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1.
Int J Mol Sci ; 21(9)2020 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-32397436

RESUMO

The influences of (1) a high fiber content, (2) the arrangement of fibers in fiber groups, and (3) a layered hierarchical composition of the bark of the giant sequoia (Sequoiadendron giganteum) on its energy dissipation capability are analyzed and discussed regarding the relevance for an application in bioinspired components in civil engineering. The giant sequoia is native to the Sierra Nevada (USA), a region with regular rockfalls. It is thus regularly exposed to high-energy impacts, with its bark playing a major protective role, as can be seen in the wild and has been proven in laboratory experiments. The authors quantify the fundamental biomechanical properties of the bark at various length scales, taking into account its hierarchical setup ranging from the integral level (whole bark) down to single bark fibers. Microtensile tests on single fibers and fiber pairs give insights into the properties of single fibers as well as the benefits of the strong longitudinal interconnection between single fibers arranged in pairs. Going beyond the level of single fibers or fiber pairs, towards the integral level, quasistatic compression tests and dynamic impact tests are performed on samples comprising the whole bark (inner and outer bark). These tests elucidate the deformation behavior under quasistatic compression and dynamic impact relevant for the high energy dissipation and impact-damping behavior of the bark. The remarkable energy dissipation capability of the bark at the abovementioned hierarchical levels are linked to the layered and fibrous structure of the bark structurally analyzed by thin sections and SEM and µCT scans.


Assuntos
Casca de Planta/fisiologia , Sequoiadendron/fisiologia , Estresse Mecânico , Árvores/fisiologia , Ailanthus/fisiologia , Parede Celular/ultraestrutura , Módulo de Elasticidade , Microscopia Eletrônica de Varredura , Casca de Planta/ultraestrutura , Resistência à Tração , Microtomografia por Raio-X
2.
BMC Plant Biol ; 19(1): 8, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30616545

RESUMO

BACKGROUND: Although the wound response of plants has been extensively studied, little is known of the rapid occlusion of wounded cell itself. The laticifer in rubber tree is a specific type of tissue for natural rubber biosynthesis and storage. In natural rubber production, tapping is used to harvest the latex which flows out from the severed laticifer in the bark. Therefore, study of the rapid wound-occlusion of severed laticifer cells is important for understanding the rubber tree being protected from the continuously mechanical wounding. RESULTS: Using cytological and biochemical techniques, we revealed a biochemical mechanism for the rapid occlusion of severed laticifer cells. A protein-network appeared rapidly after tapping and accumulated gradually along with the latex loss at the severed site of laticifer cells. Triple immunofluorescence histochemical localization showed that the primary components of the protein-network were chitinase, ß-1,3-glucanase and hevein together with pro-hevein (ProH) and its carboxyl-terminal part. Molecular sieve chromatography showed that the physical interactions among these proteins occurred under the condition of neutral pH. The interaction of ß-1,3-glucanase respectively with hevein, chitinase and ProH was testified by surface plasmon resonance (SPR). The interaction between actin and ß-1,3-glucanase out of the protein inclusions of lutoids was revealed by pull-down. This interaction was pharmacologically verified by cytochalasin B-caused significant prolongation of the duration of latex flow in the field. CONCLUSIONS: The formation of protein-network by interactions of the proteins with anti-pathogen activity released from lutoids and accumulation of protein-network by binding to the cytoskeleton are crucial for the rapid occlusion of laticifer cells in rubber tree. The protein-network at the wounded site of laticifer cells provides not only a physical barrier but also a biochemical barrier to protect the wounded laticifer cells from pathogen invasion.


