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










Base de dados
Intervalo de ano de publicação
1.
Front Plant Sci ; 13: 920054, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35720535

RESUMO

Species' phylogeographic patterns reflect the interplay between landscape features, climatic forces, and evolutionary processes. Here, we used two chloroplast DNA (cpDNA) markers (trnL and trnL-F) to explore the role of stepped geomorphology in shaping the phylogeographic structure of Toxicodendron vernicifluum, an economically important tree species widely distributed in East Asia. The range-wide pattern of sequence variation was analyzed based on a dataset including 357 individuals from China, together with published sequences of 92 individuals mainly from Japan and South Korea. We identified five chloroplast haplotypes based on seven substitutions across the 717-bp alignment. A clear east-west phylogeographic break was recovered according to the stepped landforms of mainland China. The wild trees of the western clade were found to be geographically restricted to the "middle step", which is characterized by high mountains and plateaus, while those of the eastern clade were confined to the "low step", which is mainly made up of hills and plains. The two major clades were estimated to have diverged during the Early Pleistocene, suggesting that the cool glacial climate may have caused the ancestral population to retreat to at least two glacial refugia, leading to allopatric divergence in response to long-term geographic isolation. Migration vector analyses based on the outputs of ecological niche models (ENMs) supported a gradual range expansion since the Last Interglacial. Mountain ranges in western China and the East China Sea land bridge were inferred to be dispersal corridors in the western and eastern distributions of T. vernicifluum, respectively. Overall, our study provides solid evidence for the role of stepped geomorphology in shaping the phylogeographic patterns of T. vernicifluum. The resulting east-west genetic discontinuities could persist for a long time, and could occur at a much larger scale than previously reported, extending from subtropical (e.g., the Xuefeng Mountain) to warm-temperate China (e.g., the Taihang Mountain).

2.
Physiother Res Int ; 25(3): e1832, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31889391

RESUMO

OBJECTIVE: To develop a revised definition of the Bobath concept that incorporates the perspectives of members of the International Bobath Instructors Training Association (IBITA). METHODS: A three-phase consensus building design utilizing (i) focus groups; (ii) survey methods; and, (iii) real-time Delphi. This paper presents the findings from the real-time Delphi, an iterative process to collect and synthesize expert opinions anonymously, provide controlled feedback, with the overall goal of achieving consensus. RESULTS: One hundred and twenty-one IBITA members participated in the real-time Delphi. Over three Delphi Rounds, consensus was reached on six overarching conceptual statements and 11 statements representing unique aspects of Bobath clinical practice. One statement that aimed to describe the Bobath clinical term of "placing" was eliminated in Round One due to participant reservations that a text description was insufficient for this term. Seven statements underwent minor wording revisions in Round Two and Three to improve sentence clarity. CONCLUSION: Using the real-time Delphi, we were successful in gaining consensus in an expert group on a series of statements on which a revised definition of the Bobath concept could be based.


Assuntos
Doenças do Sistema Nervoso Central/reabilitação , Formação de Conceito , Consenso , Transtornos dos Movimentos/reabilitação , Técnica Delphi , Grupos Focais , Humanos , Modalidades de Fisioterapia , Inquéritos e Questionários
4.
Medicines (Basel) ; 6(1)2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30823475

RESUMO

Dental caries and periodontal disease are two major diseases in the dentistry. As the society is aging, their pathological meaning has been changing. An increasing number of patients are displaying symptoms of systemic disease and so we need to pay more attention to immunologic aggression in our medical treatment. For this reason, we focused on natural products. Kampo consists of natural herbs-roots and barks-and has more than 3000 years of history. It was originated in China as traditional medicine and introduced to Japan. Over the years, Kampo medicine in Japan has been formulated in a way to suit Japan's natural features and ethnic characteristics. Based on this traditional Japanese Kampo medicine, we have manufactured a Kampo gargle and Mastic Gel dentifrice. In order to practically utilize the effectiveness of mastic, we have developed a dentifrice (product name: IMPLA CARE) and treated implant periodontitis and severe periodontitis.

