gypsy retroelements found in distantly related species, but also highly diverse Ty3-gypsy retroelements observed in closely related species. The results of this study provide genetic and evolutionary information about the bamboo genome that could contribute to further studies of repetitive elements in bamboo as well as in other species.


Assuntos
Evolução Molecular , Retroelementos , Sasa/genética , Transferência Genética Horizontal , Genoma de Planta , Filogenia , Análise de Sequência de DNA , Sequências Repetidas Terminais
11.
Braz J Biol ; 76(4): 834-844, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27143056

RESUMO

Palms, bromeliads and bamboos are key elements of tropical forests and understanding the effects of climate, anthropogenic pressure and forest structure on these groups is crucial to forecast structural changes in tropical forests. Therefore, we investigated the effects of these factors on the abundance of these groups in 22 Atlantic forest fragments of Northeastern Brazil. Abundance of bromeliads and bamboos were assessed through indexes. Palms were counted within a radius of 20 m. We also obtained measures of vegetation structure, fragment size, annual precipitation, precipitation seasonality and human population density. We tested the effects of these predictors on plant groups using path analysis. Palm abundance was higher in taller forests with larger trees, closed canopy and sparse understory, which may be a result of the presence of seed dispersers and specific attributes of local palm species. Bromeliads were negatively affected by both annual precipitation and precipitation seasonality, what may reflect adaptations of these plants to use water efficiently, but also the need to capture water in a regular basis. Bamboos were not related to any predictor variable. As climate and forest structure affected the abundance of bromeliads and palms, human-induced climatic changes and disturbances in forest structure may modify the abundance of these groups. In addition, soil properties and direct measurements of human disturbance should be used in future studies in order to improve the predictability of models about plant groups in Northeastern Atlantic Forest.


Assuntos
Arecaceae/fisiologia , Bromeliaceae/fisiologia , Clima , Florestas , Sasa/fisiologia , Brasil , Atividades Humanas/estatística & dados numéricos , Humanos , Densidade Demográfica , Solo/química , Árvores/fisiologia
12.
PLoS One ; 7(3): e33373, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22428035

RESUMO

Fire has become an increasingly important disturbance event in south-western Amazonia. We conducted the first assessment of the ecological impacts of these wildfires in 2008, sampling forest structure and biodiversity along twelve 500 m transects in the Chico Mendes Extractive Reserve, Acre, Brazil. Six transects were placed in unburned forests and six were in forests that burned during a series of forest fires that occurred from August to October 2005. Normalized Burn Ratio (NBR) calculations, based on Landsat reflectance data, indicate that all transects were similar prior to the fires. We sampled understorey and canopy vegetation, birds using both mist nets and point counts, coprophagous dung beetles and the leaf-litter ant fauna. Fire had limited influence upon either faunal or floral species richness or community structure responses, and stems <10 cm DBH were the only group to show highly significant (p = 0.001) community turnover in burned forests. Mean aboveground live biomass was statistically indistinguishable in the unburned and burned plots, although there was a significant increase in the total abundance of dead stems in burned plots. Comparisons with previous studies suggest that wildfires had much less effect upon forest structure and biodiversity in these south-western Amazonian forests than in central and eastern Amazonia, where most fire research has been undertaken to date. We discuss potential reasons for the apparent greater resilience of our study plots to wildfire, examining the role of fire intensity, bamboo dominance, background rates of disturbance, landscape and soil conditions.


Assuntos
Biodiversidade , Incêndios , Sasa/crescimento & desenvolvimento , Árvores , Animais , Formigas/crescimento & desenvolvimento , Biomassa , Aves/crescimento & desenvolvimento , Brasil , Besouros/crescimento & desenvolvimento , Dinâmica Populacional , Comunicações Via Satélite
13.
Bioresour Technol ; 102(17): 8225-31, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21703854

RESUMO

Bamboo has wide range of moisture content, low bulk energy density and is difficult to transport, handle, store and feed into existing combustion and gasification systems. Because of its important fuel characteristics such as low ash content, alkali index and heating value, bamboo is a promising energy crop for the future. The aim of this study was to evaluate the effects of torrefaction on the main energy properties of Bambusa vulgaris. Three different torrefaction temperatures were employed: 220, 250 and 280°C. The elemental characteristics of lignite and coal were compared to the torrefied bamboo. The characteristics of the biomass fuels tend toward those of low rank coals. Principal component analysis of FTIR data showed a clear separation between the samples by thermal treatment. The loadings plot indicated that the bamboo samples underwent chemical changes related to carbonyl groups, mostly present in hemicelluloses, and to aromatic groups present in lignin.