Assuntos
Hevea/fisiologia , Casca de Planta/fisiologia , Proteínas de Plantas/fisiologia , Western Blotting , Cromatografia em Gel , Produção Agrícola , Eletroforese em Gel de Poliacrilamida , Imunofluorescência , Hevea/citologia , Hevea/metabolismo , Hevea/ultraestrutura , Microscopia Eletrônica , Casca de Planta/citologia , Casca de Planta/metabolismo , Casca de Planta/ultraestrutura , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Borracha/metabolismo , Ressonância de Plasmônio de Superfície
3.
Planta ; 245(3): 507-521, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27888361

RESUMO

MAIN CONCLUSION: The attachment of aerial roots of Syngonium podophyllum involves a multi-step process adjusted by multi-scale structures. Helical-crack root hairs are first found in the attachment system, representing specialized structures for surface anchorage. The morphological variability of attachment organs reflects diverse climbing strategies. One such anchoring mode in clinging-climbers involves the time-dependent interaction between roots and the support: By naturally occurring adhesive roots with root hairs, the plant can ascend on supports of any shape and size. As a typical root-climber, Syngonium podophyllum develops elongate aerial roots at nodes. Here, we studied its attachment behavior from the external morphology to the internal structure in detail. Through SEM and LM observation on several root-substrate interfaces, we suggested that the attachment of aerial roots was mediated by a multi-step process, in which root hairs played significant roles in releasing mucilaginous substance and securing the durable anchorage. We summarized all the types of shape changes of root hairs with particular focus on the abnormal transition from a tube to a helical-crack ribbon. We demonstrated our understanding with respect to the formation of the helical-crack root hairs, based on the structural evidence of cellulose microfibrils orientation on the cell wall lamellae. The helical-crack root hairs serving as energy-dissipating units retard the failure of adhesion under high winds and loads.


Assuntos
Araceae/anatomia & histologia , Araceae/ultraestrutura , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/ultraestrutura , Casca de Planta/ultraestrutura
4.
PLoS One ; 11(6): e0158099, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27362422

RESUMO

Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae) was performed to reconstruct the molecular distribution of rohitukine (Rh) and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. Desorption electrospray ionization mass spectrometry imaging (DESI MSI) and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) analysis detected Rh as well as its glycosylated, acetylated, oxidized, and methoxylated analogues. Rh was predominantly distributed in the main roots, collar region of the stem, and young leaves. In the stem and roots, Rh was primarily restricted to the cortex region. The identities of the metabolites were assigned based on both the fragmentation patterns and exact mass analyses. We discuss these results, with specific reference to the possible pathways of Rh biosynthesis and translocation during seedling development in D. binectariferum.


Assuntos
Cromonas/análise , Meliaceae/ultraestrutura , Piperidinas/análise , Plântula/ultraestrutura , Espectrometria de Massas por Ionização por Electrospray/métodos , Acetilação , Glicosilação , Meliaceae/química , Redes e Vias Metabólicas , Casca de Planta/química , Casca de Planta/ultraestrutura , Caules de Planta/química , Caules de Planta/ultraestrutura , Plântula/química , Sementes/química , Sementes/ultraestrutura , Distribuição Tecidual
5.
Carbohydr Polym ; 111: 979-87, 2014 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-25037439

RESUMO

The present study reports for the first time the isolation of cellulose fibers and cellulose nanocrystals (CNCs) from the bark of Norway spruce. The upgrading of bark cellulose to value-added products, such as CNCs, is part of the "bark biorefinery" concept. The removal of non-cellulosic constituents was monitored throughout the isolation process by detailed chemical composition analyses. The morphological investigation of the CNCs was performed using AFM and showed the presence of nanocrystals with an average length of 175.3 nm and a diameter of 2.8 nm, giving an aspect ratio of around 63. X-ray diffraction (XRD) analyses showed that the crystallinity index increased with successive treatments to reach a final value greater than 80% for CNCs. The thermal degradation of the isolated bark CNCs started at 190 °C. Spruce bark appeared to be a new promising industrial source of cellulose fibers and CNCs.