5.
Disabil Rehabil ; 41(17): 2080-2092, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-29250987

RESUMO

Background and purpose: The model of Bobath clinical practice provides a framework identifying the unique aspects of the Bobath concept in terms of contemporary neurological rehabilitation. The utilisation of a framework to illustrate the clinical application of the Bobath concept provides the basis for a common understanding with respect to Bobath clinical practice, education, and research. The development process culminating in the model of Bobath clinical practice is described. Case description: The use of the model in clinical practice is illustrated using two cases: a client with a chronic incomplete spinal cord injury and a client with a stroke. Discussion: This article describes the clinical application of the Bobath concept in terms of the integration of posture and movement with respect to the quality of task performance, applying the Model of Bobath Clinical Practice. Facilitation, a key aspect of Bobath clinical practice, was utilised to positively affect motor control and perception in two clients with impairment-related movement problems due to neurological pathology and associated activity limitations and participation restrictions - the outcome measures used to reflect the individual clinical presentation. Implications for Rehabilitation The model of Bobath clinical practice provides a framework identifying the unique aspects of the Bobath-concept. The model of Bobath clinical practice provides the basis for a common understanding with respect to Bobath clinical practice, education, and research. The clinical application of the Bobath-concept highlights the integration of posture and movement with respect to the quality of task performance. Facilitation, a key aspect of Bobath clinical practice, positively affects motor control, and perception.


Assuntos
Reabilitação Neurológica/métodos , Traumatismos da Medula Espinal/reabilitação , Reabilitação do Acidente Vascular Cerebral/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Resolução de Problemas
6.
Physiother Res Int ; 24(2): e1762, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30556333

RESUMO

OBJECTIVE: This study was developed as a consensus-building exercise within the International Bobath Instructors Training Association (IBITA) to develop a revised definition of the Bobath concept. METHODS: A three-phase design utilizing (a) focus groups, (b) survey methods, and, (c) real-time Delphi. This paper details Phase 1 and 2. RESULTS: Forty IBITA members participated in five focus groups. Eight broad themes were developed from the focus groups from which the survey statements were developed. There was a high level of agreement on all nine survey statements identifying overarching constructs and on 12 of the 13 statements identifying unique aspects of Bobath clinical practice. Lower scores were attributed to lack of understanding of the term humanistic, Bobath clinical practice addressing multiple domains such as impairments, activities, and participation and limited agreement on the description of the term "placing." CONCLUSION: Focus groups and a web-based survey were successful in soliciting the opinions of IBITA members on themes and statements of importance for the development of a revised Bobath definition. The results of Phase 1 and 2 will inform Phase 3, a real-time Delphi, to gain consensus within IBITA on statements on which a revised Bobath definition is to be based.


Assuntos
Consenso , Transtornos dos Movimentos/reabilitação , Especialidade de Fisioterapia/normas , Técnica Delphi , Grupos Focais , Humanos , Modelos Teóricos , Inquéritos e Questionários
7.
Exp Brain Res ; 193(3): 445-54, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19030850

RESUMO

Functional decline in locomotion is common among the elderly, and the prevalence of gait disorders increases with age. Recently, increasing interest has been focused on the influence of age-related decline in brain function and neurological disorders such as dementia and Alzheimer's disease on gait capacity. However, the neural mechanisms underlying gait control in the elderly remain poorly understood. We examined whether cortical activation patterns associated with the control of gait speed were related to the walking capacity in elderly subjects. Fifteen healthy elderly subjects participated in the study (mean +/- SD 63 +/- 4). Using functional near-infrared spectroscopy, we measured the changes in the cortical oxygenated hemoglobin (oxyHb) while the subjects walked on a treadmill at low, moderate, and high speeds corresponding to 30, 50, and 70% intensity of work load in each subject. We found a greater increase in oxyHb in the left prefrontal cortex (PFC) and the supplementary motor area (SMA) during walking at 70% intensity than at 50 or 30%. The degree of medial sensorimotor cortex (mSMC) and SMA activations was correlated with the locomotor speed and cadence. Heart rate response was only related with left PFC activation. Furthermore, at the highest speed, the change in the PFC activation was greater in subjects with low gait capacity than in those with high gait capacity. Our results indicate that the left PFC, SMA, and SMC control gait speed, and that the involvement of the left PFC might depend on an age-related decline in gait capacity in the elderly.