Assuntos
Produtos Agrícolas , Sasa/metabolismo , Biomassa , Temperatura
14.
New Phytol ; 181(4): 880-889, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19076297

RESUMO

Rare gregarious flowering of understorey bamboo species occurs in temperate and subtropical forests around the world, but the ecological consequences of this phenomenon for forest regeneration are not well understood.Field experiments were conducted in an old-growth temperate forest in Patagonia,Argentina after a massive bamboo flowering event, to examine whether light quality and other changes in microhabitats could affect seed germination and growth of overstorey species. Germination of southern beech (Nothofagus obliqua) was positively correlated with red:far red (R:FR) ratios in a range of microhabitats generated by the death of the understorey bamboo (Chusquea culeou). Experimental modification of understorey R:FR ratios to mimic alternative light environments reversed this germination response in plots with senescent understorey, but not in plots with live bamboo. Laboratory incubations demonstrated a significant interaction between R:FR ratios and thermal amplitude in promoting seed germination. Microhabitats also significantly affected the growth of emerged seedlings. Microenvironmental changes generated by this flowering event appear to have opened a window of opportunity for germination and growth of overstorey species.We demonstrate that natural gradients in light quality associated with this ecological phenomenon are a major component affecting forest regeneration in this ecosystem.


Assuntos
Luz , Sasa/fisiologia , Argentina , Ecossistema , Fagus/crescimento & desenvolvimento , Fagus/fisiologia , Fagus/efeitos da radiação , Flores/crescimento & desenvolvimento , Flores/fisiologia , Germinação , Regeneração , Sasa/crescimento & desenvolvimento , Sasa/efeitos da radiação
15.
Ecology ; 88(10): 2541-54, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18027757

RESUMO

Resource pulses often involve extraordinary increases in prey availability that "swamp" consumers and reverberate through indirect interactions affecting other community members. We developed a model that predicts predator-mediated indirect effects induced by an epidemic prey on co-occurring prey types differing in relative profitability/preference and validated our model by examining current-season and delayed effects of a bamboo mass seeding event on seed survival of canopy tree species in mixed Patagonian forests. The model shows that predator foraging behavior, prey profitability, and the scale of prey swamping influence the character and strength of short-term indirect effects on various alternative prey. When in large prey-swamped patches, nonselective predators decrease predation on all prey types. Selective predators, instead, only benefit prey of similar quality to the swamping species, while very low or high preference prey remain unaffected. Negative indirect effects (apparent competition) may override such positive effects (apparent mutualism), especially for highly preferred prey, when prey-swamped patches are small enough to allow predator aggregation and/or predators show a reproductive numerical response to elevated food supply. Seed predation patterns during bamboo (Chusquea culeou) masting were consistent with predicted short-term indirect effects mediated by a selective predator foraging in large prey-swamped patches. Bamboo seeds and similarly-sized Austrocedrus chilensis (ciprés) and Nothofagus obliqua (roble) seeds suffered lower predation in bamboo flowered than nonflowered patches. Predation rates on the small-seeded Nothofagus dombeyi (coihue) and the large-seeded Nothofagus alpina (rauli) were independent of bamboo flowering. Indirect positive effects were transient; three months after bamboo seeding, granivores preyed heavily upon all seed types, irrespective of patch flowering condition. Moreover, one year after bamboo seeding, predation rates on the most preferred seed (rauli) was higher in flowered than in nonflowered patches. Despite rapid predator numerical responses, short-term positive effects can still influence community recruitment dynamics because surviving seeds may find refuge beneath the litter produced by bamboo dieback. Together, our theoretical analysis and experiments indicate that indirect effects experienced by alternative prey during and after prey-swamping episodes need not be universal but can change across a prey quality spectrum, and they critically depend on predator-foraging rules and the spatial scale of swamping.