Assuntos
Celulose/química , Nanopartículas/química , Picea/química , Casca de Planta/química , Celulose/isolamento & purificação , Hidrólise , Nanopartículas/ultraestrutura , Picea/ultraestrutura , Casca de Planta/ultraestrutura , Difração de Raios X
6.
Molecules ; 19(7): 9689-711, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-25004075

RESUMO

An effective ionic liquid vacuum microwave-assisted method was developed for extraction of the thermo- and oxygen-sensitive glycosides salicin, hyperin and rutin from Populus bark due to the strong solvating effects of ionic liquids on plant cell walls. In this study, [C4mim]BF4 solution was selected as the extracting solution for extraction of the target analytes. After optimization by single factor experiments and response surface methodology, the optimum condition parameters were achieved, which included 1.0 M [C4mim]BF4, 2 h soaking time, -0.08 MPa vacuum, 20 min microwave irradiation time, 400 W microwave irradiation power and 25 mL/g liquid/solid ratio. Under the optimum conditions, higher extraction yields of salicin (35.53 mg/g), hyperin (1.32 mg/g) and rutin (2.40 mg/g) were obtained. Compared with other extraction methods, the developed method provided higher yields of the three target components after a relatively shorter extraction time (20 min). No obvious degradation of the target analytes was observed under the optimum conditions in performed stability studies and the proposed method had a high reproducibility. Meanwhile, after adsorption and desorption on macroporous D101 resin, the target analytes can be effectively separated from the [C4mim]BF4 ionic liquid extraction solution and the yields of salicin, hyperin and rutin were 89%, 82% and 84%, respectively. The recovered [C4mim]BF4 ionic liquid presented a good extraction effect on the three analytes after recycling five times.


Assuntos
Álcoois Benzílicos/química , Glucosídeos/química , Extração Líquido-Líquido , Casca de Planta/química , Populus/química , Quercetina/análogos & derivados , Rutina/química , Álcoois Benzílicos/isolamento & purificação , Glucosídeos/isolamento & purificação , Líquidos Iônicos/química , Extração Líquido-Líquido/métodos , Micro-Ondas , Casca de Planta/ultraestrutura , Extratos Vegetais , Quercetina/química , Quercetina/isolamento & purificação , Reprodutibilidade dos Testes , Rutina/isolamento & purificação , Vácuo
7.
Bioresour Technol ; 139: 410-4, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23697662

RESUMO

The effects of subcritical water (SCW) and dilute acid pretreatments on the shedding bark of Melaleuca leucadendron (paper bark tree, PBT) biomass morphology, crystallinity index (CrI) and enzymatic saccharification were studied. The morphology of PBT bark was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. SCW pretreatment mainly extracted amorphous parts of the biomass hence its CrI increased, partial decrystallization of cellulose and exposing of intact nanofibers of cellulose were observed for SCW pretreatment at 180°C. On the other hand, dilute acid pretreatment at 160°C exhibited a large decrease in CrI, an increase in surface area, a decrease in lignin content and decrystallization of cellulose as well as the peel-off and degradation of some nanofiber bundles. Dilute acid and SCW pretreatments of PBT biomass resulted in about 4.5 fold enhancement in glucose release relative to the untreated one.


Assuntos
Metabolismo dos Carboidratos , Celulase/metabolismo , Melaleuca/metabolismo , Casca de Planta/metabolismo , beta-Glucosidase/metabolismo , Biomassa , Metabolismo dos Carboidratos/efeitos dos fármacos , Cristalização , Hidrólise/efeitos dos fármacos , Melaleuca/efeitos dos fármacos , Melaleuca/ultraestrutura , Casca de Planta/efeitos dos fármacos , Casca de Planta/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Ácidos Sulfúricos/farmacologia , Água/farmacologia , Difração de Raios X
8.
Plant Physiol ; 162(1): 424-39, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23530184

RESUMO

Bark tissue of Populus × canescens can hyperaccumulate cadmium, but microstructural, transcriptomic, and physiological response mechanisms are poorly understood. Histochemical assays, transmission electron microscopic observations, energy-dispersive x-ray microanalysis, and transcriptomic and physiological analyses have been performed to enhance our understanding of cadmium accumulation and detoxification in P. × canescens. Cadmium was allocated to the phloem of the bark, and subcellular cadmium compartmentalization occurred mainly in vacuoles of phloem cells. Transcripts involved in microstructural alteration, changes in nutrition and primary metabolism, and stimulation of stress responses showed significantly differential expression in the bark of P. × canescens exposed to cadmium. About 48% of the differentially regulated transcripts formed a coregulation network in which 43 hub genes played a central role both in cross talk among distinct biological processes and in coordinating the transcriptomic regulation in the bark of P. × canescens in response to cadmium. The cadmium transcriptome in the bark of P. × canescens was mirrored by physiological readouts. Cadmium accumulation led to decreased total nitrogen, phosphorus, and calcium and increased sulfur in the bark. Cadmium inhibited photosynthesis, resulting in decreased carbohydrate levels. Cadmium induced oxidative stress and antioxidants, including free proline, soluble phenolics, ascorbate, and thiol compounds. These results suggest that orchestrated microstructural, transcriptomic, and physiological regulation may sustain cadmium hyperaccumulation in P. × canescens bark and provide new insights into engineering woody plants for phytoremediation.


Assuntos
Cádmio/metabolismo , Casca de Planta/genética , Proteínas de Plantas/genética , Populus/genética , Transcriptoma , Adaptação Fisiológica , Antioxidantes/metabolismo , Cádmio/análise , Cádmio/farmacologia , Metabolismo dos Carboidratos , Microanálise por Sonda Eletrônica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Homeostase , Nitrogênio/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Especificidade de Órgãos , Estresse Oxidativo , Fenóis/metabolismo , Fotossíntese/efeitos dos fármacos , Casca de Planta/efeitos dos fármacos , Casca de Planta/fisiologia , Casca de Planta/ultraestrutura , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Raízes de Plantas/ultraestrutura , Populus/efeitos dos fármacos , Populus/fisiologia , Populus/ultraestrutura , RNA Mensageiro/genética , RNA de Plantas/genética , Estresse Fisiológico , Enxofre/metabolismo
9.
Bol. latinoam. Caribe plantas med. aromát ; 11(2): 172-187, mar. 2012. ilus
Artigo em Espanhol | LILACS | ID: lil-647629

RESUMO

Quassia amara L. popularly known as “quasia”, is a shrubby plant from Tropical America. The wood, bark and leave are used in either folk medicine or in procuring phytotherapeutic drugs. The aim of the present work was to analize morphoanatomical and micrographic features which might provide assistance in the identification, analysis and standardization of Quasia amara L wood, bark and leaves. Results. Anatomical study showed white yellowish and diffuse porous wood, confluent paratracheal parenchyma. Rays width 1 cell wide and 8-30 cells high. CaOx crystals are absent. Cortex, 1-4 mm thick, a periderm up to 12 layers phellem cells. Leaf, hipostomatic with dorsiventral mesophyll and high number of sclerosed idioblasts.


Quassia amara L. popularmente conocida como “quasia” es un planta arbustiva de América Tropical. El leño, corteza y hojas son usadas tanto en medicina popular como en la obtención de drogas fitoterapéuticas. El objetivo del presente trabajo es analizar características morfoanatómicas y micrográficas las cuales provean asistencia en la identificación, análisis y estandarización de la madera, corteza y hojas de Quassia amara L. Resultados. El estudio anatómico mostró leño, blanco amarillento, de porosidad difusa. Parénquima paratraqueal confluente. Radios de 1 célula de ancho y 8-30 hileras de alto. Faltan cristales CaOx. Corteza, 1-4 mm de espesor, una peridermis de hasta 12 estratos de células de súber. Hoja, hipoestomática, con mesófilo dorsiventral, con elevado número de idioblastos esclerosados.


Assuntos
Casca de Planta/anatomia & histologia , Folhas de Planta/anatomia & histologia , Madeira/anatomia & histologia , Quassia/anatomia & histologia , Casca de Planta/ultraestrutura , Folhas de Planta/ultraestrutura , Madeira/ultraestrutura , Fotomicrografia , Quassia/ultraestrutura
10.
Zhong Yao Cai ; 34(11): 1697-9, 2011 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-22506391

RESUMO

OBJECTIVE: To study the microscopic and UV-Vis spectrum characteristic of Sapium sebiferum. METHODS: The microscopic identification and UV-Vis spectrum identification were adopted. RESULTS: There were cluster crystals in cortical cells of roots and stems and parenchyma cells of the leaves. A few stone cells were found in cortex of the stem. The vascular bundles arranged in the form of a circle in the main vein of the leaves. It could be observed that many crystals and crystal fibers in the powder. Six kinds of solvent of crude drug had absorption peaks between 200 - 800 nm. CONCLUSION: These results can provide the scientific evidence for the establishment of standard for quality control and further study.


Assuntos
Casca de Planta/citologia , Plantas Medicinais/citologia , Sapium/citologia , Microscopia , Casca de Planta/ultraestrutura , Folhas de Planta/citologia , Folhas de Planta/ultraestrutura , Raízes de Plantas/citologia , Raízes de Plantas/ultraestrutura , Caules de Planta/citologia , Caules de Planta/ultraestrutura , Plantas Medicinais/ultraestrutura , Pós , Controle de Qualidade , Sapium/ultraestrutura , Espectrofotometria Ultravioleta
11.
Bioresour Technol ; 102(2): 724-8, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20884200

RESUMO

In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model.


Assuntos
Bombacaceae/química , Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Casca de Planta/química , Tolueno/isolamento & purificação , Biodegradação Ambiental , Cinética , Microscopia Eletrônica de Varredura , Modelos Químicos , Casca de Planta/ultraestrutura , Porosidade , Espectrometria por Raios X , Propriedades de Superfície
12.
Bioresour Technol ; 101(24): 9778-84, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20705459

RESUMO

Torrefaction is a mild pyrolysis process (usually up to 300 degrees C) that changes the chemical and physical properties of biomass. This process is a possible pre-treatment prior to further processes (transport, grinding, combustion, gasification, etc) to generate energy or biofuels. In this study, three eucalyptus wood species and bark were subjected to different torrefaction conditions to determine the alterations in their structural and energy properties. The most severe treatment (280 degrees C, 5h) causes mass losses of more than 35%, with severe damage to anatomical structure, and an increase of about 27% in the specific energy content. Bark is more sensitive to heat than wood. Energy yields are always higher than mass yields, thereby demonstrating the benefits of torrefaction in concentrating biomass energy. The overall mass loss is proposed as a relevant parameter to synthesize the effect of torrefaction conditions (temperature and duration). Accordingly, all results are summarised by analytical expressions able to predict the energy properties as a function of the overall mass loss. These expressions are intended to be used in any optimization procedure, from production in the field to the final use.


Assuntos
Biomassa , Biotecnologia/métodos , Fontes Geradoras de Energia , Eucalyptus/metabolismo , Casca de Planta/metabolismo , Temperatura , Madeira/metabolismo , Biocombustíveis , Carbono , Eucalyptus/ultraestrutura , Modelos Lineares , Casca de Planta/ultraestrutura , Madeira/ultraestrutura
13.
Zhong Yao Cai ; 31(2): 206-9, 2008 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-18619263

RESUMO

OBJECTIVE: To provide evidence for identification of the morphology and histology of Pinellia pedatisecta Schott. METHODS: Using microscope and scanning electron microscope, characteristics of the Pinellia pedatisecta Schott. were studied comparatively. RESULTS: The surface of leaves, fruits, testa and pollen grain of the cultivated Pinellia pedatisecta Schott. showed different characteristics. CONCLUSION: The results of the study can be used for the identification of the Pinellia pedatisecta Schott. in Shandong.


Assuntos
Pinellia/anatomia & histologia , Plantas Medicinais/anatomia & histologia , Frutas/anatomia & histologia , Frutas/ultraestrutura , Microscopia Eletrônica de Varredura , Farmacognosia , Pinellia/ultraestrutura , Casca de Planta/anatomia & histologia , Casca de Planta/ultraestrutura , Folhas de Planta/anatomia & histologia , Folhas de Planta/ultraestrutura , Plantas Medicinais/ultraestrutura , Pólen/ultraestrutura , Sementes/anatomia & histologia , Sementes/ultraestrutura
14.
Mycologia ; 99(4): 612-21, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18065012

RESUMO

Theissenia rogersii deviates from known Theissenia species primarily in having large ascospores with a thick wall layer and a unique configuration of two stromatal tissue types, one carbonaceous and the other fibrous. The carbonaceous tissue forms palisades on and beneath the perithecial layer as well as encasing individual perithecia, whereas the fibrous tissue fills the spaces between columns of the palisades as well as between encased perithecia. Phylogenetic analyses based on DNA sequences of beta-tubulin and alpha-actin genes placed Theissenia in the subfamily Hypoxyloideae among the genera that are characterized by having bipartite stromata (i.e. with the stromata differentiated into an outer dehiscing layer and an inner perithecium-bearing layer).


Assuntos
Lauraceae/microbiologia , Casca de Planta/microbiologia , Xylariales/classificação , Xylariales/genética , DNA Fúngico/análise , Lauraceae/ultraestrutura , Microscopia de Interferência , Dados de Sequência Molecular , Filogenia , Casca de Planta/ultraestrutura , Análise de Sequência de DNA , Especificidade da Espécie , Esporos Fúngicos/fisiologia , Esporos Fúngicos/ultraestrutura , Xylariales/fisiologia , Xylariales/ultraestrutura
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(7): 1428-32, 2007 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-17944430

RESUMO

Twelve camphor (cinnamomum camphora) tree bark samples were collected from Hiroshima and Kyoto, and the matrix element composition and morphology of the outer surface of these camphor tree bark samples were studied by EDXS and SEM respectively. After a dry decomposition, DOWEX 1-X8 anion exchange resin was used to separate uranium from matrix elements in these camphor tree bark samples. Finally, 235U/238 U isotope ratios in purified uranium solutions were determined by MC-ICP-MS. It was demonstrated that the outer surface of these camphor tree bark samples is porous and rough, with Al, Ca, Fe, K, Mg, Si, C, O and S as its matrix element composition. Uranium in these camphor tree bark samples can be efficiently separated and quantitatively recovered from the matrix element composition. Compared with those collected from Kyoto, the camphor tree bark samples collected from Hiroshima have significantly higher uranium contents, which may be due to the increased aerosol mass concentration during the city reconstruction. Moreover, the 235 U/23.U isotope ratios in a few camphor tree bark samples collected from Hiroshima are slightly higher than 0.007 25.


Assuntos
Cinnamomum camphora/química , Espectrometria de Massas/métodos , Casca de Planta/química , Poluentes Radioativos/análise , Urânio/análise , Cinnamomum camphora/ultraestrutura , Japão , Microscopia Eletrônica de Varredura , Casca de Planta/ultraestrutura , Monitoramento de Radiação/métodos , Poluentes Radioativos/isolamento & purificação , Urânio/isolamento & purificação
16.
Tree Physiol ; 27(7): 977-84, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17403650

RESUMO

Functional and structural characteristics of corticular photosynthesis of sun-exposed bark of olive tree (Olea europaea L.) were examined. Stomata are only sporadically present during stem primary growth. Light transmission through the phellem was age dependent, decreasing rapidly in stems older than five years of age. Light transmission was also low in pubescent 1-year-old stems. Light transmission was about 50% higher in wet phellem than in dry phellem. Photosynthetic capacity on a unit area basis (measured with an oxygen disc electrode at 27 degrees C and about 5% CO(2) on chlorophyllous tissue discs isolated from the stem) was higher in 1-, 20- and 30-year-old stems compared with 2-10-year-old stems. Low chlorophyll a/b ratio and light compensation points were recorded in olive stems with low phellem light transmission, in accordance with the shade acclimation hypothesis. The intrinsic photochemical efficiency of photosystem II of all stems, especially young stems, was less than that of the leaves. Our results show that olive tree bark possesses an efficient photosynthetic mechanism that may significantly contribute not only to the reduction in concentrations of CO(2) in the inner bark, but also to whole-tree carbon balance.


Assuntos
Olea/fisiologia , Fotossíntese/fisiologia , Casca de Planta/fisiologia , Clorofila/metabolismo , Clorofila A , Microscopia Eletrônica de Varredura , Olea/metabolismo , Olea/ultraestrutura , Casca de Planta/metabolismo , Casca de Planta/ultraestrutura
17.
J Environ Monit ; 8(9): 904-12, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16951750

RESUMO

Tree barks and attic dusts were examined as historical archives of smelter emissions, with the aim of elucidating the pathways of pollution associated with a plume of Sn and Pb contamination in top soils, found close to the former Capper Pass smelter, Humberside, UK. Samples were collected from three villages within the area of the contamination plume. Scanning electron microscopy (SEM) and bulk chemical analyses were used to assess particle type, number and deposition patterns. SEM analysis of dusts and bark revealed that Sn and Pb particles were present in samples from all three villages along with copper, zinc and iron particles. These were almost entirely <10 microm in diameter and occurred mostly as oxides, frequently forming clusters of sub-micron crystals. Samples further from the smelter contained considerably fewer particles. We present images of smelter derived Sn particles. Chemical assays of the barks and attic dusts demonstrated that concentrations of Sn, Pb, Cu, As, Sb and Cd diminished with increasing distance from the source. Strong positive correlations were found between Sn and Pb, As, Sb and Cd in the attic dusts. Enrichment factors (EF) were calculated for these trace elements based on topsoil element concentrations obtained from the soil survey of the study area. Decreases in these trace element concentrations and EF values with distance away from the smelter are consistent with trends found in the soil survey for Sn and Pb and are typical of deposition patterns around smelter stacks. The study demonstrates that tree bark and attic dusts can be effective archives of metal particulates deposited from large static emission sources.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Poeira/análise , Metais Pesados/análise , Casca de Planta/química , Poluentes do Solo/análise , Monitoramento Ambiental/métodos , Humanos , Indústrias , Chumbo/análise , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Casca de Planta/ultraestrutura , Estanho/análise , Oligoelementos/análise , Reino Unido
18.
Inhal Toxicol ; 18(12): 969-73, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16920670

RESUMO

The understanding of historical ambient asbestos concentrations is critical to exposure mapping and retrospective health impact studies involving asbestos related diseases. Two presentations at the University of Montana Center for Environmental Health Sciences Asbestos Conference (July 28, 2005) introduced novel methods for detecting evidence of past airborne asbestos contamination. In each of these studies, transmission electron microscopy was used to identify and measure asbestos fibers collected in samples from unconventional environmental sources. In the first study, paleolimnology, analytical transmission electron microscopy, particle-separation techniques, and empirical aerosol-sediment modeling were combined to provide the first measurements of airborne asbestos concentrations prior to the 1980s. In an upstate New York study area, airborne concentrations of chrysotile followed its 20th-century usage, with highest concentrations near mid-century (approximately 0.1 fibers/cm3), followed by a decrease in the last quarter century. Airborne concentrations of anthophyllite asbestos (a contaminant from nearby talc mines and mills) increased from <0.004 to 0.022 fibers/cm3 from 1847 to 1995. In the second study, tree bark and core samples were collected from areas near the asbestos-contaminated vermiculite mine in Libby, MT. We originally hypothesized that trees in the areas surrounding the mine could serve as reservoirs for ambient amphibole fibers. Though gravimetric reduction of a tree core sample did not indicate the presence of amphibole fibers, transmission electron microscopy analysis of bark samples yielded substantial amphibole fiber concentrations ranging from 14 to 260 million amphibole fibers/cm2. Based on these preliminary results, we conclude that trees in the Libby valley can serve as reservoirs for amphibole fibers, and that a continued potential for exposure exists for those who harvest contaminated wood.


Assuntos
Poluentes Atmosféricos/análise , Asbestos/análise , Monitoramento Ambiental/métodos , Mineração , Poluentes Atmosféricos/história , Asbestos/história , História do Século XX , Microscopia Eletrônica de Transmissão/métodos , Fibras Minerais , Modelos Teóricos , Montana , New York , Casca de Planta/química , Casca de Planta/ultraestrutura , Árvores/química , Árvores/ultraestrutura
19.
Bioresour Technol ; 97(16): 1986-93, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16311033

RESUMO

Studies were carried out on adsorption of Cr(VI) on an adsorbent made from eucalyptus bark. Results revealed that sorption of chromium on activated eucalyptus bark (AEB) was endothermic in nature. Thermodynamic parameters such as the entropy change, enthalpy change and Gibb's free energy change were found out to be 100.97 J mol(-1)K(-1), 33 kJ mol(-1) and -0.737 kJ mol(-1), respectively. Industrial chrome effluent of different chromium concentration at different pH was used as feedstock for the fixed bed adsorption studies. When effluent was fed to the column at low pH of 2, the breakthrough volume increased significantly compared to effluent at higher pH of 4.85. The surface properties of sorbent were characterized by the Scanning electron microscopy, X-ray diffraction technique and Infrared techniques. It was concluded that AEB sorbent column could be used effectively for removal of chromium from industrial effluents by reducing the pH of chrome effluent to two and at optimal column conditions.


Assuntos
Cromo/química , Eucalyptus , Casca de Planta/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Cromo/análise , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Casca de Planta/ultraestrutura , Termodinâmica , Difração de Raios X
20.
Planta ; 216(1): 72-82, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12430016

RESUMO

The objectives of this study were to define cell structure during pine secondary xylem development and to integrate this information with current knowledge of the biochemistry and physiology of secondary cell wall biosynthesis in gymnosperms. Lodgepole pine (Pinus contorta var. latifolia Englem.) cambium and secondary xylem were cryofixed using high pressure freezing and freeze-substitution which allowed excellent preservation of the cell structure of developing secondary xylem and enabled high-resolution transmission electron microscopic viewing of these cells for the first time. In contrast to their precursors in the adjacent cambial zone, developing tracheids were active in secondary wall deposition, with abundant cortical microtubules and developing bordered pits. These cells were also characterized by unusual Golgi structures: the trans-Golgi network was highly developed and the associated vesicles were large and darkly stained. These unusual Golgi structures persisted throughout the period of xylem maturation until programmed cell death occurred. Immuno-cytochemistry and enzyme-gold probes were used to investigate the distribution of key secretory products (mannans) and a lignification-associated enzyme (coniferin beta-glucosidase) during xylogenesis. Mannans were localized to the secondary cell wall, the trans-Golgi cisternae and trans-Golgi network vesicles of developing xylem. Coniferin beta-glucosidase was found only in the secondary cell wall. The cell wall localization of coniferin beta-glucosidase, the enzyme responsible for cleaving glucose from coniferin to generate free coniferyl alcohol, provides a mechanism to de-glucosylate monolignols in muro. A two-step model of lignification of conifer tracheids is proposed. First, Golgi-mediated secretion deposits monolignols into the cell wall, where they polymerize in cell corners and middle lamella. Secondly, cell lysis releases stored, vacuolar monolignol glucosides into the wall where they are deglucosylated and their polymerization is influenced by the wall environment including the lignin deposited earlier.


Assuntos
Lignina/metabolismo , Pinus/crescimento & desenvolvimento , Casca de Planta/crescimento & desenvolvimento , Diferenciação Celular , Parede Celular/química , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Cinamatos/metabolismo , Complexo de Golgi/metabolismo , Complexo de Golgi/ultraestrutura , Imuno-Histoquímica , Microscopia Eletrônica , Pinus/citologia , Pinus/metabolismo , Casca de Planta/metabolismo , Casca de Planta/ultraestrutura , Polissacarídeos/biossíntese , beta-Glucosidase/metabolismo
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