Assuntos
Lobo Frontal/fisiologia , Marcha , Lobo Parietal/fisiologia , Caminhada/fisiologia , Análise de Variância , Pressão Sanguínea , Teste de Esforço , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Espectroscopia de Luz Próxima ao Infravermelho
8.
Ann Bot ; 101(3): 463-8, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18045795

RESUMO

BACKGROUND AND AIMS: Bamboos have long-lived, evergreen leaves that continue to accumulate silica throughout their life. Silica accumulation has been suggested to suppress their photosynthetic activity. However, nitrogen content per unit leaf area (N(area)), an important determinant of maximum photosynthetic capacity per unit leaf area (P(max)), decreases as leaves age and senescence. In many species, P(max) decreases in parallel with the leaf nitrogen content. It is hypothesized that if silica accumulation affects photosynthesis, then P(max) would decrease faster than N(area), leading to a decrease in photosynthetic rate per unit leaf nitrogen (photosynthetic nitrogen use efficiency, PNUE) with increasing silica content in leaves. METHODS: The hypothesis was tested in leaves of Sasa veitchii, which have a life span of 2 years and accumulate silica up to 41 % of dry mass. Seasonal changes in P(max), stomatal conductance, N(area) and silica content were measured for leaves of different ages. KEY RESULTS: Although P(max) and PNUE were negatively related with silica content across leaves of different ages, the relationship between PNUE and silica differed depending on leaf age. In second-year leaves, PNUE was almost constant although there was a large increase in silica content, suggesting that leaf nitrogen was a primary factor determining the variation in P(max) and that silica accumulation did not affect photosynthesis. PNUE was strongly and negatively correlated with silica content in third-year leaves, suggesting that silica accumulation affected photosynthesis of older leaves. CONCLUSIONS: Silica accumulation in long-lived leaves of bamboo did not affect photosynthesis when the silica concentration of a leaf was less than 25 % of dry mass. Silica may be actively transported to epidermal cells rather than chlorenchyma cells, avoiding inhibition of CO2 diffusion from the intercellular space to chloroplasts. However, in older leaves with a larger silica content, silica was also deposited in chlorenchyma cells, which may relate to the decrease in PNUE.


Assuntos
Fotossíntese , Folhas de Planta/metabolismo , Poaceae/metabolismo , Dióxido de Silício/metabolismo
9.
Neuroimage ; 39(2): 600-7, 2008 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-17950626

RESUMO

Neural activities in the primary motor cortex and supplementary motor area increase during the preparation as well as execution of voluntary movements of the hand and foot. However, there are few studies concerning preparatory activities of the brain preceding walking performance. We investigated how a verbal instruction "ready" before walking affected cortical activations and walking performances using a functional near-infrared spectroscopy. Seven healthy subjects performed two locomotor tasks on a treadmill with a verbal instruction "ready" before the treadmill was started (prepared walking; PW) and without it (simple walking; SW). Cadence was smaller and stride length was longer in PW than in SW. Increases of oxygenated hemoglobin (oxyHb) in the frontal regions especially in the prefrontal and premotor cortices were greater in PW than in SW both during the preparation and walking periods. These results suggested that preparation for walking cued by a verbal instruction enhanced frontal activations both during the preparation and execution of walking as well as walking performance.


Assuntos
Marcha/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto , Mapeamento Encefálico , Sinais (Psicologia) , Interpretação Estatística de Dados , Feminino , Hemoglobinas/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Oxiemoglobinas/metabolismo , Córtex Somatossensorial/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho
10.
Exp Brain Res ; 169(1): 85-91, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16237521

RESUMO

Treadmill training with body weight support (BWS) was shown to improve locomotion after stroke. We investigated whether BWS affected cortical activation during gait using an optical imaging system. In six patients with subcortical stroke, BWS lowered activation in the sensorimotor cortex (SMC) as assessed by task-related changes of oxygenated hemoglobin levels (P<0.01). The changes of SMC activation correlated with those of cadence (P<0.05). Improvement of asymmetry in SMC activation also correlated with improvement of asymmetric gait (P<0.05). In five age-matched controls, BWS increased overall activation (P<0.05) but did not modify gait parameters and there was no correlation between gait parameters and SMC activation. It is suggested that BWS might improve efficacy of SMC function in patients with stroke.


Assuntos
Peso Corporal/fisiologia , Marcha/fisiologia , Córtex Motor/fisiologia , Aparelhos Ortopédicos , Reabilitação do Acidente Vascular Cerebral , Adulto , Análise de Variância , Mapeamento Encefálico , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Oxiemoglobinas/fisiologia , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/fisiopatologia
11.
J Plant Res ; 118(4): 285-94, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16059658

RESUMO

The aerenchyma differentiation in cable roots, pneumatophores, anchor roots, and feeding roots of the mangrove plant, Avicennia marina (Verbenaceae) was analyzed using a light microscope and scanning electron microscope. In all types, cortex cells were arranged in longitudinal columns extending from the endodermis to the epidermis. No cells in the cortex had intercellular spaces at the root tip (0-150 microm), and aerenchyma started developing at 200 microm from the root apex. The aerenchyma formation was due to cell separation (schizogeny) rather than cell lysis. The cell separation occurred between the longitudinal cell columns, forming long intercellular spaces along the root axis. During aerenchyma formation, the cortex cells enlarged longitudinally by 1.8-3.9 times and widened horizontally by 2.2-2.9 times. As a result, the aerenchyma had a pronounced tubular structure that was radially long, elliptical or oval in cross section and that ran parallel to the root axis. The tube had tapering ends, as did vessel elements, although there were no perforated plates. The interconnection between neighboring tubes was made by abundant small pores or canals that were schizogenous intercellular spaces between the wall cells. All aerenchyma tubes in the root were interconnected by these small pores serving as a gas pathway.


Assuntos
Gases/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Verbenaceae/crescimento & desenvolvimento , Verbenaceae/metabolismo , Microscopia Eletrônica de Varredura , Raízes de Plantas/citologia , Verbenaceae/citologia
12.
Neuroimage ; 23(3): 1020-6, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15528102

RESUMO

We investigated changes of regional activation in the frontal cortices as assessed by changes of hemoglobin oxygenation during walking at 3 and 5 km/h and running at 9 km/h on a treadmill using a near-infrared spectroscopic (NIRS) imaging technique. During the acceleration periods immediately preceded reaching the steady walking or running speed, the levels of oxygenated hemoglobin (oxyHb) increased, but those of deoxygenated hemoglobin (deoxyHb) did not in the frontal cortices. The changes were greater at the higher locomotor speed in the bilateral prefrontal cortex and the premotor cortex, but there were less speed-associated changes in the sensorimotor cortices. The medial prefrontal activation was most prominent during the running task. These results indicate that the prefrontal and premotor cortices are involved in adapting to locomotor speed on the treadmill. These areas might predominantly participate in the control of running rather than walking.


Assuntos
Adaptação Fisiológica/fisiologia , Córtex Motor/fisiologia , Córtex Pré-Frontal/fisiologia , Corrida/fisiologia , Caminhada/fisiologia , Aceleração , Adulto , Feminino , Lateralidade Funcional/fisiologia , Hemodinâmica/fisiologia , Hemoglobinas/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Espectroscopia de Luz Próxima ao Infravermelho
13.
J Plant Res ; 117(6): 465-72, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15538653

RESUMO

Aerenchyma gas spaces are important for plants that grow in flooded and anaerobic sites or habitats, because these gas spaces provide an internal pathway for oxygen transport. The objective of this study is to characterize the development of aerenchyma gas spaces and observe the porosity in roots of Sonneratia alba. Tissue at different developmental stages was collected from four root types, i.e. cable root, pneumatophore, feeding root and anchor root, of S. alba. In S. alba, gas space is schizogenously produced in all root types, and increases in volume from the root meristem to mature root tissues. The aerenchyma formation takes place immediately, or 3-5 mm behind the root apex. At first, cortical cells are relatively round in cross sections (near the root apex); they then become two kinds of cells, rounded and armed, which combine together, forming intercellular spaces behind the root apex. The average dimensions of cortical cells increased more than 1.3 times in the vertical direction and over 3.3 times in the horizontal direction. At maturity, aerenchyma gas spaces are long tuberous structures without diaphragms and with numerous small pores on the lateral walls. Within the aerenchyma, many sclereids grow intrusively. Root porosity in all root types ranged from 0-60%. Pneumatophores and cable roots had the highest aerenchyma area (50-60%).


Assuntos
Lythraceae/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Lythraceae/citologia , Raízes de Plantas/citologia
14.
J Plant Res ; 117(4): 311-7, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15232717

RESUMO

Chloroplast DNA polymorphism in four oak species (Quercus serrata, Q. mongolica var. crispula, Q. dentata and Q. aliena) was studied using collections from a total of 127 localities in Japan and South Korea on the basis of five intergenic spacers (trnD-trnT, trnT-trnL, rps14-psaB, trnS-trnT and trnQ-trnS). Although no variation existed in sequences among the four species, a single nucleotide (T/C) substitution in the trnQ-trnS intergenic spacer was found in all the four species, resulting in two haplotypes (T- and C-type). Phylogenetic analyses of the four species and related species showed that the C-type is derived and even likely of monophyletic origin, while the T-type is ancestral. Geographically, the T-type is widespread from South Korea to Japan, whereas the C-type is restricted to eastern Japan with rare exceptions. "Eastern Japan" approximately coincides with the distribution range of the boreal conifer forest during the last glacial maximum. Overall evidence suggests that the mutation from T- to C-type occurred in an individual of one of the four oak species and then was transferred to all the species by hybridization in eastern Japan, and that the Kanto District provided individuals with the C-type with a refugium during the last glacial maximum.


Assuntos
DNA de Cloroplastos/genética , Quercus/genética , Sequência de Bases , Haplótipos , Japão , Filogenia , Especificidade da Espécie
15.
J Plant Res ; 117(3): 183-9, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15042415

RESUMO

Sixty-four silicified fossil woods were collected from the Early Miocene Upper Coal-bearing Formation of Janggi Group in Pohang City, the Korean Peninsula. Out of them 23 specimens were identified as gymnosperms and 27 specimens as dicotyledons. The taxa identified include Picea palaeomaximowiczii Watari, Taxodioxylon cunninghamioides (Watari) Watari, T. sequoianum (Merckl.) Gothan, Fagus hondoensis (Watari) Watari, Cercidiphyllum sp., Camellia japonoxyla Suzuki et Terada, Distylium chiharu-hirayae Suzuki et Terada, Aesculus sp., Wataria miocenica (Watari) Terada et Suzuki and W. parvipora Terada et Suzuki. All of these species are reported for the first time from the Tertiary basins of Korea. Compared with those of the Miocene Formations in Japan, most taxa we found are common between the paleo-floras in Korea and Japan during the Early to Middle Miocene.


Assuntos
Fósseis , Árvores/classificação , Cycadopsida/classificação , Cycadopsida/citologia , Japão , Coreia (Geográfico) , Magnoliopsida/classificação , Magnoliopsida/citologia , Árvores/citologia
16.
Gynecol Oncol ; 92(2): 713-5, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14766273

RESUMO

BACKGROUND: Treatment of elderly patient with advanced cancer includes considerable problems because of their limited life expectancy. CASE: A 104-year-old woman with FIGO stage IIIB uterine cervical carcinoma treated with external beam radiotherapy and high dose-rate brachytherapy. After the treatment, the serum squamous cell carcinoma (SCC) antigen had fallen to normal level. She is now living 66 months after the treatment without recurrent symptoms. CONCLUSION: In this specific case, the significance of this treatment is that the patient is surviving at the age of 109.


Assuntos
Serpinas , Neoplasias do Colo do Útero/radioterapia , Idoso , Idoso de 80 Anos ou mais , Antígenos de Neoplasias/sangue , Braquiterapia , Feminino , Humanos , Neoplasias do Colo do Útero/sangue
17.
J Plant Res ; 116(2): 83-91, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12736780

RESUMO

The effects of sugars on root growth and on development of adventitious roots were analyzed in Arabidopsis thaliana. Seeds were sown on agar plates containing 0.0-5.0% sugars and placed vertically in darkness (DD) or under long day (LD, 16 h:8 h) conditions, so that the seedlings were constantly attached to the agar medium. In the sucrose-supplemented medium, seedlings showed sustained growth in both DD and LD. However, only dark-grown seedlings developed adventitious roots from the elongated hypocotyl. The adventitious roots began to develop 5 days after imbibition and increased in number until day 11. They could, however, be initiated at any position along the hypocotyl, near the cotyledon or the primary root. They were initiated in the pericycle in the same manner as ordinary lateral roots. Sucrose, glucose and fructose greatly stimulated the induction of adventitious roots, but mannose or sorbitol did not. Sucrose at concentrations of 0.5-2.0% was most effective in inducing adventitious roots, although 5.0% sucrose suppressed induction. Direct contact of the hypocotyl with the sugar-supplemented agar medium was indispensable for the induction of adventitious roots.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Carboidratos/farmacologia , Luz , Fotoperíodo
18.
J Exp Bot ; 54(387): 1627-35, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12730266

RESUMO

The role of vascular tissue in conducting light was analysed in 21 species of woody plants. Vessels, fibres (both xylem and phloem fibres) and tracheids in woody plants are shown to conduct light efficiently along the axial direction of both stems and roots, via their lumina (vessels) or cell walls (fibres and tracheids). Other components, such as sieve tubes and parenchyma cells, are not efficient axial light conductors. Investigation of the spectral properties of the conducted light indicated that far-red light was conducted most efficiently by vascular tissue. Light gradients in the axial direction were also investigated and revealed that conducted light leaked out of the light-conducting structures to the surrounding living tissues. These properties of the conducted light suggest a close relationship with metabolic activities mediated by phytochromes. The results therefore indicate not only that signals from the external light environment can enter the interior of stems above ground and are conducted by vascular tissue towards roots under ground, but also that the light conducted probably contributes directly to photomorphogenic activities within them.


Assuntos
Raízes de Plantas/fisiologia , Caules de Planta/fisiologia , Árvores/fisiologia , Transporte Biológico/fisiologia , Transporte Biológico/efeitos da radiação , Parede Celular/fisiologia , Desenho de Equipamento , Luz , Fitocromo/metabolismo , Raízes de Plantas/efeitos da radiação , Caules de Planta/efeitos da radiação , Árvores/efeitos da radiação
19.
J Plant Res ; 116(1): 13-8, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12605295

RESUMO

It is well known that stems of woody plants shrink and swell diurnally. These fluctuations of stem diameter are induced mainly by the changes of water contents in plants, which are caused by the combination of leaf transpiration and root absorption of water. This implies that dormant-like deciduous broadleaved trees in a leafless state should show no or less changes in stem diameter. However, some physiological activities in woody plants are also known to precede their winter bud opening. Whether and how diameter changes occur in deciduous tree stems during winter was investigated using Zelkova serrata saplings in a leafless state. Measurements of stem diameter changes were done for more than 4 months continuously. The saplings showed distinct diameter changes with periodicities from diurnal to a few weeks, and these changes were initiated 2 months before winter bud opening. These results indicate that some physiological and/or developmental activities occur in the stem of deciduous trees before winter bud opening, and do not correspond to changes in water relations as a result of leaf transpiration. These internal activities cause fluctuations in stem diameter prior to winter bud opening in deciduous trees.


Assuntos
Folhas de Planta/crescimento & desenvolvimento , Caules de Planta/crescimento & desenvolvimento , Ulmaceae/crescimento & desenvolvimento , Água/metabolismo , Folhas de Planta/metabolismo , Caules de Planta/metabolismo , Transpiração Vegetal/fisiologia , Estações do Ano , Ulmaceae/metabolismo
20.
J Plant Res ; 115(1118): 107-12, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12884133

RESUMO

We examined morphological changes in the first-formed protoxylem vessels in Arabidopsis seedlings. Between 2.5 and 8 days after imbibition, mean hypocotyl and root length increased 1.52 and 23.3 times, respectively. In the 2.5-day-old seedlings, two continuous protoxylem vessels were present in the hypocotyl-root axis. In the 8-day-old upper hypocotyls, six protoxylem vessels were observed, and in the lower hypocotyls, four protoxylem vessels and one or two metaxylem vessels were observed. In the 8-day-old roots, there were two protoxylem vessels and two or three metaxylem vessels. Two protoxylem vessels in the hypocotyls connected to two metaxylem vessels in the roots of 8-day-old seedlings. At the 0.3-mm part below the hypocotyl-root boundary, the mean intervals of neighboring annular secondary wall thickenings in protoxylem vessels in 8-day-old roots were 12.9% larger than those in 2.5-day-old roots. In more apical parts of 8-day-old roots, the mean intervals fluctuated between 1.71 and 2.29 microm. In 8-day-old seedlings, metaxylem vessels were formed between 0.4 mm above the hypocotyl-root boundary and 17 mm below the boundary. The intervals in these regions were not extended so much as protoxylem vessels were collapsed. The first-formed protoxylem vessels presumably retain their water-conductive function after metaxylem formation.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...