Assuntos
Cadeia Alimentar , Preferências Alimentares , Comportamento Predatório/fisiologia , Sasa/fisiologia , Animais , Ecossistema , Abastecimento de Alimentos , Dinâmica Populacional , Estações do Ano , Sementes/crescimento & desenvolvimento
16.
Bioresour Technol ; 98(8): 1602-7, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-16973355

RESUMO

Small-scale sour starch agroindustry in Colombia suffer from absence of water treatment. Although starch processing plants produce diluted wastewater, it is a source of pollution and cause environmental problems to the nearby rural population. A laboratory scale anaerobic horizontal flow filter packed with bamboo pieces was evaluated for the treatment of cassava starch extraction wastewater. The wastewater used in the experimentation was the draining water of the starch sedimentation basin. The reactor was operated for 6 months. It was inoculated with a semi-granular sludge from an anaerobic UASB reactor of a slaughterhouse. Maximum organic loading rate (OLR) applied was 11.8g COD/L d without dilution of the wastewater. At steady state and maximum OLR applied, 87% of the COD was removed and a gas productivity of 3.7L/L d was achieved. The average biogas yield was 0.36L/g COD removed. Methane content in the biogas was in the range of 69-81%. The total suspended solids (TSS) removed were 67%. The relative high lactic acid content did not negatively influence the performance of the reactor. No perturbation due to cyanide (3-5mg/L) was observed during the reactor operation. The results obtained indicated that the anaerobic horizontal flow filter could be used efficiently for the treatment of wastewater from Colombian starch processing small-scale agroindustry.


Assuntos
Bactérias Anaeróbias/metabolismo , Reatores Biológicos , Manihot/química , Amido/metabolismo , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Colômbia , Metano/análise , Metano/biossíntese , Sasa
17.
Mycologia ; 98(5): 821-7, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17256585

RESUMO

Gloeoporus guerreroanus sp. nov. is described and illustrated from specimens collected on bamboo in Rio Grande do Sul State, southern Brazil. The new taxon presents hymenium continuum along the tubular internal surface and dissepiments and represents an addition into the relatively small, poroid-merulioid genus Gloeoporus.


Assuntos
Basidiomycota/classificação , Sasa/microbiologia , Basidiomycota/citologia , Basidiomycota/crescimento & desenvolvimento , Brasil
18.
Mycologia ; 97(3): 710-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16392258

RESUMO

During a recent collection trip to Barro Colorado Island, Panama, two species belonging to genus Ascopolyporus (Clavicipitaceae, Hypocreales) were collected. Species of Ascopolyporus are epibionts of their bamboo (Poaceae) host and long thought to be biotrophs of their plant hosts. However, based on morphological observations and phylogenetic evidence using large subunit ribosomal DNA data, we propose that genus Ascopolyporus is likely composed of pathogens of scale insects (Coccoideae, Homoptera). Phylogenetic analyses included Ascopolyporus spp. in a clade containing only entomopathogenic clavicipitaceous species (100% posterior probability), and the scale insect pathogen Hyperdermium bertonii was found to share the most recent common ancestor with the Ascopolyporus clade (98% posterior probability). In addition remnants of the scale insect were observed to be embedded within stromata during early stages of stroma development. Ascopolyporus philodendrus sp. nov. was described and distinguished from the type species of the genus, A. polychrous, based on perithecial size, ascus size, plant host substrate and phylogenetic evidence. Furthermore subfamily Clavicipitoideae (Clavicipitaceae) was included and well supported in a single clade (100% posterior probability).


Assuntos
Ascomicetos/classificação , Sasa/microbiologia , Ascomicetos/citologia , Ascomicetos/isolamento & purificação , Ascomicetos/fisiologia , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Microscopia , Dados de Sequência Molecular , Panamá , Filogenia , RNA Ribossômico 28S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA