WorldWideScience

Sample records for decreased stomatal conductance

  1. Decreased photosynthesis in the erect panicle 3 (ep3) mutant of rice is associated with reduced stomatal conductance and attenuated guard cell development.

    Science.gov (United States)

    Yu, Hongyang; Murchie, Erik H; González-Carranza, Zinnia H; Pyke, Kevin A; Roberts, Jeremy A

    2015-03-01

    The ERECT PANICLE 3 gene of rice encodes a peptide that exhibits more than 50% sequence identity with the Arabidopsis F-box protein HAWAIIAN SKIRT (HWS). Ectopic expression of the Os02g15950 coding sequence, driven by the HWS (At3g61950) promoter, rescued the hws-1 flower phenotype in Arabidopsis confirming that EP3 is a functional orthologue of HWS. In addition to displaying an erect inflorescence phenotype, loss-of-function mutants of Os02g15950 exhibited a decrease in leaf photosynthetic capacity and stomatal conductance. Analysis of a range of physiological and anatomical features related to leaf photosynthesis revealed no alteration in Rubisco content and no notable changes in mesophyll size or arrangement. However, both ep3 mutant plants and transgenic lines that have a T-DNA insertion within the Os02g15950 (EP3) gene exhibit smaller stomatal guard cells compared with their wild-type controls. This anatomical characteristic may account for the observed decrease in leaf photosynthesis and provides evidence that EP3 plays a role in regulating stomatal guard cell development.

  2. Herbivore perception decreases photosynthetic carbon-assimilation and reduces stomatal conductance by engaging 12-oxo-phytodienoic acid, mitogen-activated protein kinase 4 and cytokinin perception.

    Science.gov (United States)

    Meza-Canales, Ivan D; Meldau, Stefan; Zavala, Jorge A; Baldwin, Ian T

    2016-12-07

    Herbivory-induced changes in photosynthesis have been documented in many plant species, however the complexity of photosynthetic regulation and analysis has thwarted progress in understanding the mechanism involved, particularly those elicited by herbivore-specific elicitors. Here we analyzed the early photosynthetic gas-exchange responses in Nicotiana attenuata plants after wounding and elicitation with Manduca sexta oral-secretions, and the pathways regulating these responses. Elicitation with M. sexta oral-secretions rapidly decreased photosynthetic carbon-assimilation (AC ) in treated and systemic (untreated, vascularly connected) leaves, which were associated with changes in stomatal conductance, rather than with changes in Rubisco activity and RuBP-turnover. Phytohormone profiling and gas-exchange-analysis of oral-secretion-elicited transgenic plants altered in phytohormone regulation, biosynthesis and perception, combined with micrografting techniques, revealed that the local photosynthetic-responses were mediated by 12-oxo-phytodienoic acid (OPDA), while the systemic responses involved interactions among jasmonates, cytokinins and abscisic acid signaling mediated by mitogen activated protein kinase 4 (MPK4). The analysis also revealed a role for cytokinins interacting with MPK4 in CO2 -mediated stomatal regulation. Hence oral-secretions, while eliciting jasmonic acid-mediated defense responses, also elicits OPDA-mediated changes in stomatal conductance and AC , an observation illustrating the complexity and economy of the signaling that regulates defense and carbon assimilation pathways in response to herbivore attack.

  3. Water deficit in field-grown Gossypium hirsutum primarily limits net photosynthesis by decreasing stomatal conductance, increasing photorespiration, and increasing the ratio of dark respiration to gross photosynthesis.

    Science.gov (United States)

    Chastain, Daryl R; Snider, John L; Collins, Guy D; Perry, Calvin D; Whitaker, Jared; Byrd, Seth A

    2014-11-01

    Much effort has been expended to improve irrigation efficiency and drought tolerance of agronomic crops; however, a clear understanding of the physiological mechanisms that interact to decrease source strength and drive yield loss has not been attained. To elucidate the underlying mechanisms contributing to inhibition of net carbon assimilation under drought stress, three cultivars of Gossypium hirsutum were grown in the field under contrasting irrigation regimes during the 2012 and 2013 growing season near Camilla, Georgia, USA. Physiological measurements were conducted on three sample dates during each growing season (providing a broad range of plant water status) and included, predawn and midday leaf water potential (ΨPD and ΨMD), gross and net photosynthesis, dark respiration, photorespiration, and chlorophyll a fluorescence. End-of-season lint yield was also determined. ΨPD ranged from -0.31 to -0.95MPa, and ΨMD ranged from -1.02 to -2.67MPa, depending upon irrigation regime and sample date. G. hirsutum responded to water deficit by decreasing stomatal conductance, increasing photorespiration, and increasing the ratio of dark respiration to gross photosynthesis, thereby limiting PN and decreasing lint yield (lint yield declines observed during the 2012 growing season only). Conversely, even extreme water deficit, causing a 54% decline in PN, did not negatively affect actual quantum yield, maximum quantum yield, or photosynthetic electron transport. It is concluded that PN is primarily limited in drought-stressed G. hirsutum by decreased stomatal conductance, along with increases in respiratory and photorespiratory carbon losses, not inhibition or down-regulation of electron transport through photosystem II. It is further concluded that ΨPD is a reliable indicator of drought stress and the need for irrigation in field-grown cotton.

  4. Protection of ash (Fraxinus excelsior) trees from ozone injury by ethylenediurea (EDU): roles of biochemical changes and decreased stomatal conductance in enhancement of growth.

    Science.gov (United States)

    Paoletti, Elena; Contran, Nicla; Manning, William J; Castagna, Antonella; Ranieri, Annamaria; Tagliaferro, Francesco

    2008-10-01

    Treatments with ethylenediurea (EDU) protect plants from ozone foliar injury, but the processes underlying this protection are poorly understood. Adult ash trees (Fraxinus excelsior), with or without foliar ozone symptoms in previous years, were treated with EDU at 450 ppm by gravitational trunk infusion in May-September 2005 (32.5 ppm h AOT40). At 30-day intervals, shoot growth, gas exchange, chlorophyll a fluorescence, and water potential were determined. In September, several biochemical parameters were measured. The protective influence of EDU was supported by enhancement in the number of leaflets. EDU did not contribute its nitrogen to leaf tissue as a fertiliser, as determined from lack of difference in foliar N between treatments. Both biochemical (increase in ascorbate-peroxidase and ascorbic acid, and decrease in apoplastic hydrogen peroxide) and biophysical (decrease in stomatal conductance) processes regulated EDU action. As total ascorbic acid increased only in the asymptomatic trees, its role in alleviating O(3) effects on leaf growth and visible injury is controversial.

  5. Effects of stomatal development on stomatal conductance and on stomatal limitation of photosynthesis in Syringa oblata and Euonymus japonicus Thunb.

    Science.gov (United States)

    Wu, Bing-Jie; Chow, Wah Soon; Liu, Yu-Jun; Shi, Lei; Jiang, Chuang-Dao

    2014-12-01

    During leaf development, the increase in stomatal conductance cannot meet photosynthetic demand for CO2, thus leading to stomatal limitation of photosynthesis (Ls). Considering the crucial influences of stomatal development on stomatal conductance, we speculated whether stomatal development limits photosynthesis to some extent. To test this hypothesis, stomatal development, stomatal conductance and photosynthesis were carefully studied in both Syringa oblata (normal greening species) and Euonymus japonicus Thunb (delayed greening species). Our results show that the size of stomata increased gradually with leaf expansion, resulting in increased stomatal conductance up to the time of full leaf expansion. During this process, photosynthesis also increased steadily. Compared to that in S. oblata, the development of chloroplasts in E. japonicus Thunb was obviously delayed, leading to a delay in the improvement of photosynthetic capacity. Further analysis revealed that before full leaf expansion, stomatal limitation increased rapidly in both S. oblata and E. japonicus Thunb; after full leaf expansion, stomatal limitation continually increased in E. japonicus Thunb. Accordingly, we suggested that the enhancement of photosynthetic capacity is the main factor leading to stomatal limitation during leaf development but that stomatal development can alleviate stomatal limitation with the increase of photosynthesis by controlling gas exchange.

  6. Decreased photosynthesis in the erect panicle 3 (ep3) mutant of rice is associated with reduced stomatal conductance and attenuated guard cell development

    OpenAIRE

    2015-01-01

    The ERECT PANICLE 3 gene of rice encodes a peptide that exhibits more than 50% sequence identity with the Arabidopsis F-box protein HAWAIIAN SKIRT (HWS). Ectopic expression of the Os02g15950 coding sequence, driven by the HWS (At3g61950) promoter, rescued the hws-1 flower phenotype in Arabidopsis confirming that EP3 is a functional orthologue of HWS. In addition to displaying an erect inflorescence phenotype, loss-of-function mutants of Os02g15950 exhibited a decrease in leaf photosynthetic c...

  7. Relationship between 18O enrichment in leaf biomass and stomatal conductance.

    Science.gov (United States)

    Sheshshayee, Madavalam Sreeman; Bindumadhava, Hanumantha Rao; Ramesh, Rengaswamy; Prasad, Trichy Ganesh; Udayakumar, Makarla

    2010-03-01

    Models that explain the oxygen isotope enrichment in leaf water (and biomass) treat the relationship between the kinetic fractionation that occurs during evapotranspiration and the stomatal conductance in an empirical way. Consequently, the isotopic enrichment is always predicted to decrease with increasing stomatal conductance, regardless of the experimental evidence to the contrary. We explain why and suggest an alternative method to reconcile theory and experiment. We support this with our experimental data on rice and groundnut plants.

  8. Remote sensing of vegetation canopy photosynthetic and stomatal conductance efficiencies

    Science.gov (United States)

    Myneni, R. B.; Ganapol, B. D.; Asrar, G.

    1992-01-01

    The problem of remote sensing the canopy photosynthetic and stomatal conductance efficiencies is investigated with the aid of one- and three-dimensional radiative transfer methods coupled to a semi-empirical mechanistic model of leaf photosynthesis and stomatal conductance. Desertlike vegetation is modeled as clumps of leaves randomly distributed on a bright dry soil with partial ground cover. Normalized difference vegetation index (NDVI), canopy photosynthetic (Ep), and stomatal efficiencies (Es) are calculated for various geometrical, optical, and illumination conditions. The contribution of various radiative fluxes to estimates of Ep is evaluated and the magnitude of errors in bulk canopy formulation of problem parameters are quantified. The nature and sensitivity of the relationship between Ep and Es to NDVI is investigated, and an algorithm is proposed for use in operational remote sensing.

  9. Verification of the stomatal conductance of Nebbiolo grapevine

    Institute of Scientific and Technical Information of China (English)

    Stefania PRINO; Federico SPANNA; Claudio CASSARDO

    2009-01-01

    Wine is one of the most important Italian export products, and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007, a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d'Alba, near Cuneo, Italy. Using a gauge of trade gases and some other insU'uments, we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and, in particular, of the functional dependence of the stomatal conductance on the following variables: the photosynthetically active radiation, the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The observations allowed us to check and, in some cases, to adapt the existing' general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The parameterizations obtained in this experiment, although referring to a specific plant and site (namely the Nebbiolo at Vezza d'Alba), could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best, and in future could be tested for other grapevines or climates.

  10. Modeling stomatal conductance and ozone uptake of Fagus crenata grown under different nitrogen loads.

    Science.gov (United States)

    Azuchi, Fumika; Kinose, Yoshiyuki; Matsumura, Tomoe; Kanomata, Tomoaki; Uehara, Yui; Kobayashi, Ayumi; Yamaguchi, Masahiro; Izuta, Takeshi

    2014-01-01

    A multiplicative stomatal conductance model was constructed to estimate stomatal O3 uptake of Fagus crenata exposed to O3 under different N loads to the soil. Our stomatal conductance model included environmental functions such as the stomatal responses of F. crenata to diurnal changes, chronic O3 stress (AOT0), acute O3 stress (O3 concentration), and nitrogen load to soil. The model could explain 62% of the variability in stomatal conductance. We suggest therefore that stomatal closure induced by O3 and N load-induced soil acidification must be taken into account in developing a stomatal conductance model for estimating stomatal O3 uptake for future risk assessment of O3 impact on Japanese forest tree species such as F. crenata.

  11. The effect of competition from neighbours on stomatal conductance in lettuce and tomato plants.

    Science.gov (United States)

    Vysotskaya, Lidiya; Wilkinson, Sally; Davies, William J; Arkhipova, Tatyana; Kudoyarova, Guzel

    2011-05-01

    Competition decreased transpiration from young lettuce plants after 2 days, before any reductions in leaf area became apparent, and stomatal conductance (g(s) ) of lettuce and tomato plants was also reduced. Stomatal closure was not due to hydraulic signals or competition for nutrients, as soil water content, leaf water status and leaf nitrate concentrations were unaffected by neighbours. Competition-induced stomatal closure was absent in an abscisic acid (ABA)-deficient tomato mutant, flacca, indicating a fundamental involvement of ABA. Although tomato xylem sap ABA concentrations were unaffected by the presence of neighbours, ABA/pH-based stomatal modulation is still likely to underlie the response to competition, as soil and xylem sap alkalization was observed in competing plants. Competition also modulated leaf ethylene production, and treatment of lettuce plants with an ethylene perception inhibitor (1-methylcyclopropene) diminished the difference in g(s) between single and competing plants grown in a controlled environment room, but increased it in plants grown in the greenhouse: ethylene altered the extent of the stomatal response to competition. Effects of competition on g(s) are discussed in terms of the detection of the absence of neighbours: increases in g(s) and carbon fixation may allow faster initial space occupancy within an emerging community/crop.

  12. Using Plant Temperature to Evaluate the Response of Stomatal Conductance to Soil Moisture Deficit

    Directory of Open Access Journals (Sweden)

    Ming-Han Yu

    2015-10-01

    Full Text Available Plant temperature is an indicator of stomatal conductance, which reflects soil moisture stresses. We explored the relationship between plant temperature and soil moisture to optimize irrigation schedules in a water-stress experiment using Firmiana platanifolia (L. f. Marsili in an incubator. Canopy temperature, leaf temperature, and stomatal conductance were measured using thermal imaging and a porometer. The results indicated that (1 stomatal conductance decreased with declines in soil moisture, and reflected average canopy temperature; (2 the variation of the leaf temperature distribution was a reliable indicator of soil moisture stress, and the temperature distribution in severely water-stressed leaves exhibited greater spatial variation than that in the presence of sufficient irrigation; (3 thermal indices (Ig and crop water stress index (CWSI were theoretically proportional to stomatal conductance (gs, Ig was certified to have linearity relationship with gs and CWSI have a logarithmic relationship with gs, and both of the two indices can be used to estimate soil moisture; and (4 thermal imaging data can reflect water status irrespective of long-term water scarcity or lack of sudden rainfall. This study applied thermal imaging methods to monitor plants and develop adaptable irrigation scheduling, which are important for the formulation of effective and economical agriculture and forestry policy.

  13. Thermal infrared imaging of the temporal variability in stomatal conductance for fruit trees

    Science.gov (United States)

    Struthers, Raymond; Ivanova, Anna; Tits, Laurent; Swennen, Rony; Coppin, Pol

    2015-07-01

    Repeated measurements using thermal infrared remote sensing were used to characterize the change in canopy temperature over time and factors that influenced this change on 'Conference' pear trees (Pyrus communis L.). Three different types of sensors were used, a leaf porometer to measure leaf stomatal conductance, a thermal infrared camera to measure the canopy temperature and a meteorological sensor to measure weather variables. Stomatal conductance of water stressed pear was significantly lower than in the control group 9 days after stress began. This decrease in stomatal conductance reduced transpiration, reducing evaporative cooling that increased canopy temperature. Using thermal infrared imaging with wavelengths between 7.5 and13 μm, the first significant difference was measured 18 days after stress began. A second order derivative described the average rate of change of the difference between the stress treatment and control group. The average rate of change for stomatal conductance was 0.06 (mmol m-2 s-1) and for canopy temperature was -0.04 (°C) with respect to days. Thermal infrared remote sensing and data analysis presented in this study demonstrated that the differences in canopy temperatures between the water stress and control treatment due to stomata regulation can be validated.

  14. Electrical signaling, stomatal conductance, ABA and ethylene content in avocado trees in response to root hypoxia.

    Science.gov (United States)

    Gil, Pilar M; Gurovich, Luis; Schaffer, Bruce; García, Nicolás; Iturriaga, Rodrigo

    2009-02-01

    Avocado (Persea americana Mill.) trees are among the most sensitive of fruit tree species to root hypoxia as a result of flooded or poorly drained soil. Similar to drought stress, an early physiological response to root hypoxia in avocado is a reduction of stomatal conductance. It has been previously determined in avocado trees that an extracellular electrical signal between the base of stem and leaves is produced and related to reductions in stomatal conductance in response to drought stress. The current study was designed to determine if changes in the extracellular electrical potential between the base of the stem and leaves in avocado trees could also be detected in response to short-term (min) or long-term (days) root hypoxia, and if these signals could be related to stomatal conductance (gs), root and leaf ABA and ACC concentrations, ethylene emission from leaves and leaf abscission. In contrast to previous observations for drought-stressed trees, short-term or long-term root hypoxia did not stimulate an electrical potential difference between the base of the stem and leaves. Short-term hypoxia did not result in a significant decrease in gs compared with plants in the control treatment, and no differences in ABA concentration were found between plants subjected to hypoxia and control plants. Long-term hypoxia in the root zone resulted in a significant decrease in gs, increased leaf ethylene and increased leaf abscission. The results indicate that for avocado trees exposed to root hypoxia, electrical signals do not appear to be the primary root-to-shoot communication mechanism involved in signaling for stomatal closure as a result of hypoxia in the root zone.

  15. Electrical signaling, stomatal conductance, ABA and Ethylene content in avocado trees in response to root hypoxia

    Science.gov (United States)

    Gurovich, Luis; Schaffer, Bruce; García, Nicolás; Iturriaga, Rodrigo

    2009-01-01

    Avocado (Persea americana Mill.) trees are among the most sensitive of fruit tree species to root hypoxia as a result of flooded or poorly drained soil. Similar to drought stress, an early physiological response to root hypoxia in avocado is a reduction of stomatal conductance. It has been previously determined in avocado trees that an extracellular electrical signal between the base of stem and leaves is produced and related to reductions in stomatal conductance in response to drought stress. The current study was designed to determine if changes in the extracellular electrical potential between the base of the stem and leaves in avocado trees could also be detected in response to short-term (min) or long-term (days) root hypoxia, and if these signals could be related to stomatal conductance (gs), root and leaf ABA and ACC concentrations, ethylene emission from leaves and leaf abscission. In contrast to previous observations for drought-stressed trees, short-term or long-term root hypoxia did not stimulate an electrical potential difference between the base of the stem and leaves. Short-term hypoxia did not result in a significant decrease in gs compared with plants in the control treatment, and no differences in ABA concentration were found between plants subjected to hypoxia and control plants. Long-term hypoxia in the root zone resulted in a significant decrease in gs, increased leaf ethylene and increased leaf abscission. The results indicate that for avocado trees exposed to root hypoxia, electrical signals do not appear to be the primary root-to-shoot communication mechanism involved in signaling for stomatal closure as a result of hypoxia in the root zone. PMID:19649181

  16. Effects of pulses of elevated carbon dioxide concentration on stomatal conductance and photosynthesis in wheat and rice.

    Science.gov (United States)

    Bunce, James A

    2013-10-01

    Systems for exposing plants to elevated concentrations of CO₂ may expose plants to pulses of CO₂ concentrations considerably above the control set point. The importance of such pulses to plant function is unknown. Single leaves of wheat (Triticum aestivum cv Choptank) and rice (Oryza sativa cv Akitakomachi) were exposed for 30 minutes to pulses of elevated CO₂ similar to the frequency, duration and magnitude of pulses observed in free-air CO₂ enrichment systems. Stomatal conductance decreased within a few minutes of exposure to once per minute pulses of high CO₂ of all the durations tested, in both species. Both species had 20-35% lower stomatal conductance for at least 30 min after the termination of the pulses. After the pulses had stopped, in all cases photosynthesis was below the values expected for the observed substomatal CO₂ concentration, which suggests that either patchy stomatal closure occurred or that photosynthesis was directly inhibited. It was also found that a single, 2 s pulse of elevated CO₂ concentration reaching a maximum of 1000 µmol mol⁻¹ decreased stomatal conductance in both species. On the basis of these results, it is probable that plants in many CO₂ enrichment systems have lower photosynthesis and stomatal conductance than would plants exposed to the same mean CO₂ concentration but without pulses of higher concentration.

  17. RELATIONSHIPS BETWEEN STOMATAL CONDUCTANCE AND YIELD UNDER DEFICIT IRRIGATION IN MAIZE (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Ayman EL Sabagh

    2017-02-01

    Full Text Available This study was conducted to evaluate the adaptability of maize hybrids under water deficit condition by measuring of stomatal conductance with the corresponding yield of maize hybrids. Seven maize hybrids were grown at two different irrigation regimes (well water and deficit water conditions at the agricultural research area of Cukurova University, Adana, Turkey. The results of study indicated that at drought stress (deficit water remarkably influenced maize yield. The hybrid Sancia produced maximum grain yield under water deficient condition while 71May69 hybrid achieved the higher yield under wellwatered condition. Stomatal conductance was strongly correlated with grain yield in this study and higher stomatal conductance indicates higher grain yield, higher stomatal conductance at 7 days after pollination helps to increase grain yield. A positive and significant correlation between grain yield and stomatal conductance was observed at 7th and 21st days after anthesis (DAA. Moderately high stomatal conductance under stress condition helps to produce the highest grain yield. Based on the results, stomatal conductance can be used as selection criterion to identify the drought stress genotypes in maize under Mediterranean condition.

  18. Role of leaf hydraulic conductance in the regulation of stomatal conductance in almond and olive in response to water stress.

    Science.gov (United States)

    Hernandez-Santana, Virginia; Rodriguez-Dominguez, Celia M; Fernández, J Enrique; Diaz-Espejo, Antonio

    2016-06-01

    The decrease of stomatal conductance (gs) is one of the prime responses to water shortage and the main determinant of yield limitation in fruit trees. Understanding the mechanisms related to stomatal closure in response to imposed water stress is crucial for correct irrigation management. The loss of leaf hydraulic functioning is considered as one of the major factors triggering stomatal closure. Thus, we conducted an experiment to quantify the dehydration response of leaf hydraulic conductance (Kleaf) and its impact on gs in two Mediterranean fruit tree species, one deciduous (almond) and one evergreen (olive). Our hypothesis was that a higher Kleaf would be associated with a higher gs and that the reduction in Kleaf would predict the reduction in gs in both species. We measured Kleaf in olive and almond during a cycle of irrigation withholding. We also compared the results of two methods to measure Kleaf: dynamic rehydration kinetics and evaporative flux methods. In addition, determined gs, leaf water potential (Ψleaf), vein density, photosynthetic capacity and turgor loss point. Results showed that gs was higher in almond than in olive and so was Kleaf (Kmax = 4.70 and 3.42 mmol s(-1) MPa(-1) m(-2), in almond and olive, respectively) for Ψleaf > -1.2 MPa. At greater water stress levels than -1.2 MPa, however, Kleaf decreased exponentially, being similar for both species, while gs was still higher in almond than in olive. We conclude that although the Kleaf decrease with increasing water stress does not drive unequivocally the gs response to water stress, Kleaf is the variable most strongly related to the gs response to water stress, especially in olive. Other variables such as the increase in abscisic acid (ABA) may be playing an important role in gs regulation, although in our study the gs-ABA relationship did not show a clear pattern.

  19. Ozone exposure causes a decoupling of conductance and photosynthesis: implications for the Ball-Berry stomatal conductance model.

    Science.gov (United States)

    Lombardozzi, Danica; Sparks, Jed P; Bonan, Gordon; Levis, Samuel

    2012-07-01

    Industrialization has significantly altered atmospheric chemistry by increasing concentrations of chemicals such as nitrogen oxides (NO( x )) and volatile organic carbon, which react in the presence of sunlight to produce tropospheric ozone (O(3)). Ozone is a powerful oxidant that causes both visual and physiological damage to plants, impairing the ability of the plant to control processes like photosynthesis and transpiration. Damage to photosynthesis and stomatal conductance does not always occur at the same rate, which generates a problem when using the Ball-Berry model to predict stomatal conductance because the calculations directly rely on photosynthesis rates. The goals of this work were to develop a modeling framework to modify Ball-Berry stomatal conductance predictions independently of photosynthesis and to test the framework using experimental data. After exposure to elevated O(3) in open-top chambers, photosynthesis and stomatal conductance in tulip poplar changed at different rates through time. We were able to accurately model observed photosynthetic and stomatal conductance responses to chronic O(3) exposure in a Ball-Berry framework by adjusting stomatal conductance in addition to photosynthesis. This led to a significant improvement in the modeled ability to predict both photosynthesis and stomatal conductance responses to O(3).

  20. Simulating canopy stomatal conductance of winter wheat and its distribution using remote sensing information

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The canopy stomatal movement, a plant physiological process, generally occurs within leaves but its influence on exchange of CO2, water vapor, and sensible heat fluxes between atmosphere and terrestrial ecosystem. Many studies have documentedthat the interaction between leaf photosynthesis and canopy stomatal conductance is obvious. Thus, information on stomatal conductance is valuable in climate and ecosystem models. In curren study, a newly developed model was adopted to calculate canopy stomatal conductance of winter wheat in Huang-Huai-Hai (H-H-H) Plain of China (31.5-42.7, 110.0-123.0). The remote sensing information from NOAA-AVHRR and meteorological observed data were used to estimate regional scale stomatal conductance distribution. Canopy stomatal conductance distribution pattern of winter wheat onMarch 18, 1997 was also presented. The developed canopy stomatalconductance model might be used to estimate canopy stomatal conductance in land surface schemes and seems can be acted as a boundary condition in regional climatic model runs.

  1. Photocontrol of the functional coupling between photosynthesis and stomatal conductance in the intact leaf

    Energy Technology Data Exchange (ETDEWEB)

    Zeiger, E.; Field, C.

    1982-08-01

    The photocontrol of the functional coupling between photosynthesis and stomatal conductance in the leaf was investigated in gas exchange experiments using monochromatic light provided by lasers. Net photosynthesis and stomatal conductance were measured in attached leaves of Malva parviflora L. as a function of photon irradiance at 457.9 and 640.0 nanometers. Photosynthetic rates and quantum yields of photosynthesis were higher under red light than under blue, on an absorbed or incident basis. Stomatal conductance was higher under blue than under red light at all intensities. Based on a calculated apparent photon efficiency of conductance, blue and red light had similar effects on conductance at intensities higher than 0.02 millimoles per square meter per second, but blue light was several-fold more efficient at very low photon irradiances. Red light had no effect on conductance at photon irradiances below 0.02 millimoles per square meter per second. These observations support the hypothesis that stomatal conductance is modulated by two photosystems: a blue light-dependent one, driving stomatal opening at low light intensities and a photosynthetically active radiation (PAR)-dependent one operating at higher irradiances. When low intensity blue light was used to illuminate a leaf already irradiated with high intensity, 640 nanometers light, the leaf exhibited substantial increases in stomatal conductance. Net photosynthesis changed only slightly. Additional far-red light increased net photosynthesis without affecting stomatal conductance. These observations indicate that under conditions where the PAR-dependent system is driven by high intensity red light, the blue light-dependent system has an additive effect on stomatal conductance.

  2. Does the empirical Ball-Berry law of stomatal conductance emerge from maximization of productivity?

    Science.gov (United States)

    Patwardhan, S.; Pavlick, R.; Kleidon, A.

    2006-12-01

    The stomatal conductance of vegetation canopies links the exchange fluxes of energy, water, and carbon at the interface of the land surface and the atmospheric boundary layer. The Ball-Berry empirical law describes the behavior of stomatal conductance as a function of environmental conditions and net photosynthetic rate. Here we test whether the Ball-Berry law of stomatal functioning can be understood as the emergent result of optimized vegetation behavior that maximizes productivity. We conducted a range of sensitivity simulations with PlaSim, an Earth system model of intermediate complexity, in which we varied maximum surface conductance, which is strongly affected by stomatal functioning. We then evaluated how the emergent relationship between simulated productivity, relative humidity, surface conductance, and optimal functioning compares to the empirical Ball-Berry model. The model simulations show that the best correspondence with the Ball-Berry relationship (expressed by r2 values) corresponds roughly to the value of maximum surface conductance that maximizes productivity. This implies the Ball-Berry relationship emerges from optimized stomatal functioning. Hence, it would seem to be more appropriate to use an optimality principle for modelling stomatal functioning than to "force" land-atmosphere models with an empirical, emergent relationship.

  3. A test of an optimal stomatal conductance scheme within the CABLE land surface model

    Science.gov (United States)

    De Kauwe, M. G.; Kala, J.; Lin, Y.-S.; Pitman, A. J.; Medlyn, B. E.; Duursma, R. A.; Abramowitz, G.; Wang, Y.-P.; Miralles, D. G.

    2015-02-01

    Stomatal conductance (gs) affects the fluxes of carbon, energy and water between the vegetated land surface and the atmosphere. We test an implementation of an optimal stomatal conductance model within the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model (LSM). In common with many LSMs, CABLE does not differentiate between gs model parameters in relation to plant functional type (PFT), but instead only in relation to photosynthetic pathway. We constrained the key model parameter "g1", which represents plant water use strategy, by PFT, based on a global synthesis of stomatal behaviour. As proof of concept, we also demonstrate that the g1 parameter can be estimated using two long-term average (1960-1990) bioclimatic variables: (i) temperature and (ii) an indirect estimate of annual plant water availability. The new stomatal model, in conjunction with PFT parameterisations, resulted in a large reduction in annual fluxes of transpiration (~ 30% compared to the standard CABLE simulations) across evergreen needleleaf, tundra and C4 grass regions. Differences in other regions of the globe were typically small. Model performance against upscaled data products was not degraded, but did not noticeably reduce existing model-data biases. We identified assumptions relating to the coupling of the vegetation to the atmosphere and the parameterisation of the minimum stomatal conductance as areas requiring further investigation in both CABLE and potentially other LSMs. We conclude that optimisation theory can yield a simple and tractable approach to predicting stomatal conductance in LSMs.

  4. A test of an optimal stomatal conductance scheme within the CABLE Land Surface Model

    Directory of Open Access Journals (Sweden)

    M. G. De Kauwe

    2014-10-01

    Full Text Available Stomatal conductance (gs affects the fluxes of carbon, energy and water between the vegetated land surface and the atmosphere. We test an implementation of an optimal stomatal conductance model within the Community Atmosphere Biosphere Land Exchange (CABLE land surface model (LSM. In common with many LSMs, CABLE does not differentiate between gs model parameters in relation to plant functional type (PFT, but instead only in relation to photosynthetic pathway. We therefore constrained the key model parameter "g1" which represents a plants water use strategy by PFT based on a global synthesis of stomatal behaviour. As proof of concept, we also demonstrate that the g1 parameter can be estimated using two long-term average (1960–1990 bioclimatic variables: (i temperature and (ii an indirect estimate of annual plant water availability. The new stomatal models in conjunction with PFT parameterisations resulted in a large reduction in annual fluxes of transpiration (~ 30% compared to the standard CABLE simulations across evergreen needleleaf, tundra and C4 grass regions. Differences in other regions of the globe were typically small. Model performance when compared to upscaled data products was not degraded, though the new stomatal conductance scheme did not noticeably change existing model-data biases. We conclude that optimisation theory can yield a simple and tractable approach to predicting stomatal conductance in LSMs.

  5. Lower responsiveness of canopy evapotranspiration rate than of leaf stomatal conductance to open-air CO2 elevation in rice.

    Science.gov (United States)

    Shimono, Hiroyuki; Nakamura, Hirofumi; Hasegawa, Toshihiro; Okada, Masumi

    2013-08-01

    An elevated atmospheric CO2 concentration ([CO2 ]) can reduce stomatal conductance of leaves for most plant species, including rice (Oryza sativa L.). However, few studies have quantified seasonal changes in the effects of elevated [CO2 ] on canopy evapotranspiration, which integrates the response of stomatal conductance of individual leaves with other responses, such as leaf area expansion, changes in leaf surface temperature, and changes in developmental stages, in field conditions. We conducted a field experiment to measure seasonal changes in stomatal conductance of the uppermost leaves and in the evapotranspiration, transpiration, and evaporation rates using a lysimeter method. The study was conducted for flooded rice under open-air CO2 elevation. Stomatal conductance decreased by 27% under elevated [CO2 ], averaged throughout the growing season, and evapotranspiration decreased by an average of 5% during the same period. The decrease in daily evapotranspiration caused by elevated [CO2 ] was more significantly correlated with air temperature and leaf area index (LAI) rather than with other parameters of solar radiation, days after transplanting, vapor-pressure deficit and FAO reference evapotranspiration. This indicates that higher air temperatures, within the range from 16 to 27 °C, and a larger LAI, within the range from 0 to 4 m(2)  m(-2) , can increase the magnitude of the decrease in evapotranspiration rate caused by elevated [CO2 ]. The crop coefficient (i.e. the evapotranspiration rate divided by the FAO reference evapotranspiration rate) was 1.24 at ambient [CO2 ] and 1.17 at elevated [CO2 ]. This study provides the first direct measurement of the effects of elevated [CO2 ] on rice canopy evapotranspiration under open-air conditions using the lysimeter method, and the results will improve future predictions of water use in rice fields.

  6. The Effect of Drought on Stomatal Conductance in the Biosphere 2 Rainforest

    Science.gov (United States)

    Gay, J. D.; Van Haren, J. L. M.

    2015-12-01

    Drought is a major climate change concern for the Earth's rainforests; however little is currently known about how these forests and individual plants will respond to water stress. At the individual level, the ability of plants to regulate their stomatal conductance is an important preservation mechanism that helps to cool leaves, regulate water loss, and uptake carbon dioxide. At the ecosystem level, transpiration in rainforests is a major contributor to the positive feedback loop that returns moisture to the atmosphere for continued precipitation cycles. Nearly 60% of atmospheric moisture in the Amazon rain forests has been traced back to origins of transpiration from its plants. In relation to current climatic conditions, stomatal conductance rates are highly variable across rainforest species and environmental conditions. It is still unknown to what extent these rates will decrease at leaf and forest level in response to periods of drought. The University of Arizona's Biosphere 2 (B2) served as the study site for a simulated 4-week long drought because of its ability to mimic the micrometeorology of an Amazonian rainforest. Three species of plants were chosen at various levels in the canopy: Clitoria racemosa, Cissus sicyoides, and Hibiscus elatus. These plants were selected based on their relative abundance and distribution in the B2 forest. It was revealed that two out of the three species exhibited decreases in H20 efflux at each elevation, while one species (C. racemosa) proved much more resistant, at each elevation, to H20 loss. These results may be useful for future integrative modeling of how individual leaf level responses extend to entire ecosystem scales. It will be important to better understand how rainforests conserve, recycle, and lose water to gauge their response to warming climate, and increased periods of drought in the tropics.

  7. Modeling of stomatal conductance to estimate stomatal ozone uptake by Fagus crenata, Quercus serrata, Quercus mongolica var. crispula and Betula platyphylla.

    Science.gov (United States)

    Kinose, Yoshiyuki; Azuchi, Fumika; Uehara, Yui; Kanomata, Tomoaki; Kobayashi, Ayumi; Yamaguchi, Masahiro; Izuta, Takeshi

    2014-11-01

    To construct stomatal conductance models and estimate stomatal O3 uptake for Fagus crenata, Quercus serrata, Quercus mongolica var. crispula and Betula platyphylla, stomatal conductance (gs) was measured in seedlings of the four tree species. Better estimates of gs were made by incorporating the acute effects of O3 on gs into the models and the models could explain 34-52% of the variability in gs. Although the O3 concentration was relatively high in spring from April to May, COU of F. crenata, Q. serrata and Q. mongolica var. crispula were relatively low and the ratios of COU in spring to total COU in one year were 16.8% in all tree species because of low gs limited mainly by leaf pre-maturation and/or low temperature. The COU of B. platyphylla were relatively high mainly because of rapid leaf maturation and lower optimal temperature for stomatal opening.

  8. Factors influencing stomatal conductance in response to water availability in grapevine: a meta-analysis.

    Science.gov (United States)

    Lavoie-Lamoureux, Anouk; Sacco, Dario; Risse, Paul-André; Lovisolo, Claudio

    2017-04-01

    The main factors regulating grapevine response to decreasing water availability were assessed under statistical support using published data related to leaf water relations in an extensive range of scion and rootstock genotypes. Matching leaf water potential (Ψleaf ) and stomatal conductance (gs ) data were collected from peer-reviewed literature with associated information. The resulting database contained 718 data points from 26 different Vitis vinifera varieties investigated as scions, 15 non-V. vinifera rootstock genotypes and 11 own-rooted V. vinifera varieties. Linearised data were analysed using the univariate general linear model (GLM) with factorial design including biological (scion and rootstock genotypes), methodological and environmental (soil) fixed factors. The first GLM performed on the whole database explained 82.4% of the variability in data distribution having the rootstock genotype the greatest contribution to variability (19.1%) followed by the scion genotype (16.2%). A classification of scions and rootstocks according to their mean predicted gs in response to moderate water stress was generated. This model also revealed that gs data obtained using a porometer were in average 2.1 times higher than using an infra-red gas analyser. The effect of soil water-holding properties was evaluated in a second analysis on a restricted database and showed a scion-dependant effect, which was dominant over rootstock effect, in predicting gs values. Overall the results suggest that a continuum exists in the range of stomatal sensitivities to water stress in V. vinifera, rather than an isohydric-anisohydric dichotomy, that is further enriched by the diversity of scion-rootstock combinations and their interaction with different soils. © 2016 Scandinavian Plant Physiology Society.

  9. Effects of Moisture and Mycorrhiza on Stomatal Conductance and ...

    African Journals Online (AJOL)

    acer

    week for moisture stressed plants) and three mycorrhizal treatments namely; endomycorrhizal plants, ectomycorrhizal ... The role of mycorrhiza in enhancing water retention ability of ... in the pre-sun rise values, the Stomata. Conductance at ...

  10. Stomatal and mesophyll conductances to CO2 are the main limitations to photosynthesis in sugar beet (Beta vulgaris) plants grown with excess zinc.

    Science.gov (United States)

    Sagardoy, R; Vázquez, S; Florez-Sarasa, I D; Albacete, A; Ribas-Carbó, M; Flexas, J; Abadía, J; Morales, F

    2010-07-01

    *The effects of zinc (Zn) toxicity on photosynthesis and respiration were investigated in sugar beet (Beta vulgaris) plants grown hydroponically with 1.2, 100 and 300 microM Zn. *A photosynthesis limitation analysis was used to assess the stomatal, mesophyll, photochemical and biochemical contributions to the reduced photosynthesis observed under Zn toxicity. *The main limitation to photosynthesis was attributable to stomata, with stomatal conductances decreasing by 76% under Zn excess and stomata being unable to respond to physiological and chemical stimuli. The effects of excess Zn on photochemistry were minor. Scanning electron microscopy showed morphological changes in stomata and mesophyll tissue. Stomatal size and density were smaller, and stomatal slits were sealed in plants grown under high Zn. Moreover, the mesophyll conductance to CO(2) decreased by 48% under Zn excess, despite a marked increase in carbonic anhydrase activity. Respiration, including that through both cytochrome and alternative pathways, was doubled by high Zn. *It can be concluded that, in sugar beet plants grown in the presence of excess Zn, photosynthesis is impaired due to a depletion of CO(2) at the Rubisco carboxylation site, as a consequence of major decreases in stomatal and mesophyll conductances to CO(2).

  11. Increased leaf photosynthesis caused by elevated stomatal conductance in a rice mutant deficient in SLAC1, a guard cell anion channel protein

    OpenAIRE

    2012-01-01

    In rice (Oryza sativa L.), leaf photosynthesis is known to be highly correlated with stomatal conductance; however, it remains unclear whether stomatal conductance dominantly limits the photosynthetic rate. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. In order to examine stomatal limitations to photosynthesis, a SLAC1-deficient mutant of rice was isolated and characterized. A TILLING screen of N-methyl-N-nitrosourea-derived mutant ...

  12. Effects of CO2 Concentration on Leaf Photosynthesis and Stomatal Conductance of Potatoes Grown Under Different Irradiance Levels and Photoperiods

    Science.gov (United States)

    Wheeler, R. M.; Fitzpatrick, A. H.; Tibbitts, T. W.

    2012-01-01

    Potato (Solanum tuberosum L.) cvs. Russet Burbank, Denali, and Norland, were grown in environmental rooms controlled at approx 350 micro mol/mol (ambient during years 1987/1988) and 1000 micro mol/mol (enriched) CO2 concentrations. Plants and electric lamps were arranged to provide two irradiance zones, 400 and 800 micro mol/mol/square m/S PPF and studies were repeated using two photoperiods (12-h light / 12-h dark and continuous light). Leaf photosynthetic rates and leaf stomatal conductance were measured using fully expanded, upper canopy leaves at weekly intervals throughout growth (21 through 84 days after transplanting). Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod increased leaf photosynthetic rates by 39% at 400 micro mol/mol/square m/S PPF and 27% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under continuous light decreased leaf photosynthetic rates by 7% at 400 micro mol/mol/square m/S PPF and 13% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod plants decreased stomatal conductance by an average of 26% at 400 micro mol/mol/square m/S PPF and 42% at 800 micro mol/mol/square m/S PPF. Under continuous light, CO2 enrichment resulted in a small increase (2%) of stomatal conductance at 400 micro mol/mol/square m/S PPF, and a small decrease (3%) at 800 micro mol/mol/square m/S PPF. Results indicate that CO2 enrichment under the 12-h photoperiod showed the expected increase in photosynthesis and decrease in stomatal conductance for a C3 species like potato, but the decreases in leaf photosynthetic rates and minimal effect on conductance from CO2 enrichment under continuous light were not expected. The plant leaves under continuous light showed more chlorosis and some rusty flecking versus plants under the 12-h photoperiod, suggesting the continuous light was more stressful on the plants. The increased

  13. Drought-Induced Changes in Xylem Sap pH,ABA and Stomatal Conductance

    Institute of Scientific and Technical Information of China (English)

    GUO Xiu-lin; LIU Zi-hui; Razzaq; LI Guang-min

    2004-01-01

    Upstream signals potentially regulating evaporation and stomatal conductance were investigated using 6-8-leaf-old maize(Zea may L.)seedlings which were grown in a greenhouse.Pressure chamber was used to measure leaf water potential and to collect xylem sap.The pH of xylem sap in stems was higher than that in root,and the abscisic acid(ABA)concentration in stems was the highest in well-watered seedlings.The ABA concentration and pH of xylem sap in roots,stems and leaves increased,and the ABA concentration in leaves reached the maximum during drought stress.The treatment of roots with exogenous ABA solution(100 μmol L-1)increased xylem sap ABA concentration in all organs measured,and induced stomatal closure,but did not change ABA distribution among organs of maize seedlings.The combined effects of external pH buffer on pH,ABA of xylem sap and stomatal behavior indicated that pH,as a root-source signal to leaves under drought stress,regulated stomatal closure through accumulating ABA in leaves or guard cells.

  14. Response of canopy stomatal conductance of Acacia mangium forest to environmental driving factors

    Institute of Scientific and Technical Information of China (English)

    Xiaojing LIU; Ping ZHAO; Xingquan RAO; Ling MA; Xian CAI; Xiaoping ZENG

    2008-01-01

    Granier's probes were applied to measure the sap flow of 14 sample trees in an Acacia mangium forest on the hilly lands in Heshan City, Guangdong, during the time period of October, 2003. The photosynthetically active radi-ation (PAR), air relative humidity (RH) and temperature of air (T) above the forest canopy were recorded. The sap flow measurement was used in combination with morphological characteristics of tree and forest structure to calculate the whole-tree transpiration (E), stand transpiration (Et), and mean canopy stomatal conductance (gc). Analyses on the rela-tionships between tree morphological characters and whole-tree water use, and on the responses of gc to PAR and vapor pressure deficit (D) were conducted. The results showed that whole-tree transpiration correlated significantly and positively with tree diameter at breast height (DBH) (p < 0.0001), with sapwood area (p < 0.0001), and with canopy size (p = 0.0007) logarithmically, but exponentially with tree height (p = 0.014). The analyses on the responses of canopy stomatal conductance showed that the maximum gc (gcmax) changed with PAR in a hyperbolic curve (p <0.0001) and with D in a logarithmic one (p < 0.0001). The results obtained with sap flow technique indicate its reliability and accuracy of the methods of estimation of whole-tree and stand transpirations and canopy stomatal conductance.

  15. Optimal stomatal behavior theory for simulating stomatal conductance%最优气孔行为理论和气孔导度模拟

    Institute of Scientific and Technical Information of China (English)

    范嘉智; 王丹; 胡亚林; 景盼盼; 王朋朋; 陈吉泉

    2016-01-01

    气孔调节功能是陆地生态系统碳-水耦合过程中最重要的环节.与即时的气孔导度测量相比,气孔导度斜率能有效地反映气孔导度对CO2浓度、饱和水汽压亏缺和光合作用的敏感性,包含了环境因子对光合作用和临界水分利用效率等的综合影响,为研究全球变化下陆地生态系统碳-水耦合关系提供了一个简明且综合的框架.气孔导度模型从经验模型、半经验模型发展到机理模型,经过很多学者的改进,但是模型参数的生物学意义和变化规律还不明确.鉴于气孔导度斜率方面研究的重要性和研究的不足,为了加强对气孔导度调节规律的认识,并减少气孔导度模拟的不确定性,该文主要综述了长期以来国内外关于最优气孔行为理论和气孔导度模拟方面的研究成果,其中包括广泛使用的气孔导度模型及参数意义,讨论影响气孔导度斜率的主要因素以及气孔导度机理模型的应用,并对最优气孔行为理论和气孔导度模拟方面的研究做了简单展望.%Among the most critical processes in simulating terrestrial ecosystem performance is the regulatory role of stomata in carbon and water cycles.Compared with field measurements,the changes in stomatal slope caused by the biophysical environment provide a simple but effective synthetic framework for studying climate-related carbon and water cycling,due to its sensitivity to CO2,vapor pressure deficit,and photosynthesis.It is also crucial in understanding the effects of climate change on photosynthesis and water use efficiency.Endeavored by numerous scholastic efforts,stomatal conductance models have been improved based on experimental,semi-experimental,and mechanical processes.However,the underlying biological mechanisms and the dynamics of key parameters in these models remain unexplored,especially regarding the changes in stomatal slope.By improving the understanding of the stomata's regulatory role

  16. QTLs Associated with Crown Root Angle, Stomatal Conductance, and Maturity in Sorghum.

    Science.gov (United States)

    Lopez, Jose R; Erickson, John E; Munoz, Patricio; Saballos, Ana; Felderhoff, Terry J; Vermerris, Wilfred

    2017-07-01

    Three factors that directly affect the water inputs in cropping systems are root architecture, length of the growing season, and stomatal conductance to water vapor (). Deeper-rooted cultivars will perform better under water-limited conditions because they can access water stored deeper in the soil profile. Reduced limits transpiration rate () and thus throughout the vegetative phase conserves water that may be used during grain filling in water-limited environments. Additionally, growing early-maturing varieties in regions that rely on soil-stored water is a key water management strategy. To further our understanding of the genetic basis underlying root depth, growing season length, and we conducted a quantitative trait locus (QTL) study. A QTL for crown root angle (a proxy for root depth) new to sorghum was identified in chromosome 3. For , a QTL in chromosome seven was identified. In a follow-up field study it was determined that the QTL for was associated with reduced but not with net carbon assimilation rate () or shoot biomass. No differences in guard-cell length or stomatal density were observed among the lines, leading to the conclusion that the observed differences in must be explained by partial stomatal closure. The well-studied maturity gene was identified in the QTL for maturity. The transgressive segregation of the population was explained by the possible interaction of with other loci. Finally, the most probable position of the genes underlying the QTLs and candidate genes were proposed. Copyright © 2017 Crop Science Society of America.

  17. Diurnal and seasonal variations in stomatal conductance of rice at elevated atmospheric CO(2) under fully open-air conditions.

    Science.gov (United States)

    Shimono, Hiroyuki; Okada, Masumi; Inoue, Meguru; Nakamura, Hirofumi; Kobayashi, Kazuhiko; Hasegawa, Toshihiro

    2010-03-01

    Understanding of leaf stomatal responses to the atmospheric CO(2) concentration, [CO(2)], is essential for accurate prediction of plant water use under future climates. However, limited information is available for the diurnal and seasonal changes in stomatal conductance (g(s)) under elevated [CO(2)]. We examined the factors responsible for variations in g(s) under elevated [CO(2)] with three rice cultivars grown in an open-field environment under flooded conditions during two growing seasons (a total of 2140 individual measurements). Conductance of all cultivars was generally higher in the morning and around noon than in the afternoon, and elevated [CO(2)] decreased g(s) by up to 64% over the 2 years (significantly on 26 out of 38 measurement days), with a mean g(s) decrease of 23%. We plotted the g(s) variations against three parameters from the Ball-Berry model and two revised versions of the model, and all parameters explained the g(s) variations well at each [CO(2)] in the morning and around noon (R(2) > 0.68), but could not explain these variations in the afternoon (R(2) rice production.

  18. Environmental controls on saltcedar (Tamarix spp.) transpiration and stomatal conductance and implications for determining evapotranspiration by remote sensing

    Science.gov (United States)

    Nagler, P. L.; Glenn, E. P.; morino, K.

    2012-12-01

    Saltcedar is an introduced, salt-tolerant shrub that now dominates many flow-regulated western U.S. rivers. Saltcedar control programs have been implemented to salvage water and to allow the return of native vegetation to infested rivers. However, there is much debate about how much water saltcedar actually uses and the range of ecohydrological niches it occupies. Ground methods for measuring riparian zone ET have improved and there is considerable interest in developing remote sensing methods for saltcedar to conduct wide-area monitoring of water use. Both thermal band and vegetation index methods have been used to estimate riparian ET. However, several problems present themselves in applying existing remote sensing methods to riparian corridors. First, many riparian corridors are narrow and are surrounded by arid uplands, hence they cannot be treated as energetically closed systems, an assumption of thermal band methods that calculate ET as a residual in the surface energy balance. Second, contrary to the assumption that riparian phreatophytes typically grow under unstressed conditions since they are rooted into groundwater, we find that saltcedar stands are under substantial degrees of apparent moisture stress, exhibiting midday depression of transpiration and stomatal conductance, and decreases in stomatal conductance over the growing season as depth to groundwater increases. Furthermore, the degree of stress is site-specific, depending on local soil texture, salinity of the groundwater and distance from the river. This violates a key assumption of vegetation index methods for estimating ET. The implications of these findings for arid-zone riparian ecohydrology and for remote sensing methods that assume either a constant daily evaporative fraction or rate of stomatal conductance will be discussed using saltcedar stands measured in the Cibola NWR on the lower Colorado River as a case study. Daily rates of saltcedar transpiration ranged from 1.6-3.0 mm/m2 leaf

  19. Canopy-scale relationships between stomatal conductance and photosynthesis in irrigated rice.

    Science.gov (United States)

    Ono, Keisuke; Maruyama, Atsushi; Kuwagata, Tsuneo; Mano, Masayoshi; Takimoto, Takahiro; Hayashi, Kentaro; Hasegawa, Toshihiro; Miyata, Akira

    2013-07-01

    Modeling stomatal behavior is critical in research on land-atmosphere interactions and climate change. The most common model uses an existing relationship between photosynthesis and stomatal conductance. However, its parameters have been determined using infrequent and leaf-scale gas-exchange measurements and may not be representative of the whole canopy in time and space. In this study, we used a top-down approach based on a double-source canopy model and eddy flux measurements throughout the growing season. Using this approach, we quantified the canopy-scale relationship between gross photosynthesis and stomatal conductance for 3 years and their relationships with leaf nitrogen content throughout each growing season above a paddy rice canopy in Japan. The canopy-averaged stomatal conductance (gsc ) increased with increasing gross photosynthesis per unit green leaf area (Ag ), as was the case with leaf-scale measurements, and 41-90% of its variation was explained by variations in Ag adjusted to account for the leaf-to-air vapor-pressure deficit and CO2 concentration using the Leuning model. The slope (m) in this model (gsc versus the adjusted Ag ) was almost constant within a 15-day period, but changed seasonally. The m values determined using an ensemble dataset for two mid-growing-season 15-day periods were 30.8 (SE = 0.5), 29.9 (SE = 0.7), and 29.9 (SE = 0.6) in 2004, 2005, and 2006, respectively; the overall mid-season value was 30.3 and did not greatly differ among the 3 years. However, m appeared to be higher during the early and late growing seasons. The ontogenic changes in leaf nitrogen content strongly affected Ag and thus gsc . In addition, we have discussed the agronomic impacts of the interactions between leaf nitrogen content and gsc . Despite limitations in the observations and modeling, our canopy-scale results emphasize the importance of continuous, season-long estimates of stomatal model parameters for crops using top-down approaches.

  20. Carbonyl sulfide (COS) as a tracer for canopy photosynthesis, transpiration and stomatal conductance: potential and limitations

    Science.gov (United States)

    Wohlfahrt, G.; Brilli, F.; Hörtnagl, L.; Xu, X.; Bingemer, H.; Hansel, A.; Loreto, F.

    2011-12-01

    We review the theoretical basis for the link between the leaf exchange of COS, CO2 and H2O and the assumptions that need to be made in order to use COS as a tracer for canopy net photosynthesis, transpiration and stomatal conductance. The ratios of COS to CO2 and H2O deposition velocities used to this end are shown to vary with the ratio of the internal to ambient CO2 and H2O mole fractions and the relative limitations by boundary layer, stomatal and internal conductance for COS. Back of the envelope calculations suggest these deposition velocity ratios to exhibit considerable variability, in accordance with available empirical literature data, a finding that challenges current parameterisations which treat these as vegetation specific constants. Due to the comparably more conservative nature of the internal to ambient CO2 mole fraction ratio we conclude that COS is a better tracer for CO2 than H2O. Using COS as a tracer for stomatal conductance is hampered by our present poor understanding of the leaf internal conductance to COS. Estimating canopy level CO2 and H2O fluxes requires disentangling leaf COS exchange from other sources/sinks of COS, in particular the soil. Some practical approaches to this end, in analogy to current practises of CO2 flux partitioning, are discussed. We conclude that future priorities for COS research should be to develop a better quantitative understanding of the variability in the ratios of COS to CO2 and H2O deposition velocities and the controlling factors and to develop operational methods for disentangling ecosystem COS exchange into contributions by leaves and other sources/sinks of COS. In order to test our present understanding of COS exchange and its relation to canopy photosynthesis and transpiration integrated studies are needed which concurrently quantify the ecosystem scale CO2, H2O and COS exchange and the corresponding component fluxes.

  1. Carbonyl sulfide (COS) as a tracer for canopy photosynthesis, transpiration and stomatal conductance: potential and limitations.

    Science.gov (United States)

    Wohlfahrt, Georg; Brilli, Federico; Hörtnagl, Lukas; Xu, Xiaobin; Bingemer, Heinz; Hansel, Armin; Loreto, Francesco

    2012-04-01

    The theoretical basis for the link between the leaf exchange of carbonyl sulfide (COS), carbon dioxide (CO(2)) and water vapour (H(2)O) and the assumptions that need to be made in order to use COS as a tracer for canopy net photosynthesis, transpiration and stomatal conductance, are reviewed. The ratios of COS to CO(2) and H(2)O deposition velocities used to this end are shown to vary with the ratio of the internal to ambient CO(2) and H(2)O mole fractions and the relative limitations by boundary layer, stomatal and internal conductance for COS. It is suggested that these deposition velocity ratios exhibit considerable variability, a finding that challenges current parameterizations, which treat these as vegetation-specific constants. COS is shown to represent a better tracer for CO(2) than H(2)O. Using COS as a tracer for stomatal conductance is hampered by our present poor understanding of the leaf internal conductance to COS. Estimating canopy level CO(2) and H(2)O fluxes requires disentangling leaf COS exchange from other ecosystem sources/sinks of COS. We conclude that future priorities for COS research should be to improve the quantitative understanding of the variability in the ratios of COS to CO(2) and H(2)O deposition velocities and the controlling factors, and to develop operational methods for disentangling ecosystem COS exchange into contributions by leaves and other sources/sinks. To this end, integrated studies, which concurrently quantify the ecosystem-scale CO(2), H(2)O and COS exchange and the corresponding component fluxes, are urgently needed.

  2. Effect of different soil water potential on leaf transpiration and on stomatal conductance in poinsettia

    Directory of Open Access Journals (Sweden)

    Jacek S. Nowak

    2013-12-01

    Full Text Available Euphorbia pulcherrima Wild.'Lilo' was grown in containers in 60% peat, 30% perlite and 10% clay (v/v mixture, with different irrigation treatments based on soil water potential. Plants were watered at two levels of drought stress: -50kPa or wilting. The treatments were applied at different stages of plant development for a month or soil was brought to the moisture stress only twice. Additionally, some plants were watered at -50 kPa during the entire cultivation period while the control plants were watered at -5kPa. Plants were also kept at maximum possible moisture level (watering at -0,5kPa or close to it (-1.OkPa through the entire growing period. Soil water potential was measured with tensiometer. Drought stress applied during entire cultivation period or during the flushing stage caused significant reduction in transpiration and conductance of leaves. Stress applied during bract coloration stage had not as great effect on the stomatal conductance and transpiration of leaves as the similar stress applied during the flushing stage. High soil moisture increased stomatal conductance and transpiration rate, respectively by 130% and 52% (flushing stage, and 72% and 150% (bract coloration stage at maximum, compared to the control.

  3. [Responses of canopy stomatal conductance of Acacia mangium forest to environmental driving factors].

    Science.gov (United States)

    Zhao, Ping; Rao, Xingquan; Ma, Ling; Cai, Xi'an; Zeng, Xiaoping

    2006-07-01

    Employing Granierś probes, this paper measured the sap flow of 14 sample trees in an Acacia mangium forest on the Heshan hilly lands of Guangdong Province, and recorded the photosynthetic active radiation (PAR), air relative humidity (RH) , and air temperature (T) above the forest canopy. The whole-tree transpiration (E), stand transpiration (Et), and mean canopy stomatal conductance (gc) were calculated, and the relationships between tree morphological characters and whole-tree water use as well as the responses of gc to PAR and vapor pressure deficit (D) were analyzed. The results showed that the whole-tree transpiration had logarithmical positive correlations with tree diameter at breast height (DBH) (P < 0.0001) , sapwood area (P < 0.0001) and canopy size (P = 0.0007), and an exponential positive correlation with tree height (P = 0. 014). The maximum gc (gc max) changed with PAR hyperbolically (P < 0.0001), and with D logarithmically (P < 0.0001). The sap flow measurement system used in this study was reliable and accurate in estimating the transpiration of whole-tree and stand and the canopy stomatal conductance, being an effective tool in studying the relationships between forest water use and environmental factors.

  4. Stomatal conductance of semi-natural Mediterranean grasslands: Implications for the development of ozone critical levels

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, R. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain)]. E-mail: rocio.alonso@ciemat.es; Bermejo, V. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain); Sanz, J. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain); Valls, B. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain); Elvira, S. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain); Gimeno, B.S. [Ecotoxicology of Air Pollution, CIEMAT (Ed. 70), Avda. Complutense 22, Madrid 28040 (Spain)

    2007-04-15

    Intra-genus and intra-specific variation and the influence of nitrogen enrichment on net assimilation and stomatal conductance of some annual Trifolium species of Mediterranean dehesa grasslands were assessed under experimental conditions. Also gas exchange rates were compared between some Leguminosae and Poaceae species growing in the field in a dehesa ecosystem in central Spain. The results showed that the previously reported different O{sub 3} sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g {sub s} values. In addition, no clear differences on gas exchange rates could be attributed to Leguminosae and Poaceae families growing in the field, with intra-genus variation being more important than differences found between families. Further studies are needed to increase the database for developing a flux-based approach for setting O{sub 3} critical levels for semi-natural Mediterranean species. - The stomatal conductance model incorporated within the EMEP DO{sub 3}SE deposition module needs to be re-parameterised for Mediterranean semi-natural vegetation.

  5. A mutation that eliminates bundle sheath extensions reduces leaf hydraulic conductance, stomatal conductance and assimilation rates in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Zsögön, Agustin; Negrini, Ana Clarissa Alves; Peres, Lázaro Eustáquio Pereira; Nguyen, Hoa Thi; Ball, Marilyn C

    2015-01-01

    Bundle sheath extensions (BSEs) are key features of leaf structure whose distribution differs among species and ecosystems. The genetic control of BSE development is unknown, so BSE physiological function has not yet been studied through mutant analysis. We screened a population of ethyl methanesulfonate (EMS)-induced mutants in the genetic background of the tomato (Solanum lycopersicum) model Micro-Tom and found a mutant lacking BSEs. The leaf phenotype of the mutant strongly resembled the tomato mutant obscuravenosa (obv). We confirmed that obv lacks BSEs and that it is not allelic to our induced mutant, which we named obv-2. Leaves lacking BSEs had lower leaf hydraulic conductance and operated with lower stomatal conductance and correspondingly lower assimilation rates than wild-type leaves. This lower level of function occurred despite similarities in vein density, midvein vessel diameter and number, stomatal density, and leaf area between wild-type and mutant leaves, the implication being that the lack of BSEs hindered water dispersal within mutant leaves. Our results comparing near-isogenic lines within a single species confirm the hypothesised role of BSEs in leaf hydraulic function. They further pave the way for a genetic model-based analysis of a common leaf structure with deep ecological consequences.

  6. Assessment of Interactions Between Stomatal Conductance, Evapotranspiration, Carbon and Irrigated Soil Salinity

    Science.gov (United States)

    Runkle, B.; Liang, X.

    2006-12-01

    Hydrological behavior and soil salinity are intricately linked in many agricultural environments. Fluxes of energy, water, and carbon dioxide are critical to the response of plants to soil salinity. A physically based plant water use model is developed to examine the problem of soil salinity as it relates to evapotranspiration and plant water uptake in an arid agricultural region. This model incorporates carbon dynamics and photosynthetic activity into the plant water use model, and examines the nonlinear manner in which plants respond to increased soil salinity. Higher soil osmotic pressure resulting from increased ionic presence increases the resistance to water flow through the plant; this change also impacts the assimilation of carbon dioxide through the stomatal opening. Canopy and ecosystem fluxes are now measured with such intensity as to allow comprehensive diurnal analysis of the effects of soil water and salt status on plant water, carbon, and energy fluxes. Initial results show that at higher salinity levels, non-linear and higher variable changes occur to stomatal conductance and evapotranspiration. Scaling these results to the daily or weekly level may be of great use to agricultural planners in their water management decisions.

  7. Combining sap flow meas- urement-based canopy stomatal conductance and 13C discrimination to estimate forest carbon assimilation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ping; LU Ping; MA Ling; SUN Guchou; RAO Xingquan; CAI Xian; ZENG Xiaoping

    2005-01-01

    The available methods for studying C uptake of forest and their problems in practices are reviewed, and a new approach to combining sap flow and 13C techniques is proposed in this paper. This approach, obtained through strict mathematic derivation, combines sap flow measurement-based canopy stomatal conductance and 13C discrimination to estimate instantaneous carbon assimilation rate of a forest. Namely the mean canopy stomatal conductance (gc) acquired from accurate measurement of sap flux density is integrated with the relationship between 13C discrimination (() and Ci/Ca (intercellular/ambient CO2 concentrations) and with that between Anet (net photosynthetic rate) and gCO2 (stomatal conductance for CO2) so that a new relation between forest C uptake and ( as well as gc is established. It is a new method of such kind for studying the C exchange between forest and atmosphere based on experimental ecology.

  8. Hydraulic conductance and water potential gradients in squash leaves showing mycorrhiza-induced increases in stomatal conductance.

    Science.gov (United States)

    Augé, Robert M; Toler, Heather D; Sams, Carl E; Nasim, Ghazala

    2008-03-01

    Stomatal conductance (gs) and transpiration rates vary widely across plant species. Leaf hydraulic conductance (k leaf) tends to change with g (s), to maintain hydraulic homeostasis and prevent wide and potentially harmful fluctuations in transpiration-induced water potential gradients across the leaf (Delta Psi leaf). Because arbuscular mycorrhizal (AM) symbiosis often increases gs in the plant host, we tested whether the symbiosis affects leaf hydraulic homeostasis. Specifically, we tested whether k leaf changes with gs to maintain Delta Psi leaf or whether Delta Psi leaf differs when gs differs in AM and non-AM plants. Colonization of squash plants with Glomus intraradices resulted in increased gs relative to non-AM controls, by an average of 27% under amply watered, unstressed conditions. Stomatal conductance was similar in AM and non-AM plants with exposure to NaCl stress. Across all AM and NaCl treatments, k leaf did change in synchrony with gs (positive correlation of gs and k leaf), corroborating leaf tendency toward hydraulic homeostasis under varying rates of transpirational water loss. However, k leaf did not increase in AM plants to compensate for the higher gs of unstressed AM plants relative to non-AM plants. Consequently, Delta Psi leaf did tend to be higher in AM leaves. A trend toward slightly higher Delta Psi leaf has been observed recently in more highly evolved plant taxa having higher productivity. Higher Delta Psi leaf in leaves of mycorrhizal plants would therefore be consistent with the higher rates of gas exchange that often accompany mycorrhizal symbiosis and that are presumed to be necessary to supply the carbon needs of the fungal symbiont.

  9. Photosynthesis and stomatal conductance related to reflectance on the canopy scale

    Science.gov (United States)

    Verma, S. B.; Sellers, P. J.; Walthall, C. L.; Hall, F. G.; Kim, J.; Goetz, S. J.

    1993-01-01

    Field measurements of carbon dioxide and water vapor fluxes were analyzed in conjunction with reflectances obtained from a helicopter-mounted Modular Multiband Radiometer at a grassland study site during the First International Satellite Land Surface Climatology Project Field Experiment. These measurements are representative of the canopy scale and were made over a range of meteorological and soil moisture conditions during different stages in the annual life cycle of the prairie vegetation, and thus provide a good basis for investigating hpotheses/relationships potentially useful in remote sensing applications. We tested the hypothesis (Sellers, 1987) that the simple ratio vegetation index should be near-linearly related to the derivatives of the unstressed canopy stomatal conductance and the unstressed canopy photosynthesis with respect to photosynthetically active radiation. Even though there is some scatter in our data, the results seem to support this hypothesis.

  10. Testing two models for the estimation of leaf stomatal conductance in four greenhouse crops cucumber, chrysanthemum, tulip and lilium

    NARCIS (Netherlands)

    Li, G.; Lin, L.; Dong, Y.; An, D.; Li, Y.; Luo, W.; Yin, X.; Li, W.; Shao, J.; Zhou, Y.; Dai, J.; Chen, W.; Zhao, C.

    2012-01-01

    Estimating leaf stomatal conductance for CO2 diffusion (gsc) is pivotal for further estimation of crop transpiration as well as energy and mass balances between air and plant in greenhouses. In this study, we tested two models, i.e. the Jarvis model and a new version of BWB–Leuning model (BWB–Leunin

  11. Decreased production of proinflammatory cytokines by monocytes from individuals presenting Candida-associated denture stomatitis.

    Science.gov (United States)

    Pinke, Karen Henriette; Freitas, Patrícia; Viera, Narciso Almeida; Honório, Heitor Marques; Porto, Vinicius Carvalho; Lara, Vanessa Soares

    2016-01-01

    Candida-associated denture stomatitis (DS) is the most frequent lesion among denture wearers, especially the elderly. DS is strongly associated with Candida albicans, as well as local and systemic factors, such as impaired immune response. Monocytes are important in the protective immune response against the fungus by the production of cytokines that recruit and activate leukocytes. There are functional changes in these cells with age, and individual alterations involving monocyte response may predispose the host to developing infections by Candida spp. In this study, our aim was to evaluate the production of TNF-α, IL-6, CXCL8, IL-1β, MCP-1 and IL-10 by monocytes from elderly denture wearers with/without DS and elderly or young non-denture wearers. We detected that monocytes from elderly denture wearers with Candida-related denture stomatitis produced lower levels of CXCL-8, IL-6 and MCP-1. This imbalance in cytokine levels was observed in spontaneous or LPS-stimulated production. Therefore, our data suggested that inherent aspects of the host, such as changes in cytokine production by monocytes, might be associated with the development and the persistence of DS irrespective of aging. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nighttime stomatal conductance differs with nutrient availability in two temperate floodplain tree species.

    Science.gov (United States)

    Eller, Franziska; Jensen, Kai; Reisdorff, Christoph

    2016-12-14

    Nighttime water flow varies between plant species and is a phenomenon for which the magnitude, purpose and consequences are widely discussed. A potential benefit of nighttime stomata opening may be increased nutrient availability during the night since transpiration affects the mass flow of soil water towards plant roots. We investigated how nitrogen (N) and phosphorus (P) fertilization, and short-term drought affected stomatal conductance of Fraxinus excelsior L. and Ulmus laevis Pallas during the day (gs) and night (gn), and how these factors affected growth for a period of 18 weeks. Both species were found to open their stomata during the night, and gn responded to nutrients and water in a different manner than gs Under N-deficiency, F. excelsior had higher gn, especially when P was sufficient, and lower pre-dawn leaf water potential (Ψpd), supporting our assumption that nutrient limitation leads to increases in nighttime water uptake. Under P-deficiency, F. excelsior had higher relative root production and, thus, adjusted its biomass allocation under P shortage, while sufficient N but not P contributed to overall higher biomasses. In contrast, U. laevis had higher gn and lower root:shoot ratio under high nutrient (especially N) availability, whereas both sufficient N and P produced higher biomasses. Compared with well-watered trees, the drought treatment did not affect any growth parameter but it resulted in lower gn, minimum stomatal conductance and Ψpd of F. excelsior For U. laevis, only gs during July was lower when drought-treated. In summary, the responses of gs and gn to nutrients and drought depended on the species and its nutrient uptake strategy, and also the timing of measurement during the growing season. Eutrophication of floodplain forests dominated by F. excelsior and U. laevis may, therefore, considerably change nighttime transpiration rates, leading to ecosystem-level changes in plant-water dynamics. Such changes may have more severe

  13. Scale effects on the controls on mountain grassland leaf stomatal and ecosystem surface conductance to water vapour

    Science.gov (United States)

    Haslwanter, Alois; Hammerle, Albin; Wohlfahrt, Georg

    2010-05-01

    Stomata are the major pathway by which plants exert control on the exchange of trace gases and water vapour with the aerial environment and thus provide a key link between the functioning of terrestrial ecosystems and the state and composition of the atmosphere. Understanding the nature of this control, i.e. how stomatal conductance differs between plant species and ecosystems and how it varies in response to external and internal forcings, is key to predicting feedbacks plants may be providing to changing climatic conditions. Despite a long history of research on stomatal functioning, a fully mechanistic understanding of how stomata function in response to biotic and abiotic controls is still elusive which has led to the development of a large number of (semi-)empirical models of varying complexity. Two of the most widely used models go back to Jarvis (1976) and Ball, Woodrow and Berry (1987), termed J-model and BWB-model, respectively, in the following. The J-model simulates stomatal conductance as some maximal value attenuated by a series of multiplicative functions which are bound between zero and unity, while the BWB-model predicts stomatal conductance as a linear function of photosynthesis, relative humidity and carbon dioxide concentration in the leaf boundary layer. Both models were developed for the prediction of leaf-scale stomatal conductance to water vapour, but have been applied for simulating ecosystem-scale surface conductance as well. The objective of the present paper is to compare leaf- and ecosystem-scale conductances to water vapour and to assess the respective controls using the two above-mentioned models as analysis frameworks. To this end leaf-level stomatal conductance has been measured by means of leaf-gas exchange methods and ecosystem-scale surface conductance by inverting eddy covariance evapotranspiration estimates at a mountain grassland site in Austria. Our major findings are that the proportionality parameter in the BWB-model is

  14. Maximal stomatal conductance to water and plasticity in stomatal traits differ between native and invasive introduced lineages of Phragmites australis in North America.

    Science.gov (United States)

    Douhovnikoff, V; Taylor, S H; Hazelton, E L G; Smith, C M; O'Brien, J

    2016-01-27

    The fitness costs of reproduction by clonal growth can include a limited ability to adapt to environmental and temporal heterogeneity. Paradoxically, some facultatively clonal species are not only able to survive, but colonize, thrive and expand in heterogeneous environments. This is likely due to the capacity for acclimation (sensu stricto) that compensates for the fitness costs and complements the ecological advantages of clonality. Introduced Phragmites australis demonstrates great phenotypic plasticity in response to temperature, nutrient availability, geographic gradient, water depths, habitat fertility, atmospheric CO2, interspecific competition and intraspecific competition for light. However, no in situ comparative subspecies studies have explored the difference in plasticity between the non-invasive native lineage and the highly invasive introduced lineage. Clonality of the native and introduced lineages makes it possible to control for genetic variation, making P. australis a unique system for the comparative study of plasticity. Using previously identified clonal genotypes, we investigated differences in their phenotypic plasticity through measurements of the lengths and densities of stomata on both the abaxial (lower) and adaxial (upper) surfaces of leaves, and synthesized these measurements to estimate impacts on maximum stomatal conductance to water (gwmax). Results demonstrated that at three marsh sites, invasive lineages have consistently greater gwmax than their native congeners, as a result of greater stomatal densities and smaller stomata. Our analysis also suggests that phenotypic plasticity, determined as within-genotype variation in gwmax, of the invasive lineage is similar to, or exceeds, that shown by the native lineage.

  15. Root hydraulic conductivity and adjustments in stomatal conductance: hydraulic strategy in response to salt stress in a halotolerant species.

    Science.gov (United States)

    Vitali, Victoria; Bellati, Jorge; Soto, Gabriela; Ayub, Nicolás D; Amodeo, Gabriela

    2015-11-24

    Recent advances at the molecular level are introducing a new scenario that needs to be integrated into the analysis of plant hydraulic properties. Although it is not yet clear to what extent this scenario alters the current proposal for the hydraulic circuit models, it introduces new insights when studying plants that are able to easily overcome water restrictions. In this context, our aim was to explore water adjustments in a halotolerant model (Beta vulgaris) by studying the coordination between the root in terms of root hydraulic conductivity (Lpr) and the shoot as reflected in the stomatal conductance (gs). The root water pathways were also analysed in terms of root suberization (apoplastic barrier) and aquaporin transcript levels (cell-to-cell pathway). Beta vulgaris showed the ability to rapidly lose (4 h) and gain (24 h) turgor when submitted to salt stress (200 mM). The reduction profile observed in Lpr and gs was consistent with a coupled process. The tuning of the root water flow involved small variations in the studied aquaporin's transcripts before anatomical modifications occurred. Exploring Lpr enhancement after halting the stress contributed to show not only a different profile in restoring Lpr but also the capacity to uncouple Lpr from gs. Beta vulgaris root plays a key role and can anticipate water loss before the aerial water status is affected.

  16. Characteristics of Stomatal Conductance of Populus pruinosa and the Quantitative Simulation%灰胡杨叶片气孔导度特征及数值模拟

    Institute of Scientific and Technical Information of China (English)

    王海珍; 韩路; 徐雅丽; 牛建龙; 于军

    2016-01-01

    -Ball models were used to simulate the dynamic process of leaf stomatal conductance,and applicability of the two models in extreme arid region was compared. [Result]The diurnal courses of stomatal conductance of P. pruinosa were a single peak curve in growth season,there were obviously differences in peak values,time and amplitude in every months. Especially,peak time appeared the earliest and largest amplitude in September,and minimum amplitude of peak value in June. The leaf stomatal conductance was sensitive to photosynthesis active radiation,vapor pressure deficit and air temperature. The leaf stomatal conductance increased with photosynthesis active radiation,atmospheric CO2 concentration and air humidity,and decreased with increase of the vapor pressure deficit and air temperature. Statistical analysis showed that photosynthesis active radiation, vapor pressure deficit and air temperature significantly affected stomatal conductance of whole day and forenoon,while the stomatal conductance in afternoon was affected obviously by atmospheric CO2 concentration and air humidity. Stomatal conductance of P. pruinosa in different periods was regulated by the different environmental factors. The fitted models of stomatal conductance of P. pruinosa in different periods were simulated and constructed with two representative stomatal conductance models,Jarvis model could explain on average 69 . 1%,62 . 2%,and 63 . 3% of variation and Leuning-Ball model could explain on average 53. 5%,30. 6%,and 44. 5% of variation in the observed stomatal conductance at whole day,forenoon and afternoon,respectively. The sensitivity and fitting effect of Jarvis model was better than that of Leunning-Ball model at different periods. The fitting effect of Leunning-Ball model in afternoon was better than that in forenoon,indicating that the environmental factors that affected stomatal conductance were different in different periods. The validations of Leuning-Ball linear and Jarvis non-linear models

  17. Decreased Nerve Conduction Velocity in Football Players

    Directory of Open Access Journals (Sweden)

    Daryoush Didehdar

    2014-06-01

    Full Text Available Background: Lower limbs nerves are exposed to mechanical injuries in the football players and the purpose of this study is to evaluate the influence of football on the lower leg nerves. Materials and Methods: Nerve conduction studies were done on 35 male college students (20 football players, 15 non active during 2006 to 2007 in the Shiraz rehabilitation faculty. Standard nerve conduction techniques using to evaluate dominant and non dominant lower limb nerves. Results: The motor latency of deep peroneal and tibial nerves of dominant leg of football players and sensory latency of superficial peroneal, tibial and compound nerve action potential of tibial nerve of both leg in football players were significantly prolonged (p<0.05. Motor and sensory nerve conduction velocity of tibial and common peroneal in football players were significant delayed (p<0.05. Conclusion: It is concluded that football is sport with high contact and it causes sub-clinical neuropathies due to nerve entrapment.

  18. Modeling stomatal conductance in the earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

    Science.gov (United States)

    Bonan, G. B.; Williams, M.; Fisher, R. A.; Oleson, K. W.

    2014-09-01

    The Ball-Berry stomatal conductance model is commonly used in earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs) on vapor pressure deficit (Ds) and soil moisture must be empirically parameterized. We evaluated the Ball-Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil-plant-atmosphere continuum (SPA). The SPA model simulates stomatal conductance numerically by (1) optimizing photosynthetic carbon gain per unit water loss while (2) constraining stomatal opening to prevent leaf water potential from dropping below a critical minimum. We evaluated two optimization algorithms: intrinsic water-use efficiency (ΔAn /Δgs, the marginal carbon gain of stomatal opening) and water-use efficiency (ΔAn /ΔEl, the marginal carbon gain of transpiration water loss). We implemented the stomatal models in a multi-layer plant canopy model to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using leaf analyses, eddy covariance fluxes at six forest sites, and parameter sensitivity analyses. The primary differences among stomatal models relate to soil moisture stress and vapor pressure deficit responses. Without soil moisture stress, the performance of the SPA stomatal model was comparable to or slightly better than the CLM Ball-Berry model in flux tower simulations, but was significantly better than the CLM Ball-Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from water flow along the soil-to-leaf pathway rather than being imposed a priori, as in the CLM Ball-Berry model. Similar functional dependence of gs on Ds emerged from the ΔAn/ΔEl optimization, but not the ΔAn /gs optimization. Two parameters (stomatal efficiency and root hydraulic

  19. Buckwheat stomatal traits under aluminium toxicity

    Directory of Open Access Journals (Sweden)

    Oleksandr E. Smirnov

    2014-04-01

    Full Text Available Aluminium influence on some stomatal parameters of common buckwheat (Fagopyrum esculentum Moench. was studied. Significant changes in stomatal density, stomatal index and stomatal shape coefficient under aluminium treatment were revealed. Stomatal closure and no difference in total stomatal potential conductance index of treatment plants were suggested as aluminium resistance characteristics.

  20. Optimization of stomatal conductance for maximum carbon gain under dynamic soil moisture

    Science.gov (United States)

    Manzoni, Stefano; Vico, Giulia; Palmroth, Sari; Porporato, Amilcare; Katul, Gabriel

    2013-12-01

    Optimization theories explain a variety of forms and functions in plants. At the leaf scale, it is often hypothesized that carbon gain is maximized, thus providing a quantifiable objective for a mathematical definition of optimality conditions. Eco-physiological trade-offs and limited resource availability introduce natural bounds to this optimization process. In particular, carbon uptake from the atmosphere is inherently linked to water losses from the soil as water is taken up by roots and evaporated. Hence, water availability in soils constrains the amount of carbon that can be taken up and assimilated into new biomass. The problem of maximizing photosynthesis at a given water availability by modifying stomatal conductance, the plant-controlled variable to be optimized, has been traditionally formulated for short time intervals over which soil moisture changes can be neglected. This simplification led to a mathematically open solution, where the undefined Lagrange multiplier of the optimization (equivalent to the marginal water use efficiency, λ) is then heuristically determined via data fitting. Here, a set of models based on different assumptions that account for soil moisture dynamics over an individual dry-down are proposed so as to provide closed analytical expressions for the carbon gain maximization problem. These novel solutions link the observed variability in λ over time, across soil moisture changes, and at different atmospheric CO2 concentrations to water use strategies ranging from intensive, in which all soil water is consumed by the end of the dry-down period, to more conservative, in which water stress is avoided by reducing transpiration.

  1. Effects of mid-season frost and elevated growing season temperature on stomatal conductance and specific xylem conductivity of the arctic shrub, Salix pulchra

    Energy Technology Data Exchange (ETDEWEB)

    Gorsuch, D. M.; Oberbauer, S. F. [Florida International Univ., Dept. of Biological Sciences, Miami, FL (United States)

    2002-10-01

    It is hypothesized that because deciduous plants have a growth season limited in length and also have generally larger conduit volumes, they are more likely to be injured by freeze-thaw induced cavitation during the growing season. To test this hypothesis, the deciduous arctic shrub, Salix pulchra, was grown in simulated Alaskan summer temperatures and at five degrees C above the ambient simulation in controlled environments. Specific hydraulic conductivity and leaf stomatal conductance were measured in plants grown at both temperatures before and after freeze treatment simulating a mid-season frost. Before freeze treatment specific hydraulic conductivity was 2.5 times higher and stomatal conductance was 1.3 times higher in plants grown at elevated temperature. After freeze treatment reduction in hydraulic conductivity and stomatal conductance was 3.5 and 1.8 times higher in the plants grown at the higher temperature than plants grown at ambient temperature. Plants grown at the higher temperature also had larger vessel diameters and higher vessel densities than ambient-grown plants. These results suggest that higher growing season temperatures will make arctic deciduous shrubs more susceptible to frost damage. The implication of these results for plant growth in the arctic tundra is that while climate warming favours plants with larger vessels and higher specific xylem conductivity over plants with lower values, this competitive advantage may be lost if there is an increase in the risk of frost during the growing season. 43 refs., 5 figs.

  2. The Shortwave Infrared Bands’ Response to Stomatal Conductance in “Conference” Pear Trees (Pyrus communis L.

    Directory of Open Access Journals (Sweden)

    Raymond Struthers

    2015-10-01

    Full Text Available In situ measurements consisting of stomatal conductance, air temperature, vapor pressure deficit and the spectral reflectance in the shortwave infrared (SWIR regions of thirty “Conference” pear trees (Pyrus communis L. were repeatedly measured for eighty-six days. The SWIR was segmented into eight regions between 1550 and 2365 nm, where distances ranged from 40–200 nm. Each of the regions was used to describe the change in canopy water status over a period of approximately three months. Stomatal conductance of the water stress treatment was first determined to be significantly different from the control group nine days after stress initiation. The most suitable SWIR region for this study had wavelengths between 1550 and 1750 nm, where the first significant difference was also measured nine days after stress was initiated. After the period of water stress ended, forty-seven days after stress was initiated, all of the trees received full irrigation, where the SWIR region between 1550 and 1750 nm determined that stomatal conductance of the stress treatment lagged behind the control group for thirty days. Using a temporal sequence of SWIR measurements, we were able to successfully measure the beginning and the recovery of water stress in pear trees.

  3. Increased leaf photosynthesis caused by elevated stomatal conductance in a rice mutant deficient in SLAC1, a guard cell anion channel protein.

    Science.gov (United States)

    Kusumi, Kensuke; Hirotsuka, Shoko; Kumamaru, Toshiharu; Iba, Koh

    2012-09-01

    In rice (Oryza sativa L.), leaf photosynthesis is known to be highly correlated with stomatal conductance; however, it remains unclear whether stomatal conductance dominantly limits the photosynthetic rate. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO(2)]. In order to examine stomatal limitations to photosynthesis, a SLAC1-deficient mutant of rice was isolated and characterized. A TILLING screen of N-methyl-N-nitrosourea-derived mutant lines was conducted for the rice SLAC1 orthologue gene Os04g0674700, and four mutant lines containing mutations within the open reading frame were obtained. A second screen using an infrared thermography camera revealed that one of the mutants, named slac1, had a constitutive low leaf temperature phenotype. Measurement of leaf gas exchange showed that slac1 plants grown in the greenhouse had significantly higher stomatal conductance (g (s)), rates of photosynthesis (A), and ratios of internal [CO(2)] to ambient [CO(2)] (C (i)/C (a)) compared with wild-type plants, whereas there was no significant difference in the response of photosynthesis to internal [CO(2)] (A/C (i) curves). These observations demonstrate that in well-watered conditions, stomatal conductance is a major determinant of photosynthetic rate in rice.

  4. Is optimality in stomatal conductance an endogenous process or an emergent property arising from interactions with the environment?

    Science.gov (United States)

    Resco de Dios, Victor; Gessler, Arthur; Ferrio, Juan Pedro; Bahn, Michael; Milcu, Alexandru; Tissue, David; Voltas, Jordi; Roy, Jacques

    2016-04-01

    Plants are sessile and poikilothermic organisms that need to respond and adjust promptly to an ever-changing environment. Over a single 24 h period, a plant may experience the same level of variation in radiation as in its entire life-time and, in some climates, the oscillation in day-night temperature and vapor pressure deficit might be of similar magnitude to that experienced across a full year. Plants need to maintain a positive C balance without depleting soil water reserves in the face of such a diverse environment, and feedbacks between assimilation (A) and water losses (E) are thought to have evolved to optimize stomatal conductance (gs). In short, the optimal conductance hypothesis proposes that cross-talks between A and stomatal conductance gs lead to a constant marginal water use (λ) during a day, such that A is maximized and E minimized. The biological mechanism by which biochemical processes would feedback gs remains unknown, but multiple studies have shown empirical support for this hypothesis, leading to its current consideration of theory by many. Here we test whether optimal stomatal conductance is an endogenous property, that is, driven solely by factors internal to the plant, and in the absence of environmental fluctuations. After 5 days of entrainment, where monoculture canopies of bean and of cotton were subjected to the average environmental conditions of an August sunny day in Montpellier (at the CNRS European Ecotron, FR), we kept temperature, relative humidity and photosynthetically active radiation constant for 48 h at the values observed at noon. During this period, we monitored leaf gas exchange continuously every two minutes, and canopy gas exchange every 15 minutes. We observed a periodic oscillation in λ, showing a 24 h period, and consistent with a circadian regulation of water use efficiency. Hourly variations in λ could thus not be explained by the optimal stomatal hypothesis. Moreover, the pattern of variation (of maximal water

  5. Tree level hydrodynamic approach for resolving aboveground water storage and stomatal conductance and modeling the effects of tree hydraulic strategy

    Science.gov (United States)

    Mirfenderesgi, Golnazalsadat; Bohrer, Gil; Matheny, Ashley M.; Fatichi, Simone; Moraes Frasson, Renato Prata; Schäfer, Karina V. R.

    2016-07-01

    The finite difference ecosystem-scale tree crown hydrodynamics model version 2 (FETCH2) is a tree-scale hydrodynamic model of transpiration. The FETCH2 model employs a finite difference numerical methodology and a simplified single-beam conduit system to explicitly resolve xylem water potentials throughout the vertical extent of a tree. Empirical equations relate water potential within the stem to stomatal conductance of the leaves at each height throughout the crown. While highly simplified, this approach brings additional realism to the simulation of transpiration by linking stomatal responses to stem water potential rather than directly to soil moisture, as is currently the case in the majority of land surface models. FETCH2 accounts for plant hydraulic traits, such as the degree of anisohydric/isohydric response of stomata, maximal xylem conductivity, vertical distribution of leaf area, and maximal and minimal xylem water content. We used FETCH2 along with sap flow and eddy covariance data sets collected from a mixed plot of two genera (oak/pine) in Silas Little Experimental Forest, NJ, USA, to conduct an analysis of the intergeneric variation of hydraulic strategies and their effects on diurnal and seasonal transpiration dynamics. We define these strategies through the parameters that describe the genus level transpiration and xylem conductivity responses to changes in stem water potential. Our evaluation revealed that FETCH2 considerably improved the simulation of ecosystem transpiration and latent heat flux in comparison to more conventional models. A virtual experiment showed that the model was able to capture the effect of hydraulic strategies such as isohydric/anisohydric behavior on stomatal conductance under different soil-water availability conditions.

  6. Modeling stomatal conductance in the Earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

    Directory of Open Access Journals (Sweden)

    G. B. Bonan

    2014-05-01

    Full Text Available The empirical Ball–Berry stomatal conductance model is commonly used in Earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs on vapor pressure deficit (Ds and soil moisture must both be empirically parameterized. We evaluated the Ball–Berry model used in the Community Land Model version 4.5 (CLM4.5 and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil–plant–atmosphere continuum (SPA to numerically optimize photosynthetic carbon gain per unit water loss while preventing leaf water potential dropping below a critical minimum level. We evaluated two alternative optimization algorithms: intrinsic water-use efficiency (Δ An/Δ gs, the marginal carbon gain of stomatal opening and water-use efficiency (Δ An/Δ El, the marginal carbon gain of water loss. We implemented the stomatal models in a multi-layer plant canopy model, to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using: (1 leaf analyses; (2 canopy net radiation, sensible heat flux, latent heat flux, and gross primary production at six AmeriFlux sites spanning 51 site–years; and (3 parameter sensitivity analyses. Without soil moisture stress, the performance of the SPA stomatal conductance model was generally comparable to or somewhat better than the Ball–Berry model in flux tower simulations, but was significantly better than the Ball–Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from the physiological theory linking leaf water-use efficiency and water flow to and from the leaf along the soil-to-leaf pathway rather than being imposed a priori, as in the Ball–Berry model. Similar functional dependence of gs on Ds emerged from the water-use efficiency optimization. Sensitivity analyses showed that two

  7. Network regulation of calcium signal in stomatal development

    Institute of Scientific and Technical Information of China (English)

    Zhu-xia SHEN; Gen-xuan WANG; Zhi-qiang LIU; Hao ZHANG; Mu-qing QIU; Xing-zheng ZHAO; Yi GAN

    2006-01-01

    Aim: Each cell is the production of multiple signal transduction programs involving the expression of thousands of genes. This study aims to gain insights into the gene regulation mechanisms of stomatal development and will investigate the relationships among some signaling transduction pathways. Methods: Nail enamel printing was conducted to observe the stomatal indices of wild type and 10 mutants (plant hormone mutants, Pi-starvation induced CaM mutants and Pi-starvation-response mutant) in Arabidopsis, and their stomatal indices were analyzed by ANOVA. We analyzed the stomatal indices of 10 Arabidopsis mutants were analyzed by a model PRGE (potential relative effect of genes) to research relations among these genes. Results: In wild type and 10 mutants, the stomatal index didn't differ with respect to location on the lower epidermis. Compared with wild type, the stomatal indices of 10 mutants all decreased significantly. Moreover, significant changes and interactions might exist between some mutant genes. Conclusion: It was the stomatal intensity in Arabidopsis might be highly sensitive to most mutations in genome. While the effect of many gene mutations on the stomatal index might be negative, we also could assume the stomatal development was regulated by a signal network in which one signal transduction change might influence the stomatal development more or less, and the architecture might be reticulate. Furthermore, we could speculate that calcium was a hub in stomatal development signal regulation network, and other signal transduction pathways regulated stomtal development by influencing or being influenced by calcium signal transduction pathways.

  8. Photocontrol of the Functional Coupling between Photosynthesis and Stomatal Conductance in the Intact Leaf : Blue Light and Par-Dependent Photosystems in Guard Cells.

    Science.gov (United States)

    Zeiger, E; Field, C

    1982-08-01

    The photocontrol of the functional coupling between photosynthesis and stomatal conductance in the leaf was investigated in gas exchange experiments using monochromatic light provided by lasers. Net photosynthesis and stomatal conductance were measured in attached leaves of Malva parviflora L. as a function of photon irradiance at 457.9 and 640.0 nanometers.Photosynthetic rates and quantum yields of photosynthesis were higher under red light than under blue, on an absorbed or incident basis.Stomatal conductance was higher under blue than under red light at all intensities. Based on a calculated apparent photon efficiency of conductance, blue and red light had similar effects on conductance at intensities higher than 0.02 millimoles per square meter per second, but blue light was several-fold more efficient at very low photon irradiances. Red light had no effect on conductance at photon irradiances below 0.02 millimoles per square meter per second. These observations support the hypothesis that stomatal conductance is modulated by two photosystems: a blue light-dependent one, driving stomatal opening at low light intensities and a photosynthetically active radiation (PAR)-dependent one operating at higher irradiances.When low intensity blue light was used to illuminate a leaf already irradiated with high intensity, 640 nanometers light, the leaf exhibited substantial increases in stomatal conductance. Net photosynthesis changed only slightly. Additional far-red light increased net photosynthesis without affecting stomatal conductance. These observations indicate that under conditions where the PAR-dependent system is driven by high intensity red light, the blue light-dependent system has an additive effect on stomatal conductance.The wavelength dependence of photosynthesis and stomatal conductance demonstrates that these processes are not obligatorily coupled and can be controlled by light, independent of prevailing levels of intercellular CO(2). The blue light

  9. Stomatal Conductance and Chlorophyll Characteristics and Their Relationship with Yield of Some Cocoa Clones Under Tectona grandis, Leucaena sp., and Cassia surattensis.

    Directory of Open Access Journals (Sweden)

    Fakhrusy Zakariyya

    2015-08-01

    Full Text Available An optimum physiological condition will support high yield and quality of cocoa production. The research was aimed to study the effects of stomatal conductance and chlorophyll content related to cocoa production under three shade regimes.This research was conducted in Kaliwining Experimental Station, elevation of 45 m above sea level with D climate type based on Schmidt & Fergusson. Cocoa trees which were planted in 1994 at a spacing of 3 X 3 m were used in the study planted by using split plot design. The shade tree species were teak (Tectona grandis, krete (Cassiasurattensis, and lamtoro (Leucaena sp. as the main plots, and cocoa clones of Sulawesi 01,Sulawesi 02, KKM 22 and KW 165 as sub plots. This study showed that there was interaction between cocoa clone and shade species for stomatal conductance where stomatal diffusive resistance of KKM 22 was the best under Leucaena sp.and Cassiasurattensis with the values of 1.38 and 1.34 s.cm -1, respectively. The highest chlorophyll content, stomatal index and transpiration values was under Leucaena sp. shade. There was positive correlation between chlorophyll content and transpiration with pod yield of cocoa. The highest yield and the lowest bean count wereobtainedon Sulawesi 01 clone under Leucaenasp. shade.Keywords: stomatal conductance, transpiration, diffusive resistance, shades trees, clones,pod yield

  10. Temporal dynamics of stomatal conductance of plants under water deficit: can homeostasis be improved by more complex dynamics?

    Directory of Open Access Journals (Sweden)

    Gustavo Maia Souza

    2004-07-01

    Full Text Available In this study we hypothesized that chaotic or complex behavior of stomatal conductance could improve plant homeostasis after water deficit. Stomatal conductance of sunflower and sugar beet leaves was measured in plants grown either daily irrigation or under water deficit using an infrared gas analyzer. All measurements were performed under controlled environmental conditions. In order to measure a consistent time series, data were scored with time intervals of 20s during 6h. Lyapunov exponents, fractal dimensions, KS entropy and relative LZ complexity were calculated. Stomatal conductance in both irrigated and non-irrigated plants was chaotic-like. Plants under water deficit showed a trend to a more complex behaviour, mainly in sunflower that showed better homeostasis than in sugar beet. Some biological implications are discussed.Este estudo testou a hipótese de que a condutância estomática de uma população de estômatos em uma folha poderia apresentar um comportamento caótico ou complexo sob diferentes condições hídricas, o que poderia favorecer a capacidade homeostática das plantas. A condutância estomática em folhas de girassol e de beterraba cultivadas com irrigação diária e sob deficiência hídrica foi medida com um analisador de gás por infra-vermelho em condições controladas. Os dados foram registrados a cada 20s durante 6h. As séries temporais obtidas foram analisadas por meio dos coeficientes de Lyapunov, dimensão fractal, entropia KS e complexidade LZ relativa. A condutância estomática nas plantas cultivadas com e sem deficiência hídrica exibiu um comportamento provavelmente caótico. As plantas sob estresse hídrico mostraram uma tendência para um comportamento mais complexo, principalmente as plantas de girassol cuja capacidade homeostática foi superior. Algumas implicações biológicas destes comportamentos são discutidas no texto.

  11. Scaling up stomatal conductance from leaf to canopy using a dual-leaf model for estimating crop evapotranspiration.

    Directory of Open Access Journals (Sweden)

    Risheng Ding

    Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and

  12. Photosynthetic pigments and stomatal conductance in ecotypes of copoazu (Theobroma grandi orum Willd. Ex. Spreng K. Schum..

    Directory of Open Access Journals (Sweden)

    Juan Carlos Suárez-Salazar

    2016-12-01

    Full Text Available The objective of this work was to evaluate the variability of photosynthetic pigment content and daily stomatal conductance was evaluated in relation to environmental variables in Copoazú (Theobroma grandi orum ecotypes. The ecotypes used were part of the germoplasm bank of the University of the Amazon (Colombia. The study was carried out during the year 2015. Four leaves of the average stratum of four plants were collected for each ecotype, to extract and read at different levels of absorbance and determine the content of photosynthetic pigments. During the hours of 04:00 a.m. to 6:00 p.m., the stomatal conductance (gs was monitored for environmental variables (relative humidity, air temperature, radiation and vapor pressure de cit (VPD. An analysis of variance was made using the Tukey test, correlations and regressions were made between gs and environmental variables. The contents of chlorophyll a, b, total and carotenoids among ecotypes were different (P<0.0001, the ecotype UA-31 presented the highest values, contrasting with the ecotype UA-37. Concerning gs, the interaction ecotype*hour showed signi cant differences (P<0.0001 .The ecotypes that presented the highest values of gs were UA-67 and UA-039, (P<0.0001, radiation (-0.91, P<0.0001 and DPV (-0.94; P<0.0001 0.0001.The results suggest that ecotypes UA-039 and UA-31 were the most suitable in terms of gaseous exchange and content of photosynthetic pigments.

  13. Optimizing stomatal conductance for maximum carbon gain under water stress: A meta-analysis across plant functional types and climates

    Science.gov (United States)

    Stomatal responses to environmental variables, in particular atmospheric CO2 concentration and soil water status, are needed for quantifying the controls on carbon and water exchanges between plants and the atmosphere. Building on previous leaf-scale gas exchange models and stomatal optimality theor...

  14. A photosynthesis-based two-leaf canopy stomatal conductance model for meteorology and air quality modeling with WRF/CMAQ PX LSM

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorol...

  15. A photosynthesis-based two-leaf canopy stomatal conductance model for meteorology and air quality modeling with WRF/CMAQ PX LSM

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorol...

  16. Wheat cultivars selected for high Fv/Fm under heat stress maintain high photosynthesis, total chlorophyll, stomatal conductance, transpiration and dry matter

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto

    2015-01-01

    ) than the low group, accompanied by higher stomatal conductance (gs), transpiration rate (E) and evaporative cooling of the leaf (ΔT). The difference in PN between the groups was not caused by differences in PSII capacity or gs as the variation in Fv/Fm and intracellular CO2 (Ci) was non...

  17. Changes in foliar carbon isotope composition and seasonal stomatal conductance reveal adaptive traits in Mediterranean coppices affected by drought

    Institute of Scientific and Technical Information of China (English)

    Giovanni Di Matteo; Luigi Perini; Paolo Atzori; Paolo De Angelis; Tiziano Mei; Giada Bertini; Gianfranco Fabbio; Giuseppe Scarascia Mugnozza

    2014-01-01

    We estimated water-use efficiency and potential photosyn-thetic assimilation of Holm oak (Quercus ilex L.) on slopes of NW and SW aspects in a replicated field test examining the effects of intensifying drought in two Mediterranean coppice forests. We used standard tech-niques for quantifying gas exchange and carbon isotopes in leaves and analyzed total chlorophyll, carotenoids and nitrogen in leaves collected from Mediterranean forests managed under the coppice system. We pos-tulated that responses to drought of coppiced trees would lead to differ-ential responses in physiological traits and that these traits could be used by foresters to adapt to predicted warming and drying in the Mediterra-nean area. We observed physiological responses of the coppiced trees that suggested acclimation in photosynthetic potential and water-use effi-ciency:(1) a significant reduction in stomatal conductance (p<0.01) was recorded as the drought increased at the SW site;(2) foliarδ13C increased as drought increased at the SW site (p<0.01);(3) variations in levels of carotenoids and foliar nitrogen, and differences in foliar morphology were recorded, and were tentatively attributed to variation in photosyn-thetic assimilation between sites. These findings increase knowledge of the capacity for acclimation of managed forests in the Mediterranean region of Europe.

  18. Detection of a quantitative trait locus controlling carbon isotope discrimination and its contribution to stomatal conductance in japonica rice.

    Science.gov (United States)

    Takai, Toshiyuki; Ohsumi, Akihiro; San-oh, Yumiko; Laza, Ma Rebecca C; Kondo, Motohiko; Yamamoto, Toshio; Yano, Masahiro

    2009-05-01

    Increasing leaf photosynthesis offers a possible way to improve yield potential in rice (Oryza sativa L.). Carbon isotope discrimination (Delta(13)C) has potential as an indirect selection criterion. In this study, we searched for quantitative trait loci (QTLs) controlling Delta(13)C, and assessed their association with leaf photosynthesis. Substitution mapping by using chromosome segment substitution lines (CSSLs), that carry segments from the indica cultivar Kasalath in the genetic background of the japonica cultivar Koshihikari, identified genomic regions affecting Delta(13)C on chromosomes (Chr.) 2, 3, 6, 7, and 12. One of the CSSLs, SL208, in which most regions on Chr. 3 were substituted with Kasalath segments, showed higher leaf stomatal conductance for CO(2) (g (s)) and Delta(13)C than Koshihikari during the vegetative stage although leaf photosynthetic rate did not differ between them. These results suggest an association between Delta(13)C and g (s). To test this association, we performed a QTL analysis for Delta(13)C at vegetative and heading stages in an F(2) population derived from a cross between SL208 and Koshihikari. The results confirmed a QTL controlling Delta(13)C on the long arm of Chr. 3. By using a near-isogenic line specific to Hd6, we ruled out the possibility that variation in Delta(13)C was generated through the pleiotropic effect of heading date.

  19. Stomatal and mesophyll conductances to CO₂ in different plant groups: underrated factors for predicting leaf photosynthesis responses to climate change?

    Science.gov (United States)

    Flexas, Jaume; Carriquí, Marc; Coopman, Rafael E; Gago, Jorge; Galmés, Jeroni; Martorell, Sebastià; Morales, Fermín; Diaz-Espejo, Antonio

    2014-09-01

    The climate change conditions predicted for the end of the current century are expected to have an impact on the performance of plants under natural conditions. The variables which are foreseen to have a larger effect are increased CO2 concentration and temperature. Although it is generally considered CO2 assimilation rate could be increased by the increasing levels of CO2, it has been reported in previous studies that acclimation to high CO2 results in reductions of physiological parameters involved in photosynthesis, like the maximum carboxylation rate (Vc,max), stomatal conductance (gs) and mesophyll conductance to CO2 (gm). On the one hand, most of the previous modeling efforts have neglected the potential role played by the acclimation of gm to high CO2 and temperature. On the other hand, the effect of climate change on plant clades other than angiosperms, like ferns, has received little attention, and there are no studies evaluating the potential impact of increasing CO2 and temperature on these species. In this study we predicted responses of several representative species among angiosperms, gymnosperms and ferns to increasing CO2 and temperature. Our results show that species with lower photosynthetic capacity - such as some ferns and gymnosperms - would be proportionally more favored under these foreseen environmental conditions. The main reason for this difference is the lower diffusion limitation imposed by gs and gm in plants having high capacity for photosynthesis among the angiosperms, which reduces the positive effect of increasing CO2. However, this apparent advantage of low-diffusion species would be canceled if the two conductances - gs and gm - acclimate and are down regulated to high CO2, which is basically unknown, especially for gymnosperms and ferns. Hence, for a better understanding of different plant responses to future climate, studies are urged in which the actual photosynthetic response/acclimation to increased CO2 and temperature of

  20. Long-distance signals regulating stomatal conductance and leaf growth in tomato (Lycopersicon esculentum) plants subjected to partial root-zone drying.

    Science.gov (United States)

    Sobeih, Wagdy Y; Dodd, Ian C; Bacon, Mark A; Grierson, Donald; Davies, William J

    2004-11-01

    Tomato (Lycopersicon esculentum Mill. cv. Ailsa Craig) plants were grown with roots split between two soil columns. After plant establishment, water was applied daily to one (partial root-zone drying-PRD) or both (well-watered control-WW) columns. Water was withheld from the other column in the PRD treatment, to expose some roots to drying soil. Soil and plant water status were monitored daily and throughout diurnal courses. Over 8 d, there were no treatment differences in leaf water potential (psileaf) even though soil moisture content of the upper 6 cm (theta) of the dry column in the PRD treatment decreased by up to 70%. Stomatal conductance (gs) of PRD plants decreased (relative to WW plants) when of the dry column decreased by 45%. Such closure coincided with increased xylem sap pH and did not require increased xylem sap abscisic acid (ABA) concentration ([X-ABA]). Detached leaflet ethylene evolution of PRD plants increased when of the dry column decreased by 55%, concurrent with decreased leaf elongation. The physiological significance of enhanced ethylene evolution of PRD plants was examined using a transgenic tomato (ACO1AS) with low stress-induced ethylene production. In response to PRD, ACO1AS and wild-type plants showed similar xylem sap pH, [X-ABA] and gs, but ACO1AS plants showed neither enhanced ethylene evolution nor significant reductions in leaf elongation. Combined use of genetic technologies to reduce ethylene production and agronomic technologies to sustain water status (such as PRD) may sustain plant growth under conditions where yield would otherwise be significantly reduced.

  1. Sensitivity of simulated terrestrial carbon assimilation and canopy transpiration to different stomatal conductance and carbon assimilation schemes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haishan [Nanjing University of Information Science and Technology, Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing (China); Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States); Dickinson, Robert E. [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States); The University of Texas at Austin, Department of Geological Sciences, Austin, TX (United States); Dai, Yongjiu [Beijing Normal University, State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Global Change and Earth System Science, Beijing (China); Zhou, Liming [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States)

    2011-03-15

    Accurate simulations of terrestrial carbon assimilation and canopy transpiration are needed for both climate modeling and vegetation dynamics. Coupled stomatal conductance and carbon assimilation (A - g{sub s}) models have been widely used as part of land surface parameterizations in climate models to describe the biogeophysical and biogeochemical roles of terrestrial vegetation. Differences in various A - g{sub s} schemes produce substantial differences in the estimation of carbon assimilation and canopy transpiration, as well as in other land-atmosphere fluxes. The terrestrial carbon assimilation and canopy transpiration simulated by two different representative A - g{sub s} schemes, a simple A-g{sub s} scheme adopted from the treatments of the NCAR model (Scheme I) and a two-big-leaf A - g{sub s} scheme newly developed by Dai et al. (J Clim 17:2281-2299, 2004) (Scheme II), are compared via some sensitivity experiments to investigate impacts of different A - g{sub s} schemes on the simulations. Major differences are found in the estimate of canopy carbon assimilation rate, canopy conductance and canopy transpiration between the two schemes, primarily due to differences in (a) functional forms used to estimate parameters for carbon assimilation sub-models, (b) co-limitation methods used to estimate carbon assimilation rate from the three limiting rates, and (c) leaf-to-canopy scaling schemes. On the whole, the differences in the scaling approach are the largest contributor to the simulation discrepancies, but the different methods of co-limitation of assimilation rate also impact the results. Except for a few biomes, the residual effects caused by the different parameter estimations in assimilation sub-models are relatively small. It is also noted that the two-leaf temperature scheme produces distinctly different sunlit and shaded leaf temperatures but has negligible impacts on the simulation of the carbon assimilation. (orig.)

  2. Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of soybean (Glycine max) at elevated [CO₂] and temperatures under fully open air field conditions.

    Science.gov (United States)

    Rosenthal, David M; Ruiz-Vera, Ursula M; Siebers, Matthew H; Gray, Sharon B; Bernacchi, Carl J; Ort, Donald R

    2014-09-01

    The net effect of elevated [CO2] and temperature on photosynthetic acclimation and plant productivity is poorly resolved. We assessed the effects of canopy warming and fully open air [CO2] enrichment on (1) the acclimation of two biochemical parameters that frequently limit photosynthesis (A), the maximum carboxylation capacity of Rubisco (Vc,max) and the maximum potential linear electron flux through photosystem II (Jmax), (2) the associated responses of leaf structural and chemical properties related to A, as well as (3) the stomatal limitation (l) imposed on A, for soybean over two growing seasons in a conventionally managed agricultural field in Illinois, USA. Acclimation to elevated [CO2] was consistent over two growing seasons with respect to Vc,max and Jmax. However, elevated temperature significantly decreased Jmax contributing to lower photosynthetic stimulation by elevated CO2. Large seasonal differences in precipitation altered soil moisture availability modulating the complex effects of elevated temperature and CO2 on biochemical and structural properties related to A. Elevated temperature also reduced the benefit of elevated [CO2] by eliminating decreases in stomatal limitation at elevated [CO2]. These results highlight the critical importance of considering multiple environmental factors (i.e. temperature, moisture, [CO2]) when trying to predict plant productivity in the context of climate change. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Patterns of stomatal conductance among blue oak (Quercus douglasii) size classes and populations: implications for seedling establishment.

    Science.gov (United States)

    Matzner, Steven L; Rice, Kevin J; Richards, James H

    2003-08-01

    Quercus douglasii Hook. & Arn. (blue oak) is a deciduous white oak that is currently failing to regenerate throughout much of its range in California, USA. Patterns of water use were observed in adult trees, saplings and seedlings to determine if ontogenetic changes in water use occur, which might be important in the establishment of this long-lived perennial species in a Mediterranean-type system. Seasonal and diurnal stomatal conductance (g(s)), late-season predawn xylem water potentials (Psi(pre)), carbon isotopic ratio (delta(13)C) and soil water status were compared among the three size classes at three sites differing in mean precipitation and soil water characteristics. Comparisons were also made between microsites with and without regeneration (defined by the presence or absence of saplings). Overall patterns of water use were consistent among the three sites, except that, at the site with the highest rainfall, Q. douglasii plants had higher g(s) and more positive Psi(pre) values. Although no differences in water use patterns were found between regeneration and non-regeneration microsites, the observed ontogenetic differences in water use may have important implications for Q. douglasii establishment. Compared with adult trees and saplings, seedlings had higher gas exchange rates during periods of high soil water content (early in the season and in the morning). Seedling g(s) was correlated with percent extractable soil water (ESW) throughout the season; adult tree and sapling g(s) was correlated with ESW between June and September. Despite experiencing greater water stress (indicated by more negative Psi(pre) values) than older trees, seedlings had more negative delta(13)C values, implying lower water-use efficiencies.

  4. Decreasing the Effective Thermal Conductivity in Glass Supported Thermoelectric Layers.

    Science.gov (United States)

    Bethke, Kevin; Andrei, Virgil; Rademann, Klaus

    2016-01-01

    As thermoelectric devices begin to make their way into commercial applications, the emphasis is put on decreasing the thermal conductivity. In this purely theoretical study, finite element analysis is used to determine the effect of a supporting material on the thermal conductivity of a thermoelectric module. The simulations illustrate the heat transfer along a sample, consisting from Cu, Cu2O and PbTe thermoelectric layers on a 1 mm thick Pyrex glass substrate. The influence of two different types of heating, at a constant temperature and at a constant heat flux, is also investigated. It is revealed that the presence of a supporting material plays an important role on lowering the effective thermal conductivity of the layer-substrate ensemble. By using thinner thermoelectric layers the effective thermal conductivity is further reduced, almost down to the value of the glass substrate. As a result, the temperature gradient becomes steeper for a fixed heating temperature, which allows the production of devices with improved performance under certain conditions. Based on the simulation results, we also propose a model for a robust thin film thermoelectric device. With this suggestion, we invite the thermoelectric community to prove the applicability of the presented concept for practical purposes.

  5. Fine Mapping of Carbon Assimilation Rate 8, a Quantitative Trait Locus for Flag Leaf Nitrogen Content, Stomatal Conductance and Photosynthesis in Rice

    Science.gov (United States)

    Adachi, Shunsuke; Yoshikawa, Kazuaki; Yamanouchi, Utako; Tanabata, Takanari; Sun, Jian; Ookawa, Taiichiro; Yamamoto, Toshio; Sage, Rowan F.; Hirasawa, Tadashi; Yonemaru, Junichi

    2017-01-01

    Increasing the rate of leaf photosynthesis is one important approach for increasing grain yield in rice (Oryza sativa). Exploiting the natural variation in CO2 assimilation rate (A) between rice cultivars using quantitative genetics is one promising means to identify genes contributing to higher photosynthesis. In this study, we determined precise location of Carbon Assimilation Rate 8 (CAR8) by crossing a high-yielding indica cultivar with a Japanese commercial cultivar. Fine mapping suggested that CAR8 encodes a putative Heme Activator Protein 3 (OsHAP3) subunit of a CCAAT-box-binding transcription factor called OsHAP3H. Sequencing analysis revealed that the indica allele of CAR8 has a 1-bp deletion at 322 bp from the start codon, resulting in a truncated protein of 125 amino acids. In addition, CAR8 is identical to DTH8/Ghd8/LHD1, which was reported to control rice flowering date. The increase of A is largely due to an increase of RuBP regeneration rate via increased leaf nitrogen content, and partially explained by reduced stomatal limitation via increased stomatal conductance relative to A. This allele also increases hydraulic conductivity, which would promote higher stomatal conductance. This indicates that CAR8 affects multiple physiological aspects relating to photosynthesis. The detailed analysis of molecular functions of CAR8 would help to understand the association between photosynthesis and flowering and demonstrate specific genetic mechanisms that can be exploited to improve photosynthesis in rice and potentially other crops. PMID:28197156

  6. Instantaneous-to-daily GPP upscaling schemes based on a coupled photosynthesis-stomatal conductance model: correcting the overestimation of GPP by directly using daily average meteorological inputs.

    Science.gov (United States)

    Wang, Fumin; Gonsamo, Alemu; Chen, Jing M; Black, T Andrew; Zhou, Bin

    2014-11-01

    Daily canopy photosynthesis is usually temporally upscaled from instantaneous (i.e., seconds) photosynthesis rate. The nonlinear response of photosynthesis to meteorological variables makes the temporal scaling a significant challenge. In this study, two temporal upscaling schemes of daily photosynthesis, the integrated daily model (IDM) and the segmented daily model (SDM), are presented by considering the diurnal variations of meteorological variables based on a coupled photosynthesis-stomatal conductance model. The two models, as well as a simple average daily model (SADM) with daily average meteorological inputs, were validated using the tower-derived gross primary production (GPP) to assess their abilities in simulating daily photosynthesis. The results showed IDM closely followed the seasonal trend of the tower-derived GPP with an average RMSE of 1.63 g C m(-2) day(-1), and an average Nash-Sutcliffe model efficiency coefficient (E) of 0.87. SDM performed similarly to IDM in GPP simulation but decreased the computation time by >66%. SADM overestimated daily GPP by about 15% during the growing season compared to IDM. Both IDM and SDM greatly decreased the overestimation by SADM, and improved the simulation of daily GPP by reducing the RMSE by 34 and 30%, respectively. The results indicated that IDM and SDM are useful temporal upscaling approaches, and both are superior to SADM in daily GPP simulation because they take into account the diurnally varying responses of photosynthesis to meteorological variables. SDM is computationally more efficient, and therefore more suitable for long-term and large-scale GPP simulations.

  7. Diversity in leaf anatomy, and stomatal distribution and conductance, between salt marsh and freshwater species in the C(4) genus Spartina (Poaceae).

    Science.gov (United States)

    Maricle, Brian R; Koteyeva, Nuria K; Voznesenskaya, Elena V; Thomasson, Joseph R; Edwards, Gerald E

    2009-01-01

    Leaf anatomy, stomatal density, and leaf conductance were studied in 10 species of Spartina (Poaceae) from low versus high salt marsh, and freshwater habitats. Internal structure, external morphology, cuticle structure, and stomatal densities were studied with light and electron microscopy. Functional significance of leaf structure was examined by measures of CO(2) uptake and stomatal distributions. All species have Kranz anatomy and C(4)delta(13)C values. Freshwater species have thin leaves with small ridges on adaxial sides and stomata on both adaxial and abaxial sides. By contrast, salt marsh species have thick leaves with very pronounced ridges on the adaxial side and stomata located almost exclusively on adaxial leaf surfaces. Salt marsh species also have a thicker cuticle on the abaxial than on the adaxial side of leaves, and CO(2) uptake during photosynthesis is restricted to the adaxial leaf surface. Salt marsh species are adapted to controlling water loss by having stomata in leaf furrows on the adaxial side, which increases the boundary layer, and by having large leaf ridges that fit together as the leaf rolls during water stress. Differences in structural-functional features of photosynthesis in Spartina species are suggested to be related to adaptations to saline environments.

  8. Condutância estomática em folhas de feijoeiro submetido a diferentes regimes de irrigação Stomatal conductance in leaves of bean plants submitted to different irrigation regimes

    Directory of Open Access Journals (Sweden)

    Auricleia S. Paiva

    2005-04-01

    capacity in the soil decreased to 40; 60 and 80% (respectively, treatments T1, T2 and T3, while irrigation in T4 occurred only to assure seedling emergence. Direct measurements of stomatal conductance were taken every day under field conditions in both adaxial and abaxial leaf surfaces using porometer. In all treatments, several measurements showed reduced stomatal conductance in response to low values of matric potential and high values of vapor pressure deficit (DPV and vice-versa. The lowest values of stomatal conductance of T4 leaves, taken from plants under the most restrictive water supply regime tested in this study, were observed during the period of plant flowering and grain development.

  9. Ozone-induced stomatal sluggishness develops progressively in Siebold's beech (Fagus crenata).

    Science.gov (United States)

    Hoshika, Yasutomo; Watanabe, Makoto; Inada, Naoki; Koike, Takayoshi

    2012-07-01

    We investigated the effects of ozone and leaf senescence on steady-state stomatal conductance and stomatal response to light variation. Measurements were carried out in a free-air ozone exposure experiment on a representative deciduous broadleaved tree species in Japan (Fagus crenata). Both steady-state and dynamic stomatal response to light variation varied intrinsically with season due to leaf senescence. Ozone induced the decrease in steady-state leaf gas exchange and the sluggish stomatal closure progressively. These findings suggest that ozone reduces the ability of plants to adapt to a fluctuating light environment under natural conditions, and therefore impairs plant growth and ability to control water loss.

  10. Observations and models of emissions of volatile terpenoid compounds from needles of ponderosa pine trees growing in situ: control by light, temperature and stomatal conductance

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Peter; Eller, Allyson; Guenther, Alex; Monson, Russell K.

    2014-07-12

    Terpenoid emissions from ponderosa pine (Pinus ponderosa subsp. scopulorum) were measured in Colorado, USA over two growing seasons to evaluate the role of incident light, needle temperature and stomatal conductance in controlling emissions of 2-methyl-3-buten-2-ol (MBO) and several monoterpenes. MBO was the dominant daylight terpenoid emission, comprising on average 87% of the total flux, and diurnal variations were largely determined by light and temperature. During daytime, oxygenated monoterpenes (especially linalool) comprised up to 75% of the total monoterpenoid flux from needles. A significant fraction of monoterpenoid emissions was light dependent and 13CO2 labeling studies confirmed de novo production. Thus, modeling of monoterpenoid emissions required a hybrid model in which a significant fraction of emissions was dependent on both light and temperature, while the remainder was dependent on temperature alone. Experiments in which stomata were forced to close using abscisic acid demonstrated that MBO and a large fraction of the monoterpene flux, presumably linalool, could be limited at the scale of seconds to minutes by stomatal conductance. Using a previously published model of terpenoid emissions which explicitly accounts for the physico-chemical properties of emitted compounds, we are able to simulate these observed stomatal effects, whether induced through experimentation or arising under naturally fluctuation conditions of temperature and light. This study shows unequivocally that, under naturally occurring field conditions, de novo light dependent monoterpenes can comprise a large fraction of emissions. Differences between the monoterpene composition of ambient air and needle emissions imply a significant non-needle emission source enriched in Δ-3-carene.

  11. Observations and models of emissions of volatile terpenoid compounds from needles of ponderosa pine trees growing in situ: control by light, temperature and stomatal conductance.

    Science.gov (United States)

    Harley, Peter; Eller, Allyson; Guenther, Alex; Monson, Russell K

    2014-09-01

    Terpenoid emissions from ponderosa pine (Pinus ponderosa subsp. scopulorum) were measured in Colorado, USA over two growing seasons to evaluate the role of incident light, needle temperature, and stomatal conductance in controlling emissions of 2-methyl-3-buten-2-ol (MBO) and several monoterpenes. MBO was the dominant daylight terpenoid emission, comprising on average 87% of the total flux, and diurnal variations were largely determined by light and temperature. During daytime, oxygenated monoterpenes (especially linalool) comprised up to 75% of the total monoterpenoid flux from needles. A significant fraction of monoterpenoid emissions was dependent on light and 13CO2 labeling studies confirmed de novo production. Thus, modeling of monoterpenoid emissions required a hybrid model in which a significant fraction of emissions was dependent on both light and temperature, while the remainder was dependent on temperature alone. Experiments in which stomata were forced to close using abscisic acid demonstrated that MBO and a large fraction of the monoterpene flux, presumably linalool, could be limited at the scale of seconds to minutes by stomatal conductance. Using a previously published model of terpenoid emissions, which explicitly accounts for the physicochemical properties of emitted compounds, we were able to simulate these observed stomatal effects, whether induced experimentally or arising under naturally fluctuation conditions of temperature and light. This study shows unequivocally that, under naturally occurring field conditions, de novo light-dependent monoterpenes comprise a significant fraction of emissions in ponderosa pine. Differences between the monoterpene composition of ambient air and needle emissions imply a significant non-needle emission source enriched in Δ-3-carene.

  12. Effects of enhanced ultraviolet-B radiation on water use efficiency, stomatal conductance, leaf nitrogen content and morphological characteristics of Spiraea pubesoens in a warm-temperate deciduous broad-leaved forest

    Institute of Scientific and Technical Information of China (English)

    CHEN Lan; ZHANG Shouren

    2007-01-01

    Spiraeapubescens,a common shrub in the warm temperate deciduous forest zone which is distributed in the Dongling Mountain area of Beijing,was exposed to ambient and enhanced ultraviolet-B(UV-B,280-320 nm)radiation by artificially supplying a daily dose of 9.4 kJ/m2 for three growing seasons,a level that simulated a 17% depletion in stratospheric ozone.The objective of this study was to explore the effects of long-term UV-B enhancement on stomatal conductance,leaf tissue δ13C,leaf water content,and leaf area.Particular attention was paid to the effects of UV-B radiation on water use efficiency(WUE)and leaf total nitrogen content.Enhanced UV-B radiation significantly reduced leaf area (50.1%)but increased leaf total nitrogen content(102%).These changes were associated with a decrease in stomatal conductance(16.1%)and intercellular CO2 concentration/air CO2 concentration(C/Ca)(4.0%),and an increase in leaf tissue δ13C(20.5%),leaf water content(3.1%),specific leaf weight(SLW)(5.2%)and WUE(4.1%).The effects of UV-B on the plant were greatly affected by the water content of the deep soil(30-40 cm).During the dry season,differences in the stomatat conductance δ13C,and WUE between the control and UV-B treated shrubs were very small;whereas,differences became much greater when soil water stress disappeared.Furthermore,the effects of UV-B became much less significant as the treatment period progressed over the three growing seasons.Correlation analysis showed that enhanced UV-B radiation decreased the strength of the correlation between soil water content and leaf water content, δ13C,Ci/Ca,stomatal conductance,with the exception of WUE that had a significant correlation coefficient with soil water content.These results suggest that WUE would become more sensitive to soil water variation due to UV-B radiation.Based on this experiment,it was found that enhanced UV-B radiation had much more significant effects on morphological traits and growth of S.pubescens than hydro

  13. Measurement of leaf hydraulic conductance and stomatal conductance and their responses to irradiance and dehydration using the Evaporative Flux Method (EFM).

    Science.gov (United States)

    Sack, Lawren; Scoffoni, Christine

    2012-12-31

    Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration(1,2). Water evaporating from the airspaces is replaced from cell walls, in turn drawing water from the xylem of leaf veins, in turn drawing from xylem in the stems and roots. As water is pulled through the system, it experiences hydraulic resistance, creating tension throughout the system and a low leaf water potential (Ψ(leaf)). The leaf itself is a critical bottleneck in the whole plant system, accounting for on average 30% of the plant hydraulic resistance(3). Leaf hydraulic conductance (K(leaf) = 1/ leaf hydraulic resistance) is the ratio of the water flow rate to the water potential gradient across the leaf, and summarizes the behavior of a complex system: water moves through the petiole and through several orders of veins, exits into the bundle sheath and passes through or around mesophyll cells before evaporating into the airspace and being transpired from the stomata. K(leaf) is of strong interest as an important physiological trait to compare species, quantifying the effectiveness of the leaf structure and physiology for water transport, and a key variable to investigate for its relationship to variation in structure (e.g., in leaf venation architecture) and its impacts on photosynthetic gas exchange. Further, K(leaf) responds strongly to the internal and external leaf environment(3). K(leaf) can increase dramatically with irradiance apparently due to changes in the expression and activation of aquaporins, the proteins involved in water transport through membranes(4), and K(leaf) declines strongly during drought, due to cavitation and/or collapse of xylem conduits, and/or loss of permeability in the extra-xylem tissues due to mesophyll and bundle sheath cell shrinkage or aquaporin deactivation(5

  14. Uptake of NO, NO 2 and O 3 by sunflower ( Helianthus annuus L.) and tobacco plants ( Nicotiana tabacum L.): dependence on stomatal conductivity

    Science.gov (United States)

    Neubert, A.; Kley, D.; Wildt, J.; Segschneider, H. J.; Förstel, H.

    The uptake of NO, NO 2 and O 3 by sunflowers ( Helianthus annuus L. var. giganteus) and tobacco plants ( Nicotiana tabacum L. var. Bel W3), using concentrations representative for moderately polluted air, has been determined by gas exchange experiments. Conductivities for these trace gases were measured at different light fluxes ranging from 820 μEm -2s -1 to darkness. The conductivities to water vapor and the trace gases are highly correlated. It is concluded that the uptake of NO, NO 2 and O 3 by sunflowers and tobacco plants is linearly dependent on stomatal opening. While the uptake of NO is limited by the mesophyll resistance, the uptake of NO 2 is only by diffusion through the stomata. Loss processes by deposition to the leaf surfaces are more pronounced for O 3 than for NO and NO 2.

  15. Capability of the ‘Ball-Berry' model for predicting stomatal conductance and water use efficiency of potato leaves under different irrigation regimes

    DEFF Research Database (Denmark)

    Liu, Fulai; Andersen, Mathias Neumann; Jensen, Christian Richardt

    2009-01-01

    of soil water deficits on gs, a simple equation modifying the slope (m) based on the mean soil water potential (Ψs) in the soil columns was incorporated into the original BB-model. Compared with the original BB-model, the modified BB-model showed better predictability for both gs and WUE of potato leaves......The capability of the ‘Ball-Berry' model (BB-model) in predicting stomatal conductance (gs) and water use efficiency (WUE) of potato (Solanum tuberosum L.) leaves under different irrigation regimes was tested using data from two independent pot experiments in 2004 and 2007. Data obtained from 2004....... The simulation results showed that the modified BB-model better simulated gs for the NI and DI treatments than the original BB-model, whilst the two models performed equally well for predicting gs of the FI and PRD treatments. Although both models had poor predictability for WUE (0.47 

  16. Fotossíntese, condutância estomática e transpiração em pupunheira sob deficiência hídrica Photosynthesis, stomatal conductance and transpiration in peach palm under water stress

    Directory of Open Access Journals (Sweden)

    Maria Aparecida José de Oliveira

    2002-03-01

    . Data were collected daily in a laboratory, under a photosynthetic photon flux (PPF of 1200 mum-2 s-1, and studied by variance and regression analysis. Significant decreases of leaf water potential values and gas exchange rates were verified when water was withhold for more than six days. The smallest values were found at the tenth day without water replacement, with a reduction of 92% of the net photosynthetic rate, 87% of the stomatal conductance and 70% of the transpiration. By that time, the smallest measured leaf water potential was --1.9 MPa. Recovering from water stress was accomplished two days after rewatering, except for stomatal conductance. The partial closing of the stomata (decrease in stomatal conductance and the reduction of photosynthesis, suggest the existence of an acclimation mechanism of the peach palm, diminishing water loss under moderate stress.

  17. Stomatal Conductance, Plant Species Distribution, and an Exploration of Rhizosphere Microbes and Mycorrhizae at a Deliberately Leakimg Experimental Carbon Sequestration Field (ZERT)

    Science.gov (United States)

    Sharma, B.; Apple, M. E.; Morales, S.; Zhou, X.; Holben, B.; Olson, J.; Prince, J.; Dobeck, L.; Cunningham, A. B.; Spangler, L.

    2010-12-01

    One measure to reduce atmospheric CO2 is to sequester it in deep geological formations. Rapid surface detection of any CO2 leakage is crucial. CO2 leakage rapidly affects vegetation above sequestration fields. Plant responses to high CO2 are valuable tools in surface detection of leaking CO2. The Zero Emission Research Technology (ZERT) site in Bozeman, MT is an experimental field for surface detection of CO2 where 0.15 ton/day of CO2 was released (7/19- 8/15/2010) from a 100m horizontal injection well, HIW, 1.5 m underground with deliberate leaks of CO2 at intervals, and from a vertical injector, VI, (6/3-6/24/2010). The vegetation includes Taraxacum officinale (Dandelion), Dactylis glomerata (Orchard Grass), and other herbaceous plants. We collected soil and roots 1, 3 and 5 m from the VI to determine the responses of mycorrhizal fungi and rhizosphere microbes to high CO2. Mycorrhizal fungi obtain C from root exudates, increase N and P availability, and reduce desiccation, while prokaryotic rhizosphere microbes fix atmospheric N and will be examined for abundance and expression of carbon and nitrogen cycling genes. We are quantifying mycorrhizal colonization and the proportion of spores, hyphae, and arbuscules in vesicular-arbuscular mycorrhizae (VAM) in cleared and stained roots. Stomatal conductance is an important measure of CO2 uptake and water loss via transpiration. We used a porometer (5-40°C, 0-90% RH, Decagon) to measure stomatal conductivity in dandelion and orchard grass at 1, 3, and 5 m from the VI and along a transect perpendicular to the HIW. Dandelion conductance was highest close to the VI and almost consistently higher close to hot spots (circular regions with maximum CO2 and leaf dieback) at the HIW, with 23.2 mmol/m2/s proximal to the hot spot, and 10.8 mmol/m2/s distally. Average conductance in grass (50.3 mmol/m2/s) was higher than in dandelion, but grass did not have high conductance near hot spots. Stomata generally close at elevated CO2

  18. Stomatal malfunctioning under low VPD conditions: induced by alterations in stomatal morphology and leaf anatomy or in the ABA signaling?

    Science.gov (United States)

    Aliniaeifard, Sasan; Malcolm Matamoros, Priscila; van Meeteren, Uulke

    2014-12-01

    Exposing plants to low VPD reduces leaf capacity to maintain adequate water status thereafter. To find the impact of VPD on functioning of stomata, stomatal morphology and leaf anatomy, fava bean plants were grown at low (L, 0.23 kPa) or moderate (M, 1.17 kPa) VPDs and some plants that developed their leaves at moderate VPD were then transferred for 4 days to low VPD (M→L). Part of the M→L-plants were sprayed with ABA (abscisic acid) during exposure to L. L-plants showed bigger stomata, larger pore area, thinner leaves and less spongy cells compared with M-plants. Stomatal morphology (except aperture) and leaf anatomy of the M→L-plants were almost similar to the M-plants, while their transpiration rate and stomatal conductance were identical to that of L-plants. The stomatal response to ABA was lost in L-plants, but also after 1-day exposure of M-plants to low VPD. The level of foliar ABA sharply decreased within 1-day exposure to L, while the level of ABA-GE (ABA-glucose ester) was not affected. Spraying ABA during the exposure to L prevented loss of stomatal closing response thereafter. The effect of low VPD was largely depending on exposure time: the stomatal responsiveness to ABA was lost after 1-day exposure to low VPD, while the responsiveness to desiccation was gradually lost during 4-day exposure to low VPD. Leaf anatomical and stomatal morphological alterations due to low VPD were not the main cause of loss of stomatal closure response to closing stimuli.

  19. An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

    Directory of Open Access Journals (Sweden)

    Juan Rodríguez-Gamir

    Full Text Available Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L. Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.. The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy.

  20. An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

    Science.gov (United States)

    Rodríguez-Gamir, Juan; Primo-Millo, Eduardo; Forner-Giner, María Ángeles

    2016-01-01

    Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L.) Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.). The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy.

  1. Effects of deficit irrigation and partial root-zone drying on soil and plant water status, stomatal conductance, plant growth and water use efficiency in tomato during early fruiting stage

    DEFF Research Database (Denmark)

    Liu, Fulai; Shahnazari, Ali; Jacobsen, S.-E.;

    2008-01-01

    elongation rate (LER) among treatments. Given the same irrigation water, PRD and DI had a similar effect on LER. At eight out of fourteen instances FI plants had the highest stomatal conductance while DI-50 and PRD-50 had the lowest. No significant differences were found between treatments in plant leaf area...

  2. Can the Responses of Photosynthesis and Stomatal Conductance to Water and Nitrogen Stress Combinations Be Modeled Using a Single Set of Parameters?

    Science.gov (United States)

    Zhang, Ningyi; Li, Gang; Yu, Shanxiang; An, Dongsheng; Sun, Qian; Luo, Weihong; Yin, Xinyou

    2017-01-01

    Accurately predicting photosynthesis in response to water and nitrogen stress is the first step toward predicting crop growth, yield and many quality traits under fluctuating environmental conditions. While mechanistic models are capable of predicting photosynthesis under fluctuating environmental conditions, simplifying the parameterization procedure is important toward a wide range of model applications. In this study, the biochemical photosynthesis model of Farquhar, von Caemmerer and Berry (the FvCB model) and the stomatal conductance model of Ball, Woodrow and Berry which was revised by Leuning and Yin (the BWB-Leuning-Yin model) were parameterized for Lilium (L. auratum × speciosum “Sorbonne”) grown under different water and nitrogen conditions. Linear relationships were found between biochemical parameters of the FvCB model and leaf nitrogen content per unit leaf area (Na), and between mesophyll conductance and Na under different water and nitrogen conditions. By incorporating these Na-dependent linear relationships, the FvCB model was able to predict the net photosynthetic rate (An) in response to all water and nitrogen conditions. In contrast, stomatal conductance (gs) can be accurately predicted if parameters in the BWB-Leuning-Yin model were adjusted specifically to water conditions; otherwise gs was underestimated by 9% under well-watered conditions and was overestimated by 13% under water-deficit conditions. However, the 13% overestimation of gs under water-deficit conditions led to only 9% overestimation of An by the coupled FvCB and BWB-Leuning-Yin model whereas the 9% underestimation of gs under well-watered conditions affected little the prediction of An. Our results indicate that to accurately predict An and gs under different water and nitrogen conditions, only a few parameters in the BWB-Leuning-Yin model need to be adjusted according to water conditions whereas all other parameters are either conservative or can be adjusted according to

  3. Towards an improved and more flexible representation of water stress in coupled photosynthesis-stomatal conductance models; implications for simulated land surface fluxes and variables at various spatiotemporal scales

    Science.gov (United States)

    Egea, G.; Verhoef, A.; Vidale, P. L.; Black, E.; Van den Hoof, C.

    2012-04-01

    Coupled photosynthesis-stomatal conductance (A-gs) models are commonly used in ecosystem models to represent the exchange rate of CO2 and H2O between vegetation and the atmosphere. The ways these models account for water stress differ greatly among modelling schemes. This study provides insight into the impact of contrasting model configurations of water stress on the simulated leaf-level values of net photosynthesis (A), stomatal conductance (gs), the functional relationship among them and their ratio, the intrinsic water use efficiency (A/gs), as soil dries. A simple, yet versatile, normalized soil moisture dependent function was used to account for the effects of water stress on gs, on mesophyll conductance (gm ) and on the biochemical capacity (Egea et al., 2011). Model output was compared to leaf-level values obtained from the literature. The sensitivity analyses emphasized the necessity to combine both stomatal and non-stomatal limitations of A in coupled A-gs models to accurately capture the observed functional relationships A vs. gs and A/gs vs. gs in response to drought. Accounting for water stress in coupled A-gs models by imposing either stomatal or biochemical limitations of A, as commonly practiced in most ecosystem models, failed to reproduce the observed functional relationship between key leaf gas exchange attributes. A quantitative limitation analysis revealed that the general pattern of C3 photosynthetic response to water stress can be represented in coupled A-gs models by imposing the highest limitation strength to mesophyll conductance, then to stomatal conductance and finally to the biochemical capacity. This more realistic representation of soil water stress on the simulated leaf-level values of A and gs was embedded in the JULES (Joint UK Land Environment Simulator; Best et al., 2011), model and tested for a number of vegetation types, for which driving and flux verification data were available. These simulations provide an insight into the

  4. 冬小麦气孔导度模型的比较%Comparison of Stomatal Conductance Models for Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    李永秀; 娄运生; 张富存

    2011-01-01

    为评估不同模型模拟冬小麦气孔导度的适用性,从常用的Jarvis模型和Ball-Berry模型中分别选择两种,根据试验资料估算模型参数,并对模型预测效果进行检验和比较.结果表明:运用Jarvis模型1、Jarvis模型2、Ball-Berry模型1和Ball-Berry模型2预测冬小麦气孔导度时预测值与实测值之间的相关系数分别为0.854、0.777、0.751、0.784,均方根误差分别为0.149、0.247、0.183、0.169mol·m·s,据此可确定4种模型的预测精度为Jarvis模型1>Ball-Berry模型2>Ball-Berry模型1>Jarvis模型2.研究结果可为现有的基于Jarvis模型和Ball-Berry模型的农田蒸散、陆面过程和生态系统模型提供参考.%To evaluate the applicability of four common-used stomatal conductance models for winter wheat, parameters of two Ball-Berry models and two Jarvis models were determined using experimental data. Then the four models were validated and compared. Results showed that the correlation coefficients between predicted and observed stomatal conductance for Jarvis model 1, Jarvis model 2, Ball-Berry model 1 and Ball-Berry model 2 were 0. 854, 0. 777, 0. 751, 0. 784, respectively. The corresponding root mean squared error (RMSE) for the four models were 0. 149, 0. 247, 0. 183, 0. 169 mol · m-2 · s-1, respectively. Based on these results, it was concluded that the prediction accuracy of the four models were in order of Jarvis model 1 > Ball-Berry model 2 > Ball-Berry model 1 > Jarvis model 2. The results of this study were expected to provide references for simulation of field evapotranspiration, land surface process and ecosystem.

  5. Internal and external control of net photosynthesis and stomatal conductance of mature eastern white pine (Pinus strobus)

    Science.gov (United States)

    Chris A. Maier; R.O. Teskey

    1992-01-01

    Leaf gas exchange and water relations were monitored in the upper canopy of two 25 m tall eastern white pine (Pinus strobus L.) trees over two consecutive growing seasons (1986 and 1987). Examination of the seasonal and diurnal patterns of net photosynthesis and leaf conductance showed that both internal and external (environmental) factors were...

  6. Using combined measurements for comparison of light induction of stomatal conductance, electron transport rate and CO2 fixation in woody and fern species adapted to different light regimes.

    Science.gov (United States)

    Wong, Shau-Lian; Chen, Chung-Wei; Huang, Hsien-Wen; Weng, Jen-Hsien

    2012-05-01

    We aimed to understand the relation of photosynthetic rate (A) with g(s) and electron transport rate (ETR) in species of great taxonomic range and light adaptation capability during photosynthetic light induction. We studied three woody species (Alnus formosana, Ardisia crenata and Ardisia cornudentata) and four fern species (Pyrrosia lingus, Asplenium antiquum, Diplazium donianum and Archangiopteris somai) with different light adaptation capabilities. Pot-grown materials received 100 and/or 10% sunlight according to their light adaptation capabilities. At least 4 months after light acclimation, CO(2) and H(2)O exchange and chlorophyll fluorescence were measured simultaneously by equipment in the laboratory. In plants adapted or acclimated to low light, dark-adapted leaves exposed to 500 or 2000 µmol m(-2) s(-1) photosynthetic photon flux (PPF) for 30 min showed low gross photosynthetic rate (P(g)) and short time required to reach 90% of maximum P(g) (). At the initiation of illumination, two broad-leaved understory shrubs and the four ferns, especially ferns adapted to heavy shade, showed higher stomatal conductance (g(s)) than pioneer tree species; materials with higher g(s) had short at both 500 and 2000 µmol m(-2) s(-1) PPF. With 500 or 2000 µmol m(-2) s(-1) PPF, the g(s) for the three woody species increased from 2 to 30 min after the start of illumination, but little change in the g(s) of the four ferns. Thus, P(g) and g(s) were not correlated for all material measured at the same PPF and induction time. However, P(g) was positively correlated with ETR, even though CO(2) assimilation may be influenced by stomatal, biochemical and photoinhibitory limitations. In addition, was closely related to time required to reach 90% maximal ETR for all materials and with two levels of PPF combined. Thus, ETR is a good indicator for estimating the light induction of photosynthetic rate of species, across a wide taxonomic range and light adaptation and acclimation

  7. A rate equation model of stomatal responses to vapour pressure deficit and drought

    Directory of Open Access Journals (Sweden)

    Shanahan ST

    2002-08-01

    Full Text Available Abstract Background Stomata respond to vapour pressure deficit (D – when D increases, stomata begin to close. Closure is the result of a decline in guard cell turgor, but the link between D and turgor is poorly understood. We describe a model for stomatal responses to increasing D based upon cellular water relations. The model also incorporates impacts of increasing levels of water stress upon stomatal responses to increasing D. Results The model successfully mimics the three phases of stomatal responses to D and also reproduces the impact of increasing plant water deficit upon stomatal responses to increasing D. As water stress developed, stomata regulated transpiration at ever decreasing values of D. Thus, stomatal sensitivity to D increased with increasing water stress. Predictions from the model concerning the impact of changes in cuticular transpiration upon stomatal responses to increasing D are shown to conform to experimental data. Sensitivity analyses of stomatal responses to various parameters of the model show that leaf thickness, the fraction of leaf volume that is air-space, and the fraction of mesophyll cell wall in contact with air have little impact upon behaviour of the model. In contrast, changes in cuticular conductance and membrane hydraulic conductivity have significant impacts upon model behaviour. Conclusion Cuticular transpiration is an important feature of stomatal responses to D and is the cause of the 3 phase response to D. Feed-forward behaviour of stomata does not explain stomatal responses to D as feedback, involving water loss from guard cells, can explain these responses.

  8. Height-related decreases in mesophyll conductance, leaf photosynthesis and compensating adjustments associated with leaf nitrogen concentrations in Pinus densiflora.

    Science.gov (United States)

    Han, Qingmin

    2011-09-01

    Hydraulic limitations associated with increasing tree height result in reduced foliar stomatal conductance (g(s)) and light-saturated photosynthesis (A(max)). However, it is unclear whether the decline in A(max) is attributable to height-related modifications in foliar nitrogen concentration (N), to mesophyll conductance (g(m)) or to biochemical capacity for photosynthesis (maximum rate of carboxylation, V(cmax)). Simultaneous measurements of gas exchange and chlorophyll fluorescence were made to determine g(m) and V(cmax) in four height classes of Pinus densiflora Sieb. & Zucc. trees. As the average height of growing trees increased from 3.1 to 13.7 m, g(m) decreased from 0.250 to 0.107 mol m(-2) s(-1), and the CO(2) concentration from the intercellular space (C(i)) to the site of carboxylation (C(c)) decreased by an average of 74 µmol mol(-1). Furthermore, V(cmax) estimated from C(c) increased from 68.4 to 112.0 µmol m(-2) s(-1) with the increase in height, but did not change when it was calculated based on C(i). In contrast, A(max) decreased from 14.17 to 10.73 µmol m(-2) s(-1). Leaf dry mass per unit area (LMA) increased significantly with tree height as well as N on both a dry mass and an area basis. All of these parameters were significantly correlated with tree height. In addition, g(m) was closely correlated with LMA and g(s), indicating that increased diffusive resistance for CO(2) may be the inevitable consequence of morphological adaptation. Foliar N per unit area was positively correlated with V(cmax) based on C(c) but negatively with A(max), suggesting that enhancement of photosynthetic capacity is achieved by allocating more N to foliage in order to minimize the declines in A(max). Increases in the N cost associated with carbon gain because of the limited water available to taller trees lead to a trade-off between water use efficiency and photosynthetic nitrogen use efficiency. In conclusion, the height-related decrease in photosynthetic

  9. Stomatal factors and vulnerability of stem xylem to cavitation in poplars.

    Science.gov (United States)

    Arango-Velez, Adriana; Zwiazek, Janusz J; Thomas, Barb R; Tyree, Melvin T

    2011-10-01

    The relationships between the vulnerability of stem xylem to cavitation, stomatal conductance, stomatal density, and leaf and stem water potential were examined in six hybrid poplar (P38P38, Walker, Okanese, Northwest, Assiniboine and Berlin) and balsam poplar (Populus balsamifera) clones. Stem xylem cavitation resistance was examined with the Cavitron technique in well-watered plants grown in the greenhouse. To investigate stomatal responses to drought, plants were subjected to drought stress by withholding watering for 5 (mild drought) and 7 (severe drought) days and to stress recovery by rewatering severely stressed plants for 30 min and 2 days. The clones varied in stomatal sensitivity to drought and vulnerability to stem xylem cavitation. P38P38 reduced stomatal conductance in response to mild stress while the balsam poplar clone maintained high leaf stomatal conductance under more severe drought stress conditions. Differences between the severely stressed clones were also observed in leaf water potentials with no or relatively small decreases in Assiniboine, P38P38, Okanese and Walker. Vulnerability to drought-induced stem xylem embolism revealed that balsam poplar and Northwest clones reached loss of conductivity at lower stem water potentials compared with the remaining clones. There was a strong link between stem xylem resistance to cavitation and stomatal responsiveness to drought stress in balsam poplar and P38P38. However, the differences in stomatal responsiveness to mild drought suggest that other drought-resistant strategies may also play a key role in some clones of poplars exposed to drought stress. Copyright © Physiologia Plantarum 2011.

  10. The evolution of the role of ABA in the regulation of water-use efficiency: From biochemical mechanisms to stomatal conductance.

    Science.gov (United States)

    Negin, Boaz; Moshelion, Menachem

    2016-10-01

    Abscisic acid is found in a wide variety of organisms. In the plant kingdom, ABA's role in mediating responses to abiotic stress has been conserved and enhanced throughout evolution. The emergence of plants to terrestrial environments required the development of mechanisms to cope with ongoing and severe abiotic stress such as drought and rapid changes in humidity and temperature. The common understanding is that terrestrial plants evolved strategies ranging from desiccation-tolerance mechanisms (mosses) to drought tolerance (CAM plants), to better exploit different ecological niches. In between these divergent water regulation strategies, ABA plays a significant role in managing plants' adaptation to new environments by optimizing water-use efficiency (WUE) under particular environmental conditions. ABA plays some very different roles in the regulation of WUE. ABA's role in the regulation of guard cells and transpiration has yielded a wide variety of WUE-regulation mechanisms, ranging from no sensitivity (ferns) to low sensitivity (anisohydric behavior) to hypersensitivity to ABA (isohydric behavior and putatively CAM plants). ABA also plays a role in the regulation of non-stomatal, biochemical mechanisms of WUE regulation. In angiosperms, this includes the control of osmotic adjustment and morphological changes, including changes in leaf size, stomatal density, stomatal size and root development. Under severe stress, ABA also appears to initiate leaf senescence via transcriptional regulation, to directly inhibit photosynthesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. Prosthetic stomatitis with removable dentures

    Directory of Open Access Journals (Sweden)

    Rozalieva Yu.Yu.

    2012-06-01

    Full Text Available The Research Objective: To study patients with prosthetic stomatitis, who use the removable laminar dentures. Materials: The consultations and treatment of 79 patients aged 47-65 years have been conducted. The patients have been divided into two clinical groups. The first clinical group (39 persons with the performance of immediate prosthet-ics; the second control clinical group (40 persons — the permanent dentures were produced without the preliminary instruction. Results: All the patients, having the laminar dentures without the preliminary use of immediate constructions of dentures, in spite of repeated correction of them, have had changes of dentures and transitory fold. Patients have been exposed to prosthetic stomatitis of different etiology (without trauma; the single-shot or multiple correction of dentures by the method of rebasing with using of cold cure plastics has been made. Conclusion: Structural and functional changes of dentition during the prosthetic stomatitis lead to disorders, associated by the mucositis. Use of the term of «prosthetic stomatitis» reflects etiological and pathogenetic component of changes in the denture-supporting tissues

  12. Epidemiology and etiology of denture stomatitis.

    Science.gov (United States)

    Gendreau, Linda; Loewy, Zvi G

    2011-06-01

    Denture stomatitis, a common disorder affecting denture wearers, is characterized as inflammation and erythema of the oral mucosal areas covered by the denture. Despite its commonality, the etiology of denture stomatitis is not completely understood. A search of the literature was conducted in the PubMed electronic database (through November 2009) to identify relevant articles for inclusion in a review updating information on the epidemiology and etiology of denture stomatitis and the potential role of denture materials in this disorder. Epidemiological studies report prevalence of denture stomatitis among denture wearers to range from 15% to over 70%. Studies have been conducted among various population samples, and this appears to influence prevalence rates. In general, where reported, incidence of denture stomatitis is higher among elderly denture users and among women. Etiological factors include poor denture hygiene, continual and nighttime wearing of removable dentures, accumulation of denture plaque, and bacterial and yeast contamination of denture surface. In addition, poor-fitting dentures can increase mucosal trauma. All of these factors appear to increase the ability of Candida albicans to colonize both the denture and oral mucosal surfaces, where it acts as an opportunistic pathogen. Antifungal treatment can eradicate C. albicans contamination and relieve stomatitis symptoms, but unless dentures are decontaminated and their cleanliness maintained, stomatitis will recur when antifungal therapy is discontinued. New developments related to denture materials are focusing on means to reduce development of adherent biofilms. These may have value in reducing bacterial and yeast colonization, and could lead to reductions in denture stomatitis with appropriate denture hygiene.

  13. Consumo de água em plantios de eucalipto: parte 1 determinação da condutância estomática em tratamentos irrigado e não-irrigado Water consumption in eucalypt plantation: part 1 determination of stomatal conductance in irrigated and non-irrigated treatments

    Directory of Open Access Journals (Sweden)

    Rogério Lessa de Castro Carneiro

    2008-02-01

    '23" S latitude, 42º22'46" W longitude and 220 m altitude. Stomatal conductance was measured in three different periods: humid period, early dry period, and dry period. Average values of stomatal conductance ranged from 0.41to 0.22mol m-2 s-1 for the irrigated treatment and from 0.38 to 0.24 mol m-2 s-1 for the non-irrigated treatment. Stomatal conductance was also found to decrease between the humid and dry periods. This variation was related with some environmental variables and soil moisture.

  14. Effect of High Temperature Stress on Leaf Growth and Stomatal Conductance in Rice%高温对水稻剑叶生长和气孔导度影响

    Institute of Scientific and Technical Information of China (English)

    张玉屏; 朱德峰; 林贤青; 向镜; 张浩

    2012-01-01

    In this study, different early rice varieties were studied in different temperature treatments, and the effect of high temperature stress on leaf growth and stomatal conductance in rice were probed. The results showed that: ( 1 ) in a certain temperature range, the higher the temperature, the longer the leaf elongation. The value of leaf elongation of Shengtai No. 1 was the maximum, and that of Xianxiaozhan was the minimum. (2) Leaf temperature increased significantly. The changing trend of four varieties was the same, and leaf temperature was slightly lower than the air temperature. (3) The stomatal conductance and the value of SPAD were increasing, especially when the temperature rose from 36 X. To 38 t , the stomatal conductance almost grew sharply, and the transpiration strengthened. (4) Yuexiangzhan was less sensitive to high temperature and its heat resistance was stronger.%为探讨高温对剑叶生长及气孔导度的影响,采用人工气候箱模拟抽穗期高温,对不同的早稻品种采用不同温度处理.结果表明:(1)在一定温度范围内,温度越高,叶片伸长越长,胜泰1号叶片伸长量最大,籼小占叶片伸长量最小;(2)大气温度升高,叶片温度明显升高,4个品种处理间变化趋势一致,且无显著性差异,叶片温度变化与气温变化一致,叶片温度略低于气温;(3)温度升高,气孔导度明显增加,SPAD值增大,特别是气温从36℃升到38℃时,气孔导度几乎成直线增长,蒸腾作用增强;(4)4个品种中粤香占对高温敏感性较小,耐高温性较强.

  15. Stomatal density and responsiveness of banana fruit stomates.

    Science.gov (United States)

    Johnson, B E; Brun, W A

    1966-01-01

    Determination of stomatal densities of the banana peel (Musa acuminata L. var Hort. Valery) by microscopic observations showed 30 times fewer stomates on fruit epidermis than found on the banana leaf. Observations also showed that peel stomates were not laid down in a linear pattern as on the leaf.It was demonstrated that stomatal responses occurred in banana fruit. Specific conditions of high humidity and light were necessary for stomatal opening: low humidity and darkness were necessary for closure. Responsiveness of the stomates continued for a considerable length of time after the fruit had been severed from the host.

  16. Trocas gasosas e condutância estomática em três espécies de gramíneas Gas exchanges and stomatal conductance on three gramineous species

    Directory of Open Access Journals (Sweden)

    Eduardo Caruso Machado

    1994-01-01

    Full Text Available Avaliou-se, sob condições naturais e sem deficiência hídrica, o comportamento diário das taxas de assimilação de CO2 (A e de transpiração (E, a condutância estomática (g e a eficiência fotossintética do uso de água (E/A em milho (C4, arroz (C3 e trigo (C3. Nas três espécies, a curva de resposta de A em função da irradiância (I, apresentou a forma de uma hipérbole retangular, porém em milho não houve saturação lumínica. A resposta de g em relação a I apresentou a mesma forma, respondendo E linearmente, nas três espécies. Em relação à variação de g, a curva de resposta de A também mostrou a forma de hipérbole retangular, enquanto E respondeu linearmente. Devido à resposta diferencial de A e de E, tanto em função de I como de g, a razão E/A aumentou com o aumento de I. As espécies C3 (arroz e trigo revelaram valores maiores de E/A que a C4 (milho, em todos os níveis de I e valores de g, indicando melhor adaptabilidade da C4 na limitação de abertura estomática.Under natural condition and without water deficit, assimilation of CO2 (A and transpiration (E rates, stomatal conductance (g and photosyntetic efficiency of water use (E/A, were monitored daily on maize (C4, rice (C3 and wheat (C3. In all species, the shape of response curves of A in function of irradiance (I, was a retangular hyperbole. However, luminic saturation was not observed in maize. Stomatal conductance response curve in function of I was also a retangular hyperbole, while E was linear in all species. Due to differential response of A and E, as a function of I as well as g, the ratio E/A was increased with the increase of I. The C3 species (rice and wheat showed higher values of E/A than the C4 specie (maize, in all levels of I and g, showing the better C4 adaptation when stomatal limitation aperture occurs.

  17. Contrasting Water-Use Efficiency (WUE) Responses of a Potato Mapping Population and Capability of Modified Ball-Berry Model to Predict Stomatal Conductance and WUE Measured at Different Environmental Conditions

    DEFF Research Database (Denmark)

    Kaminski, K. P.; Sørensen, Kirsten Kørup; Kristensen, Kristian

    2015-01-01

    .001). The leaf chlorophyll content was lower in the high-WUE group indicating that the higher net photosynthesis rate was not due to higher leaf-N status. Less negative value of carbon isotope discrimination (δ13C) in the high-WUE group was only found in 2011. A modified Ball-Berry model was fitted to measured...... stomatal conductance (gs) under the systematically varied environmental conditions to identify parameter differences between the two groups, which could explain their contrasting WUE. Compared to the low-WUE group, the high-WUE group showed consistently lower values of the parameter m, which is inversely...... 0.5 to 3.5 kPa. The mapping population was normally distributed with respect to WUE suggesting a multigenic nature of this trait. The WUE groups identified can be further employed for quantitative trait loci (QTL) analysis by use of gene expression studies or genome resequencing. The differences...

  18. Stomatal and Non-Stomatal Turbulent Deposition Flux of Ozone to a Managed Peatland

    Directory of Open Access Journals (Sweden)

    Tarek S. El-Madany

    2017-09-01

    Full Text Available Ozone is a key trace gas in the troposphere; because it is a greenhouse gas, it is very reactive, and it is potentially toxic to humans, fauna, and vegetation. The main sink processes for ozone are chemical reactions and the turbulent deposition flux to the earth’s surface. The deposition process itself is rather complex: The interactions between co-varying drivers such as the tropospheric ozone concentration, turbulence, and chemical reactions are not well understood. In the case of ozone deposition to vegetation, another aspect that must be studied is the role of stomatal regulation for a wide range of conditions. Therefore, we measured turbulent deposition fluxes of ozone with the eddy covariance technique during the peak of the growing season in 2014 over a managed, rewetted peatland in NW Germany. The deposition flux was large during the day (up to −15 nmol m−2 s−1 and relatively small during the night (between −1 and −2 nmol m−2 s−1. Flux partitioning by applying the surface resistance analogy and further analysis showed that the stomatal uptake was smaller than non-stomatal deposition. The correction of stomatal conductance with the gross primary production (GPP improved the estimation of day- and nighttime stomatal deposition fluxes. Statistical analysis confirmed that the friction velocity (u* was the single most important driver of non-stomatal ozone deposition and that relationships with other environmental drivers are not linear and highly variable. Further research is needed to develop a better process understanding of non-stomatal ozone deposition, to quantify the role of surface deposition to the ozone budget of the atmospheric boundary layer, and to estimate uncertainties associated with the partitioning of ozone deposition into stomatal and non-stomatal fluxes.

  19. Decrease of muscle fiber conduction velocity correlates with strength loss after an endurance run.

    Science.gov (United States)

    Boccia, Gennaro; Dardanello, Davide; Tarperi, Cantor; Rosso, Valeria; Festa, Luca; La Torre, Antonio; Pellegrini, Barbara; Schena, Federico; Rainoldi, Alberto

    2017-02-01

    Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated. After the run, knee extensors showed a decreased strength (-13  ±  9%, p  =  0.001) together with a reduction in EMG amplitude (-13  ±  10%, p  =  0.003) and in CV (-6  ±  8%, p  =  0.032). Knee extensor strength loss positively correlated with vastus lateralis CV differences (r  =  0.76, p  =  0.006). Thus, the exercises-induced muscle fatigue was associated not only with a decrease in EMG amplitude, but also with a reduction in CV. This finding suggests that muscle fibers with higher CV (i.e. those with greater fiber size) were the most impaired during strength production after an endurance run.

  20. Decrease in work function of transparent conducting ZnO tin films by phosphorus ion implantation.

    Science.gov (United States)

    Heo, Gi-Seok; Hong, Sang-Jin; Park, Jong-Woon; Choi, Bum-Ho; Lee, Jong-Ho; Shin, Dong-Chan

    2008-09-01

    To confirm the possibility of engineering the work function of ZnO thin films, we have implanted phosphorus ions into ZnO thin films deposited by radio-frequency magnetron sputtering. The fabricated films show n-type characteristics. It is shown that the electrical and optical properties of those thin films vary depending sensitively on the ion dose and rapid thermal annealing time. Compared to as-deposited ZnO films, the work-function of phosphorus ion-implanted ZnO thin films is observed to be lower and decreases with increasing ion doses. It is likely that the zinc or oxygen vacancies are firstly filled with the implanted phosphorus ions. With further increased ions, free electrons are generated as Zn2+ sites are replaced by those ions or interstitial phosphorus ions increase at the lattice sites, the fermi level by which approaches the conduction band and thus the work function decreases. Those films exhibit the optical transmittance higher than 85% within the visible wavelength range (up to 800 nm).

  1. Relationship between stomatal behavior and characteristics of photosynthesis and transpiration of Adenophora Iobophylla and A. potaninii at different altitudes

    Institute of Scientific and Technical Information of China (English)

    Ma Shu rong; Yan Xiufeng; Zu Yuangang

    1999-01-01

    The photosynthesis and transpiration characteristics ofAdenophora Iobophylla and A. potaninii, as well as stomatal behavior such as stomatal size, stomatal density, stomatal open and stomatal conductivity were measured at different altitudes. The relationship between the photosynthesis and transpiration characteristics and the stomatal behavior was analysed by correlation coefficient and path coefficient analysis with altitude changes.The results showed that the influences of stomatal behavior were not evident on the photosynthesis and transpiration characteristics of A. Lobophylla, but evident on that of A. potaninii.

  2. Effects of exogenous 5-aminolevulinic acid on photosynthesis, stomatal conductance, transpiration rate, and PIP gene expression of tomato seedlings subject to salinity stress.

    Science.gov (United States)

    Zhao, Y Y; Yan, F; Hu, L P; Zhou, X T; Zou, Z R; Cui, L R

    2015-06-11

    The effects of exogenous 5-aminolevulinic acid (ALA) on photosynthesis, plant growth, and the expression of two aquaporin genes in tomato seedlings under control and salinity conditions were investigated. Exogenous ALA application significantly improved net photosynthetic rate (Pn), total chlorophyll content, and plant biomass accumulation of tomato seedlings under salinity stress. As revealed by real-time PCR analyses, after treatment with ALA alone, expression of both LePIP1 and LePIP2 in the two tomato cultivars was up-regulated at 2 h and subsequently decreased to normal levels. Under salinity stress, transcript levels of LePIP1 in both leaves and roots of salt-sensitive cultivars (cv. Zhongza No.9) increased significantly and were considerably higher than in cultivars exposed to ALA alone. In contrast, the expression levels of LePIP1 and LePIP2 in cvs. Jinpeng No.1 cultivars were slightly lower under salinity stress than under ALA treatment. In addition, transcript levels of both LePIP1 and LePIP2 in the roots of Jinpeng No. 1 cultivars were considerably lower than those in the roots of Zhongza No. 9 cultivars under salinity stress, regardless of ALA supplementation, implying that Jinpeng No. 1 cultivars had a better capacity to maintain membrane intrinsic protein stability. Further, ALA application distinctly counteracted the up- or down-regulation of LePIP1 and LePIP2 in both cultivars under salinity stress, in accordance with the improvements instomatal conductance, transpiration rate, and Pn of tomato leaves. The results presented here indicate that ALA controls aquaporin expression, thus, presumably ALA regulates water homeostasis and enhances salt tolerance of tomato seedlings.

  3. Recurrent aphthous stomatitis

    Directory of Open Access Journals (Sweden)

    L Preeti

    2011-01-01

    Full Text Available Recurrent aphthous ulcers are common painful mucosal conditions affecting the oral cavity. Despite their high prevalence, etiopathogenesis remains unclear. This review article summarizes the clinical presentation, diagnostic criteria, and recent trends in the management of recurrent apthous stomatitis.

  4. 半干旱地区3种植物叶片水平的抗旱耐旱特性分析--两个气孔导度模型的应用和比较%LEAF-SCALE DROUGHT RESISTANCE AND TOLERANCE OF THREE PLANT SPECIES IN A SEMI-ARID ENVIRONMENT: APPLICATION AND COMPARISON OF TWO STOMATAL CONDUCTANCE MODELS

    Institute of Scientific and Technical Information of China (English)

    刘颖慧; 高琼; 贾海坤

    2006-01-01

    We measured diurnal gas exchange properties of three major species in a semi-arid site, and two stomatal conductance models were then applied to the data. The result indicated that the BBL model and the Gao model could explain on average 77.6 % and 59.3 % of variation in the observed stomatal conductance, respectively. Sensitivity analysis of the models indicated that the BBL model tended to give higher predictions of stomatal conductance than the Gao model. Both models showed similar responses to changes in vapor pressure.The sharp contrast between the two models, however, was that the Gao model responded to changes in soil water stress to different extents. The BBL model coupled with the TJ photosynthesis model was indifferent to increases of soil water stresses, which contradicts concurrent understanding and observations about plant physiology in arid and semiarid regions. Thus the BBL model, even though it provided better explanations of the variations in field stomata data, may not be appropriate for experimental data analysis and ecosystem simulation applications. The analysis using the Gao model indicated that Populus simonii was the least tolerant and resistant to water stresses among the three species studied. Pinus tabulaeformis had both high tolerance and resistance,but stomatal conductance of the pine tree was the least insensitive to changes in soil water stresses. Hence this pine tree may not be good for water conservation under extremely dry conditions. Caragana intermedia, however, had both larger drought tolerance and larger sensitivity to incremental soil water stresses, and thus can provide large stomatal conductance for photosynthesis when soil water stress was low, but reduce water consumption under severe water stresses by decreasing stomatal conductance with increasing soil water stress.%在对半干旱区3种植物进行生理生态特性测定的基础上,应用两种气孔导度模型进行参数的非线性

  5. Root signalling and modulation of stomatal closure in flooded citrus seedlings.

    Science.gov (United States)

    Rodríguez-Gamir, Juan; Ancillo, Gema; González-Mas, M Carmen; Primo-Millo, Eduardo; Iglesias, Domingo J; Forner-Giner, M Angeles

    2011-06-01

    In this work, we studied the sequence of responses induced by flooding in citrus plants, with the aim of identifying the signals that lead to stomatal closure. One-year-old seedlings of Carrizo citrange, grown in sand under greenhouse conditions, were waterlogged for 35 d and compared with normally watered well-drained plants. Significant decreases in stomatal conductance and transpiration were detected between flooded and control seedlings from a week after the beginning of the experiment. However ABA concentration in leaves only started to increase after three weeks of flooding, suggesting that stomata closed in the absence of a rise in foliar ABA. Therefore, stomatal closure in waterlogged seedlings does not appear to be induced by ABA, at least during the early stages of flood-stress. The low levels of ABA detected in roots and xylem sap from flooded seedlings indicated that it is very unlikely that the ABA increase in the leaves of these plants is due to ABA translocation from roots to shoots. We propose that ABA is produced in old leaves and transported to younger leaves. Flooding had no effect on water potential or the relative water content of leaves. Soil flooding reduced root hydraulic conductance in citrus seedlings. This effect was already evident after a week of waterlogging, and at the end of the experiment, flood-stressed seedlings reached values of root hydraulic conductance below 12% of that of control plants. This reduction was related to down-regulation of the expression of PIP aquaporins. In addition, whole plant transpiration was reduced by 56% after 35 d under flooding conditions. Flood-stress also decreased the pH of sap extracted from citrus roots. Evidence is presented suggesting that acidosis induced by anoxic stress in roots causes gating of aquaporins, thereby decreasing hydraulic conductance. Additionally, stomatal closure finely balances-out low pH-mediated losses of root hydraulic conductance therefore maintaining stable leaf

  6. Streptozotocin-induced diabetes decreases conducted vasoconstrictor response in mouse cremaster arterioles

    DEFF Research Database (Denmark)

    Rai, A; Riemann, M; Gustafsson, F

    2008-01-01

    . The mouse cremasteric arterioles were stimulated locally with KCl and the resulting local response as well as conducted responses at 500 microm and 1000 microm were measured in control and STZ treated mice. Diabetes (n=8) induced by intraperitoneal injection of STZ in a dose of 100 mg/kg (mean blood glucose...... reduces conducted vasoconstriction to KCl in mouse cremasteric arterioles, and combined treatment with both an oxygen radical scavenger and a protein kinase C beta II inhibitor improves the reduced conducted vasoconstriction....

  7. A safety vs efficiency trade-off identified in the hydraulic pathway of grass leaves is decoupled from photosynthesis, stomatal conductance and precipitation.

    Science.gov (United States)

    Ocheltree, Troy W; Nippert, Jesse B; Prasad, P V Vara

    2016-04-01

    A common theme in plant physiological research is the trade-off between stress tolerance and growth; an example of this trade-off at the tissue level is the safety vs efficiency hypothesis, which suggests that plants with the greatest resistance to hydraulic failure should have low maximum hydraulic conductance. Here, we quantified the leaf-level drought tolerance of nine C4 grasses as the leaf water potential at which plants lost 50% (P50 × RR ) of maximum leaf hydraulic conductance (Ksat ), and compared this trait with other leaf-level and whole-plant functions. We found a clear trade-off between Ksat and P50 × RR when Ksat was normalized by leaf area and mass (P = 0.05 and 0.01, respectively). However, no trade-off existed between P50 × RR and gas-exchange rates; rather, there was a positive relationship between P50 × RR and photosynthesis (P = 0.08). P50 × RR was not correlated with species distributions based on precipitation (P = 0.70), but was correlated with temperature during the wettest quarter of the year (P hydraulic system of grass leaves, which can be decoupled from other leaf-level functions. The unique physiology of C4 plants and adaptations to pulse-driven systems may provide mechanisms that could decouple hydraulic conductance from other plant functions.

  8. Stomatal- and growth responses in willow to deficits in water- and nitrogen supply. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stadenberg, I. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dep. for Production Ecology

    2002-02-01

    The two plants, grown with an [N] of 100 mg per litre and subjected to a decrease in N-supply decreased their leaf relative growth rate from 22% per day to 13% per day within 2 days. Stomatal conductance did not change significantly after the decrease in N-supply. Xylem samples did not show any significant changes in its composition of mineral nutrient elements after decreased N-supply. The three plants, grown with an [N] of 50 mg per litre and subjected to a decrease in N-supply, significantly decreased leaf relative growth rate from 18.5 % to 9 % per day within 2 days. Stomatal conductance did not change significantly after the decrease in N-supply. Xylem sap samples showed a significant decrease in [K] (74 mg/l to 42 mg/l) and [S] (11 mg/l to 3.2 mg/l) within 2 days after decreased N-supply. The four plants subjected to root drying decreased their leaf relative growth rate slightly but not significantly during the drying period. Xylem samples showed a significant decrease in S-concentration (11 mg/l to 1.3 mg/l) and [NO{sub 3}] (8.0 mg/l to 1.0 mg/l), while [Fe] increased significantly (0.065 mg/l to 0.14 mg/l). Stomatal conductance is known to decrease when plants are subjected to drying of part of the root system. This was shown for Salix dasyclados in a recent publication.

  9. Regulation Mechanisms of Stomatal Oscillation

    Institute of Scientific and Technical Information of China (English)

    Hui-Min YANG; Jian-Hua ZHANG; Xiao-Yan ZHANG

    2005-01-01

    Stomata function as the gates between the plant and the atmospheric environment. Stomatal movement, including stomatal opening and closing, controls CO2 absorption as the raw material for photosynthesis and water loss through transpiration. How to reduce water loss and maintain enough CO2 absorption has been an interesting research topic for some time. Simple stomatal opening may elevate CO2 absorption,but, in the meantime, promote the water loss, whereas simple closing of stomatal pores may reduce both water loss and CO2 absorption, resulting in impairment of plant photosynthesis. Both processes are not economical to the plant. As a special rhythmic stomatal movement that usually occurs at smaller stomatal apertures, stomatal oscillation can keep CO2 absorption at a sufficient level and reduce water loss at the same time, suggesting a potential improvement in water use efficiency. Stomatal oscillation is usually found after a sudden change in one environmental factor in relatively constant environments. Many environmental stimuli can induce stomatal oscillation. It appears that, at the physiological level, feedback controls are involved in stomatal oscillation. At the cellular level, possibly two different patterns exist: (i) a quicker responsive pattern; and (ii) a slower response. Both involve water potential changes and water channel regulation, but the mechanisms of regulation of the two patterns are different. Some evidence suggests that the regulation of water channels may play a vital and primary role in stomatal oscillation. The present review summarizes studies on stomatal oscillation and concludes with some discussion regarding the mechanisms of regulation of stomatal oscillation.

  10. Stomatal movement in response to long distance- communicated signals initiated by heat shock in partial roots of Commelina communis L.

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The systematic or long-distance signal transmission plays crucial roles in animal lives. Compared with animals, however, much less is known about the roles of long-distance signal communication in plant lives. Using the model plant Commelina communis L., we have probed the root to shoot communication mediated by heat-shock signals. The results showed that a heat shock of 5 min at 40℃ in partial roots, i.e. half or even 1/4 root system, could lead to a significant decrease in stomatal conductance. The regulation capability depends on both heat shock temperature and the amount of root system, i.e. with higher temperature and more roots stressed, the leaf conductance would decrease more significantly. Interestingly, the stomatal regulation by heat shock signal is in a manner of oscillation: when stomata conductance decreased to the lowest level within about 30 min, it would increase rapidly and sometimes even exceed the initial level, and after several cycles the stomata conductance would be finally stabilized at a lower level. Feeding xylem sap collected from heat-shocked plants could lead to a decrease in stomata conductance, suggesting that the heat shock-initiated signal is basically a positive signal. Further studies showed that heat shock was not able to affect ABA content in xylem sap, and also, not able to lead to a decrease in leaf water status, which suggested that the stomatal regulation was neither mediated by ABA nor by a hydraulic signal. Heat shock could lead to an increase in xylem sap H2O2 content, and moreover, the removal of H2O2 by catalase could partially recover the stomatal inhibition by xylem sap collected from heat-shocked plants, suggesting that H2O2 might be able to act as one of the root signals to control the stomatal movement. Due to the fact that heat-shock and drought are usually two concomitant stresses, the stomatal regulation by heat-shock signal should be of significance for plant response to stresses. The observation for the

  11. Sites With Small Impedance Decrease During Catheter Ablation for Atrial Fibrillation Are Associated With Recovery of Pulmonary Vein Conduction.

    Science.gov (United States)

    Chinitz, Jason S; Kapur, Sunil; Barbhaiya, Chirag; Kumar, Saurabh; John, Roy; Epstein, Laurence M; Tedrow, Usha; Stevenson, William G; Michaud, Gregory F

    2016-12-01

    To correlate impedance decrease during atrial fibrillation (AF) ablation with lesion durability and PV conduction recovery demonstrated during redo procedures. Markers of successful ablation beyond acute conduction block are needed to improve durability of pulmonary vein (PV) isolation (PVI). Local impedance decrease resulting from ablation is a real-time marker of tissue heating and is correlated with lesion creation. Impedance changes associated with point-by-point radiofrequency ablation in the PV antra were recorded during 167 consecutive first-time AF ablations. During clinically indicated redo procedures, sites of recovered PV conduction were identified, and were correlated with the impedance change achieved during ablation at these locations during the initial procedure. Redo procedures were performed in 28 patients, in whom 19 sites of recovered PV conduction were documented. Most sites of PV reconnection (58%) occurred along the posterior PV antra. Ablation resulting in impedance decrease decrease decrease than patients without PV conduction recovery (Group 2) (21.9 ± 15.5 mm vs. 11.5 ± 2.1 mm, P decreases <10 ohms. Impedance-guided ablation strategies may improve durability of PVI. © 2016 Wiley Periodicals, Inc.

  12. Cordycepin Decreases Compound Action Potential Conduction of Frog Sciatic Nerve In Vitro Involving Ca2+-Dependent Mechanisms

    Directory of Open Access Journals (Sweden)

    Li-Hua Yao

    2015-01-01

    Full Text Available Cordycepin has been widely used in oriental countries to maintain health and improve physical performance. Compound nerve action potential (CNAP, which is critical in signal conduction in the peripheral nervous system, is necessary to regulate physical performance, including motor system physiological and pathological processes. Therefore, regulatory effects of cordycepin on CNAP conduction should be elucidated. In this study, the conduction ability of CNAP in isolated frog sciatic nerves was investigated. Results revealed that cordycepin significantly decreased CNAP amplitude and conductive velocity in a reversible and concentration-dependent manner. At 50 mg/L cordycepin, CNAP amplitude and conductive velocity decreased by 62.18 ± 8.06% and 57.34% ± 6.14% compared with the control amplitude and conductive velocity, respectively. However, the depressive action of cordycepin on amplitude and conductive velocity was not observed in Ca2+-free medium or in the presence of Ca2+ channel blockers (CdCl2/LaCl3. Pretreatment with L-type Ca2+ channel antagonist (nifedipine/deltiazem also blocked cordycepin-induced responses; by contrast, T-type and P-type Ca2+ channel antagonists (Ni2+ failed to block such responses. Therefore, cordycepin decreased the conduction ability of CNAP in isolated frog sciatic nerves via L-type Ca2+ channel-dependent mechanism.

  13. The Dynamic Simulation of Stomatal Conductance of Cherry Leaf%樱桃叶片气孔导度模型构建

    Institute of Scientific and Technical Information of China (English)

    高照全; 赵晨霞; 冯社章

    2012-01-01

    A coupled model of gas exchange was developed which was able to systematically simulate the diurnal courses of Gs and the response of Gs to microclimatic factors. The experiment was conducted in a Hongdeng cherry (Prunus avium L. Hongdeng) orchard. The parameters of the model were tested by the data observed in upper canopy from 2008 to 2011 during the growing seasons.The simulation showed that Gs depends on plant characteristics and microclimatic factors including leaf water potential (41), photosynthetically active radiation (PAR), air temperature (Ta), relative humidity (RH) and air CO2 concentration. The results showed that Gs was mostly affected by ψ1, RH and Ta. Gs increased with the increase of ψ1 and RH, especially when ψ1 was below -1.5 MPa. As Ta increased, the change of Gs followed a bell-shaped curve. 28 ℃ was the optimum Ta for Gs in normal conditions. It should be noted that the optimum Ta for Gs shifted to a higher level as PAR or CO2 increased. There existed a positive linear relationship between Gs and PAR when PAR was below 600μmol·m^-2·s^-1 and Gs did not show a significant increase when PAR increased from 600 to 1800 μmol·m^-2·s^-1 Generally there was a negative correlation between CO2 concentration and Gs. Strong interactions existed among the various microclimatic factors to Gs, especially between Ta and PAR, PAR and CO2.%通过构建樱桃叶片气孔导度模型模拟Gs对小气候因子的响应。试验于2008—2011年在红灯樱桃(Prunus avium L.Hongdeng)园中进行,利用树冠上层叶片气体交换数据拟合了相应参数。结果表明,Gs的变化主要与小气候因子(如光合有效辐射PAR、空气温度Ta、相对湿度RH和CO2浓度等)和自身特性(如叶片水势ψ1)有关,其中ψ1、RH和Ta对Gs的影响较大。G8随ψ1,和RH增加而增加,当ψ1低于-1.5MPa时两者之间相关性尤为显著。当温度增加时Gs呈“钟

  14. A novel congenital myasthenic syndrome due to decreased acetylcholine receptor ion-channel conductance.

    Science.gov (United States)

    Webster, Richard; Maxwell, Susan; Spearman, Hayley; Tai, Kaihsu; Beckstein, Oliver; Sansom, Mark; Beeson, David

    2012-04-01

    Muscle acetylcholine receptor ion channels mediate neurotransmission by depolarizing the postsynaptic membrane at the neuromuscular junction. Inherited disorders of neuromuscular transmission, termed congenital myasthenic syndromes, are commonly caused by mutations in genes encoding the five subunits of the acetylcholine receptor that severely reduce endplate acetylcholine receptor numbers and/or cause kinetic abnormalities of acetylcholine receptor function. We tracked the cause of the myasthenic disorder in a female with onset of first symptoms at birth, who displayed mildly progressive bulbar, respiratory and generalized limb weakness with ptosis and ophthalmoplegia. Direct DNA sequencing revealed heteroallelic mutations in exon 8 of the acetylcholine receptor ε-subunit gene. Two alleles were identified: one with the missense substitution p.εP282R, and the second with a deletion, c.798_800delCTT, which result in the loss of a single amino acid, residue F266, within the M2 transmembrane domain. When these acetylcholine receptor mutations were expressed in HEK 293 cells, the p.εP282R mutation caused severely reduced expression on the cell surface, whereas p.εΔF266 gave robust surface expression. Single-channel analysis for p.εΔF266 acetylcholine receptor channels showed the longest burst duration population was not different from wild-type acetylcholine receptor (4.39 ± 0.6 ms versus 4.68 ± 0.7 ms, n = 5 each) but that the amplitude of channel openings was reduced. Channel amplitudes at different holding potentials showed that single-channel conductance was significantly reduced in p.εΔF266 acetylcholine receptor channels (42.7 ± 1.4 pS, n = 8, compared with 70.9 ± 1.6 pS for wild-type, n = 6). Although a phenylalanine residue at this position within M2 is conserved throughout ligand-gated excitatory cys-loop channel subunits, deletion of equivalent residues in the other subunits of muscle acetylcholine receptor did not

  15. 几种气孔导度模型在华北地区适应性研究%Research on the Applicability of Several Stomatal Conductance Models on the North China Plain

    Institute of Scientific and Technical Information of China (English)

    王治海; 刘建栋; 刘玲; 邬定荣; 毕建杰

    2012-01-01

    The eco-physiological indexes of winter wheat Lu 23 were systematically measured by using the LI - 6400 portable photosynthesis analyzer in Shandong Agricultural University. The parameters of several stomatal conductance models,which were selected from the Jarvis and Ball - Berry models, were fitted by using the least square method. Then the models were validated and compared. The results indicated that Ball - Berry model 2 performed the best with the highest correlation coefficient value of 0. 625 (P < 0. 01) and the lowest root mean squared error (RMSE) value of 0. 158 mol·m-2·s-1 . Meanwhile, Jarvis model 1 performed better than Jarvis model 2 and Ball - Berry model 1 performed the worst, with the lowest correlation coefficient value of 0. 369 ( P < 0. 01 ) and the highest root mean squared error ( RMSE ) value of 0. 235 mol · m-2 · s-1. The applicability of the four models was quite different from that in the Yangtze River delta, which meant further research on the applicability of stomatal conductance models in different regions was necessary to provide more reliable references for the future study on the SPAC.%利用LI-6400便携式光合测定仪,在山东农业大学试验基地对冬小麦品种鲁麦23生理生态多项指标进行系统测定,在此基础上,从Jarvis和Ball-Berry模型中分别选取两种模型,利用最小二乘法对气孔导度参数进行拟合检验,并对模型预测效果进行统计分析和对比.结果表明,Ball-Berry模型2预测精度最高,其预测值与实测值的相关系数和均方根误差分别为0.625(P<0.01)和0.158mol·m-2·s-1,Jarvis模型1优于Jarvis模型2,Ball-Berry模型1预测效果最差,其预测值与实测值的相关系数和均方根误差分别为0.369(P<0.01)和0.235mol·m-2·s-1.4种模型在华北地区的适应性与长江中下游地区相比存在一定差异,因此需要在更多地区对气孔导度模型进行更深入研究,以期为土壤-植被-大气系统研究提供更为可靠的参考依据.

  16. Stomatal response of an anisohydric grapevine cultivar to evaporative demand, available soil moisture and abscisic acid.

    Science.gov (United States)

    Rogiers, Suzy Y; Greer, Dennis H; Hatfield, Jo M; Hutton, Ron J; Clarke, Simon J; Hutchinson, Paul A; Somers, Anthony

    2012-03-01

    Stomatal responsiveness to evaporative demand (air vapour pressure deficit (VPD)) ranges widely between species and cultivars, and mechanisms for stomatal control in response to VPD remain obscure. The interaction of irrigation and soil moisture with VPD on stomatal conductance is particularly difficult to predict, but nevertheless is critical to instantaneous transpiration and vulnerability to desiccation. Stomatal sensitivity to VPD and soil moisture was investigated in Semillon, an anisohydric Vitis vinifera L. variety whose leaf water potential (Ψ(l)) is frequently lower than that of other grapevine varieties grown under similar conditions in the warm grape-growing regions of Australia. A survey of Semillon vines across seven vineyards revealed that, regardless of irrigation treatment, midday Ψ(l) was dependent on not only soil moisture but VPD at the time of measurement. Predawn Ψ(l) was more closely correlated to not only soil moisture in dry vineyards but to night-time VPD in drip-irrigated vineyards, with incomplete rehydration during high night-time VPD. Daytime stomatal conductance was low only under severe plant water deficits, induced by extremes in dry soil. Stomatal response to VPD was inconsistent across irrigation regime; however, in an unirrigated vineyard, stomatal sensitivity to VPD-the magnitude of stomatal response to VPD-was heightened under dry soils. It was also found that stomatal sensitivity was proportional to the magnitude of stomatal conductance at a reference VPD of 1kPa. Exogenous abscisic acid (ABA) applied to roots of Semillon vines growing in a hydroponic system induced stomatal closure and, in field vines, petiole xylem sap ABA concentrations rose throughout the morning and were higher in vines with low Ψ(l). These data indicate that despite high stomatal conductance of this anisohydric variety when grown in medium to high soil moisture, increased concentrations of ABA as a result of very limited soil moisture may augment

  17. Leaf conductance decreased under free-air CO2 enrichment (FACE) for three perennials in the Nevada desert

    Science.gov (United States)

    Nowak, Robert S.; Defalco, Lesley A.; Wilcox, Carolyn S.; Jordan, Dean N.; Coleman, James S.; Seemann, Jeffrey R.; Smith, Stanley D.

    2001-01-01

    A common response of plants to elevated atmospheric CO2 concentration (CO2) is decreased leaf conductance. Consequently, leaf temperature is predicted to increase under elevated CO2.Diurnal patterns of leaf conductance and temperature were measured for three desert perennials, the C3 shrub Larrea tridentata, C3 tussock grass Achnatherum hymenoides and C4tussock grass Pleuraphis rigida, at the Nevada Desert FACE facility. Measurements were made on ambient and c. 550 µmol mol−1 CO2 plots through both a wet and dry year.Reductions in conductance were 35%, 20% and 13% for Pleuraphis, Achnatherum and Larrea, respectively. Decreased conductance occurred throughout the day only for Pleuraphis. Both C3species had smaller CO2 effects during dry periods than wet. Leaf temperature did not differ significantly between elevated and ambient CO2 for any species. Comparisons of blower-control and nonring plots indicated that the FACE apparatus did not confound our results.All three species exhibited decreased leaf conductance under elevated CO2, although reductions were not uniform during the day or among years. Nonetheless, leaf energy balance was only minimally changed for these microphyllous desert perennials.

  18. Significant decrease in thermal conductivity of multi-walled carbon nanotube induced by inter-wall van der Waals interactions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xue; Zhou, Wu-Xing, E-mail: wuxingzhou@hnu.edu.cn; Chen, Xue-Kun; Liu, Yue-Yang; Chen, Ke-Qiu, E-mail: keqiuchen@hnu.edu.cn

    2016-05-06

    The thermal transport properties of multi-walled carbon nanotubes (MWCNTs) were investigated by using non-equilibrium molecular dynamics simulation. The results show that the thermal conductivity of MWCNTs decreases significantly comparing to that of single-walled carbon nanotubes (SWCNTs) due to the inter-wall van der Waals interactions. The more interesting is a fact that the thermal conductance of MWCNTs is significantly greater than the thermal conductance summation of each SWCNTs. This is because the thermal conductance of a carbon nanotube protected by an outer tube is much larger than that of one that is not protected. Moreover, we also studied the thermal flux distribution of MWCNTs, and found that the outer tube plays a dominant role in heat energy transfer. - Highlights: • Significant decrease in thermal conductivity of multi-walled carbon nanotube induced by inter-wall interactions. • The thermal conductivity of the inner tube is increased significantly due to protected by outer tube. • The outer tube plays a dominant role in heat energy transfer in multi-walled carbon nanotube.

  19. A new stomatal paradigm for earth system models? (Invited)

    Science.gov (United States)

    Bonan, G. B.; Williams, M. D.; Fisher, R. A.; Oleson, K. W.; Lombardozzi, D.

    2013-12-01

    The land component of climate, and now earth system, models has simulated stomatal conductance since the introduction in the mid-1980s of the so-called second generation models that explicitly represented plant canopies. These second generation models used the Jarvis-style stomatal conductance model, which empirically relates stomatal conductance to photosynthetically active radiation, temperature, vapor pressure deficit, CO2 concentration, and other factors. Subsequent models of stomatal conductance were developed from a more mechanistic understanding of stomatal physiology, particularly that stomata are regulated so as to maximize net CO2 assimilation (An) and minimize water loss during transpiration (E). This concept is embodied in the Ball-Berry stomatal conductance model, which relates stomatal conductance (gs) to net assimilation (An), scaled by the ratio of leaf surface relative humidity to leaf surface CO2 concentration, or the Leuning variant which replaces relative humidity with a vapor pressure deficit term. This coupled gs-An model has been widely used in climate and earth system models since the mid-1990s. An alternative approach models stomatal conductance by directly optimizing water use efficiency, defined as the ratio An/gs or An/E. Conceptual developments over the past several years have shown that the Ball-Berry style model can be derived from optimization theory. However, an explicit optimization model has not been tested in an earth system model. We compare the Ball-Berry model with an explicit optimization model, both implemented in a new plant canopy parameterization developed for the Community Land Model, the land component of the Community Earth System Model. The optimization model is from the Soil-Plant-Atmosphere (SPA) model, which integrates plant and soil hydraulics, carbon assimilation, and gas diffusion. The canopy parameterization is multi-layer and resolves profiles of radiation, temperature, vapor pressure, leaf water stress

  20. Significant decrease in thermal conductivity of multi-walled carbon nanotube induced by inter-wall van der Waals interactions

    Science.gov (United States)

    Zhang, Xue; Zhou, Wu-Xing; Chen, Xue-Kun; Liu, Yue-Yang; Chen, Ke-Qiu

    2016-05-01

    The thermal transport properties of multi-walled carbon nanotubes (MWCNTs) were investigated by using non-equilibrium molecular dynamics simulation. The results show that the thermal conductivity of MWCNTs decreases significantly comparing to that of single-walled carbon nanotubes (SWCNTs) due to the inter-wall van der Waals interactions. The more interesting is a fact that the thermal conductance of MWCNTs is significantly greater than the thermal conductance summation of each SWCNTs. This is because the thermal conductance of a carbon nanotube protected by an outer tube is much larger than that of one that is not protected. Moreover, we also studied the thermal flux distribution of MWCNTs, and found that the outer tube plays a dominant role in heat energy transfer.

  1. Tonic GABAA conductance decreases membrane time constant and increases EPSP-spike precision in hippocampal pyramidal neurons

    Directory of Open Access Journals (Sweden)

    Agnieszka I Wlodarczyk

    2013-12-01

    Full Text Available Because of a complex dendritic structure, pyramidal neurons have a large membrane surface relative to other cells and so a large electrical capacitance and a large membrane time constant (τm. This results in slow depolarizations in response to excitatory synaptic inputs, and consequently increased and variable action potential latencies, which may be computationally undesirable. Tonic activation of GABAA receptors increases membrane conductance and thus regulates neuronal excitability by shunting inhibition. In addition, tonic increases in membrane conductance decrease the membrane time constant (τm, and improve the temporal fidelity of neuronal firing. Here we performed whole-cell current clamp recordings from hippocampal CA1 pyramidal neurons and found that bath application of 10 µM GABA indeed decreases τm in these cells. GABA also decreased first spike latency and jitter (standard deviation of the latency produced by current injection of 2 rheobases (500 ms. However, when larger current injections (3-6 rheobases were used, GABA produced no significant effect on spike jitter, which was low. Using mathematical modelling we demonstrate that the tonic GABAA conductance decreases rise time, decay time and half-width of EPSPs in pyramidal neurons. A similar effect was observed on EPSP/IPSP pairs produced by stimulation of Schaffer collaterals: the EPSP part of the response became shorter after application of GABA. Consistent with the current injection data, a significant decrease in spike latency and jitter was obtained in cell attached recordings only at near-threshold stimulation (50% success rate, S50. When stimulation was increased to 2- or 3- times S50, GABA significantly affected neither spike latency nor spike jitter. Our results suggest that a decrease in τm associated with elevations in ambient GABA can improve EPSP-spike precision at near-threshold synaptic inputs.

  2. Tonic GABAA conductance decreases membrane time constant and increases EPSP-spike precision in hippocampal pyramidal neurons.

    Science.gov (United States)

    Wlodarczyk, Agnieszka I; Xu, Chun; Song, Inseon; Doronin, Maxim; Wu, Yu-Wei; Walker, Matthew C; Semyanov, Alexey

    2013-01-01

    Because of a complex dendritic structure, pyramidal neurons have a large membrane surface relative to other cells and so a large electrical capacitance and a large membrane time constant (τm). This results in slow depolarizations in response to excitatory synaptic inputs, and consequently increased and variable action potential latencies, which may be computationally undesirable. Tonic activation of GABAA receptors increases membrane conductance and thus regulates neuronal excitability by shunting inhibition. In addition, tonic increases in membrane conductance decrease the membrane time constant (τm), and improve the temporal fidelity of neuronal firing. Here we performed whole-cell current clamp recordings from hippocampal CA1 pyramidal neurons and found that bath application of 10μM GABA indeed decreases τm in these cells. GABA also decreased first spike latency and jitter (standard deviation of the latency) produced by current injection of 2 rheobases (500 ms). However, when larger current injections (3-6 rheobases) were used, GABA produced no significant effect on spike jitter, which was low. Using mathematical modeling we demonstrate that the tonic GABAA conductance decreases rise time, decay time and half-width of EPSPs in pyramidal neurons. A similar effect was observed on EPSP/IPSP pairs produced by stimulation of Schaffer collaterals: the EPSP part of the response became shorter after application of GABA. Consistent with the current injection data, a significant decrease in spike latency and jitter was obtained in cell attached recordings only at near-threshold stimulation (50% success rate, S50). When stimulation was increased to 2- or 3- times S50, GABA significantly affected neither spike latency nor spike jitter. Our results suggest that a decrease in τm associated with elevations in ambient GABA can improve EPSP-spike precision at near-threshold synaptic inputs.

  3. Tulip-poplar leaf diffusion resistance calculated from stomatal dimensions and varying environmental parameters

    Energy Technology Data Exchange (ETDEWEB)

    McConathy, R.K.

    1983-03-01

    The study describes the gradients of stomatal size and density in the crown of a mature forest-grown tulip-poplar (Liriodendron tulipifera L.) in eastern Tennessee. These data are used to predict leaf resistance to vapor diffusion in relation to stomatal width and boundary layer resistance. Stomatal density on individual leaves did not vary, but density increased with increasing crown height. Stomatal size decreased with increasing height of leaves within the crown. Stomatal size and density variations interacted to result in a constant number of stomata per leaf at all crown heights. Stomatal diffusive resistance values calculated from stomatal measurements and varying environmental parameters indicated that stomatal resistance controlled transpiration water losses only at small apertures (<0.6 ..mu..m). Boundary layer resistance was controlling at large stomatal apertures (>0.6 ..mu..m) and at low wind speeds (approx.100 cm/s). Under normal forest conditions tulip-poplar stomatal resistance exercised more control over transpiration than did boundary layer resistance.

  4. 水分胁迫对紫花苜蓿叶水势、蒸腾速率和气孔导度的影响%Impact of Water Stress on Leaf Water Potential, Transpiration Rate(Tr)and Stomatal Conductance (Gs) of Alfalfa

    Institute of Scientific and Technical Information of China (English)

    罗永忠; 成自勇

    2011-01-01

    In order to reveal the stomatal response of Alfalfa under water stress, leaf water potential, transpiration rate (Tr), stomatal conductance (Gs) of alfalfa (Medicago sativa) and their relationship under water stress are studied by adopting pot-cultivation designs. Results show that the leaf water potential, Tr and Gs of alfalfa decreased with water stress increasing. The daily change of the leaf potential, Trand Gs display a bimodal curve pattern with the same mean value. The maximum is obtained under full water supply, followed by light water stress, moderate water stress and severe water stress. The lowest leaf water potential decreases with the decreasing of soil moisture, the peak appearing time of leaf potential and Trun der moderate and severe water stress is earlier than that of full water supply and light water stress. Under moderate and severe water stress, when the water potential was -4. 68 MPa, or Tr was 3.27 g · m-2 ·h-1 , the stomata begin to close. Under full water supply and light water stress, Tr increases with the decreasing water potential, and G, increases with the increasing of Tr. The leaf water potential changes not only related with the soil moisture, but also closely related with the leaf development.%采用盆栽水分试验,研究了不同土壤水分条件下紫花苜蓿(Medicago sativa)叶水势、蒸腾速率和气孔导度的变化规律及相互关系,以期揭示其对土壤水分胁迫的气孔响应机制.结果表明:苜蓿叶水势、蒸腾速率(Tr)、气孔导度(Gs)均随水分胁迫加剧而降低,三者日变化均呈双峰曲线特征,日平均值表现为充分供水>轻度胁迫>中度胁迫>重度胁迫.最低叶水势随土壤水分降低而降低;在中度和重度胁迫下,叶水势和蒸腾速率日变化峰值出现的时间提前,当叶水势为-4.68 MPa或Tr为3.27 g·m-2·h-1时,气孔开始关闭;在充分供水和轻度胁迫下,Tr越高,叶水势越低,且G随着Tr增加而增加.叶水势的变化

  5. Mineralocorticoids decrease the activity of the apical small-conductance K channel in the cortical collecting duct.

    Science.gov (United States)

    Wei, Yuan; Babilonia, Elisa; Sterling, Hyacinth; Jin, Yan; Wang, Wen-Hui

    2005-11-01

    We used the patch-clamp technique to examine the effect of DOCA treatment (2 mg/kg) on the apical small-conductance K (SK) channels, epithelial Na channels (ENaC), and the basolateral 18-pS K channels in the cortical collecting duct (CCD). Treatment of rats with DOCA for 6 days significantly decreased the plasma K from 3.8 to 3.1 meq and reduced the activity of the SK channel, defined as NP(o), from 1.3 in the CCD of control rats to 0.6. In contrast, DOCA treatment significantly increased ENaC activity from 0.01 to 0.53 and the basolateral 18-pS K channel activity from 0.67 to 1.63. Moreover, Western blot analysis revealed that DOCA treatment significantly increased the expression of the nonreceptor type of protein tyrosine kinase (PTK), cSrc, and the tyrosine phosphorylation of ROMK in the renal cortex and outer medulla. The possibility that decreases in apical SK channel activity induced by DOCA treatment were the result of stimulation of PTK activity was further supported by experiments in which inhibition of PTK with herbimycin A significantly increased NP(o) from 0.6 to 2.1 in the CCD from rats receiving DOCA. Also, when rats were fed a high-K (10%) diet, DOCA treatment did not increase the expression of c-Src and decrease the activity of the SK channel in the CCD. We conclude that DOCA treatment decreased the apical SK channel activity in rats on a normal-K diet and that an increase in PTK expression may be responsible for decreased channel activity in the CCD from DOCA-treated rats.

  6. Enhancement of leaf photosynthetic capacity through increased stomatal density in Arabidopsis.

    Science.gov (United States)

    Tanaka, Yu; Sugano, Shigeo S; Shimada, Tomoo; Hara-Nishimura, Ikuko

    2013-05-01

    Photosynthetic rate is determined by CO2 fixation and CO2 entry into the plant through pores in the leaf epidermis called stomata. However, the effect of increased stomatal density on photosynthetic rate remains unclear. This work investigated the effect of alteration of stomatal density on leaf photosynthetic capacity in Arabidopsis thaliana. Stomatal density was modulated by overexpressing or silencing STOMAGEN, a positive regulator of stomatal development. Leaf photosynthetic capacity and plant growth were examined in transgenic plants. Increased stomatal density in STOMAGEN-overexpressing plants enhanced the photosynthetic rate by 30% compared to wild-type plants. Transgenic plants showed increased stomatal conductance under ambient CO2 conditions and did not show alterations in the maximum rate of carboxylation, indicating that the enhancement of photosynthetic rate was caused by gas diffusion changes. A leaf photosynthesis-intercellular CO2 concentration response curve showed that photosynthetic rate was increased under high CO2 conditions in association with increased stomatal density. STOMAGEN overexpression did not alter whole plant biomass, whereas its silencing caused biomass reduction. Our results indicate that increased stomatal density enhanced leaf photosynthetic capacity by modulating gas diffusion. Stomatal density may be a target trait for plant engineering to improve photosynthetic capacity.

  7. CO2, H2O exchange and stomatal regulation of regenerated Camptotheca acuminata plantlets during ex vitro acclimatization

    Institute of Scientific and Technical Information of China (English)

    WANG Hui-mei; LI Yan-hua; GAO Yin-xiang; ZU Yuan-gang

    2006-01-01

    For finding the changes in CO2, H2O exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate (Pn), respiration rate (Rd), light compensation point (Lc) and light saturation point (Ls), transpiration rate (Tr), stomatal conductance (gs) and water use efficiency(WUE) were measured during 37 days of ex vitro acclimatization. The results showed that Pn sharply increased until 29 days, then slightly decreased. A substantial decrease in Lc and a substantial increase of Ls in the former two weeks were observed, indicating the light regime enlargement for effective leaf photosynthesis. Tr and gs abruptly decreased during the first week then linearly increased until 29days ex vitro acclimatization, reflecting the strong regulation effect of stomata on water changes of ex vitro acclimating plantlets. Stomatal regulation effect on CO2 exchange was different from that on water exchange, i.e. Pn was almost independent of gs during the first week, while Pn was significantly correlated with gs thereafter (i.e. dual patterns). Different from dual patterns of gs-Pn relation, the Tr monotonously linearly increased with gs. Furthermore, WUE was almost independent on gs during the first week, while a marked decreasing tendency with gs was found thereafter. At the beginning of the acclimatization, WUE was mainly determined by photosynthetic capacity, while transpiration becomes a main determinant factor for WUE from 7 to 37 days' acclimatization.

  8. DEXMEDETOMIDINE DECREASES PROPOFOL DOSE REQUIREMENT FOR INDUCTION OF ANAESTHESIA: A COMPARATIVE STUDY CONDUCTED ON PATIENTS UNDERGOING LAPAROSCOPIC CHOLECYSTECTOMY

    Directory of Open Access Journals (Sweden)

    Farhana

    2015-04-01

    Full Text Available Dexmedetomidine is a highly selective α - 2 agonist with properties of sedation, analgesia and anxiolysis. We conducted this study on dexmedetomidine to evaluate its effect in reducing dose of propofol for induction of anaesthesia. A prospective, double blind, placebo controlled study was conducted on 100 patients of ASA I and II statu s of both sexes in the age group of 20 - 60 years. Patients were randomly allocated to two groups: Group A(n=50 that received dexmedetomidine loading dose of 1μ g /kg wt.(50ml over 10 minutes that was given 15 minutes prior to induction of anaesthesia and Group B(n=50 received same volume (50 ml of 0.9% normal saline(NS as placebo. Dose requirement of propofol was calculated at induction maintaining BIS of 40 - 60. It was observed that mean requirement of propofol for induction of anaesthesia was reduced to 50.6% in group A patients as compared to group B patients. CONCLUSION: Induction dose of propofol is significantly decreased after administration of dexmedetomidine.

  9. Evidence-based modelling of diverse plant water use strategies on stomatal and non-stomatal components under drought

    Science.gov (United States)

    zhou, S.; Prentice, C.; Medlyn, B. E.; Sabaté, S.

    2013-12-01

    Models disagree on how to represent effects of drought stress on plant gas exchange. Some models assume drought stress affects the marginal water use efficiency of plants (marginal WUE; i.e. the change in photosynthesis per unit of change in transpiration) whereas others assume drought stress acts directly on photosynthetic capacity. It is not clear whether either of these approaches is sufficient to capture the drought response, or whether the effect of drought varies among species and functional types. A collection of Eucalyptus and Quercus species derived from different hydro-climate habitats, in together with two European riparian species, were conducted with drought treatments respectively in Australia and Spain for three months. Measurements included net CO2 assimilation rate versus substomatal CO2 concentration (A-Ci) curves, fluorescence, and predawn leaf water potential at increasing levels of water stress. The correlations with quantitative plant traits of leaf, stomata, vessel, and wood density, leaf nitrogen content and 13C discrimination were also explored. We analysed the effect of drought effect on leaf gas exchange with a recently developed stomatal model that reconciles the empirical and optimal approaches on predicting optimal stomatal conductance. The model's single parameter g1 is a decreasing function of marginal WUE. The two genera showed consistence on the contrasting response patterns between species derived from mesic and arid habitats, which differed greatly in their estimated g1 values under moist conditions, and in the rate at which g1 declined with water stress. They also differed greatly in the predawn water potential at which apparent carboxylation capacity (apparent Vcmax) and mesophyll conductance (gm) declined most steeply, and in the steepness of this decline. Principal components analysis revealed a gradient in water relation strategies from sclerophyll species to malacophyll species. Malacophylls had higher g1, apparent Vcmax

  10. [CORRELATION MATRIX OF CHARACTERISTICS OF CHRONIC RECURRENT APHTHOUS STOMATITIS].

    Science.gov (United States)

    Koridze, Kh; Aladashvili, L; Taboridze, I

    2015-09-01

    The purpose of the present work is to study the correlation between the risk factors of chronic recurrent aphthous stomatitis. The research was conducted on 62 patients between ages of 40 and 70 years at Tbilisi Hospital for Veterans of War. The analysis was carried out by Spearman's Rank Correlation method using the statistical package SPSS 11.5. We investigated: harmful habits, professional factors, background and accompanying illnesses, pathology of teeth, focal infection, emotional stress, genetic factors. Correlation matrix between the significant risk factors of chronic recurrent aphthous stomatitis is defined. Multiple correlations have the following factors: industrial dust, focal infections, emotional stress, anemia. Correlation diagram of etiological factors of chronic recurrent aphthous stomatitis is helpful for providing professional and expert services.

  11. Canopy Transpiration and Stomatal Responses to Prolonged Drought by a Dominant Desert Species in Central Asia

    Directory of Open Access Journals (Sweden)

    Daxing Gu

    2017-06-01

    Full Text Available In arid and semiarid lands, canopy transpiration and its dynamics depend largely on stomatal sensitivity to drought. In this study, the sap flow of a dominant species, Haloxylon ammodendron growing in Central Asian deserts, was monitored using Granier-type sensors, from which the canopy stomatal conductance was derived. The responses of canopy transpiration and stomatal conductance to environmental variables during the second half of the growing season, when annual prolonged drought occurred, was analyzed for four continuous years, from 2013 to 2016. A soil water content (SWC of 3% was identified as the lower soil water threshold for this species, below which the plant lost the ability for stomatal regulation on water loss and suffered the risk of mortality. Above this threshold, the sensitivity of canopy transpiration to vapor pressure deficit, VPD (K, was linearly correlated with SWC, which mainly resulted from different stomatal behaviors at varying drought intensities. Stomatal sensitivity to VPD (m/Gsref increased linearly with soil moisture deficit, inducing a shift from more anisohydric to a more isohydric stomatal behavior. The flexibility of stomatal behavior regarding soil drought was one key element facilitating the survival of H. ammodendron in such an extreme dry environment.

  12. Guard cell photosynthesis is critical for stomatal turgor production, yet does not directly mediate CO2 - and ABA-induced stomatal closing.

    Science.gov (United States)

    Azoulay-Shemer, Tamar; Palomares, Axxell; Bagheri, Andisheh; Israelsson-Nordstrom, Maria; Engineer, Cawas B; Bargmann, Bastiaan O R; Stephan, Aaron B; Schroeder, Julian I

    2015-08-01

    Stomata mediate gas exchange between the inter-cellular spaces of leaves and the atmosphere. CO2 levels in leaves (Ci) are determined by respiration, photosynthesis, stomatal conductance and atmospheric [CO2 ]. [CO2 ] in leaves mediates stomatal movements. The role of guard cell photosynthesis in stomatal conductance responses is a matter of debate, and genetic approaches are needed. We have generated transgenic Arabidopsis plants that are chlorophyll-deficient in guard cells only, expressing a constitutively active chlorophyllase in a guard cell specific enhancer trap line. Our data show that more than 90% of guard cells were chlorophyll-deficient. Interestingly, approximately 45% of stomata had an unusual, previously not-described, morphology of thin-shaped chlorophyll-less stomata. Nevertheless, stomatal size, stomatal index, plant morphology, and whole-leaf photosynthetic parameters (PSII, qP, qN, FV '/FM' ) were comparable with wild-type plants. Time-resolved intact leaf gas-exchange analyses showed a reduction in stomatal conductance and CO2 -assimilation rates of the transgenic plants. Normalization of CO2 responses showed that stomata of transgenic plants respond to [CO2 ] shifts. Detailed stomatal aperture measurements of normal kidney-shaped stomata, which lack chlorophyll, showed stomatal closing responses to [CO2 ] elevation and abscisic acid (ABA), while thin-shaped stomata were continuously closed. Our present findings show that stomatal movement responses to [CO2 ] and ABA are functional in guard cells that lack chlorophyll. These data suggest that guard cell CO2 and ABA signal transduction are not directly modulated by guard cell photosynthesis/electron transport. Moreover, the finding that chlorophyll-less stomata cause a 'deflated' thin-shaped phenotype, suggests that photosynthesis in guard cells is critical for energization and guard cell turgor production.

  13. Adjustments of water use efficiency by stomatal regulation during drought and recovery in the drought-adapted Vitis hybrid Richter-110 (V. berlandieri x V. rupestris).

    Science.gov (United States)

    Pou, Alícia; Flexas, Jaume; Alsina, Maria del Mar; Bota, Josefina; Carambula, Cecilia; de Herralde, Felicidad; Galmés, Jeroni; Lovisolo, Claudio; Jiménez, Miguel; Ribas-Carbó, Miquel; Rusjan, Denis; Secchi, Francesca; Tomàs, Magdalena; Zsófi, Zsolt; Medrano, Hipólito

    2008-10-01

    The hybrid Richter-110 (Vitis berlandieri x Vitis rupestris) (R-110) has the reputation of being a genotype strongly adapted to drought. A study was performed with plants of R-110 subjected to water withholding followed by re-watering. The goal was to analyze how stomatal conductance (g(s)) is regulated with respect to different physiological variables under water stress and recovery, as well as how water stress affects adjustments of water use efficiency (WUE) at the leaf level. Water stress induced a substantial stomatal closure and an increase in WUE, which persisted many days after re-watering. The g(s) during water stress was mainly related to the content of ABA in the xylem and partly related to plant hydraulic conductivity but not to leaf water potential. By contrast, low g(s) during re-watering did not correlate with ABA contents and was only related to a sustained decreased hydraulic conductivity. In addition to a complex physiological regulation of stomatal closure, g(s) and rate of transpiration (E) were strongly affected by leaf-to-air vapor pressure deficit (VPD) in a way dependent of the treatment. Interestingly, E increased with increasing VPD in control plants, but decreased with increasing VPD in severely stressed plants. All together, the fine stomatal regulation in R-110 resulted in very high WUE at the leaf level. This genotype is revealed to be very interesting for further studies on the physiological mechanisms leading to regulation of stomatal responsiveness and WUE in response to drought.

  14. Stomatal complex types, stomatal density, and the stomatal index in some species of dioscorea

    Directory of Open Access Journals (Sweden)

    Abdulrahaman A.A.

    2009-01-01

    Full Text Available Dioscorea alata L. has three stomatal complex types, namely, paracytic, anisocytic, and tetracytic stomata, with percentage frequency values of 50, 18, and 32, respectively. Dioscorea bulbifera has paracytic and anisocytic stomata, with percentage frequency values of 87.60 and 12.40, respectively. Dioscorea cayenensis has anisocytic stomata, with a percent­age frequency value of 100. Dioscorea dumetorum has tetracytic and paractytic stomata, with percentage frequency values of 91.05 and 8.95, respectively. Both D. esculenta and D. rotundata have paracytic stomata, with a percentage frequency of 100. The range of variation of stomatal density is from 10 (lowest value in D. alata and D. dumentorum to 27 (highest value in D. bulbifera. The stomatal index also varies, from 24 in D. alata to 47 in D. cayenensis. The size of stomata in all species is small, varying in length from 0.74 μm in D. alata to 1.79 μm in D. dumentorum. An indented dichotomous key based on stomatal features was constructed to distinguish and identify the species.

  15. Stomatal Density and Bio-water Saving

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Bio-water saving is to increase water use efficiency of crops or crop yield per unit of water input. Plant water use efficiency is determined by photosynthesis and transpiration, for both of which stomata are crucial. Stomata are pores on leaf epidermis for both water and carbon dioxide fluxes that are controlled by two major factors: stomatal behavior and density. Stomatal behavior has been the focus of intensive research, while less attention has been paid to stomatal density. Recently, a number of genes controlling stomatal development have been identified. This review summarizes the recent progress on the genes regulating stomatal density, and discusses the role of stomatal density in plant water use efficiency and the possibility to increase plant water use efficiency, hence bio-water saving by genetically manipulating stomatal density.

  16. Variabilidade sazonal da condutância estomática em um ecossistema de manguezal amazônico e suas relações com variáveis meteorológicas Seasonal variability of the stomatal conductance in Amazonian mangrove ecosystem and their relationships with meteorological variables

    Directory of Open Access Journals (Sweden)

    Hernani José Brazão Rodrigues

    2011-06-01

    Full Text Available No presente trabalho foram estudadas as variações da condutância estomática (g s para o período chuvoso (março e seco (agosto do ano de 2003, e suas relações de dependência com algumas variáveis meteorológicas medidas em um ecossistema de manguezal amazônico. As informações utilizadas foram do projeto ECOBIOMA, parte integrante do Experimento de Grande Escala da Biosfera-Atmosfera da Amazônia (LBA. A g s acompanha a tendência de variação do balanço de radiação, atingindo valores máximos durante o dia e mínimos durante a noite. A condutância apresentou maiores flutuações no período chuvoso, com valor médio de g s = 0,015 m s-¹, porém com magnitudes inferiores as do período seco. Durante a época seca apresentou um valor médio de g s = 0,027 m s-¹, com menor amplitude, variando de 0,010 This work investigated the variations of stomatal conductance (g s in the rainy and dry seasons and its dependence relations with meteorological variables measured in an Amazonian mangrove ecosystem. Data were originated from the ECOBIOMA project, part of the Large Scale Biosphere-Atmosphere Experiment in Amazon (LBA. Stomatal conductance followed the tendency of the radiation balance variation, reaching maximum values during the day and minimum values at night. The conductance showed greater fluctuations in the rainy season, with mean value of g s = 0.015 m s-¹, however smaller in magnitude than in the dry season. During the dry season, the mean value was g s = 0.027 m s-¹, with lower range, varying between 0.010 and 0.042 m s-¹. The meteorological variables used for establishing the dependence relations with the daily variability of stomatal conductance were the following; specific moisture deficit (δq, vapor pressure deficit (PVD, net radiation (Rn and wind velocity (Vv. The PVD showed the best correlation with g s, with R² = 0.99 for both periods. In spite of the importance of Vv in the gaseous changes between the

  17. Variação sazonal da fotossíntese, condutância estomática e potencial da água na folha de laranjeira 'Valência' Seasonal variation of photosynthetic rates, stomatal conductance and leaf water potential in 'Valencia' orange trees

    Directory of Open Access Journals (Sweden)

    Eduardo Caruso Machado

    2002-03-01

    Full Text Available Em espécies perenes podem ocorrer variações nas taxas de trocas gasosas e nas relações hídricas em função da variação das condições ambientais, durante os diferentes meses do ano. Avaliaram-se, em laranjeira ´Valência´ enxertada sobre quatro espécies de porta-enxerto, mantida sem deficiência hídrica, as taxas de fotossíntese (A e de transpiração (E, a condutância estomática (g e o potencial da água na folha (psi f , medidos nos períodos da manhã (9h00 às 11h00 e da tarde (13h00 às 15h00 nos meses de janeiro, março e julho em Campinas - SP. As espécies de porta-enxertos não tiveram efeitos sobre as variáveis medidas. Independente do porta-enxerto A, g e Y f foram menores no período da tarde. A queda de A deve estar relacionada com a queda de g que diminuiu em resposta ao aumento do déficit de pressão de vapor entre o ar e a folha (DPVar-folha nos horários mais quentes do dia. Apesar de ocorrer fechamento parcial dos estômatos no período da tarde E foi similar ao período da manhã, devido ao aumento do DPVar-folha. Também observou-se queda em A e em g no sentido de janeiro para julho. Sugere-se que a queda em A e em g ocorrida em março em comparação a janeiro esteja relacionada à queda da atividade de crescimento da planta, afetando as relações fonte-dreno, visto que as condições ambientais nestes dois meses foram semelhantes. As quedas de A e de g observadas em julho, em relação à janeiro e março, parecem estar relacionadas tanto à queda na temperatura noturna quanto à queda na atividade de crescimento.Seasonal variation in environmental conditions may influence gas exchange rates as well as water relations in perennial species. This work was carried out to evaluate photosynthetic rates (A, transpiration (E, stomatal conductance (g and leaf water potential (psi f in 'Valencia' orange trees grafted on four different rootstocks. Measurements were made twice a day: from 9h00 to 11h00 a.m. and

  18. Proteomic Characterization of Stomatal Movement

    Institute of Scientific and Technical Information of China (English)

    Sixue Chen

    2012-01-01

    Stomata on leaf epidermis formed by pairs of guard cells control CO2 intake and water transpiration,and respond to different environmental conditions.Stress induced stomatal closure is mediated via an intricate hormone network in guard cells.Here we report absicic acid (ABA) and methyl jasmonate (MeJA) responsive proteins and redox sensitive proteins.Both ABA and MeJA cause stomatal movement and H2O2 production.Using an isobaric tags for relative and absolute quantitation approach,we have identified many ABA and/or MeJA responsive proteins in B.napus guard cells.Most of the genes encoding these proteins contain hormone responsive elements in the promoters,indicating that they are potentially regulated at the transcriptional level.The protein level changes were validated using Western blot analysis.We have also identified redox responsive proteins in the above signaling processes.The identification of the hormone responsive proteins and redox state changes has revealed interesting molecular mechanisms underlying guard cell functions in stomatal movement.The knowledge has great potential to be applied to crop engineering for enhanced yield and stress tolerance.

  19. Study of the Effect of Decrease in the Conductivity Ahead of a Shock Wave in a Glow-Discharge Plasma

    Science.gov (United States)

    Baryshnikov, A. S.; Basargin, I. V.; Bobashev, S. V.; Monakhov, N. A.; Popov, P. A.; Sakharov, V. A.; Chistyakova, M. V.

    2016-05-01

    The electrical conductivity of a glow-discharge plasma ahead of a shock wave moving perpendicularly to the discharge axis has been investigated using a double electric probe. The obtained results have shown that the interaction of the shock wave with the glow-discharge plasma is accompanied by a change in its conductivity in the entire investigated volume simultaneously.

  20. Drought limitations to leaf-level gas exchange: results from a model linking stomatal optimization and cohesion-tension theory.

    Science.gov (United States)

    Novick, Kimberly A; Miniat, Chelcy F; Vose, James M

    2016-03-01

    We merge concepts from stomatal optimization theory and cohesion-tension theory to examine the dynamics of three mechanisms that are potentially limiting to leaf-level gas exchange in trees during drought: (1) a 'demand limitation' driven by an assumption of optimal stomatal functioning; (2) 'hydraulic limitation' of water movement from the roots to the leaves; and (3) 'non-stomatal' limitations imposed by declining leaf water status within the leaf. Model results suggest that species-specific 'economics' of stomatal behaviour may play an important role in differentiating species along the continuum of isohydric to anisohydric behaviour; specifically, we show that non-stomatal and demand limitations may reduce stomatal conductance and increase leaf water potential, promoting wide safety margins characteristic of isohydric species. We used model results to develop a diagnostic framework to identify the most likely limiting mechanism to stomatal functioning during drought and showed that many of those features were commonly observed in field observations of tree water use dynamics. Direct comparisons of modelled and measured stomatal conductance further indicated that non-stomatal and demand limitations reproduced observed patterns of tree water use well for an isohydric species but that a hydraulic limitation likely applies in the case of an anisohydric species.

  1. Evidence Regarding the Treatment of Denture Stomatitis.

    Science.gov (United States)

    Yarborough, Alexandra; Cooper, Lyndon; Duqum, Ibrahim; Mendonça, Gustavo; McGraw, Kathleen; Stoner, Lisa

    2016-06-01

    Denture stomatitis is a common inflammatory condition affecting the mucosa underlying complete dentures. It is associated with denture microbial biofilm, poor denture hygiene, poor denture quality, and nocturnal denture use. Numerous treatment methodologies have been used to treat stomatitis; however, a gold standard treatment has not been identified. The aim of this systematic review is to report on the current knowledge available in studies representing a range of evidence on the treatment of denture stomatitis.

  2. Feline gingivitis-stomatitis-pharyngitis.

    Science.gov (United States)

    Diehl, K; Rosychuk, R A

    1993-01-01

    Inflammatory conditions of the feline mouth are commonly encountered in small animal practice. Although the majority can be attributed to dental disease and a small percentage are due to autoimmune diseases, the eosinophilic granuloma complex, neoplasia, and other miscellaneous syndromes, many cases appear to be due to a gingivitis-stomatitis-pharyngitis complex, which is likely multifactorial in origin. Viruses, bacterial infection, diet, dental disease, oral conformation, genetic predisposition, hypersensitivities, immunoinsufficiencies, and other defects in oral defense mechanisms may all be contributory. The complexities of this syndrome have made it one of the most challenging diagnostic and therapeutic problems in feline medicine.

  3. Scaling of stomatal size and density optimizes allocation of leaf epidermal space for gas exchange in angiosperms

    Science.gov (United States)

    de Boer, Hugo Jan; Price, Charles A.; Wagner-Cremer, Friederike; Dekker, Stefan C.; Franks, Peter J.; Veneklaas, Erik J.

    2015-04-01

    Stomata on plant leaves are key traits in the regulation of terrestrial fluxes of water and carbon. The basic morphology of stomata consists of a diffusion pore and two guard cells that regulate the exchange of CO2 and water vapour between the leaf interior and the atmosphere. This morphology is common to nearly all land plants, yet stomatal size (defined as the area of the guard cell pair) and stomatal density (the number of stomata per unit area) range over three orders of magnitude across species. Evolution of stomatal sizes and densities is driven by selection pressure on the anatomical maximum stomatal conductance (gsmax), which determines the operational range of leaf gas exchange. Despite the importance of stomata traits for regulating leaf gas exchange, a quantitative understanding of the relation between adaptation of gsmax and the underlying co-evolution of stomatal sizes and densities is still lacking. Here we develop a theoretical framework for a scaling relationship between stomatal sizes and densities within the constraints set by the allocation of epidermal space and stomatal gas exchange. Our theory predicts an optimal scaling relationship that maximizes gsmax and minimizes epidermal space allocation to stomata. We test whether stomatal sizes and densities reflect this optimal scaling with a global compilation of stomatal trait data on 923 species reflecting most major clades. Our results show optimal scaling between stomatal sizes and densities across all species in the compiled data set. Our results also show optimal stomatal scaling across angiosperm species, but not across gymnosperm and fern species. We propose that the evolutionary flexibility of angiosperms to adjust stomatal sizes underlies their optimal allocation of leaf epidermal space to gas exchange.

  4. Histopathological study of stomatitis nicotina.

    Science.gov (United States)

    Reddy, C R; Kameswari, V R; Ramulu, C; Reddy, P G

    1971-09-01

    One hundred and thirteen biopsies of the palate in people accustomed to smoking cigars, most of them with the burning end of the cigar inside the mouth, have been studied.Thirty-eight of these showed mild to severe atypical changes in the epithelium. There were 19 lesions showing orthokeratosis and 53 showing hyperorthokeratosis.The earliest atypical change is seen in the mouths of the ducts of the glands.There were 3 cases showing microinvasive carcinomas.Pigmentation is a prominent feature in these cases.The papules with umbilication could be due to hyperplasia of the mucous glands.It is suggested that stomatitis nicotina occurring in men and women with the habit of reverse smoking is probably precancerous because of the presence of atypical changes in the epithelium and also the finding of 3 microinvasive carcinomas without any macroscopic evidence.There is no acceptable explanation why the soft palate escapes getting either stomatitis nicotina lesion or carcinoma in reverse smokers.

  5. Transmission and pathogenesis of vesicular stomatitis viruses

    Science.gov (United States)

    Vesicular Stomatitis (VS) is caused by the Vesicular Stomatitis Virus (VSV), a negative single stranded RNA arthropod-borne virus member of the Family Rhabdoviridae. The virion is composed of the host derived plasma membrane, the envelope, and an internal ribonucleoprotein core. The envelope contain...

  6. Optimal stomatal behaviour around the world

    DEFF Research Database (Denmark)

    Lin, Yan-Shih; Medlyn, Belinda E.; Duursma, Remko A.

    2015-01-01

    , a globalscale database and an associated globally applicable model of gs that allow predictions of stomatal behaviour are lacking. Here,we present a database of globally distributed gs obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour diers among...

  7. Combining sap flow and eddy covariance approaches to derive stomatal and non-stomatal O{sub 3} fluxes in a forest stand

    Energy Technology Data Exchange (ETDEWEB)

    Nunn, A.J. [Ecophysiology of Plants, Technische Universitaet Muenchen, Am Hochanger 13, D-85354 Freising- Weihenstephan (Germany); Cieslik, S. [Institute for Environment and Sustainability, Joint Research Center, Ispra (Italy); Metzger, U. [Ecophysiology of Plants, Technische Universitaet Muenchen, Am Hochanger 13, D-85354 Freising- Weihenstephan (Germany); Wieser, G. [Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Dept. of Alpine Timberline Ecophysiology, Rennweg 1, A - 6020 Innsbruck (Austria); Matyssek, R., E-mail: matyssek@wzw.tum.d [Ecophysiology of Plants, Technische Universitaet Muenchen, Am Hochanger 13, D-85354 Freising- Weihenstephan (Germany)

    2010-06-15

    Stomatal O{sub 3} fluxes to a mixed beech/spruce stand (Fagus sylvatica/Picea abies) in Central Europe were determined using two different approaches. The sap flow technique yielded the tree-level transpiration, whereas the eddy covariance method provided the stand-level evapotranspiration. Both data were then converted into stomatal ozone fluxes, exemplifying this novel concept for July 2007. Sap flow-based stomatal O{sub 3} flux was 33% of the total O{sub 3} flux, whereas derivation from evapotranspiration rates in combination with the Penman-Monteith algorithm amounted to 47%. In addition to this proportional difference, the sap flow-based assessment yielded lower levels of stomatal O{sub 3} flux and reflected stomatal regulation rather than O{sub 3} exposure, paralleling the daily courses of canopy conductance for water vapor and eddy covariance-based total stand-level O{sub 3} flux. The demonstrated combination of sap flow and eddy covariance approaches supports the development of O{sub 3} risk assessment in forests from O{sub 3} exposure towards flux-based concepts. - Combined tree sap flow and eddy covariance-based methodologies yield stomatal O{sub 3} flux as 33% in total stand flux.

  8. Stomatal control of gas-exchange is related to assimilate transport from leaves

    Science.gov (United States)

    Nikinmaa, E.; Holtta, T.; Sevanto, S.; Makela, A.; Hari, P.; Vesala, T.

    2009-04-01

    In land plants, the carbon fluxes are closely associated with those of water. The loss of water from leaves pulls water from soil in plants. High transpiration relative to compensating water flux from soil increases the tension of water column that may lead to its rupture and catastrophic dysfunction of the xylem if the transpiration rate is not regulated. Modification of the size of stomatal openings in leaves regulates the interconnected fluxes of water and carbon. Stomatal regulation of transpiration has direct influence also on the carbon transport from source leaves to sinks. Under given conditions, the water tension of xylem in leaves is linearly related to stomatal conductance while the assimilation rate, which is linked to the loading capacity, has saturating relationship with stomatal conductance. High sugar loading at source could compensate for the high water tension in xylem resulting from eg. high transpiration. However, excessive loading rate of the most commonly transported sugar, sucrose, causes rapid viscosity build up that effectively blocks the phloem transport. Assimilate transport from the shoot is a clear requirement for continuous photosynthetic production in leaves. Without transport the storage capacity of the leaves would be rapidly exhausted and accumulation of excess sugars in leaves lead to downregulation of photosynthesis. In this presentation we study the stomatal response to environment and its linkage to xylem and phloem tranport with dynamic model. We hypothesize that stomatal reaction to environment would maintain maximal assimilate transport in phloem under those conditions. We added to the xylem phloem transport model stomatal control of leaf gas-exchange, light and CO2 concentration dependent photosynthesis rate and carbon storage in leaf. For each time step we varied the stomatal conductance and selected the sollution that maximised the transport of assimilates in phloem. Our hypothesis reproduced realistically stomatal

  9. Stomatal response of Pinus sylvestriformis to elevated CO2 concentrations during the four years of exposure

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-mei; HAN Shi-jie; LIU Ying; JIA Xia

    2005-01-01

    Four-year-old Pinus sylvestriformis were exposed for four growing seasons in open top chambers to ambient CO2 concentration (approx. 350 μmol·mol-1) and high CO2 concentrations (500 and 700 μmol·mol-1) at Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences at Antu Town, Jilin Province, China (42oN, 128oE). Stomatal response to elevated CO2 concentrations was examined by stomatal conductance (gs), ratio of intercellular to ambient CO2 concentration (ci/ca) and stomatal number. Reciprocal transfer experiments of stomatal conductance showed that stomatal conductance in high-[CO2]-grown plants increased in comparison with ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration and at the same measurement CO2 concentration (except a reduction in 700 μmol·mol-1 CO2 grown plants compared with plants on unchambered field when measured at growth CO2 concentration and 350 μmol·mol-1CO2). High-[CO2]-grown plants exhibited lower ci/ca ratios than ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration. However, ci/ca ratios increased for plants grown in high CO2 concentrations compared with control plants when measured at the same CO2 concentration. There was no significant difference in stomatal number per unit long needle between elevated and ambient CO2. However, elevated CO2 concentrations reduced the total stomatal number of whole needle by the decline of stomatal line and changed the allocation pattern of stomata between upper and lower surface of needle.

  10. Low mercury concentration produces vasoconstriction, decreases nitric oxide bioavailability and increases oxidative stress in rat conductance artery.

    Directory of Open Access Journals (Sweden)

    Núbia Belem Lemos

    Full Text Available Mercury is an environmental pollutant that reduces nitric oxide (NO bioavailability and increases oxidative stress, having a close link with cardiovascular diseases, as carotid atherosclerosis, myocardial infarction, coronary heart disease and hypertension. One of the main sites affected by oxidative stress, which develops atherosclerosis, is the aorta. Under acute exposure to low mercury concentrations reactive oxygen species (ROS production were only reported for resistance vessels but if low concentrations of mercury also affect conductance arteries it is still unclear. We investigated the acute effects of 6 nM HgCl(2 on endothelial function of aortic rings measuring the reactivity to phenylephrine in rings incubated, or not, with HgCl(2 for 45 min, the protein expression for cyclooxygenase 2 (COX-2 and the AT1 receptor. HgCl(2 increased Rmax and pD2 to phenylephrine without changing the vasorelaxation induced by acetylcholine and sodium nitroprusside. Endothelial damage abolished the increased reactivity to phenylephrine. The increase of Rmax and pD2 produced by L-NAME was smaller in the presence of HgCl(2. Enalapril, losartan, indomethacin, furegrelate, the selective COX-2 inhibitor NS 398, superoxide dismutase and the NADPH oxidase inhibitor apocynin reverted HgCl(2 effects on the reactivity to phenylephrine, COX-2 protein expression was increased, and AT1 expression reduced. At low concentration, below the reference values, HgCl(2 increased vasoconstrictor activity by reducing NO bioavailability due to increased ROS production by NADPH oxidase activity. Results suggest that this is due to local release of angiotensin II and prostanoid vasoconstrictors. Results also suggest that acute low concentration mercury exposure, occurring time to time could induce vascular injury due to endothelial oxidative stress and contributing to increase peripheral resistance, being a high risk factor for public health.

  11. Evaluating stomatal ozone fluxes in WRF-Chem: Comparing ozone uptake in Mediterranean ecosystems

    Science.gov (United States)

    Rydsaa, J. H.; Stordal, F.; Gerosa, G.; Finco, A.; Hodnebrog, Ø.

    2016-10-01

    The development of modelling tools for estimating stomatal uptake of surface ozone in vegetation is important for the assessment of potential damage induced due to both current and future near surface ozone concentrations. In this study, we investigate the skill in estimating ozone uptake in plants by the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) V3.6.1, with the Wesely dry deposition scheme. To validate the stomatal uptake of ozone, the model simulations were compared with field measurements of three types of Mediterranean vegetation, over seven different periods representing various meteorological conditions. Some systematic biases in modelled ozone fluxes are revealed; the lack of an explicit and time varying dependency on plants' water availability results in overestimated daytime ozone stomatal fluxes particularly in dry periods. The optimal temperature in the temperature response function is likely too low for the woody species tested here. Also, too low nighttime stomatal conductance leads to underestimation of ozone uptake during night. We demonstrate that modelled stomatal ozone flux is improved by accounting for vapor pressure deficit in the ambient air. Based on the results of the overall comparison to measured fluxes, we propose that additional improvements to the stomatal conductance parameterization should be implemented before applying the modelling system for estimating ozone doses and potential damage to vegetation.

  12. Oral medicine case book 65: Necrotising stomatitis.

    Science.gov (United States)

    Khammissa, R A G; Ciya, R; Munzhelele, T I; Altini, M; Rikhotso, E; Lemmer, J; Feller, L

    2014-11-01

    Necrotising stomatitis is a fulminating anaerobic polybacterial infection affecting predominantly the oral mucosa of debilitated malnourished children or immunosuppressed HIV-seropositive subjects. It starts as necrotising gingivitis which progresses to necrotising periodontitis and subsequently to necrotising stomatitis. In order to prevent the progression of necrotising stomatitis to noma (cancrum oris), affected patients should be vigorously treated and may require admission to hospital. Healthcare personnel should therefore be familiar with the signs and symptoms of necrotising gingivitis/necrotising periodontitis, of their potential sequelae and of the need for immediate therapeutic intervention.

  13. Moderate water stress causes different stomatal and non-stomatal changes in the photosynthetic functioning of Phaseolus vulgaris L. genotypes.

    Science.gov (United States)

    Ramalho, J C; Zlatev, Z S; Leitão, A E; Pais, I P; Fortunato, A S; Lidon, F C

    2014-01-01

    The impact of moderate water deficit on the photosynthetic apparatus of three Phaseolus vulgaris L. cultivars, Plovdiv 10 (P10), Dobrudjanski Ran (DR) and Prelom (Prel), was investigated. Water shortage had less impact on leaf hydration, RWC (predawn and midday) and predawn water potential in Prel. RWC and Ψ(p) were more reduced in P10, while there was no osmotic adjustment in any cultivar. Although drought drastically reduced stomatal opening in P10 and DR, reduced A(max) indicated non-stomatal limitations that contributed to the negligible P(n). These limitations were on potential thylakoid electron transport rates of PSI and II, pointing to photosystem functioning as a major limiting step in photosynthesis. This agrees with decreases in actual photochemical efficiency of PSII (F(v)'/F(m)'), quantum yield of photosynthetic non-cyclic electron transport (ϕ(e)) and energy-driven photochemical events (q(P)), although the impact on these parameters would also include down-regulation processes. When compared to DR, Prel retained a higher functional state of the photosynthetic machinery, justifying reduced need for photoprotective mechanisms (non-photochemical quenching, zeaxanthin, lutein, β-carotene) and maintenance of the balance between energy capture and dissipative pigments. The highest increases in fructose, glucose, arabinose and sorbitol in Prel might be related to tolerance to a lower oxidative state. All cultivars had reduced A(max) due to daytime stomatal closure in well-watered conditions. Under moderate drought, Prel had highest tolerance, higher leaf hydration and maintenance of important photochemical use of energy. However, water shortage caused appreciable non-stomatal limitations to photosynthesis linked to regulation/imbalance at the metabolic level (and growth) in all cultivars. This included damage, as reflected in decreased potential photosystem functioning, pointing to higher sensitivity of photosynthesis to drought than is commonly assumed

  14. [The adaptation of AV-nodal conduction time on gliding increase and decrease of atrial frequency before and after autonomic blockade (author's transl)].

    Science.gov (United States)

    Runge, M; Ehlers, E; Pantlen, H; Luckmann, E

    1979-01-01

    In 19 patients with healthy AV-nodes the adaptation of the intranodal conduction time (A-H time) to gliding increase and decrease in atrial frequency and to the blockade of the autonomic nervous system was investigated using His bundle electrograms. The measurements were performed during right atrial stimulation with three frequencies, each with a duration of one minute, before and after blockade of the parasympathetic (8 pat.; 1 mg atropine i.v.) and the sympathetic (11 pat.; 0.4 mg Visken i.v.) nervous system. Gliding increase and decrease in atrial frequency results in a staircase pattern of A-H-adaptation in 18 of the patients. The height of the steps was identical in both phases of stimulation in each individual patient. One patient showed functional dissociation of intranodal conduction which was different during increase and decrease of atrial frequency. With parasympathetic blockade the staircase behavior of the A-H time basically remained unchanged with the exception of shorter A-H intervals resulting in lower steps. Atropine abolished the functional dissociation of intranodal conduction; thus the drug might prevent reentrytachycardias due to functional dissociation in the AV-node. Sympathetic blockade lengthens the intranodal conduction time; thus shifting the staircase pattern of the A-H time to higher levels. The results are discussed with respect to the electrophysiological characteristics of AV nodal cells as slow response fibers, and to the changes caused by atrial stimulation, acetylcholine and adrenaline.

  15. RESPON TERAPI ESTROGEN PADA PENDERITA STOMATITIS AFTOSA REKUREN DI MASA MENJELANG MENOPAUSE (Laporan Kasus

    Directory of Open Access Journals (Sweden)

    Dewi Priandini

    2015-08-01

    Full Text Available Recurrent aphthous stomatitis (RAS symptoms usually painful and sometimes incapacitating. This condition is severed by recurrent characteristic and many efforts are conducted to encounter these things, but the results are still not satisfying. The etiology of RAS is still uncertain, however it is suggested that there is a correlation between the occurrence of RAS in women in their menstruation and premenompause period where there is noted decrease of estrogen. This article reports a case of RAS in a 50 year old woman who have suffered RAS for a year and become more severe in relation to the menstrual cycle especially pre menopause period. After estrogen administration the lesion is healed. This case brings attention to the clinicians, that it is important to know the estrogen level of RAS patients who are in premenopause period so they will receive an appropriate therapy.

  16. Light-Regulated Stomatal Aperture in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Chen Chen; Yu-Guo Xiao; Xin Li; Min Ni

    2012-01-01

    The stomatal pores of plant leaves,situated in the epidermis and surrounded by a pair of guard cells,allow CO2 uptake for photosynthesis and water loss through transpiration.Blue light is one of the dominant environmental signals that control stomatal movements in leaves of plants in a natural environment.This blue light response is mediated by blue/UV A light-absorbing phototropins (phots) and cryptochromes (crys).Red/far-red light-absorbing phytochromes (phys) also play a role in the control of stomatal aperture.The signaling components that link the perception of light signals to the stomatal opening response are largely unknown.This review discusses a few newly discovered nuclear genes,their function with respect to the phot-,cry-,and phy-mediated signal transduction cascades,and possible involvement of circadian clock.

  17. To open or to close: species-specific stomatal responses to simultaneously applied opposing environmental factors.

    Science.gov (United States)

    Merilo, Ebe; Jõesaar, Indrek; Brosché, Mikael; Kollist, Hannes

    2014-04-01

    Plant stomatal responses to single environmental factors are well studied; however, responses to a change in two (or more) factors - a common situation in nature - have been less frequently addressed. We studied the stomatal responses to a simultaneous application of opposing environmental factors in six evolutionarily distant mono- and dicotyledonous herbs representing different life strategies (ruderals, competitors and stress-tolerators) to clarify whether the crosstalk between opening- and closure-inducing pathways leading to stomatal response is universal or species-specific. Custom-made gas exchange devices were used to study the stomatal responses to a simultaneous application of two opposing factors: decreased/increased CO2 concentration and light availability or reduced air humidity. The studied species responded similarly to changes in single environmental factors, but showed species-specific and nonadditive responses to two simultaneously applied opposing factors. The stomata of the ruderals Arabidopsis thaliana and Thellungiella salsuginea (previously Thellungiella halophila) always opened, whereas those of competitor-ruderals either closed in all two-factor combinations (Triticum aestivum), remained relatively unchanged (Nicotiana tabacum) or showed a response dominated by reduced air humidity (Hordeum vulgare). Our results, indicating that in changing environmental conditions species-specific stomatal responses are evident that cannot be predicted from studying one factor at a time, might be interesting for stomatal modellers, too.

  18. Expression of Arabidopsis hexokinase in citrus guard cells controls stomatal aperture and reduces transpiration

    Directory of Open Access Journals (Sweden)

    Nitsan eLugassi

    2015-12-01

    Full Text Available Hexokinase (HXK is a sugar-phosphorylating enzyme involved in sugar-sensing. It has recently been shown that HXK in guard cells mediates stomatal closure and coordinates photosynthesis with transpiration in the annual species tomato and Arabidopsis. To examine the role of HXK in the control of the stomatal movement of perennial plants, we generated citrus plants that express Arabidopsis HXK1 (AtHXK1 under KST1, a guard cell-specific promoter. The expression of KST1 in the guard cells of citrus plants has been verified using GFP as a reporter gene. The expression of AtHXK1 in the guard cells of citrus reduced stomatal conductance and transpiration with no negative effect on the rate of photosynthesis, leading to increased water-use efficiency. The effects of light intensity and humidity on stomatal behavior were examined in rooted leaves of the citrus plants. The optimal intensity of photosynthetically active radiation and lower humidity enhanced stomatal closure of AtHXK1-expressing leaves, supporting the role of sugar in the regulation of citrus stomata. These results suggest that HXK coordinates photosynthesis and transpiration and stimulates stomatal closure not only in annual species, but also in perennial species.

  19. Comparison of the Effect of 2% Ginger Mouthwash and Nystatin Mouthwash on Denture Stomatitis

    Directory of Open Access Journals (Sweden)

    Zahra Alizadeh

    2016-06-01

    Full Text Available Denture stomatitis is the chronic inflammation of mucus along with the presence and activity of Candida albicans. Ginger, which is a herb with antibacterial and antifungal proportion, has shown proven effects against Candida albicans. In this study the effects of ginger mouthwashes and nystatin mouthwashes on the treatment of denture stomatitis have been compared. This study was conducted in a doubled_ blind clinical trial on 50 patients with denture stomatitis. Given consent, the patients were categorized into two groups and one group was given the ginger mouthwash and another one was given the nystatin mouthwash for two weeks. At the end of the first and second week the erythematous zone was examined and its type of denture stomatitis was specified. Furthermore, in the first session and the end of the treatment sample were taken from the palate with in order to carry out microbial culture and colony count. The data was analyzed by SPSS 21 and the results were compared with Chisquare test. During the two-week treatment, both treatments resulted in the recovery of denture stomatitis significantly. However, the mentioned treatments did not have any clinically significant differences. No significant difference in the reduction of the number of colonies was seen between the two groups. Moreover, the level of the patient's satisfaction with the two treatments was similar. Considering the similar effectiveness of ginger and nystatin in the treatment of denture stomatitis and also patients similar satisfaction with both mouthwashes, the ginger mouthwashes can be an alternative treatment for nystatin.

  20. Efficacy and safety of polaprezinc as a preventive drug for radiation-induced stomatitis

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Masayuki; Kamikonya, Norihiko; Tsuboi, Keita; Nakao, Norio [Hyogo Coll. of Medicine, Nishinomiya (Japan); Irie, Miwa [Takarazuka Municipal Hospital, Hyogo (Japan); Izumi, Masayuki [Minamiosaka Total Health Care Center, Osaka (Japan); Irie, Toshihiko; Fujisawa, Hiromi; Muro, Chikaaki [Hyogo Coll. of Medicine, Nishinomiya (Japan). Hospital

    2002-03-01

    Radiation-induced stomatitis is one of the adverse effects of total body irradiation (TBI). We examined the usefulness of oral polaprezinc as a preventive drug for stomatitis. The present study was conducted with 19 patients who were diagnosed with hematologic malignancy and who underwent TBI as pretreatment for bone marrow transplantation, peripheral blood stem transplantation, or cord blood stem cell transplantation. Eleven patients ingested the suspension of polaprezinc and 2% carmellose sodium (carboxymethylcellulose sodium: CMC) beginning the day before TBI (P-CMC group), while the other eight patients did not ingest P-CMC (control group). The severity of stomatitis was assessed in each group during a four-weeks period. Stomatitis (Grade:{>=}3) developed in one of 11 patients in the polaprezinc group and in 4 of 8 patients in the control group (P=0.046). The times at which stomatitis development ranged between weeks 1 and 2 after the onset of TBI in the two groups. No adverse reaction owing to the ingestion of P-CMC was observed. These results suggested the efficacy and safety of polaprezinc as a preventive drug for radiation-induced stomatitis. (author)

  1. [Denture stomatitis - definition, etiology, classification and treatment].

    Science.gov (United States)

    Cubera, Katarzyna

    2013-01-01

    Denture stomatitis pertains to a number of pathological symptoms in the oral cavity caused by wearing acrylic dentures. Etiological factors include: mucosal trauma, fungal infection and accumulation of denture plaque. All of these factors appear to increase the ability of Candida albicans to colonize both the denture and oral mucosal surfaces. Antifungal treatment can eradicate C. albicans contamination and relieve stomatitis symptoms. Early diagnosis of the lesion is essential to assure rational therapy.

  2. Prevalensi Stomatitis Pada Masa Pubertas Berdasarkan Penyebabnya

    OpenAIRE

    Wardiningsih, Rahmy

    2012-01-01

    Skripsi alumni Fak. Kedokteran Gigi thn. 2011 latar belakang: Minimnya pengetahuan tentang kesehatan dan sikap cuek pada remaja membuat remaja sering mengabaikan hal-hal kecil yang dapat merusak kesehatan termasuk kesehatan gigi dan mulut sehingga dapat menimbulkan berbagai masalah dalam mulut. Salah satu penyakit mulut yang paling populer pada remaja adalah stomatitis. tujuan: tujuan penelitian ini adalah untuk mengetahui prevalensi stomatitis pada siswa-siswi SMU Samudera Nusantara Maka...

  3. Effects of deficit irrigation and partial root-zone drying on soil and plant water status, stomatal conductance, plant growth and water use efficiency in tomato during early fruiting stage

    DEFF Research Database (Denmark)

    Liu, Fulai; Shahnazari, Ali; Jacobsen, S.-E.

    2008-01-01

    The effects of 'partial root-zone drying' (PRD), compared with full irrigation (FI) and deficit irrigation (DI), on soil and plant water status, plant growth and water use efficiency (WUE) were investigated in potted tomatoes (Lycopersicon esculentum L., var. Cedrico) at the early fruiting stage...... system, and the irrigated side of the plants was reversed when volumetric soil water content ( ) of the dry side had decreased to 6%. of FI was about 14%. of DI decreased during the first 4-5 days after the onset of treatment (DAT) and was about 7% and 6% thereafter for DI-70 and DI-50, respectively....... of the wet side in PRD-70 declined during 3-6 DAT and was lower than that of FI by 4-6% thereafter. in both wet and dry sides of PRD-50 was slightly lower than that for PRD-70. After 5 DAT, midday leaf water potential was significantly lower in DI and PRD than in FI plants. FI plants had the highest leaf...

  4. 不同沟灌方式下玉米叶片气孔阻力差异%Leaf stomatal resistance of maize affected by different furrow irrigation methods

    Institute of Scientific and Technical Information of China (English)

    李彩霞; 周新国; 孙景生; 李新强

    2014-01-01

    maize leaf, regardless of irrigation methods, the stomatal resistance decreased gradually from the base to the tip of the maize leaf. At the population level, the stomatal resistance of maize leaf increased gradually from canopy top to bottom. For the change of the leaf stomatal resistance in time, diurnal variation of leaf stomatal resistance was in a Wshape. Diurnal and daily changes in the leaf stomatal resistance in the upper canopy were relatively small. The upper surface of maize leaf contributed more to CO2 and water vapor transfer than the ones underside. Except at the seedling stage, the leaves in the upper and middle part of maize canopy contributed more than 80% of the total CO2 and water vapor. Stomatal resistances of maize leaves decreased with the increase in leaf age during the vegetative growth stage. Differences in stomatal resistance among maize leaves of different ages were increased by the alternative deficit water supply. During the reproductive growth phase, leaf age had no significant influence on the stomatal resistance in matured leaves. Compared with the conventional furrow irrigation with sufficient water supply, the alternative deficit water supply increased the ratio of the stomatal resistances between the upper side and underside of maize leaves. The vertical gradient of stomatal resistance from canopy top to bottom increased significantly (P<0.05), decreasing leaf stomatal conductivity rapidly, and improving the contribution of the stomatal aperture in the upper canopy to water vapor transfer. Therefore, the leaf stomatal resistance of maize was regulated by furrow irrigation methods and soil water condition, and it was affected by the leaf age, leaf area index and natural feature of stomatal aperture. The study is useful for controllable irrigation technology and water vapor cycle in soil plant atmosphere continuum (SPAC).

  5. Balancing Water Uptake and Loss through the Coordinated Regulation of Stomatal and Root Development.

    Directory of Open Access Journals (Sweden)

    Christopher Hepworth

    Full Text Available Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants with high stomatal density and conductance produce a larger rooting area and as a result have enhanced phosphate uptake capacity whereas plants with low stomatal conductance produce a smaller root. Manipulating the growth environment of plants indicated that enhanced root growth is most likely a result of an increased demand for water rather than phosphate. Plants manipulated to have an increase or reduction in root hair growth show a reduction or increase respectively, in stomatal conductance and density. Our results demonstrate that plants can balance their water uptake and loss through coordinated regulation of both stomatal and root development.

  6. [Veterinary dentistry (11). Feline gingivitis-stomatitis-pharyngitis complex. Chronic/recurrent stomatitis in cats].

    Science.gov (United States)

    van Foreest, A

    1995-10-01

    This is the fourth article in a series on veterinary dentistry in cats. This article describes the clinical signs, possible investigations, and differential diagnosis of the gingivitis-stomatitis pharyngitis complex (GSP complex), a complex and frequently occurring disease. Strategies for the treatment of feline chronic stomatitis complex, which is frequently idiopathic, are presented.

  7. Relationships between stomatal behavior, xylem vulnerability to cavitation and leaf water relations in two cultivars of Vitis vinifera.

    Science.gov (United States)

    Tombesi, Sergio; Nardini, Andrea; Farinelli, Daniela; Palliotti, Alberto

    2014-11-01

    Current understanding of physiological mechanisms governing stomatal behavior under water stress conditions is still incomplete and controversial. It has been proposed that coordination of stomatal kinetics with xylem vulnerability to cavitation [vulnerability curve (VC)] leads to different levels of isohydry/anisohydry in different plant species/cultivars. In this study, this hypothesis is tested in Vitis vinifera cultivars displaying contrasting stomatal behavior under drought stress. The cv Montepulciano (MP, near-isohydric) and Sangiovese (SG, anisohydric) were compared in terms of stomatal response to leaf and stem water potential, as possibly correlated to different petiole hydraulic conductivity (k(petiole)) and VC, as well as to leaf water relations parameters. MP leaves showed almost complete stomatal closure at higher leaf and stem water potentials than SG leaves. Moreover, MP petioles had higher maximum k(petiole) and were more vulnerable to cavitation than SG. Water potential at the turgor loss point was higher in MP than in SG. In SG, the percentage reduction of stomatal conductance (PLg(s)) under water stress was almost linearly correlated with corresponding percentage loss of k(petiole) (PLC), while in MP PLg(s) was less influenced by PLC. Our results suggest that V. vinifera near-isohydric and anisohydric genotypes differ in terms of xylem vulnerability to cavitation as well as in terms of k(petiole) and that the coordination of these traits leads to their different stomatal responses under water stress conditions.

  8. Leaf Morphology, Photosynthetic Performance, Chlorophyll Fluorescence, Stomatal Development of Lettuce (Lactuca sativa L.) Exposed to Different Ratios of Red Light to Blue Light.

    Science.gov (United States)

    Wang, Jun; Lu, Wei; Tong, Yuxin; Yang, Qichang

    2016-01-01

    Red and blue light are both vital factors for plant growth and development. We examined how different ratios of red light to blue light (R/B) provided by light-emitting diodes affected photosynthetic performance by investigating parameters related to photosynthesis, including leaf morphology, photosynthetic rate, chlorophyll fluorescence, stomatal development, light response curve, and nitrogen content. In this study, lettuce plants (Lactuca sativa L.) were exposed to 200 μmol⋅m(-2)⋅s(-1) irradiance for a 16 h⋅d(-1) photoperiod under the following six treatments: monochromatic red light (R), monochromatic blue light (B) and the mixture of R and B with different R/B ratios of 12, 8, 4, and 1. Leaf photosynthetic capacity (A max) and photosynthetic rate (P n) increased with decreasing R/B ratio until 1, associated with increased stomatal conductance, along with significant increase in stomatal density and slight decrease in stomatal size. P n and A max under B treatment had 7.6 and 11.8% reduction in comparison with those under R/B = 1 treatment, respectively. The effective quantum yield of PSII and the efficiency of excitation captured by open PSII center were also significantly lower under B treatment than those under the other treatments. However, shoot dry weight increased with increasing R/B ratio with the greatest value under R/B = 12 treatment. The increase of shoot dry weight was mainly caused by increasing leaf area and leaf number, but no significant difference was observed between R and R/B = 12 treatments. Based on the above results, we conclude that quantitative B could promote photosynthetic performance or growth by stimulating morphological and physiological responses, yet there was no positive correlation between P n and shoot dry weight accumulation.

  9. Efficacy of alum for treatment of recurrent aphthous stomatitis

    Science.gov (United States)

    Rafieian, Nasrin; Abdolsamadi, Hamidreza; Moghadamnia, Aliakbar; Jazayeri, Mina; Seif-Rabiee, Mohammadali; Salmanzadeh, Mina; Radi, Shahrbanoo

    2016-01-01

    Background: Recurrent aphthous stomatitis (RAS) is the most common painful ulcers of oral mucosal which can cause many sufferings. Treatment of RAS often includes administration of corticosteroids, analgesics and regulators of the immune system. However, considering the side effects of these medications, even their topical application must be done with caution. Alum is used in traditional medicine for treatment of oral ulcers without significant side effect. This study sought to assess the effect of topical application of alum on aphthous ulcers. Methods: This clinical randomized double-blind placebo-controlled study was conducted on 50 females aged 21 to 27 years. Mucosal adhesive patches were prepared in two forms of basic and 7% alum-containing patches. Subjects in two groups of case and control randomly received the mucosal adhesive patches containing alum and the basic patches, respectively three times in five days. Duration of recovery, changes in size of lesion and severity of pain were recorded. Data were entered into SPSS Version 16 and analyzed using t-test. Results: The average period of full recovery was 7.52 days in the case and 12.2 days in the control groups; which was significantly different (p<0.001). Size of wound and severity of pain were significantly lower at one, three and five days posttreatment compared to baseline values before treatment in the case group (p<0.001) and the difference in this regard between the case and control groups was statistically significant. Conclusion: Alum can significantly decrease the size of aphthous lesions, severity of pain and expedite the recovery of patients with RAS.

  10. 樱桃叶片气孔导度动态模拟研究%Study on Dynamic Simulation of Stomatal Conductance( Gs ) of Cherry(Prunus avium L.' Hongdeng' ) Leaf

    Institute of Scientific and Technical Information of China (English)

    高照全; 赵晨霞; 冯社章; 程建军

    2012-01-01

    [ Objective] The aim was to simulate the dynamic change law of cherry leaf s Gs under different weather by Gs model. [ Method] The experiment was conducted in a ' Hongdeng' cherry orchard. The parameters of the model were tested by the data observed in upper canopy from 2008 to 2011 during the growing seasons. [ Result] The diurnal course of Gs showed a double-peak curve on sunny days. And it reached the first peak of 240 mmol/(m2 · S) at mid-morning about 08:00 and the second at mid-afternoon about 16:00. The decline of Gs at noon was caused by lower RH and ψt. During a whole day (12 h) , average Gs was about 154. 36 mmol/( m2 · S) on sunny day. [ Conclusion] The study provides a scientific basis for using Gs model to simulate Gs of fruit tree leaf under different weather.%[目的]利用气孔导度(Gs)模型模拟红灯樱桃(Prunus avium L.‘Hongdeng’)叶片G,在不同气象条件下的动态变化规律.[方法]于2008~2011年在红灯樱桃园中,利用树冠上层叶片气体交换数据拟合相应参数.[结果]在晴天,樱桃上层叶片Gs呈双峰曲线,最大峰值出现在08:00左右,约240 mmol/( m2·s);第2峰值在16:00,气孔的“午休”现象主要与中午较低的RH和ψ1有关.晴天时,一天当中Gs的平均值为154.36 mmol/( m2·s).[结论]该研究为采用Gs模型来模拟不同气象条件下果树叶片G1提供了科学依据.

  11. Stomatal and non-stomatal limitations on leaf carbon assimilation in beech (Fagus sylvatica L.) seedlings under natural conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, I.; Rodriguez-Calcerrada, J.; Robson, T. M.; Cano, F. J.; Alte, L.; Sanchez-Gomez, D.

    2012-07-01

    Limitations to diffusion and biochemical factors affecting leaf carbon uptake were analyzed in young beech seedlings (Fagus sylvtica L.) growing in natural gaps of a beech-wood at the southern limit of the species. Half of the seedlings received periodic watering in addition to natural rainfall to reduce the severity of the summer drought. Plant water status was evaluated by measuring predawn water potential. Basic biochemical parameters were inferred from chlorophyll fluorescence and photosynthesis-CO{sub 2} curves (A-C{sub c}) under saturating light. The curves were established on three dates during the summer months. The main variables studied included: stomatal and mesophyll conductance to CO{sub 2} (g{sub s} and g{sub m} respectively), maximum velocity of carboxylation (V{sub c}max) and maximum electron transport capacity (J{sub m}ax). The gm was estimated by two methodologies: the curve-fitting and J constant methods. Seedlings withstood moderate water stress, as the leaf predawn water potential ({Psi}{sub p}d) measured during the study was within the range -0.2 to -0.5 MPa. Mild drought caused gs and gm to decrease only slightly in response to {Psi}{sub p}d. However both diffusional parameters explained most of the limitations to CO{sub 2} uptake. In addition, it should be highlighted that biochemical limitations, prompted by V{sub c}max and J{sub m}ax, were related mainly to ontogenic factors, without any clear relationship with drought under the moderate water stress experienced by beech seedlings through the study. The results may help to further understanding of the functional mechanisms influencing the carbon fixation capacity of beech seedlings under natural conditions. (Author) 68 refs.

  12. [Efficacy of oral cavity care in preventing stomatitis (mucositis) in cancer chemotherapy].

    Science.gov (United States)

    Koshino, Miki; Sakai, Chie; Ogura, Takafumi; Kawasaki, Akiko; Fukuzato, Fumiko; Miyazaki, Yasuhiro

    2009-03-01

    Stomatitis is a common side effect during cancer chemotherapy. We hypothesized that careful oral cavity care using patient guidance and cleanliness index prevents stomatitis in cancer chemotherapy. We introduced oral care patient guidance including teaching good brushing methods, O'Leary's Plaque Control Record(PCR)as a cleanliness index, and Eilers' Oral Assessment Guide(OAG)as an overall index after April 2006. We evaluated the incidence of stomatitis in 20 patients(10 patients between April 2004 to May 2006 and 10 patients after April 2006)with esophageal cancer who received chemotherapy including 5-FU and CDDP. Patients receiving brushing training after 2006 were evaluated regarding cleanliness of their oral cavities using PCR index and OAG index. The rates of stomatitis were 60%(6/10)and 40%(4/10)before and after the introduction of oral care patient guidance. The average of PCR index decreased from 82% to 46% after teaching good brushing method to the patients. The average of OAG index after brushing training was 9.14 which was better score compared with previous reports. Introduction of oral care patient guidance decreased the incidence of stomatitis. Both PCR and OAG indexes were useful in evaluating the objective condition of the oral cavity and in sharing patients' information among a medical team. These indexes encouraged the patients to clean their oral cavities.

  13. PYR/RCAR receptors contribute to ozone-, reduced air humidity-, darkness-, and CO2-induced stomatal regulation.

    Science.gov (United States)

    Merilo, Ebe; Laanemets, Kristiina; Hu, Honghong; Xue, Shaowu; Jakobson, Liina; Tulva, Ingmar; Gonzalez-Guzman, Miguel; Rodriguez, Pedro L; Schroeder, Julian I; Broschè, Mikael; Kollist, Hannes

    2013-07-01

    Rapid stomatal closure induced by changes in the environment, such as elevation of CO2, reduction of air humidity, darkness, and pulses of the air pollutant ozone (O3), involves the SLOW ANION CHANNEL1 (SLAC1). SLAC1 is activated by OPEN STOMATA1 (OST1) and Ca(2+)-dependent protein kinases. OST1 activation is controlled through abscisic acid (ABA)-induced inhibition of type 2 protein phosphatases (PP2C) by PYRABACTIN RESISTANCE/REGULATORY COMPONENTS OF ABA RECEPTOR (PYR/RCAR) receptor proteins. To address the role of signaling through PYR/RCARs for whole-plant steady-state stomatal conductance and stomatal closure induced by environmental factors, we used a set of Arabidopsis (Arabidopsis thaliana) mutants defective in ABA metabolism/signaling. The stomatal conductance values varied severalfold among the studied mutants, indicating that basal ABA signaling through PYR/RCAR receptors plays a fundamental role in controlling whole-plant water loss through stomata. PYR/RCAR-dependent inhibition of PP2Cs was clearly required for rapid stomatal regulation in response to darkness, reduced air humidity, and O3. Furthermore, PYR/RCAR proteins seem to function in a dose-dependent manner, and there is a functional diversity among them. Although a rapid stomatal response to elevated CO2 was evident in all but slac1 and ost1 mutants, the bicarbonate-induced activation of S-type anion channels was reduced in the dominant active PP2C mutants abi1-1 and abi2-1. Further experiments with a wider range of CO2 concentrations and analyses of stomatal response kinetics suggested that the ABA signalosome partially affects the CO2-induced stomatal response. Thus, we show that PYR/RCAR receptors play an important role for the whole-plant stomatal adjustments and responses to low humidity, darkness, and O3 and are involved in responses to elevated CO2.

  14. STOMATITIS AFTOSA REKUREN DAN GANGGUAN FUNGSI OVARIUM (Laporan Kasus

    Directory of Open Access Journals (Sweden)

    Farida Soetiarto

    2015-08-01

    Full Text Available Recurrent aphthous stomatitis (RAS is a common disease of undefine etiology. Many studies have been conducted but the result remain unsatisfied. Fortunately some predisposing factors have been identified and one of predisposing factors is hormonal imbalance. The cases report showed that RAS in ovary disorder and disappear after ovary was amputated, and a case of infertility. IN case of RAS with hormone imbalance as predisposing factor, it is suggested to consider the condition of ovary. This suggestion is based on fact that ovary is producing hormone (estrogen, progesteron whihc influence to oral mucous.

  15. Enhanced salt resistance in apple plants overexpressing a Malus vacuolar Na+/H+ antiporter gene is associated with differences in stomatal behavior and photosynthesis.

    Science.gov (United States)

    Li, Chao; Wei, Zhiwei; Liang, Dong; Zhou, Shasha; Li, Yonghong; Liu, Changhai; Ma, Fengwang

    2013-09-01

    High salinity is a major abiotic factor that limits crop production. The dwarfing apple rootstock M.26 is sensitive to such stress. To obtain an apple that is adaptable to saline soils, we transformed this rootstock with a vacuolar Na(+)/H(+) antiporter, MdNHX1. Differences in salt tolerance between transgenic and wild-type (WT) rootstocks were examined under field conditions. We also compared differences when 'Naganofuji No. 2' apple was grafted onto these transgenic or WT rootstocks. Plants on the transgenic rootstocks grew well during 60 d of mild stress (100 mM NaCl) while the WT exhibited chlorosis, inhibited growth and even death. Compared with the untreated control, the stomatal density was greater in both non-grafted and grafted WT plants exposed to 200 mM NaCl. In contrast, that density was significantly decreased in leaves from grafted transgenic plants. At 200 mM NaCl, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and chlorophyll contents were markedly reduced in the WT, whereas the declines in those values were only minor in similarly stressed transgenic plants. Therefore, we conclude that overexpressing plants utilize a better protective mechanism for retaining higher photosynthetic capacity. Furthermore, this contrast in tolerance and adaptability to stress is linked to differences in stomatal behavior and photosynthetic rates. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  16. Gingivitis/stomatitis in cats.

    Science.gov (United States)

    Williams, C A; Aller, M S

    1992-11-01

    Any alteration in the balance of bacterial challenge versus the host's ability to resist and repair will result in oral lesions that are similar in appearance. The bacterial cause of gingivitis and periodontitis in humans and in all other animals in which it has been studied is firmly established, and specific species of predominantly gram-negative anaerobes have been implicated. Naturally occurring or acquired immunopathologies are likely to result in premature dental disease. When oral disease is associated with the accumulation of plaque, a positive response can be achieved by reducing the bacterial challenge to the host through the maintenance of oral hygiene by timely professional dental prophylaxis and home care. Disease that is the result of atypical immune responses, however, can be much more difficult to manage. Such oral disease can occur with either immune deficiencies or exaggerated immune responses, and it is likely that multiple mechanisms are active concurrently. In any case, gram-negative anaerobes present in plaque are likely to be a major contributing factor. Therefore patients with chronic refractory gingivitis-stomatitis must be considered to be plaque intolerant. Only with a frequent regimen of aggressive and thorough professional dental treatment plus meticulous oral home care on a daily basis can one expect to keep these cases in remission. Because this is often unrealistic, the only other way to keep these patients free of disease is by total dental extraction. The tissues that are colonized by the causative organisms must be eliminated. All root tips and bony sequestra must be removed and healing with intact epithelium accomplished before these cases will go into remission. Edentulous feline patients that continue to have signs of gingivostomatitis have been found to have an area of nonhealed bony sequestrum and chronic osteomyelitis. Once effective debridement has been accomplished and epithelial healing completed, nonresponsive cases can

  17. Stomatal differentiation: the beginning and the end.

    Science.gov (United States)

    Torii, Keiko U

    2015-12-01

    Differentiation of stomata follows a series of stereotypical cell divisions and cell-state transitional steps specified by the master-regulatory transcription factors. The density and numbers of stomata are regulated by cell-cell signaling and flexibly modulated by environmental and physiological inputs. This review focuses on the latest breakthroughs in Arabidopsis elucidating the mechanisms behind the initiation of stomatal precursors, asymmetric cell division and stem cell behavior, and terminal differentiation of guard cells. I discuss new insights emerging from these studies: (i) competitive actions of signals and regulatory circuits initiating stomatal precursor pattern; (ii) a subcellular partitioning of signaling components determining the stomatal lineage stem-cell divisions; and (iii) epigenetic regulation maintaining the differentiated guard cell state. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Clinical study on thermography, as modern investigation method for Candida-associated denture stomatitis.

    Science.gov (United States)

    Iosif, Laura; Preoteasa, Cristina Teodora; Murariu-Măgureanu, Cătălina; Preoteasa, Elena

    2016-01-01

    Candida-associated denture stomatitis is an infectious inflammatory condition of the oral mucosa, with frequent recurrences. The aim of this study was to assess the use of infrared thermography as investigation method for Candida-associated denture stomatitis (as inflammatory disorder of the maxillary denture bearing area), by comparing disease and non-disease groups. An observational study was conducted on maxillary edentulous patients treated by acrylic dentures, with and without Candida-associated denture stomatitis. Diagnostic test methods used were clinical examination for denture stomatitis and conventional microbiological culture method for oral candidiasis. Thermography analysis of the maxillary denture bearing area was made using the ThermaCAM PM350 infrared camera (Inframetrics, Flir Systems) and ThermaGram Pro 95 software, data being acquired by usage of standard protocol of thermographic registrations. The sample included 52 patients, 21 with and 31 without Candida-associated denture stomatitis. The temperature of the maxillary mucosa corresponding to the denture bearing area was found to be statistically significantly higher in Candida-associated denture stomatitis (mean 36.20°C), compared to healthy oral mucosa (mean 34.85°C). The thermal threshold value of 35.44°C was identified as best differentiating a pathological from normal state of the maxillary mucosa corresponding to the denture bearing area. In conclusion, infrared thermography, a rapid non-invasive investigation method, has the premises to bring valuable data in inflammatory disorders of the maxillary denture bearing area, as Candida-associated denture stomatitis that may be used for screening, diagnostic or monitoring purposes.

  19. The prevalence and causes of decreased visual acuity – a study based on vision screening conducted at Enukweni and Mzuzu Foundation Primary Schools, Malawi

    Directory of Open Access Journals (Sweden)

    Thom L

    2016-12-01

    Full Text Available Leaveson Thom,1 Sanchia Jogessar,1,2 Sara L McGowan,1 Fiona Lawless,1,2 1Department of Optometry, Mzuzu University, Mzuzu, Malawi; 2Brienholden Vision Institute, Durban, South Africa Aim: To determine the prevalence and causes of decreased visual acuity (VA among pupils recruited in two primary schools in Mzimba district, northern region of Malawi.Materials and methods: The study was based on the vision screening which was conducted by optometrists at Enukweni and Mzuzu Foundation Primary Schools. The measurements during the screening included unaided distance monocular VA by using Low Vision Resource Center and Snellen chart, pinhole VA on any subject with VA of less than 6/6, refraction, pupil evaluations, ocular movements, ocular health, and shadow test.Results: The prevalence of decreased VA was found to be low in school-going population (4%, n=594. Even though Enukweni Primary School had few participants than Mzuzu Foundation Primary School, it had high prevalence of decreased VA (5.8%, n=275 than Mzuzu Foundation Primary School (1.8%, n=319. The principal causes of decreased VA in this study were found to be amblyopia and uncorrected refractive errors, with myopia being the main cause than hyperopia.Conclusion: Based on the low prevalence of decreased VA due to myopia or hyperopia, it should not be concluded that refractive errors are an insignificant contributor to visual disability in Malawi. More vision screenings are required at a large scale on school-aged population to reflect the real situation on the ground. Cost-effective strategies are needed to address this easily treatable cause of vision impairment. Keywords: vision screening, refractive errors, visual acuity, Enukweni, Mzuzu foundation

  20. Ozone Effects on Fruit Productivity and Photosynthetic Response of Two Tomato Cultivars in Relation to Stomatal Fluxes

    Directory of Open Access Journals (Sweden)

    Giacomo Gerosa

    2008-03-01

    Full Text Available An Open-Top Chamber experiment on two tomato cultivars (cv. Oxheart and cv. San Marzano was carried out in Curno (Northern Italy between June and September 2007. Two ozone treatments were applied for a 3.5 months period: Non-Filtered OTC (NF-OTC, 95% of ambient ozone and Charcoal-Filtered OTC (CF-OTC, 50% of ambient ozone. Diurnal cycles of porometry measurements were performed during the season and allowed to draw a stomatal conductance model for each cultivar in order to calculate the ozone stomatal fluxes taken up by plants. Assessments on fruits yield were performed during the season, taking into account the number of fruits, their fresh weight and their marketability. In addition, measurements on the chlorophyll fluorescence of photosystems were carried out to assess possible negative effects on photosynthetic efficiency. Despite the two cultivars absorbed a similar ozone stomatal dose during the season (with an 8% difference, their responses to ozone treatments were totally divergent in relation to both fruits yield and photosynthetic efficiency. Plants of cv. Oxheart grown in NF-OTCs showed significant yield loss in the total weight of fruits (-35.9% which is exclusively related to a decrease in the number of fruits produced (-35.7% of total fruits; -30.6% of marketable fruits, since mean fresh weight of fruits remained unaffected. Moreover the same plants displayed low values (in comparison to CF-OTCs plants of the photosynthetic efficiency index (PIabs during the most intense period of ozone stress (July occurred in the flowering stage of plants and at the beginning of fructification. Plants of the cv. San Marzano had an opposite response behaviour with an increase of the mean fresh weight of fruits in plants grown in NF-OTC (even if not statistically significant and no difference in the number of fruits produced and in the values of photosynthetic efficiency.

  1. Ozone Effects on Fruit Productivity and Photosynthetic Response of Two Tomato Cultivars in Relation to Stomatal Fluxes

    Directory of Open Access Journals (Sweden)

    Francesco Tagliaferro

    2011-02-01

    Full Text Available An Open-Top Chamber experiment on two tomato cultivars (cv. Oxheart and cv. San Marzano was carried out in Curno (Northern Italy between June and September 2007. Two ozone treatments were applied for a 3.5 months period: Non-Filtered OTC (NF-OTC, 95% of ambient ozone and Charcoal-Filtered OTC (CF-OTC, 50% of ambient ozone. Diurnal cycles of porometry measurements were performed during the season and allowed to draw a stomatal conductance model for each cultivar in order to calculate the ozone stomatal fluxes taken up by plants. Assessments on fruits yield were performed during the season, taking into account the number of fruits, their fresh weight and their marketability. In addition, measurements on the chlorophyll fluorescence of photosystems were carried out to assess possible negative effects on photosynthetic efficiency. Despite the two cultivars absorbed a similar ozone stomatal dose during the season (with an 8% difference, their responses to ozone treatments were totally divergent in relation to both fruits yield and photosynthetic efficiency. Plants of cv. Oxheart grown in NF-OTCs showed significant yield loss in the total weight of fruits (-35.9% which is exclusively related to a decrease in the number of fruits produced (-35.7% of total fruits; -30.6% of marketable fruits, since mean fresh weight of fruits remained unaffected. Moreover the same plants displayed low values (in comparison to CF-OTCs plants of the photosynthetic efficiency index (PIabs during the most intense period of ozone stress (July occurred in the flowering stage of plants and at the beginning of fructification. Plants of the cv. San Marzano had an opposite response behaviour with an increase of the mean fresh weight of fruits in plants grown in NF-OTC (even if not statistically significant and no difference in the number of fruits produced and in the values of photosynthetic efficiency.

  2. Canopy stomatal uptake of NOX, SO2 and O3 by mature urban plantations based on sap flow measurement

    Science.gov (United States)

    Hu, Yanting; Zhao, Ping; Niu, Junfeng; Sun, Zhenwei; Zhu, Liwei; Ni, Guangyan

    2016-01-01

    Canopy stomatal uptake of NOX (NO, NO2), SO2 and O3 by three mature urban plantations (of Schima superba, Eucalyptus citriodora and Acacia auriculaeformis) were studied using the sap flow-based approach under free atmospheric conditions. The annual mean concentration for NO, NO2, SO2 and O3 were 18.2, 58.1, 12.8 and 42.4 μg m-3, respectively. The atmospheric concentration exhibited a spring or winter maximum for NO, NO2 and SO2, whereas the concentration maximum for O3 occurred in the autumn. Despite the daytime mean canopy stomatal conductance (GC) being positively related with the photosynthetically active radiation (PAR) and negatively with the vapour pressure deficit (VPD), the maximal daytime mean GC did not appear when the PAR was at its highest level or the VPD was at its lowest level because a positive correlation was noted between the daytime mean PAR and VPD (P < 0.001) under field conditions. The GC value was regulated by the cooperation of the PAR and VPD. When analysing the respective effect of the PAR or VPD on GC separately, a positive logarithmical correlation was noted between the daytime mean GC and PAR as the following equation:Gc = a × lnPAR - b (P < 0.01), and the daytime mean GC was negatively logarithmically correlated with the VPD: Gc =Gsref - m × lnVPD (P < 0.001). The daytime mean GC declined with decreases in the soil water content (SWC) under similar meteorological condition. Differences in the seasonal pattern of the canopy stomatal conductance and atmospheric concentrations led to a differentiated peak flux. The flux for NO, NO2 and SO2 exhibited a spring maximum, whereas the flux maximum for O3 appeared in the autumn or summer. The annual cumulative stomatal flux for NO, NO2, O3 and SO2 was 100.19 ± 3.76, 510.68 ± 24.78, 748.59 ± 52.81 and 151.98 ± 9.33 mg m-2 a-1, respectively. When we focus on the foliar uptake of trace gases, the effect of these gases on the vegetation in turn should be considered, particularly for regions

  3. Neurogenic detrusor overactivity is associated with decreased expression and function of the large conductance voltage- and Ca(2+-activated K(+ channels.

    Directory of Open Access Journals (Sweden)

    Kiril L Hristov

    Full Text Available Patients suffering from a variety of neurological diseases such as spinal cord injury, Parkinson's disease, and multiple sclerosis often develop neurogenic detrusor overactivity (NDO, which currently lacks a universally effective therapy. Here, we tested the hypothesis that NDO is associated with changes in detrusor smooth muscle (DSM large conductance Ca(2+-activated K(+ (BK channel expression and function. DSM tissue samples from 33 patients were obtained during open bladder surgeries. NDO patients were clinically characterized preoperatively with pressure-flow urodynamics demonstrating detrusor overactivity, in the setting of a clinically relevant neurological condition. Control patients did not have overactive bladder and did not have a clinically relevant neurological disease. We conducted quantitative polymerase chain reactions (qPCR, perforated patch-clamp electrophysiology on freshly-isolated DSM cells, and functional studies on DSM contractility. qPCR experiments revealed that DSM samples from NDO patients showed decreased BK channel mRNA expression in comparison to controls. Patch-clamp experiments demonstrated reduced whole cell and transient BK currents (TBKCs in freshly-isolated DSM cells from NDO patients. Functional studies on DSM contractility showed that spontaneous phasic contractions had a decreased sensitivity to iberiotoxin, a selective BK channel inhibitor, in DSM strips isolated from NDO patients. These results reveal the novel finding that NDO is associated with decreased DSM BK channel expression and function leading to increased DSM excitability and contractility. BK channel openers or BK channel gene transfer could be an alternative strategy to control NDO. Future clinical trials are needed to evaluate the value of BK channel opening drugs or gene therapies for NDO treatment and to identify any possible adverse effects.

  4. An observational constraint on stomatal function in forests: evaluating coupled carbon and water vapor exchange with carbon isotopes in the Community Land Model (CLM4.5)

    Science.gov (United States)

    Raczka, Brett; Duarte, Henrique F.; Koven, Charles D.; Ricciuto, Daniel; Thornton, Peter E.; Lin, John C.; Bowling, David R.

    2016-09-01

    Land surface models are useful tools to quantify contemporary and future climate impact on terrestrial carbon cycle processes, provided they can be appropriately constrained and tested with observations. Stable carbon isotopes of CO2 offer the potential to improve model representation of the coupled carbon and water cycles because they are strongly influenced by stomatal function. Recently, a representation of stable carbon isotope discrimination was incorporated into the Community Land Model component of the Community Earth System Model. Here, we tested the model's capability to simulate whole-forest isotope discrimination in a subalpine conifer forest at Niwot Ridge, Colorado, USA. We distinguished between isotopic behavior in response to a decrease of δ13C within atmospheric CO2 (Suess effect) vs. photosynthetic discrimination (Δcanopy), by creating a site-customized atmospheric CO2 and δ13C of CO2 time series. We implemented a seasonally varying Vcmax model calibration that best matched site observations of net CO2 carbon exchange, latent heat exchange, and biomass. The model accurately simulated observed δ13C of needle and stem tissue, but underestimated the δ13C of bulk soil carbon by 1-2 ‰. The model overestimated the multiyear (2006-2012) average Δcanopy relative to prior data-based estimates by 2-4 ‰. The amplitude of the average seasonal cycle of Δcanopy (i.e., higher in spring/fall as compared to summer) was correctly modeled but only when using a revised, fully coupled An - gs (net assimilation rate, stomatal conductance) version of the model in contrast to the partially coupled An - gs version used in the default model. The model attributed most of the seasonal variation in discrimination to An, whereas interannual variation in simulated Δcanopy during the summer months was driven by stomatal response to vapor pressure deficit (VPD). The model simulated a 10 % increase in both photosynthetic discrimination and water-use efficiency (WUE

  5. Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

    DEFF Research Database (Denmark)

    Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

    2016-01-01

    .5-1.3 kPa on transpiration and stomatal conductance (gs ) of tree seedlings in the temperate forest understory (Duke Forest, North Carolina, USA). We observed peaked responses of transpiration to VPD in all seedlings, and the optimum VPD for transpiration (Dopt ) shifted proportionally with increasing...... chamber VPD. Warming increased mean water use of Carya by 140% and Quercus by 150%, but had no significant effect on water use of Acer. Increased water use of ring-porous species was attributed to (1) higher air T and (2) stomatal acclimation to VPD resulting in higher gs and more sensitive stomata...

  6. Variabilidad anatómica de los sistemas de conducción y estomático de genotipos de Prunus spp. de diferentes orígenes Anatomical variability of water conduction and stomatal systems in genotypes of Prunus spp. of different origins

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Núñez-Colín

    2006-02-01

    Full Text Available El propósito de esta investigación fue estudiar las relaciones ambientales de disponibilidad de humedad, con las características anatómicas del sistema de conducción de agua y estomático, en cinco genotipos de duraznos mexicanos con diferentes orígenes (Jalatzingo y Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas, un almendro y el portainjerto Nemaguard. Fueron caracterizados anatómicamente brotes, hojas y estomas de plántulas de seis meses de edad, mediante 25 caracteres. El almendro y el portainjerto Nemaguard presentaron diferencias con respecto a los duraznos, los cuales tuvieron mayor similitud, aunque mantuvieron una separación acorde con su origen. Los caracteres que diferenciaron los grupos fueron: densidad estomática, grosor de la epidermis superior, número, frecuencia y perímetro de vasos, el índice de vulnerabilidad de la nervadura central, y el porcentaje de médula, xilema y floema del brote. Las condiciones de disponibilidad de humedad del origen presentaron fuerte asociación con las características anatómicas estudiadas, debido a que los ambientes con mayor déficit de humedad (Tulancingo y Sombrerete presentaron mayor tamaño y menor frecuencia de vasos de xilema, así como bajo porcentaje de xilema y floema en brote, lo que puede interpretarse como adaptaciones de resistencia a sequía. La zona donde es rara la ocurrencia de sequía (Jalatzingo presentó características opuestas.The aim of this research was to study the relationships between environmental humidity availability and the anatomical characteristics of water conduction and stomatal systems, in five Mexican peach genotypes with different origins (Jalatzingo and Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas, one almond and Nemaguard rootstock. Shoots, leaves and stomata of six months old plants were anatomically characterized by means of 25 characters. The almond tree and

  7. Gaseous NO2 effects on stomatal behavior, photosynthesis and respiration of hybrid poplar leaves

    Science.gov (United States)

    In this study, we used poplar as a model plant and investigated the effects of gaseous nitrogen dioxide (NO2, 4 microliter per liter) on stomatal conductance, photosynthesis, dark- and photorespiration of Populus alba x Populus berolinensis hybrid leaves using the photosynthesis system and scanning...

  8. ANALISA TINGKAT KEJADIAN STOMATITIS PADA PENDERITA TUNANETRA

    OpenAIRE

    MUH., ikhsan.s

    2012-01-01

    2011 Tujuan: Untuk Mengetahui tingkat kejadian dan faktor yang mempengaruhi terjadinya stomatitis pada penderita tunanetra. Desain: Penelitian yang akan dilakukan adalah penelitian observasional yaitu suatu rancangan penelitian dimana mengamati objek tanpa melakukan intervensi kepada objek tersebut. Pengaturan Studi: Penelitian ini dilakukan di Panti Tunanetra Yukartuni, Panti Guna Yapti, dan YPKCNI Makassar. Penelitian dilakukan selama satu minggu Bahan dan Metode: Populasi yang ...

  9. Association between serotonin transporter gene polymorphism and recurrent aphthous stomatitis

    Science.gov (United States)

    Manchanda, Aastha; Iyengar, Asha R.; Patil, Seema

    2016-01-01

    Background: Anxiety-related traits have been attributed to sequence variability in the genes coding for serotonin transmission in  the brain. Two alleles, termed long (L) and short (S) differing by 44 base pairs, are found in a polymorphism identified in the promoter region of serotonin transporter gene. The presence of the short allele  and SS and LS genotypes is found to be associated with the reduced expression of this gene decreasing the uptake of serotonin in the brain leading to various anxiety-related traits. Recurrent aphthous stomatitis (RAS) is an oral mucosal disease with varied etiology including the presence of stress, anxiety, and genetic influences. The present study aimed to determine this serotonin transporter gene polymorphism in patients with RAS and compare it with normal individuals. Materials and Methods: This study included 20 subjects with various forms of RAS and 20 normal healthy age- and gender-matched individuals. Desquamated oral mucosal cells were collected for DNA extraction and subjected to polymerase chain reaction for studying insertion/deletion in the 5-HTT gene-linked polymorphic region. Cross tabulations followed by Chi-square tests were performed to compare the significance of findings, P < 0.05 was considered statistically significant. Results: The LS genotype was the most common genotype found in the subjects with aphthous stomatitis (60%) and controls (40%). The total percentage of LS and SS genotypes and the frequency of S allele were found to be higher in the subjects with aphthous stomatitis as compared to the control group although a statistically significant correlation could not be established, P = 0.144 and 0.371, respectively. Conclusion: Within the limitations of this study, occurrence of RAS was not found to be associated with polymorphic promoter region in serotonin transporter gene. PMID:27274339

  10. Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia.

    Science.gov (United States)

    Xie, Changyan; Cao, Xu; Chen, Xibing; Wang, Dong; Zhang, Wei Kevin; Sun, Ying; Hu, Wenbao; Zhou, Zijing; Wang, Yan; Huang, Pingbo

    2016-04-01

    Mutations of cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial ligand-gated anion channel, are associated with the lethal genetic disease cystic fibrosis. The CFTR G551D mutation impairs ATP hydrolysis and thereby makes CFTR refractory to cAMP stimulation. Both wild-type (WT) and G551D CFTR have been implicated in regulatory volume decrease (RVD), but the underlying mechanism remains incompletely understood. Here, we show that the channel activity of both WT and G551D CFTR is directly stimulated by mechanical perturbation induced by cell swelling at the single-channel, cellular, and tissue levels. Hypotonicity activated CFTR single channels in cell-attached membrane patches and WT-CFTR-mediated short-circuit current (Isc) in Calu-3 cells, and this was independent of Ca(2+)and cAMP/PKA signaling. Genetic suppression and ablation but not G551D mutation of CFTR suppressed the hypotonicity- and stretch-inducedIscin Calu-3 cells and mouse duodena. Moreover, ablation but not G551D mutation of the CFTR gene inhibited the RVD of crypts isolated from mouse intestine; more importantly, CFTR-specific blockers markedly suppressed RVD in both WT- and G551D CFTR mice, demonstrating for the first time that the channel activity of both WT and G551D CFTR is required for epithelial RVD. Our findings uncover a previously unrecognized mechanism underlying CFTR involvement in epithelial RVD and suggest that the mechanosensitivity of G551D CFTR might underlie the mild phenotypes resulting from this mutation.-Xie, C., Cao, X., Chen, X, Wang, D., Zhang, W. K., Sun, Y., Hu, W., Zhou, Z., Wang, Y., Huang, P. Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia.

  11. Numerical Study on the Stomatal Responses to Dry-Hot Wind Episodes and Its Effects on Land-Atmosphere Interactions

    Science.gov (United States)

    Zheng, Hui; Liu, Shuhua; Miao, Yucong; Li, Jing

    2016-01-01

    The wheat production in midland China is under serious threat by frequent Dry-Hot Wind (DHW) episodes with high temperature, low moisture and specific wind as well as intensive heat transfer and evapotranspiration. The numerical simulations of these episodes are important for monitoring grain yield and estimating agricultural water demand. However, uncertainties still remain despite that enormous experiments and modeling studies have been conducted concerning this issue, due to either inaccurate synoptic situation derived from mesoscale weather models or unrealistic parameterizations of stomatal physiology in land surface models. Hereby, we investigated the synoptic characteristics of DHW with widely-used mesoscale model Weather Research and Forecasting (WRF) and the effects of leaf physiology on surface evapotranspiration by comparing two land surface models: The Noah land surface model, and Peking University Land Model (PKULM) with stomata processes included. Results show that the WRF model could well replicate the synoptic situations of DHW. Two types of DHW were identified: (1) prevailing heated dry wind stream forces the formation of DHW along with intense sensible heating and (2) dry adiabatic processes overflowing mountains. Under both situations, the PKULM can reasonably model the stomatal closure phenomena, which significantly decreases both evapotranspiration and net ecosystem exchange of canopy, while these phenomena cannot be resolved in the Noah simulations. Therefore, our findings suggest that the WRF-PKULM coupled method may be a more reliable tool to investigate and forecast DHW as well as be instructive to crop models. PMID:27648943

  12. Elevation-related variation in leaf stomatal traits as a function of plant functional type: evidence from Changbai Mountain, China.

    Directory of Open Access Journals (Sweden)

    Ruili Wang

    Full Text Available Understanding the variation in stomatal characteristics in relation to climatic gradients can reveal the adaptation strategies of plants, and help us to predict their responses to future climate changes. In this study, we investigated stomatal density (SD and stomatal length (SL in 150 plant species along an elevation gradient (540-2357 m in Changbai Mountain, China, and explored the patterns and drivers of stomatal characteristics across species and plant functional types (PFTs: trees, shrubs, and herbs. The average values of SD and SL for all species combined were 156 mm(-2 and 35 µm, respectively. SD was higher in trees (224 mm(-2 than in shrubs (156 mm(-2 or herbs (124 mm(-2, and SL was largest in herbs (37 µm. SD was negatively correlated with SL in all species and PFTs (P < 0.01. The relationship between stomatal characteristics and elevation differed among PFTs. In trees, SD decreased and SL increased with elevation; in shrubs and herbs, SD initially increased and then decreased. Elevation-related differences in SL were not significant. PFT explained 7.20-17.6% of the total variation in SD and SL; the contributions of CO2 partial pressure (P CO2, precipitation, and soil water content (SWC were weak (0.02-2.28%. Our findings suggest that elevation-related patterns of stomatal characteristics in leaves are primarily a function of PFT, and highlight the importance of differences among PFTs in modeling gas exchange in terrestrial ecosystems under global climate change.

  13. Decreased basal chloride secretion and altered cystic fibrosis transmembrane conductance regulatory protein, Villin, GLUT5 protein expression in jejunum from leptin-deficient mice

    Directory of Open Access Journals (Sweden)

    Leung L

    2014-07-01

    Full Text Available Lana Leung, Jonathan Kang, Esa Rayyan, Ashesh Bhakta, Brennan Barrett, David Larsen, Ryan Jelinek, Justin Willey, Scott Cochran, Tom L Broderick, Layla Al-NakkashDepartment of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USAAbstract: Patients with diabetes and obesity are at increased risk of developing disturbances in intestinal function. In this study, we characterized jejunal function in the clinically relevant leptin-deficient ob/ob mouse, a model of diabetes and obesity. We measured transepithelial short circuit current (Isc, across freshly isolated segments of jejunum from 12-week-old ob/ob and lean C57BL/6J (female and male mice. The basal Isc was significantly decreased (~30% in the ob/ob mice (66.5±5.7 µA/cm2 [n=20] (P< 0.05 compared with their lean counterparts (95.1±9.1 µA/cm2 [n=19]. Inhibition with clotrimazole (100 µM, applied bilaterally was significantly reduced in the ob/ob mice (−7.92%±3.67% [n=15] (P<0.05 compared with the lean mice (10.44%±7.92% [n=15], indicating a decreased contribution of Ca2+-activated K+ (KCa channels in the ob/ob mice. Inhibition with ouabain (100 µM, applied serosally was significantly reduced in the ob/ob mice (1.40%±3.61%, n=13 (P< 0.05 versus the lean mice (18.93%±3.76% [n=18], suggesting a potential defect in the Na+/K+-adenosine triphosphate (ATPase pump with leptin-deficiency. Expression of cystic fibrosis transmembrane conductance regulatory protein (CFTR (normalized to glyceraldehyde-3-phosphate dehydrogenase [GAPDH] was significantly decreased ~twofold (P<0.05 in the ob/ob mice compared with the leans, whilst crypt depth was unchanged. Villi length was significantly increased by ~25% (P<0.05 in the ob/ob mice compared with the leans and was associated with an increase in Villin and GLUT5 expression. GLUT2 and SGLT-1 expression were both unchanged. Our data suggests that reduced basal jejunal Isc in ob/ob mice is likely a consequence of

  14. ROOT HYDRAULIC CONDUCTIVITY AND PHOTOSYNTHETIC CAPACITY OF EUCALYPT CLONAL CUTTINGS WITH ROOT MALFORMATION INDUCTIONS

    Directory of Open Access Journals (Sweden)

    Fábio Afonso Mazzei Moura de Assis Figueiredo

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814566The gain reduction of wood biomass in trees has been assigned to root deformations even in the nursery phase. The objective of this work was the evaluation of the root system hydraulic conductivity, gas exchanges and photochemical efficiency of eucalypt clonal cuttings with and without root deformation inductions. The treatments were: 1 operational cuttings without root malformation inductions (grown according to the used methodology of Fibria Cellulose S.A.; 2 root deformation inductions. These inductions did not promote decrease in the root volume. However, the deformations brought reduction of the root system hydraulic conductivity. Lower photosynthetic rates were also observed along the day in the cuttings in the root deformed cuttings. This decreasing rate is connected to stomatal and non stomatal factors.

  15. Preparation and Evaluation of Stomatitis Film Using Xyloglucan Containing Loperamide.

    Science.gov (United States)

    Kawano, Yayoi; Sasatsu, Masanaho; Mizutani, Ayako; Hirose, Kaoru; Hanawa, Takehisa; Onishi, Hiraku

    2016-06-01

    Stomatitis induced by radiation therapy or cancer chemotherapy is a factor in sleep disorders and/or eating disorders, markedly decreasing patient quality of life. In recent years, disintegrating oral films that are easy to handle have been developed; therefore, we focused on the formulation of these films. We prepared an adhesive film for the oral cavity using xyloglucan (Xylo), which is a water-soluble macromolecule. We used loperamide, which has been reported to relieve pain caused by stomatitis effectively, as a model drug in this study. Films were prepared from Xylo solutions (3% (w/w)) and hypromellose (HPMC) solutions (1% (w/w)). Xylo and HPMC solutions were mixed at ratios of 1 : 1, 2 : 1, or 3 : 1 for each film, and films 2×2 cm weighing 3 g were prepared and dried at 37°C for 24 h. Physicochemical properties such as strength, adhesiveness, disintegration behavior, and dissolution of loperamide from films were evaluated. Films prepared from Xylo solution alone had sufficient strength and mucosal adhesion. On the other hand, films prepared from a mixture of Xylo and HPMC were inferior to those made from Xylo, but showed sufficient strength and mucosal adhesion and were flexible and easy to handle. The films prepared in this study are useful as adhesion films in the oral cavity.

  16. Ricinus communis treatment of denture stomatitis in institutionalised elderly.

    Science.gov (United States)

    Pinelli, L A P; Montandon, A A B; Corbi, S C T; Moraes, T A; Fais, L M G

    2013-05-01

    This study compared the effectiveness of Ricinus communis (RC) with Nystatin (NYS) and Miconazole (MIC) in the treatment of institutionalised elderly with denture stomatitis (DS). They (n = 30) were randomly distributed into three groups: MIC, NYS or RC. Clinical and mycological evaluations were performed prior to the use of the antifungal (baseline) and repeated after 15 and 30 days of treatment. The sample was clinically examined for oral mucosal conditions. Standard photographs were taken of the palate, and the oral candidiasis was classified (Newton's criteria). Mycological investigation was performed by swabbing the palatal mucosa, and Candida spp. were quantified by counting the number of colony-forming units (cfu mL⁻¹). The clinical and mycological data were analysed, respectively by Wilcoxon and Student's t-test (α = 0.05). Significant improvement in the clinical appearance of DS in the MIC and RC groups was observed between the 1st and 3rd collections (MIC - P = 0.018; RC - P = 0.011) as well as between the 2nd and 3rd collections (MIC - P = 0.018; RC - P = 0.011). Neither groups showed a statistically significant reduction in cfu mL⁻¹ at any time. Although none of the treatments decreased the cfu mL⁻¹, it was concluded that Ricinus communis can improve the clinical condition of denture stomatitis in institutionalised elderly patients, showing similar results to Miconazole. © 2013 Blackwell Publishing Ltd.

  17. A Recombinant Vesicular Stomatitis Virus Ebola Vaccine.

    Science.gov (United States)

    Regules, Jason A; Beigel, John H; Paolino, Kristopher M; Voell, Jocelyn; Castellano, Amy R; Hu, Zonghui; Muñoz, Paula; Moon, James E; Ruck, Richard C; Bennett, Jason W; Twomey, Patrick S; Gutiérrez, Ramiro L; Remich, Shon A; Hack, Holly R; Wisniewski, Meagan L; Josleyn, Matthew D; Kwilas, Steven A; Van Deusen, Nicole; Mbaya, Olivier Tshiani; Zhou, Yan; Stanley, Daphne A; Jing, Wang; Smith, Kirsten S; Shi, Meng; Ledgerwood, Julie E; Graham, Barney S; Sullivan, Nancy J; Jagodzinski, Linda L; Peel, Sheila A; Alimonti, Judie B; Hooper, Jay W; Silvera, Peter M; Martin, Brian K; Monath, Thomas P; Ramsey, W Jay; Link, Charles J; Lane, H Clifford; Michael, Nelson L; Davey, Richard T; Thomas, Stephen J

    2017-01-26

    Background The worst Ebola virus disease (EVD) outbreak in history has resulted in more than 28,000 cases and 11,000 deaths. We present the final results of two phase 1 trials of an attenuated, replication-competent, recombinant vesicular stomatitis virus (rVSV)-based vaccine candidate designed to prevent EVD. Methods We conducted two phase 1, placebo-controlled, double-blind, dose-escalation trials of an rVSV-based vaccine candidate expressing the glycoprotein of a Zaire strain of Ebola virus (ZEBOV). A total of 39 adults at each site (78 participants in all) were consecutively enrolled into groups of 13. At each site, volunteers received one of three doses of the rVSV-ZEBOV vaccine (3 million plaque-forming units [PFU], 20 million PFU, or 100 million PFU) or placebo. Volunteers at one of the sites received a second dose at day 28. Safety and immunogenicity were assessed. Results The most common adverse events were injection-site pain, fatigue, myalgia, and headache. Transient rVSV viremia was noted in all the vaccine recipients after dose 1. The rates of adverse events and viremia were lower after the second dose than after the first dose. By day 28, all the vaccine recipients had seroconversion as assessed by an enzyme-linked immunosorbent assay (ELISA) against the glycoprotein of the ZEBOV-Kikwit strain. At day 28, geometric mean titers of antibodies against ZEBOV glycoprotein were higher in the groups that received 20 million PFU or 100 million PFU than in the group that received 3 million PFU, as assessed by ELISA and by pseudovirion neutralization assay. A second dose at 28 days after dose 1 significantly increased antibody titers at day 56, but the effect was diminished at 6 months. Conclusions This Ebola vaccine candidate elicited anti-Ebola antibody responses. After vaccination, rVSV viremia occurred frequently but was transient. These results support further evaluation of the vaccine dose of 20 million PFU for preexposure prophylaxis and suggest that a

  18. [Clinical availability of the herbal medicine, SYOUSAIKOTOU, as a gargling agent for prevention and treatment of chemotherapy-induced stomatitis].

    Science.gov (United States)

    Matsuoka, Hitoshi; Mizushima, Yuki; Kawano, Masako; Tachibana, Naoko; Sawada, Yoshiko; Kato, Sachiko; Nagakura, Hiromi; Tanaka, Miyuki; Suzuki, Keiko; Tadanobu, Kuribayashi

    2004-11-01

    The stomatitis accompanying chemotherapy reduces a patient's QOL. Many reports have suggested that some kinds of gargling agents for oral mucositis shorten the duration and severity of symptoms. This study tested the prevention and efficacy against stomatitis of a herbal medicine (Syousaikotou) as a gargling agent for patients receiving chemotherapy. Compared to gargling with providone-iodine and amphotericin B, the Syousaikotou gargle showed a significantly decreased incidence of stomatitis, and a painkilling effect. Stomatitis occurred in about 17.4% among 23 chemotherapy cycles with the Syousaikotou gargle, against about 40.8% among 71 chemotherapy cycles without the Syousaikotou gargle. Among the patients suffering stomatitis pain after 22 chemotherapy cycles, the painkilling effect was seen to be 76.2%, and continues for about 2 hours. Critical side effects were not seen, but in 4 cases there were complaints about foul smells, such as oil and grass smells. Syousaikotou gargle was considered to be one of the useful methods against the stomatitis prevention and sharp pain mitigation from the chemotherapy.

  19. Association genetics, geography and ecophysiology link stomatal patterning in Populus trichocarpa with carbon gain and disease resistance trade-offs.

    Science.gov (United States)

    McKown, Athena D; Guy, Robert D; Quamme, Linda; Klápště, Jaroslav; La Mantia, Jonathan; Constabel, C P; El-Kassaby, Yousry A; Hamelin, Richard C; Zifkin, Michael; Azam, M S

    2014-12-01

    Stomata are essential for diffusive entry of gases to support photosynthesis, but may also expose internal leaf tissues to pathogens. To uncover trade-offs in range-wide adaptation relating to stomata, we investigated the underlying genetics of stomatal traits and linked variability in these traits with geoclimate, ecophysiology, condensed foliar tannins and pathogen susceptibility in black cottonwood (Populus trichocarpa). Upper (adaxial) and lower (abaxial) leaf stomatal traits were measured from 454 accessions collected throughout much of the species range. We calculated broad-sense heritability (H(2) ) of stomatal traits and, using SNP data from a 34K Populus SNP array, performed a genome-wide association studies (GWAS) to uncover genes underlying stomatal trait variation. H(2) values for stomatal traits were moderate (average H(2) = 0.33). GWAS identified genes associated primarily with adaxial stomata, including polarity genes (PHABULOSA), stomatal development genes (BRASSINOSTEROID-INSENSITIVE 2) and disease/wound-response genes (GLUTAMATE-CYSTEINE LIGASE). Stomatal traits correlated with latitude, gas exchange, condensed tannins and leaf rust (Melampsora) infection. Latitudinal trends of greater adaxial stomata numbers and guard cell pore size corresponded with higher stomatal conductance (gs ) and photosynthesis (Amax ), faster shoot elongation, lower foliar tannins and greater Melampsora susceptibility. This suggests an evolutionary trade-off related to differing selection pressures across the species range. In northern environments, more adaxial stomata and larger pore sizes reflect selection for rapid carbon gain and growth. By contrast, southern genotypes have fewer adaxial stomata, smaller pore sizes and higher levels of condensed tannins, possibly linked to greater pressure from natural leaf pathogens, which are less significant in northern ecosystems.

  20. Plant virus infections control stomatal development

    Science.gov (United States)

    Murray, Rose R.; Emblow, Mark S. M.; Hetherington, Alistair M.; Foster, Gary D.

    2016-01-01

    Stomata are important regulators of carbon dioxide uptake and transpirational water loss. They also represent points of vulnerability as bacterial and fungal pathogens utilise this natural opening as an entry portal, and thus have an increasingly complex relationship. Unlike the situation with bacterial and fungal pathogens, we know very little about the role of stomata in viral infection. Here we report findings showing that viral infection influences stomatal development in two susceptible host systems (Nicotiana tabacum with TMV (Tobacco mosaic virus), and Arabidopsis thaliana with TVCV (Turnip vein-clearing virus)), but not in resistant host systems (Nicotiana glutinosa and Chenopodium quinoa with TMV). Virus infected plants had significantly lower stomatal indices in systemic leaves of susceptible systems; N. tabacum 9.8% reduction and A. thaliana 12.3% reduction, but not in the resistant hosts. Stomatal density in systemic leaves was also significantly reduced in virus infected A. thaliana by 19.6% but not in N. tabacum or the resistant systems. In addition, transpiration rate was significantly reduced in TMV infected N. tabacum. PMID:27687773

  1. Plant virus infections control stomatal development

    Science.gov (United States)

    Murray, Rose R.; Emblow, Mark S. M.; Hetherington, Alistair M.; Foster, Gary D.

    2016-09-01

    Stomata are important regulators of carbon dioxide uptake and transpirational water loss. They also represent points of vulnerability as bacterial and fungal pathogens utilise this natural opening as an entry portal, and thus have an increasingly complex relationship. Unlike the situation with bacterial and fungal pathogens, we know very little about the role of stomata in viral infection. Here we report findings showing that viral infection influences stomatal development in two susceptible host systems (Nicotiana tabacum with TMV (Tobacco mosaic virus), and Arabidopsis thaliana with TVCV (Turnip vein-clearing virus)), but not in resistant host systems (Nicotiana glutinosa and Chenopodium quinoa with TMV). Virus infected plants had significantly lower stomatal indices in systemic leaves of susceptible systems; N. tabacum 9.8% reduction and A. thaliana 12.3% reduction, but not in the resistant hosts. Stomatal density in systemic leaves was also significantly reduced in virus infected A. thaliana by 19.6% but not in N. tabacum or the resistant systems. In addition, transpiration rate was significantly reduced in TMV infected N. tabacum.

  2. Use of Amorolfine in Candida- associated Denture Stomatitis

    Directory of Open Access Journals (Sweden)

    S.Sunil

    2010-01-01

    Full Text Available Denture stomatitis (DS is an inflammatory lesion, in which there is redness of theoral mucosa underneath a removable denture. Although Candida albicans is a component ofnormal microbial flora, local and systemic factors can cause opportunistic infections. Poorlyfitting or unhygienic dentures leads to the presence of yeasts attached to it., and causeinflammation. Treatment procedures include correction of ill-fitting dentures, plaquecontrol, and topical and systemic antifungal therapy. Nystatin and Amphoteresin B are usedtopically as suspension. Since candidiasis is highly resistant to antifungal agents, systemicusage of ketoconazole, fluconazole or itraconazole are necessary. But the systemic use ofthese drugs can cause side effects like liver toxicity, drug interactions etc. Lucio; Lorengoetal had conducted a study of the efficacy of amorolfine antifungal varnish, by localapplication, and found that it suppresses the nystatin resistant Candida associated denturestomatitis.

  3. Testing of models of stomatal ozone fluxes with field measurements in a mixed Mediterranean forest

    Science.gov (United States)

    Fares, S.; Matteucci, G.; Scarascia Mugnozza, G.; Morani, A.; Calfapietra, C.; Salvatori, E.; Fusaro, L.; Manes, F.; Loreto, F.

    2013-03-01

    Mediterranean forests close to urban areas are exposed to polluted plumes loaded with tropospheric ozone. This is the case of Castelporziano Estate, a 6000 ha Mediterranean forest 25 km from Rome downtown on the coast of the Mediterranean Sea. In September 2011 we started an intensive field campaign aimed at investigating ozone deposition from a mixed Mediterranean forest, mainly composed by Quercus suber, Quercus ilex, Pinus pinea. Measurements at canopy level with the eddy covariance technique were supported by a vegetation survey and the measurement of all environmental parameters which allowed to calculate stomatal ozone fluxes. Leaf-level measurements were used to parameterize models to calculate stomatal conductance based on a Jarvis-type and Ball-Berry approach. We show changes in magnitude of ozone fluxes from a warm (September) to a cold period (October-December). Stomatal component explained almost the totality of ozone fluxes during the cold days, but contributed only up to 50% to total ozone deposition during warm days, suggesting that other sinks (e.g. chemistry in the gas-phase) play a major role. Modeled stomatal ozone fluxes based on a Jarvis-type approach (DO3SE) correlated with measured fluxes better than using a Ball-Berry approach. A third model based on a modified Ball-Berry equation was proposed to account for the non-linear dependency of stomatal conductance on relative humidity. This research will help the development of metrics for ozone-risk assessment and advance our understanding of mixed Mediterranean forests in biosphere-atmosphere exchange.

  4. Seasonal stomatal behavior of a common desert shrub and the influence of plant neighbors.

    Science.gov (United States)

    Kropp, Heather; Ogle, Kiona

    2015-02-01

    Stomata simultaneously regulate plant carbon gain and water loss, and patterns of stomatal conductance (g(s)) provide insight into water use strategies. In arid systems, g(s) varies seasonally based on factors such as water availability and temperature. Moreover, the presence and species identity of neighboring plants likely affects g(s) of the focal plant by altering available soil water and microclimate conditions. We investigated stomatal behavior in Larrea tridentata, a drought-tolerant, evergreen shrub occurring throughout the arid southwestern United States. We measured g(s) in Larrea over multiple seasons in the presence of neighbors representing different woody species. The data were analyzed in the context of a commonly used phenomenological model that relates g(s) to vapor pressure deficit (D) to understand spatial and temporal differences in stomatal behavior. We found that g(s) in Larrea was affected by neighborhood association, and these effects varied seasonally. The greatest effect of neighborhood association on g(s) occurred during the winter period, where Larrea growing alone (without neighbors) had higher g(s) compared to Larrea growing with neighbors. Larrea's stomatal sensitivity to D and reference conductance (i.e., g(s) at D = 1 kPa) also differed significantly among different neighbor associations. Random effects indicated reference g(s) varied over short time scales (daily), while stomatal sensitivity showed little daily or seasonal variation, but was notably affected by neighbor associations such that neighboring species, especially trees, reduced Larrea's sensitivity to D. Overall, seasonal dynamics and neighborhood conditions appear critical to understanding temporal and spatial variation in Larrea's physiological behavior.

  5. Clinical evaluation of the essential oil of "Satureja Hortensis" for the treatment of denture stomatitis

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Sabzghabaee

    2012-01-01

    Full Text Available Background: The prevalence of denture stomatitis has been shown to vary from 15 to 65% in complete denture wearers. Satureja hortensis L. has been considered to have antinociceptive, anti-inflammatory, antifungal and antimicrobial activities in vitro and exhibits strong inhibitory effect on the growth of periodontal bacteria. The aim of this study was to evaluate the efficacy of a 1% gel formulation of S. hortensis essential oil for the treatment of denture stomatitis. Materials and Methods: A randomized, controlled clinical trial study was conducted on 80 patients (mean age 62.91±7.34 in two parallel groups treated either with S. hortensis essential oil 1% gel or placebo applied two times daily for two weeks. Denture stomatitis was diagnosed by clinical examination and paraclinical confirmation with sampling the palatal mucosa for Candida albicans. Data were analyzed using Chi-squared or Student′s t tests. Results: The erythematous lesions of palatal area were significantly reduced (P<0.0001 in the treatment group who applied 1% topical gel of S. hortensis essential oil and Candida colonies count were reduced significantly (P=0.001. Conclusion: Topical application of the essential oil of S. hortensis could be considered as an effective agent for the treatment of denture stomatitis.

  6. Acidic mist reduces foliar membrane-associated calcium and impairs stomatal responsiveness in red spruce

    Energy Technology Data Exchange (ETDEWEB)

    Borer, C. H.; DeHayes, D. H. [University of Vermont, Rubinstein School of Environment and Natural Resources, Burlington, VT (United States); Schaberg, P. G. [USDA Forest Service, Northeastern Research Station, South Burlington, VT (United States)

    2005-06-01

    The possibility of impairment of stomatal responsiveness due to acidic mist-induced depletion of foliar membrane calcium (mCa) was investigated by exposing red spruce seedlings to either pH 3.0 or pH 5.0 mist treatments for one growing season. Foliar nutrition was assessed following each treatment, and declines in stomatal conductance and net photosynthesis were measured on current year shoots following stem excision. Seedlings subjected to pH 3.0 acidic mist treatment had reduced mCa, and exhibited impaired stomatal function, including a smaller maximum aperture, slower closure, increased lag time between stomatal closure and photosynthetic decline following experimental water stress, relative to seedling treated with pH 5.0 acidic mist. The evidence supports the hypothesis that anthropogenetically caused depletion of mCa may disrupt physiological processes that depend on foliar Ca, in the process reducing the plants ability to respond adaptively to environmental stresses. 69 refs., 1 tab., 1 fig.

  7. Stomatal design principles for gas exchange in synthetic and real leaves

    Science.gov (United States)

    Jensen, Kaare H.; Haaning, Katrine; Boyce, C. Kevin; Zwieniecki, Maciej

    2016-11-01

    Stomata are portals in plant leaves that control gas exchange for photosynthesis, a process fundamental to life on Earth. Gas fluxes and plant productivity depend on external factors such as light, water, and CO2 availability and on geometric properties of the stomata pores. The link between stomata geometry and environmental factors have informed a wide range of scientific fields - from agriculture to climate science, where observed variations in stomata size and density is used to infer prehistoric atmospheric CO2 content. However, the physical mechanisms and design principles responsible for major trends in stomatal patterning, are not well understood. Here we use a combination of biomimetic experiments and theory to rationalize the observed changes in stomatal geometry. We show that the observed correlations between stomatal size and density are consistent with the hypothesis that plants favor efficient use of space and maximum control of dynamic gas conductivity, and - surprisingly - that the capacity for gas exchange in plants has remained constant over at least the last 325 million years. Our analysis provides a new measure to gauge the relative performance of species based on their stomatal characteristics. Supported by the Carlsberg Foundation (2013-01-0449), VILLUM FONDEN (13166) and the National Science Foundation (EAR-1024041).

  8. Bovine lactoferrin and piroxicam as an adjunct treatment for lymphocytic-plasmacytic gingivitis stomatitis in cats.

    Science.gov (United States)

    Hung, Yi-Ping; Yang, Yi-Ping; Wang, Hsien-Chi; Liao, Jiunn-Wang; Hsu, Wei-Li; Chang, Chao-Chin; Chang, Shih-Chieh

    2014-10-01

    Feline lymphocytic-plasmacytic gingivitis/stomatitis (LPGS) or caudal stomatitis is an inflammatory disease that causes painfully erosive lesions and proliferations of the oral mucosa. The disease is difficult to cure and can affect cats at an early age, resulting in lifetime therapy. In this study, a new treatment using a combination of bovine lactoferrin (bLf) oral spray and oral piroxicam was investigated using a randomized double-blinded clinical trial in 13 cats with caudal stomatitis. Oral lesion grading and scoring of clinical signs were conducted during and after the trial to assess treatment outcome. Oral mucosal biopsies were used to evaluate histological changes during and after treatment. Clinical signs were significantly improved in 77% of the cats. In a 4-week study, clinical signs were considerably ameliorated by oral piroxicam during the first 2 weeks. In a 12-week study, the combined bLf oral spray and piroxicam, when compared with piroxicam alone, exhibited an enhanced effect that reduced the severity of the oral lesions (P = 0.059), while also significantly improving clinical signs (P stomatitis in cats.

  9. Stomatal Blue Light Response Is Present in Early Vascular Plants.

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-10-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K(+) accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum.

  10. Remission of severe aphthous stomatitis of celiac disease with etanercept

    National Research Council Canada - National Science Library

    Hasan, Adey; Patel, Hiren; Saleh, Hana; Youngberg, George; Litchfield, John; Krishnaswamy, Guha

    2013-01-01

    ... (wheat, barley and rye) in genetically predisposed individuals. We present a patient with celiac disease complicated by severe aphthous stomatitis resulting in impairing swallowing, chewing and speaking...

  11. Analysis of Stomatal Patterning in Selected Mutants of MAPK Pathways

    KAUST Repository

    Felemban, Abrar

    2016-05-01

    Stomata are cellular valves in plants that play an essential role in the regulation of gas exchange and are distributed in the epidermis of aerial organs. In Arabidopsis thaliana, stomatal production and development are coordinated by the mitogen-activated protein kinase (MAPK) signalling pathway, which modulates a variety of other processes, including cell proliferation, regulation of cytokinesis, programed cell death, and response to abiotic and biotic stress. The environment also plays a role in stomatal development, by influencing the frequency at which stomata develop in leaves. This thesis presents an analysis of stomatal development in Arabidopsis mutants in two MAPK pathways: MEKK1-MKK1/MKK2-MPK4, and MAP3K17/18-MKK3. Obtained results demonstrate the effect of stress conditions on stomatal development and specify the involvement of analysed MAPK in stomatal patterning. First, both analysed pathways modulate stomatal patterning in Arabidopsis cotyledons. Second, plant growth-promoting bacteria tested enhance stomatal density and affect guard cell morphology. Third, the sucrose or mannitol treatment increases defects in stomatal patterning. Finally, salt stress or high temperature can suppress stomatal defects in mutants of the MEKK1-MKK1/MKK2-MPK4 pathway.

  12. Reconstructing Atmospheric CO2 Through The Paleocene-Eocene Thermal Maximum Using Stomatal Index and Stomatal Density Values From Ginkgo adiantoides

    Science.gov (United States)

    Barclay, R. S.; Wing, S. L.

    2013-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) was a geologically brief interval of intense global warming 56 million years ago. It is arguably the best geological analog for a worst-case scenario of anthropogenic carbon emissions. The PETM is marked by a ~4-6‰ negative carbon isotope excursion (CIE) and extensive marine carbonate dissolution, which together are powerful evidence for a massive addition of carbon to the oceans and atmosphere. In spite of broad agreement that the PETM reflects a large carbon cycle perturbation, atmospheric concentrations of CO2 (pCO2) during the event are not well constrained. The goal of this study is to produce a high resolution reconstruction of pCO2 using stomatal frequency proxies (both stomatal index and stomatal density) before, during, and after the PETM. These proxies rely upon a genetically controlled mechanism whereby plants decrease the proportion of gas-exchange pores (stomata) in response to increased pCO2. Terrestrial sections in the Bighorn Basin, Wyoming, contain macrofossil plants with cuticle immediately bracketing the PETM, as well as dispersed plant cuticle from within the body of the CIE. These fossils allow for the first stomatal-based reconstruction of pCO2 near the Paleocene-Eocene boundary; we also use them to determine the relative timing of pCO2 change in relation to the CIE that defines the PETM. Preliminary results come from macrofossil specimens of Ginkgo adiantoides, collected from an ~200ka interval prior to the onset of the CIE (~230-30ka before), and just after the 'recovery interval' of the CIE. Stomatal index values decreased by 37% within an ~70ka time interval at least 100ka prior to the onset of the CIE. The decrease in stomatal index is interpreted as a significant increase in pCO2, and has a magnitude equivalent to the entire range of stomatal index adjustment observed in modern Ginkgo biloba during the anthropogenic CO2 rise during the last 150 years. The inferred CO2 increase prior to the

  13. Daily changes in VPD during leaf development in high air humidity increase the stomatal responsiveness to darkness and dry air.

    Science.gov (United States)

    Arve, Louise E; Kruse, Ole Mathis Opstad; Tanino, Karen K; Olsen, Jorunn E; Futsæther, Cecilia; Torre, Sissel

    2017-04-01

    Previous studies have shown that plants developed under high relative air humidity (RH>85%) develop malfunctioning stomata and therefor have increased transpiration and reduced desiccation tolerance when transferred to lower RH conditions and darkness. In this study, plants developed at high RH were exposed to daily VPD fluctuations created by changes in temperature and/or RH to evaluate the potential improvements in stomatal functioning. Daily periods with an 11°C temperature increase and consequently a VPD increase (vpd: 0.36-2.37KPa) reduced the stomatal apertures and improved the stomatal functionality and desiccation tolerance of the rosette plant Arabidopsis thaliana. A similar experiment was performed with only a 4°C temperature increase and/or a RH decrease on tomato. The results showed that a daily change in VPD (vpd: 0.36-1.43KPa) also resulted in improved stomatal responsiveness and decreased water usage during growth. In tomato, the most effective treatment to increase the stomatal responsiveness to darkness as a signal for closure was daily changes in RH without a temperature increase. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. PYR/RCAR Receptors Contribute to Ozone-, Reduced Air Humidity-, Darkness-, and CO2-Induced Stomatal Regulation1[C][W][OA

    Science.gov (United States)

    Merilo, Ebe; Laanemets, Kristiina; Hu, Honghong; Xue, Shaowu; Jakobson, Liina; Tulva, Ingmar; Gonzalez-Guzman, Miguel; Rodriguez, Pedro L.; Schroeder, Julian I.; Broschè, Mikael; Kollist, Hannes

    2013-01-01

    Rapid stomatal closure induced by changes in the environment, such as elevation of CO2, reduction of air humidity, darkness, and pulses of the air pollutant ozone (O3), involves the SLOW ANION CHANNEL1 (SLAC1). SLAC1 is activated by OPEN STOMATA1 (OST1) and Ca2+-dependent protein kinases. OST1 activation is controlled through abscisic acid (ABA)-induced inhibition of type 2 protein phosphatases (PP2C) by PYRABACTIN RESISTANCE/REGULATORY COMPONENTS OF ABA RECEPTOR (PYR/RCAR) receptor proteins. To address the role of signaling through PYR/RCARs for whole-plant steady-state stomatal conductance and stomatal closure induced by environmental factors, we used a set of Arabidopsis (Arabidopsis thaliana) mutants defective in ABA metabolism/signaling. The stomatal conductance values varied severalfold among the studied mutants, indicating that basal ABA signaling through PYR/RCAR receptors plays a fundamental role in controlling whole-plant water loss through stomata. PYR/RCAR-dependent inhibition of PP2Cs was clearly required for rapid stomatal regulation in response to darkness, reduced air humidity, and O3. Furthermore, PYR/RCAR proteins seem to function in a dose-dependent manner, and there is a functional diversity among them. Although a rapid stomatal response to elevated CO2 was evident in all but slac1 and ost1 mutants, the bicarbonate-induced activation of S-type anion channels was reduced in the dominant active PP2C mutants abi1-1 and abi2-1. Further experiments with a wider range of CO2 concentrations and analyses of stomatal response kinetics suggested that the ABA signalosome partially affects the CO2-induced stomatal response. Thus, we show that PYR/RCAR receptors play an important role for the whole-plant stomatal adjustments and responses to low humidity, darkness, and O3 and are involved in responses to elevated CO2. PMID:23703845

  15. Mesophyll conductance and leaf carbon isotope composition of two high elevation conifers along an altitudinal gradient

    Science.gov (United States)

    Guo, J.; Beverly, D.; Cook, C.; Ewers, B.; Williams, D. G.

    2016-12-01

    Carbon isotope ratio values (δ13C) of conifer leaf material generally increases with elevation, potentially reflecting decreases in the leaf internal to ambient CO2 concentration ratio (Ci/Ca) during photosynthesis. Reduced stomatal conductance or increased carboxylation capacity with increasing elevation could account for these patterns. But some studies reported conifers δ13C increased with altitude consistently, but Ci/Ca did not significantly decrease and leaf nitrogen content remained constant with increasing of altitude in Central Rockies. Variation in leaf mesophyll conductance to CO2 diffusion, which influences leaf δ13C independently of effects related to stomatal conductance and carboxylation demand, might reconcile these conflicting observations. Leaf mass per unit area (LMA) increases with altitude and often correlates with δ13C and mesophyll conductance. Therefore, we hypothesized that increases in δ13C of conifers with altitude are controlled mainly by changes in mesophyll conductance. To test this hypothesis, leaf δ13C, photosynthetic capacity, leaf nitrogen content, LMA, and mesophyll conductance were determined on leaves of two dominant conifers (Pinus contorta and Picea engelmannii) along a 90-km transect in SE Wyoming at altitudes ranging from 2400 to 3200 m above sea level. Mesophyll conductance was determined by on-line 13C discrimination using isotope laser spectroscopy. We expected to observe relatively small differences in stomatal conductance and decreases in mesophyll conductance from lower and higher altitude sites. Such a pattern would have important implications for how differences in leaf δ13C values across altitude are interpreted in relation to forest water use and productivity from scaling of leaf-level water-use efficiency.

  16. Convergence and Divergence of Signaling Events in Guard Cells during Stomatal Closure by Plant Hormones or Microbial Elicitors

    Directory of Open Access Journals (Sweden)

    AGURLA SRINIVAS

    2016-08-01

    Full Text Available Dynamic regulation of stomatal aperture is essential for plants to optimize water use and CO2 uptake. Stomatal opening or closure is accompanied by the modulation of guard cell turgor. Among the events leading to stomatal closure by plant hormones or microbial elicitors, three signaling components stand out as the major converging points. These are reactive oxygen species (ROS, cytosolic free Ca2+ and ion channels. Once formed, the ROS and free Ca2+ of guard cells regulate both downstream and upstream events. A major influence of ROS is to increase the levels of NO and cytosolic free Ca2+ in guard cells. Although the rise in NO is an important event during stomatal closure, the available evidences do not support the description of NO as the point of convergence. The rise in ROS and NO would cause an increase of free Ca2+ and modulate ion channels, through a network of events, in such a way that the guard cells lose K+/Cl-/anions. The efflux of these ions decreases the turgor of guard cells and leads to stomatal closure. Thus, ROS, NO and cytosolic free Ca2+ act as points of divergence. The other guard cell components, which are modulated during stomatal closure are G-proteins, cytosolic pH, phospholipids and sphingolipids. However, the current information on the role of these components is not convincing so as to assign them as the points of convergence or divergence. The interrelationships and interactions of ROS, NO, cytosolic pH, and free Ca2+ are quite complex and need further detailed examination. Our review is an attempt to critically assess the current status of information on guard cells, while emphasizing the convergence and divergence of signaling components during stomatal closure. The existing gaps in our knowledge are identified to stimulate further research.

  17. Preparation and clinical application of indomethacin gel for medical treatment of stomatitis.

    Science.gov (United States)

    Momo, Kenji; Shiratsuchi, Tatsuko; Taguchi, Hiroyuki; Hashizaki, Kaname; Saito, Yoshihiro; Makimura, Mizue; Ogawa, Naotake

    2005-05-01

    The preparation and clinical applications of indomethacin (IM) gel were investigated in the treatment of stomatitis resulting from chemotherapy and radiotherapy for cancer. IM gel was prepared by adding various water-soluble polymers [hydroxypropyl cellulose (HPC), etc.] to IM aqueous solution. The release rate of IM from IM gels was found to decrease with increasing polymer concentration and viscosity and to follow a first-order reaction rate equation. The release rate of IM from the IM gel with HPC was decreased gradually with increasing polymer concentration and to be easily controllable compared with gels with other polymers. The time before pain relief occurred after application of the IM gel was slightly shorter and the duration of pain relief was longer compared with the IM aqueous solution. It was confirmed that IM gel is useful in the treatment of stomatitis.

  18. Does smoking really protect from recurrent aphthous stomatitis?

    Directory of Open Access Journals (Sweden)

    Faleh A Sawair

    2010-11-01

    Full Text Available Faleh A SawairFaculty of Dentistry, University of Jordan, Amman, JordanPurpose: To study the effect of smoking on the prevalence of recurrent aphthous stomatitis (RAS and to examine whether intensity and duration of smoking influence RAS lesions.Subjects and methods: A cross-sectional survey was conducted on a random sample of 1000 students of The University of Jordan, Amman, between May and September 2008. Sociodemographic factors and details about smoking habits and RAS in last 12 months were collected.Results: Annual prevalence (AP of RAS was 37.1%. Tobacco use was common among students: 30.2% were current smokers and 2.8% were exsmokers. AP was not significantly influenced by students’ age, gender, marital status, college, and household income but was significantly affected by place of living (P = 0.02 and presence of chronic diseases (P = 0.03. No significant difference in AP of RAS was found between smokers and nonsmokers. Cigarette smokers who smoked heavily and for a longer period of time had significantly less AP of RAS when compared to moderate smokers and those who smoked for a shorter period of time. The protective effect of smoking was only noticed when there was heavy cigarette smoking (>20 cigarettes/day (P = 0.021 or smoking for long periods of time (>5 years (P = 0.009. Nevertheless, no significant associations were found between intensity or duration of smoking and clinical severity of RAS lesions.Conclusion: The “protective effect” of smoking on RAS was dose- and time-dependent. When lesions are present, smoking had no effect on RAS severity.Keywords: recurrent aphthous stomatitis, smoking, prevalence

  19. Mechanisms of stomatal development: an evolutionary view

    Directory of Open Access Journals (Sweden)

    Vatén Anne

    2012-07-01

    Full Text Available Abstract Plant development has a significant postembryonic phase that is guided heavily by interactions between the plant and the outside environment. This interplay is particularly evident in the development, pattern and function of stomata, epidermal pores on the aerial surfaces of land plants. Stomata have been found in fossils dating from more than 400 million years ago. Strikingly, the morphology of the individual stomatal complex is largely unchanged, but the sizes, numbers and arrangements of stomata and their surrounding cells have diversified tremendously. In many plants, stomata arise from specialized and transient stem-cell like compartments on the leaf. Studies in the flowering plant Arabidopsis thaliana have established a basic molecular framework for the acquisition of cell fate and generation of cell polarity in these compartments, as well as describing some of the key signals and receptors required to produce stomata in organized patterns and in environmentally optimized numbers. Here we present parallel analyses of stomatal developmental pathways at morphological and molecular levels and describe the innovations made by particular clades of plants.

  20. Responsibility of non-stomatal limitations for the reduction of photosynthesis-response of photosynthesis and antioxidant enzyme characteristics in alfalfa (Medicago sativa L.) seedlings to water stress and rehydration

    Institute of Scientific and Technical Information of China (English)

    LI Wenrao; ZHANG Suiqi; SHAN Lun

    2007-01-01

    Water stress by polyethylene glycol (PEG)-6000 solution (Ψs=0.2 MPa,stress time:48 h,rehydration time:48 h) was performed in leaves of two alfalfa cultivar (Long-Dong and Algonquin) seedlings.Gas exchange parameters,chlorophyll fluorescence parameters,activity of antioxidant enzyme and photosynthetic pigment concentrations were measured to investigate the available photosynthetic and antioxidant enzyme response to variable water conditions as well as stomatal and non-stomatal limitations to photosynthesis.The results showed that non-stomatal limitations were responsible for the reduction of photosynthesis during water stress.At the beginning of water stress (12 h),water was lost and then the stomata closed rapidly,which resulted in a decrease of transpiration,net photosynthesis and CO2 diffusion.Therefore,when intercellular CO2 concentration and carboxylation efficiency decrease,water use efficiency and value of stomatal limitation would increase.However,the decline of net photosynthetic rate was faster than transpiration rate.At the same time,the maximal photochemical efficiency,potential activity of PSII reaction center and photochemical quenching of chlorophyll fluorescence declined significantly,the activity of antioxidant enzyme increased rapidly and the photosynthetic pigment concentrations changed slightly.The results also indicated that,at the initial period of stress,neither oxidative stress nor membrane lipid peroxidation was induced,nor were photosynthetic structures damaged,but photosynthetic functions were partly inhibited.Therefore,the stomatal limitation and non-stomatal limitations had the same responsibility for the reduction of photosynthesis.At the mid-late stage of water stress,net photosynthetic rate,stomatal conductance,maximal photochemical efficiency,potential activity of PSII reaction center and photochemical quenching of chlorophyll fluorescence decreased linearly with the decline of the relative water content.And the relative electron

  1. Experimental simulation of radio- and chemoradio stomatitis in rats.

    Science.gov (United States)

    Antushevich, A A; Grebenyuk, A N; Antushevich, A Y; Polevay, L P

    2013-04-01

    Experimental models of stomatitis developing in response to an isolated (radiation) and combined (radiation and chemical) exposure of experimental animals, were created. The severity of radiation-induced stomatitis was determined by the dose of radiation exposure. Additional exposure to a chemical factor (cyclophosphamide) augmented the destructive effect of ionizing radiation on the buccal mucosa of rats.

  2. A previously unknown zinc finger protein, DST, regulates drought and salt tolerance in rice via stomatal aperture control.

    Science.gov (United States)

    Huang, Xin-Yuan; Chao, Dai-Yin; Gao, Ji-Ping; Zhu, Mei-Zhen; Shi, Min; Lin, Hong-Xuan

    2009-08-01

    Abiotic stresses, such as drought and salinity, lead to crop growth damage and a decrease in crop yields. Stomata control CO(2) uptake and optimize water use efficiency, thereby playing crucial roles in abiotic stress tolerance. Hydrogen peroxide (H(2)O(2)) is an important signal molecule that induces stomatal closure. However, the molecular pathway that regulates the H(2)O(2) level in guard cells remains largely unknown. Here, we clone and characterize DST (drought and salt tolerance)-a previously unknown zinc finger transcription factor that negatively regulates stomatal closure by direct modulation of genes related to H(2)O(2) homeostasis-and identify a novel pathway for the signal transduction of DST-mediated H(2)O(2)-induced stomatal closure. Loss of DST function increases stomatal closure and reduces stomatal density, consequently resulting in enhanced drought and salt tolerance in rice. These findings provide an interesting insight into the mechanism of stomata-regulated abiotic stress tolerance, and an important genetic engineering approach for improving abiotic stress tolerance in crops.

  3. Rapid hydropassive opening and subsequent active stomatal closure follow heat-induced electrical signals in Mimosa pudica.

    Science.gov (United States)

    Kaiser, Hartmut; Grams, Thorsten E E

    2006-01-01

    In Mimosa pudica L., heat stimulation triggers leaflet folding in local, neighbouring and distant leaves. Stomatal movements were observed microscopically during this folding reaction and electrical potentials, chlorophyll fluorescence, and leaf CO(2)/H(2)O-gas exchange were measured simultaneously. Upon heat stimulation of a neighbouring pinna, epidermal cells depolarized and the stomata began a rapid and pronounced transient opening response, leading to an approximately 2-fold increase of stomatal aperture within 60 s. At the same time, net CO(2) exchange showed a pronounced transient decrease, which was followed by a similar drop in photochemical quantum yield at photosystem (PS) II. Subsequently, CO(2)-gas exchange and photochemical quantum yield recovered and stomata closed partly or completely. The transient and fast stomatal opening response is interpreted as a hydropassive stomatal movement caused by a sudden loss of epidermal turgor. Thus, epidermal cells appear to respond in a similar manner to heat-induced signals as the pulvinar extensor cells. The subsequent closing of the stomata confirms earlier reports that stomatal movements can be induced by electrical signals. The substantial delay (several minutes) of guard cell turgor loss compared with the immediate response of the extensor and epidermal cells suggests a different, less direct mechanism for transmission of the propagating signal to the guard cells.

  4. The Connexin40A96S mutation from a patient with atrial fibrillation causes decreased atrial conduction velocities and sustained episodes of induced atrial fibrillation in mice.

    Science.gov (United States)

    Lübkemeier, Indra; Andrié, René; Lickfett, Lars; Bosen, Felicitas; Stöckigt, Florian; Dobrowolski, Radoslaw; Draffehn, Astrid M; Fregeac, Julien; Schultze, Joachim L; Bukauskas, Feliksas F; Schrickel, Jan Wilko; Willecke, Klaus

    2013-12-01

    Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and a major cause of stroke. In the mammalian heart the gap junction proteins connexin40 (Cx40) and connexin43 (Cx43) are strongly expressed in the atrial myocardium mediating effective propagation of electrical impulses. Different heterozygous mutations in the coding region for Cx40 were identified in patients with AF. We have generated transgenic Cx40A96S mice harboring one of these mutations, the loss-of-function Cx40A96S mutation, as a model for atrial fibrillation. Cx40A96S mice were characterized by immunochemical and electrophysiological analyses. Significantly reduced atrial conduction velocities and strongly prolonged episodes of atrial fibrillation were found after induction in Cx40A96S mice. Analyses of the gating properties of Cx40A96S channels in cultured HeLa cells also revealed significantly lower junctional conductance and enhanced sensitivity voltage gating of Cx40A96S in comparison to Cx40 wild-type gap junctions. This is caused by reduced open probabilities of Cx40A96S gap junction channels, while single channel conductance remained the same. Similar to the corresponding patient, heterozygous Cx40A96S mice revealed normal expression levels and localization of the Cx40 protein. We conclude that heterozygous Cx40A96S mice exhibit prolonged episodes of induced atrial fibrillation and severely reduced atrial conduction velocities similar to the corresponding human patient.

  5. Steep Decrease of Gender Difference in DSM-IV Alcohol Use Disorder: A Comparison of Two Nation-wide Surveys Conducted 10 Years Apart in Korea.

    Science.gov (United States)

    Seong, Su Jeong; Hong, Jin Pyo; Hahm, Bong-Jin; Jeon, Hong Jin; Sohn, Jee Hoon; Lee, Jun Young; Cho, Maeng Je

    2015-11-01

    While decreasing trend in gender differences in alcohol use disorders was reported in Western countries, the change in Asian countries is unknown. This study aims to explore the shifts in gender difference in alcohol abuse (AA) and dependence (AD) in Korea. We compared the data from two nation-wide community surveys to evaluate gender differences in lifetime AA and AD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Face-to-face interviews using the Composite International Diagnostic Interview (CIDI) were applied to all subjects in 2001 (n=6,220) and 2011 (n=6,022). Male-to-female ratio of odds was decreased from 6.41 (95% CI, 4.81-8.54) to 4.37 (95% CI, 3.35-5.71) for AA and from 3.75 (95% CI, 2.96-4.75) to 2.40 (95% CI, 1.80-3.19) for AD. Among those aged 18-29, gender gap even became statistically insignificant for AA (OR, 1.59; 95% CI, 0.97-2.63) and AD (OR, 1.18; 95% CI, 0.80-2.41) in 2011. Men generally showed decreased odds for AD (0.55; 95% CI, 0.45-0.67) and women aged 30-39 showed increased odds for AA (2.13; 95% CI 1.18-3.84) in 2011 compared to 2001. Decreased AD in men and increased AA in women seem to contribute to the decrease of gender gap. Increased risk for AA in young women suggests needs for interventions.

  6. Absence of OsβCA1 causes CO2 deficit and affects leaf photosynthesis and stomatal response to CO2 in rice.

    Science.gov (United States)

    Chen, Taiyu; Wu, Huan; Wu, Jiemin; Fan, Xiaolei; Li, Xianghua; Lin, Yongjun

    2017-01-31

    Plants always adjust the opening of stomatal pores to adapt to the environments, such as [CO2 ], humidity and temperature. Low [CO2 ] will trigger the opening of stomatal pores to absorb extra CO2 . However, little is known about how CO2 supply affects the carbon fixation and opening of stomatal pores in rice. Here, a chloroplast-located β-carbonic anhydrase (β-CA) coding gene was found to be involved in carbon assimilation and CO2 -mediated stomatal pore response in rice. OsβCA1 was constitutively expressed in all tissues and its transcripts were induced by high [CO2 ] in leaves. Both T-DNA mutant and RNAi lines showed phenotypes of lower biomass and CA activities. The knock-out of OsβCA1 obviously decreased the photosynthesis capacity, as demonstrated by the increased CO2 compensation point and decreased light saturation point in the mutant; while the knock-out increased the opening ratio of stomatal pores and water loss rate. Moreover, the mutant showed a delayed response to low [CO2 ], and they could not be closed to the degree of wild plants even though the stomatal pores could rapidly respond to high [CO2 ]. Genome-wide gene expression analysis via RNA-seq demonstrated that the transcript abundance of the genes related to RuBisCO, photosystem compounds and opening of stomatal pores were globally up-regulated in the mutant. Taken together, the inadequate CO2 supply caused by the absence of OsβCA1 reduces photosynthesis efficiency, triggers the opening of stomatal pores and finally decreases their sensitivity to CO2 fluctuation. This article is protected by copyright. All rights reserved.

  7. Online CO2 and H2 O oxygen isotope fractionation allows estimation of mesophyll conductance in C4 plants, and reveals that mesophyll conductance decreases as leaves age in both C4 and C3 plants.

    Science.gov (United States)

    Barbour, Margaret M; Evans, John R; Simonin, Kevin A; von Caemmerer, Susanne

    2016-05-01

    Mesophyll conductance significantly, and variably, limits photosynthesis but we currently have no reliable method of measurement for C4 plants. An online oxygen isotope technique was developed to allow quantification of mesophyll conductance in C4 plants and to provide an alternative estimate in C3 plants. The technique is compared to an established carbon isotope method in three C3 species. Mesophyll conductance of C4 species was similar to that in the C3 species measured, and declined in both C4 and C3 species as leaves aged from fully expanded to senescing. In cotton leaves, simultaneous measurement of carbon and oxygen isotope discrimination allowed the partitioning of total conductance to the chloroplasts into cell wall and plasma membrane versus chloroplast membrane components, if CO2 was assumed to be isotopically equilibrated with cytosolic water, and the partitioning remained stable with leaf age. The oxygen isotope technique allowed estimation of mesophyll conductance in C4 plants and, when combined with well-established carbon isotope techniques, may provide additional information on mesophyll conductance in C3 plants.

  8. RNAi-Directed Downregulation of Vacuolar H+ -ATPase Subunit A Results in Enhanced Stomatal Aperture and Density in Rice

    OpenAIRE

    2013-01-01

    Stomatal movement plays a key role in plant development and response to drought and salt stress by regulating gas exchange and water loss. A number of genes have been demonstrated to be involved in the regulation of this process. Using inverse genetics approach, we characterized the function of a rice (Oryza sativa L.) vacuolar H(+)-ATPase subunit A (OsVHA-A) gene in stomatal conductance regulation and physiological response to salt and osmotic stress. OsVHA-A was constitutively expressed in ...

  9. Management of Recurrent Aphthous Stomatitis in Children.

    Science.gov (United States)

    Montgomery-Cranny, Jodie A; Wallace, Ann; Rogers, Helen J; Hughes, Sophie C; Hegarty, Anne M; Zaitoun, Halla

    2015-01-01

    Recurrent oral ulceration is common and may present in childhood. Causes of recurrent oral ulceration are numerous and there may be an association with underlying systemic disease. Recurrent aphthous stomatitis (RAS) is the most common underlying diagnosis in children. The discomfort of oral ulcers can impact negatively on quality of life of a child, interfering with eating, speaking and may result in missed school days. The role of the general dental practitioner is to identify patients who can be treated with simple measures in primary dental care and those who require assessment and treatment in secondary care. Management may include topical agents for symptomatic relief, topical corticosteroids and, in severe recalcitrant cases, systemic agents may be necessary.

  10. Comparison of stomatal characteristics and photosynthesis of polymorphic Populus euphratica leaves

    Institute of Scientific and Technical Information of China (English)

    ZHENG Caixia; QIU Jian; JIANG Chunning; YUE Ning; WANG Xiuqin; WANG Wanfu

    2007-01-01

    The leaf shapes of adult Populus euphratica vary from lanceolate to dentate broad-ovate.In order to find the mechanism regarding the ecological adaptation of the polymorphic leaves,the dentate broad-ovate,broad-ovate,and lanceolate leaves were chosen to study their stomatal and photosynthetic characteristics.It is observed that the stomas on the adaxial and abaxial epidermis of the same leaves open non-uniformly with similar densities.The stomatal densities are different among the three typical leaves,which decrease from broad-ovate to lanceolate leaves.Their stomatal sunken degree varied obviously,decreasing from broad-ovate to lanceolate leaves.The changes of the diurnal photosynthetic rate of the three typical leaves follow a single peak curve.The mean diurnal photosynthetic rates of these leaves rank from high to low as broad-ovate>dentate broad-ovate>lanceolate leaves.The light compensation points are similar in the three typical leaves,while the light saturation points vary obviously.The efficiency of solar energy conversion and potential activity of the PSⅡ in the leaves differ significantly,with the dentate broad-ovate leaves the highest.The results suggest that their leaf shapes,anatomic structures,and photosynthetic characteristics change during the leaf development.

  11. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature

    Science.gov (United States)

    Fraser, Lauchlan H.; Greenall, Amber; Carlyle, Cameron; Turkington, Roy; Friedman, Cynthia Ross

    2009-01-01

    Background and Aims Changes in rainfall and temperature brought about through climate change may affect plant species distribution and community composition of grasslands. The primary objective of this study was to test how manipulation of water and temperature would influence the plasticity of stomatal density and leaf area of bluebunch wheatgrass, Pseudoroegneria spicata. It was hypothesized that: (1) an increased water supply will increase biomass and leaf area and decrease stomatal density, while a reduced water supply will cause the opposite effect; (2) an increase in temperature will reduce biomass and leaf area and increase stomatal density; and (3) the combinations of water and temperature treatments can be aligned along a stress gradient and that stomatal density will be highest at high stress. Methods The three water supply treatments were (1) ambient, (2) increased approx. 30 % more than ambient through weekly watering and (3) decreased approx. 30 % less than ambient by rain shades. The two temperature treatments were (1) ambient and (2) increased approx. 1–3 °C by using open-top chambers. At the end of the second experimental growing season, above-ground biomass was harvested, oven-dried and weighed, tillers from bluebunch wheatgrass plants sampled, and the abaxial stomatal density and leaf area of tillers were measured. Key Results The first hypothesis was partially supported – reducing water supply increased stomatal density, but increasing water supply reduced leaf area. The second hypothesis was rejected. Finally, the third hypothesis could not be fully supported – rather than a linear response there appears to be a parabolic stomatal density response to stress. Conclusions Overall, the abaxial stomatal density and leaf area of bluebunch wheatgrass were plastic in their response to water and temperature manipulations. Although bluebunch wheatgrass has the potential to adapt to changing climate, the grass is limited in its ability to respond

  12. 水稻植株气孔分布的研究%Observations of the Stomatal Distribution in Rice Plant

    Institute of Scientific and Technical Information of China (English)

    李磊鑫

    2011-01-01

    Distribution of stomata in both epidermies of rice leaves was regular. Stomatal frequency in both epidermies of rice leaves decreased with leaf locations. Significant differences among rice types or varieties were found about Stomatal frequency in both epidermies of all leaf locations or between adaxial and abaxial epider-mies. Stomata of leaf sheath distributed among epidermal cells, Stomatal frequency in abaxial epidermies de-creased with leaf locations, presented a crosswise double peaks curve. From upper part to lower part, Stomatal frequency in one leaf sheath decreased.%试验详细研究了气孔密度在水稻上三叶及上三叶叶鞘界面层上的分布情况,气孔分布表现出一定的规律性,旨在为水稻高产栽培和高光效育种提供形态学、解剖学方面的参考依据.

  13. Evaluation of the effects of ozone on yield of Japanese rice (Oryza sativa L.) based on stomatal ozone uptake.

    Science.gov (United States)

    Yamaguchi, Masahiro; Hoshino, Daiki; Inada, Hidetoshi; Akhtar, Nahid; Sumioka, Chika; Takeda, Kenta; Izuta, Takeshi

    2014-01-01

    To evaluate the negative impact of ozone (O3) on Japanese crop plant yield based on cumulative stomatal O3 flux, a Japanese rice cultivar, Koshihikari, was exposed to O3 in O3-exposure chambers. Stomatal diffusive conductance to water vapour were measured during the experimental period. We parameterized and improved a stomatal diffusive conductance model by considering seasonal changes in stomatal diffusive conductance, as well as the acute effects of O3 on this variable. Our adjusted model accounted for 64% of the variation within the data set. Based on the results of linear regression analyses of the relationship between relative yield and cumulative O3 uptake, the negative impact of O3 on the yield of Koshihikari can be evaluated using cumulative O3 uptake with a threshold of 10 nmol O3 m(-2) projected leaf area s(-1) and an integration period of -300 to 100 °C days from anthesis.

  14. Muscarinic acetylcholine receptor is involved in acetylcholine regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In animal cells, action of acetylcholine depends on its binding with its two specific receptors on the plasma membrane: the nicotinic and muscarinic respectively. The present investigation has shown that agonists of muscarinic receptor (muscarine) could induce stomatal opening, while the antagonists (atropine) could block stomatal opening induced by acetylcholine. Their effects can only be realized in medium containing Ca2+, but not in medium containing K+. The results tend to reveal that the muscarinic receptor is involved in acetylcholine-induced stomatal movement.

  15. Have we been ignoring physiological plasticity and genetic variation in stomatal function as a significant source of error in models of water and carbon fluxes?

    Science.gov (United States)

    Wertin, T. M.; Wolz, K.; Richter, K.; Adorbo, M.; Betzelberger, A. M.; Leakey, A.

    2013-12-01

    Accurately predicting plant and ecosystem function across climatic and ecological gradients requires properly parameterized models of both net photosynthetic assimilation of CO2 and stomatal conductance. Photosynthesis models have been parameterized to account for physiological plasticity and genetic variation for decades. However, models describing physiological plasticity or genetic variation in the sensitivity of stomatal conductance to net photosynthetic CO2 assimilation (A), relative humidity (RH), and atmospheric [CO2] have rarely, if ever, been applied. There is no mechanistic basis for the prevailing assumption that models of stomatal conductance can share a universal parameterization for all C3 species. Twelve species of temperate trees were grown in a common garden to test species-specific sensitivity of stomatal conductance to A, RH and [CO2]. Additionally, a Salix and a Populus genotype, grown at three locations throughout the Eastern US in biofuels trails, were measured at three times during the growing season to test for temporal and spatial effects. Soybean was also grown at eight ozone concentrations to test for physiological plasticity in stomatal function. Laboratory-based gas exchange measurements were used to parameterize the widely used Ball et al. (1987) model of stomatal conductance and the Farquhar et al. (1980) model of photosynthesis. These models were coupled to each other and a leaf energy balance model in order to predict in situ leaf CO2 and water fluxes which were compared against field measurements. There was significant physiological plasticity and genetic variation in the sensitivity of stomatal conductance to A, RH and [CO2]. This was reflected in significant variation in parameters of the Ball et al. (1987) model, with the key slope parameter (m) ranging from more than 4-fold. Context-specific parameterization of this widely used stomatal conductance model reduced error in predictions of in situ leaf A and gs by up to 59

  16. Modulation of leaf conductance by root to shoot signaling under water stress in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Fan Yi-juan; Liu Qing; Wei Kai-fa; Li Bing-bing; Ren Hui-bo; Gao Zhi-hui; Jia Wen-suo

    2006-01-01

    Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the establishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomatal movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying (PRD)experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid (ABA) of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance,which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf temperatures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further investigation into the molecular mechanisms of the root to shoot signaling under water stress.

  17. The dilemma of saving water or being cool: What determines the stomatal response under a changing climate?

    Science.gov (United States)

    Haghighi, Erfan; Kirchner, James W.; Entekhabi, Dara

    2017-04-01

    Stomata play a critical role in terrestrial water and carbon cycles, regulating the trade-off between photosynthetic carbon gain and water loss in leaves. They adjust their aperture in response to a number of physiological and environmental factors, yet the mechanisms driving this response, particularly under climate extremes, remain poorly understood. Partial or complete stomatal closure reduces plant water stress under water-limited or high atmospheric evaporative demand conditions, but at the cost of reduced productivity, elevated heat, leaf shedding, and mortality. A proper account of such complex stomatal behavior is of particular importance for current ecosystem models that poorly capture observed vegetation responses in the context of climate change which is predicted to cause more frequent and intense temperature extremes along with an increase in the frequency of drought in many regions in the future. This study seeks to explore stomatal responses to environmental change accounted for by a varying soil-plant resistance under different atmospheric and soil moisture conditions. To this end, we developed a physically based transpiration model that couples stomatal control of leaf gas exchange to the leaf surface energy balance and the entire plant hydraulic system by considering the interdependence of the guard cell water potential (or turgor pressure) and transpiration rates. Model simulations of diurnal variations in transpiration rates were in good agreement with field observations, and facilitated quantitative prediction of stomatal and xylem flow regulation under a wide range of environmental conditions. Preliminary results demonstrate how soil and plant hydraulic conductances regulating stomatal opening and closure can help mitigate climatic water deficit (e.g., at midday) by boosting evaporative cooling. Our results are expected to advance physical understanding of the water cycle in the soil-plant-atmosphere continuum, and shed light on observed

  18. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

    Science.gov (United States)

    Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

    2011-06-01

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. Published by Elsevier Ltd.

  19. Vesicular stomatitis outbreak in the southwestern United States, 2012.

    Science.gov (United States)

    McCluskey, Brian J; Pelzel-McCluskey, Angela M; Creekmore, Lynn; Schiltz, John

    2013-09-01

    Vesicular stomatitis is a viral disease primarily affecting horses and cattle when it occurs in the United States. Outbreaks in the southwestern United States occur sporadically, with initial cases typically occurring in Texas, New Mexico, or Arizona and subsequent cases occurring in a northward progression. The viruses causing vesicular stomatitis can be transmitted by direct contact of lesioned animals with other susceptible animals, but transmission is primarily through arthropod vectors. In 2012, an outbreak of vesicular stomatitis in the United States occurred that was caused by Vesicular stomatitis New Jersey virus serotype. Overall, 51 horses on 36 premises in 2 states were confirmed positive. Phylogenetic analysis of the virus indicated that it was most closely related to viruses detected in the state of Veracruz, Mexico, in 2000.

  20. [Management of Stomatitis Associated with Treatment with Everolimus].

    Science.gov (United States)

    Ota, Yoshihide; Kurita, Hiroshi; Umeda, Masahiro

    2016-02-01

    Stomatitis is a characteristic adverse event of everolimus and other mTOR inhibitors, and occurs at a high incidence and impairs QOL owing to pain. Most cases of stomatitis are mild to moderate. However, when stomatitis becomes serious, it can interfere with the continuation of medication. Therefore, it is important to place more emphasis on the prevention as well as early detection and treatment. In addition, patient education is also important. The possible occurrence of stomatitis, its signs and symptoms, as well as the importance of oral care need to be thoroughly explained prior to starting treatment. In order to smoothly carry out these measures, it will also be essential that cancer-treating physicians coordinate and collaborate with dentists, nurses, and pharmacists. It is desirable to establish appropriate prevention and management methods on the basis of the results of the Phase III prospective study, Oral Care-BC, currently ongoing in Japan.

  1. Role of Sucrose in Emerging Mechanisms of Stomatal Aperture Regulation.

    Energy Technology Data Exchange (ETDEWEB)

    Outlaw, W. H.

    2000-09-15

    Focused on the second of 2 hypotheses that were proposed for testing that transpiration rate determines the extent to which suc accumulates in the GC wall providing a mechanism for regulating stomatal aperture size.

  2. Investigating Polyploidy: Using Marigold Stomates and Fingernail Polish.

    Science.gov (United States)

    Hunter, Kimberly L.; Leone, Rebecca S.; Kohlhepp, Kimberly; Hunter, Richard B.

    2002-01-01

    Describes a science activity on polyploidy targeting middle and high school students which can be used to discuss topics such as chromosomes, cells, plant growth, and functions of stomates. Integrates mathematics in data collection. (Contains 13 references.) (YDS)

  3. The association between psychological stress and recurrent aphthous stomatitis among medical and dental student cohorts in an educational setup in India

    Directory of Open Access Journals (Sweden)

    A Kaleswara Rao

    2015-01-01

    Full Text Available Introduction: Aphthous stomatitis is very common, affecting about 20-60% of the normal individuals to some degree. Although its etiology is not well-understood, it is multifactorial, and stress could be one possible triggering factor. Aims: The aim was to assess the prevalence of aphthous stomatitis and its association with psychological stress in both medical and dental graduate students. Materials and Methods: A cross-sectional study was conducted in 275 medical and dental student cohorts of an educational setup in India. Data were collected using a self-administered questionnaire, information regarding psychological stress, and 1-year period prevalence of aphthous stomatitis was collected. Data analysis was done with SPSS software version 20 (Chicago Inc., IL, USA. Categorical variables were compared using Chi-square test and comparison between mean stress scores and aphthous stomatitis was done with ANOVA and binary logistic regression was done. P ≤0.05 was considered as statistically significant. Results: The prevalence of aphthous stomatitis in the study population was 78.1% and males were more commonly affected than females. Among the student cohorts, final year MBBS and final year BDS students were highly affected than others, which is statistically significant. Conclusions: Stress increases the risk of aphthous stomatitis. Stress management strategies are necessary for medical and dental graduate students.

  4. Hydrogen peroxide-induced changes in intracellular pH of guard cells precede stomatal closure

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Epidermal bioassay demonstrated that benzylamine,a membrane-permeable weak base,can mimick hydrogen peroxide (H2O2) to induce stomatal closure,and butyric acid,a membrane-permeable weak acid,can partly abolish the H2O2-induced stomatal closure.Confocal pH mapping with the probe 5-(and-6)-carboxy seminaphthorhodafluor-1-acetoxymethylester (SNARF-1-AM) revealed that H2O2 leads to rapid changes in cytoplasmic and vacuolar pH in guard cells of Vicia faba L,i.e.alkalinization of cytoplasmic areas occur red in parallel with a decrease of the vacuolar pH,and that butyric acid pretreatment can abolish alkalinization of cytoplasmic areas and acidification of vacuolar areas of guard cells challenged with H2O2.These results imply that the alkalinization of cytoplasm via efflux of cytosol protons into the vacuole in guard cells challenged with H2O2 is important at an early stage in the signal cascade leading to stomatal closure.

  5. Development of a novel triamcinolone acetonide-loaded spray solution for the treatment of stomatitis.

    Science.gov (United States)

    Kim, Dong Wuk; Kim, Yong-Il; Ud Din, Fakhar; Cho, Kwan Hyung; Kim, Jong Oh; Choi, Han-Gon

    2014-07-01

    To develop a novel triamcinolone acetonide (TAA)-loaded spray for the treatment of stomatitis, several spray solutions were prepared using various amounts of TAA, Eudragit L100 (Eudragit L) and PEG 400, and 100 ml ethanol. Their viscosity and spraying potential were investigated, with the result that the spraying threshold was 9.5 cP. The effect of PEG 400 on the properties of films formed after spraying was assessed. Its anti-inflammatory effect in mice was evaluated and compared to a commercial product. As the PEG 400 concentration increased, the film elongation and washability by the saliva solution increased, and tensile strength decreased. PEG 400 had little effect on mucoadhesive force and drug release. The TAA-loaded spray solution containing TAA, Eudragit L, PEG 400 and ethanol at the ratio of 1:6:3:100 (w/w/w/v) was easy to spray onto stomatitis lesions in the mouth via a spraying vessel incorporating a long straw. After spraying, the TAA-loaded spray formed a film with suitable elongation, tensile strength and washability that attached onto the mucosal membrane and released the drug. Moreover, it had excellent anti-inflammatory properties, similar to those of the commercial product. Thus, this novel TAA-loaded spray solution was easy to administer, had good film properties and excellent anti-inflammatory efficacy, and is therefore a potential candidate for the treatment of stomatitis.

  6. Immunohistological evaluation of feline herpesvirus-1 infection in feline eosinophilic dermatoses or stomatitis.

    Science.gov (United States)

    Lee, Meichet; Bosward, Katrina L; Norris, Jacqueline M

    2010-02-01

    This study used immunohistochemistry (IHC) and histopathology to evaluate the presence of feline herpesvirus-1 (FHV-1) in feline cases of 'eosinophilic granuloma complex' (EGC) or other eosinophilic dermatoses or stomatitis, diagnosed at the Veterinary Pathology Diagnostic Service, University of Sydney between January 1996 and June 2008. Two of the 30 cases (6.6%) examined showed positive immunoreactivity to FHV-1 using IHC. Intranuclear inclusion bodies were also detected on histopathological examination of haematoxylin and eosin stained sections of both cases but were very difficult to find. Therefore, FHV-1 is uncommonly associated with EGC or other eosinophilic dermatoses or stomatitis in Sydney. However, misdiagnosis as an EGC lesion or other eosinophilic dermatoses may occur if inclusion bodies are overlooked or absent on histopathology and this may significantly decrease the chance of a favourable treatment outcome. FHV-1 should be considered in cats with severe ulcerative cutaneous or oral lesions, unresponsive to corticosteroid treatment, with or without concurrent or historical signs of upper respiratory tract or ocular disease more typical of FHV-1. IHC may be helpful in differentiating FHV-1 dermatitis or stomatitis from other eosinophilic lesions, which is of vital clinical and therapeutic importance.

  7. Comparison of Several Models for Calculating Ozone Stomatal Fluxes on a Mediterranean Wheat Cultivar (Triticum durum Desf. cv. Camacho

    Directory of Open Access Journals (Sweden)

    Daniel de la Torre Llorente

    2007-01-01

    Full Text Available Ozone stomatal fluxes were modeled for a 3-year period following different approaches for a commercial variety of durum wheat (Triticum durum Desf. cv. Camacho at the phenological stage of anthesis. All models performed in the same range, although not all of them afforded equally significant results. Nevertheless, all of them suggest that stomatal conductance would account for the main percentage of ozone deposition fluxes. A new modeling approach was tested, based on a 3-D architectural model of the wheat canopy, and fairly accurate results were obtained. Plant species-specific measurements, as well as measurements of stomatal conductance and environmental parameters, were required. The method proposed for calculating ozone stomatal fluxes (FO3_3-D from experimental gs data and modeling them as a function of certain environmental parameters in conjunction with the use of the YPLANT model seems to be adequate, providing realistic estimates of the canopy FO3_3-D, integrating and not neglecting the contribution of the lower leaves with respect to the flag leaf, although a further development of this model is needed.

  8. Use of sap flow measurements to validate stomatal functions for mature beech (Fagus sylvatica) in view of ozone uptake calculations.

    Science.gov (United States)

    Braun, Sabine; Schindler, Christian; Leuzinger, Sebastian

    2010-09-01

    For a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. Because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. This technique was applied in three beech (Fagus sylvatica) stands in Switzerland. A canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. It represents mainly stomatal conductance as the boundary layer resistance in forests is usually small. Based on this relative conductance, stomatal functions to describe the dependence on light, temperature, vapour pressure deficit and soil moisture were derived using multivariate nonlinear regression. These functions were validated by comparison with conductance values directly estimated from sap flow. The results corroborate the current flux parameterization for beech used in the DO3SE model.

  9. Ageing exacerbates damage of systemic and salivary neutrophils from patients presenting Candida-related denture stomatitis

    Directory of Open Access Journals (Sweden)

    Porto Vinicius

    2009-03-01

    Full Text Available Abstract Background Ageing leads to a decline in the function of the immune system, increasing the body's susceptibility to infections through the impairment of T-cells, macrophages, neutrophils and dendritic cells Denture stomatitis is a primary oral disease affecting elderly denture wearers. The major etiologic factor involved in this pathology is the infection by Candida albicans, an opportunistic pathogen that causes local and disseminated diseases in immunosuppressed humans. Neutrophils play a critical role in the immune response against C. albicans and are continually present in the salivary fluid and in the blood. The aim of this study was to determine ageing-related changes in salivary and blood neutrophils and their potential implications in Candida-related denture stomatitis. Results Our results showed a lower number of neutrophils in the saliva from patients presenting Candida-related denture stomatitis in comparison to their matched controls. Furthermore, fewer neutrophils were isolated from the saliva of aged control individuals in comparison to matched younger subjects. CXCR1, CD62L and CD11b expression were significantly greater on systemic neutrophils from younger control individuals. Elderly individuals showed more apoptotic salivary neutrophils and lower GM-CSF levels than younger ones, regardless of the occurrence of Candida infection. On the other hand, CXCL-8 concentrations were higher in the saliva from elderly individuals. Besides, TNF-α was detected at elevated levels in the saliva from infected elderly subjects. Salivary neutrophils from elderly and young patients presented impaired phagocytic activity against C. albicans. However, just systemic neutrophils from elderly showed decreased phagocytosis when compared to the younger ones, regardless of the occurrence of infection. In addition, neutrophils from aged individuals and young patients presented low fungicidal activity. Conclusion The data suggests that the Candida

  10. Dark Stomatal Movement in Sunflowers in Response to Illumination under Nitrogen.

    Science.gov (United States)

    Couchat, P; Lasceve, G; Audouin, P

    1982-04-01

    Experiments were performed on intact sunflowers (Helianthus annuus) placed in a specially designed experimental chamber which allows instantaneous modifications of the atmospheric composition without changing any other conditions. After one night in normal conditions, the plant was illuminated under pure nitrogen atmosphere; the opening stomatal movement, measured as a transpiration rate variation, was inhibited. After an anoxia time period not exceeding one hour, the light was turned off and normal air restored. The stomatal movement was no longer inhibited, and a transient increase in the transpiration rate, referred to here as the postillumination transpiration peak (PITP), was observed.The quantity of transpired water during the PITP can be related to the total incident light energy supplied during the light-nitrogen period. Furthermore, the addition of a dark-nitrogen period between the light-nitrogen and dark-air periods caused the PITP to decrease. The PITP is almost suppressed after a 20-minute dark-nitrogen period.It is shown that the PITP does not result from a hydropassive mechanism but is metabolically controlled. Moreover, it seems that the PITP is not due to a CO(2)-suppression effect during the light-nitrogen period.The results are interpreted in terms of stomatal mechanism. The metabolites leading to PITP originate from the reducing equivalents created during the light-nitrogen period. They could be synthesized at the beginning of the PITP period (darkness under normal air) or during the dark-nitrogen plus CO(2) period between the light-nitrogen and PITP periods. The results obtained are related to the first steps of classical photoactive stomatal opening.

  11. Stomatitis sub-prosthesis in patients with superior dental prosthesis

    Directory of Open Access Journals (Sweden)

    Antonia Martina Francisco Local

    2009-04-01

    Full Text Available Background: The stomatitis sub-prosthesis is one of the most frequent changes in hard palate mucous membrane in patients with mucous-supported dental prosthesis. It can be caused by multiple factors, which makes its study and prognosis more difficult. Objective: To describe the occurrence of stomatitis sub-prosthesis and its causes in patients with superior dental prosthesis. Method: Descriptive study including all the patients with superior dental prosthesis examined in the odontology consultation “Barrio Adentro” in the state of Miranda, Venezuela, from November, 2005 to March, 2006. The analysed variables were: age, sex, stomatitis level, teeth brushing frequency, prosthesis condition and use, palate mucous condition and frequency of odontology consultations. Results: 89 patients were attended, more 50% of them had superior dental prosthesis and presented stomatitis sub-prosthesis; the group between 35 and 59 years was the most affected, mainly females. Sub-prosthesis stomatitis type II was the most common and the main causes included constant use of the prosthesis and loose prosthesis. Buccal hygiene was not adequate in these patients. Most of them declared never attending to the dentist, or just when presenting some particular problem. Conclusion: Stomatitis prevalence was related with incorrect hygiene habits and lack of knowledge; it shows the importance of performing educative tasks to reduce this disease incidence.  

  12. Short-term water stress impacts on stomatal, mesophyll and biochemical limitations to photosynthesis differ consistently among tree species from contrasting climates.

    Science.gov (United States)

    Zhou, Shuangxi; Medlyn, Belinda; Sabaté, Santiago; Sperlich, Dominik; Prentice, I Colin

    2014-10-01

    Predicting the large-scale consequences of drought in contrasting environments requires that we understand how drought effects differ among species originating from those environments. A previous meta-analysis of published experiments suggested that the effects of drought on both stomatal and non-stomatal limitations to photosynthesis may vary consistently among species from different hydroclimates. Here, we explicitly tested this hypothesis with two short-term water stress experiments on congeneric mesic and xeric species. One experiment was run in Australia using Eucalyptus species and the second was run in Spain using Quercus species as well as two more mesic species. In each experiment, plants were grown under moist conditions in a glasshouse, then deprived of water, and gas exchange was monitored. The stomatal response was analysed with a recently developed stomatal model, whose single parameter g1 represents the slope of the relationship between stomatal conductance and photosynthesis. The non-stomatal response was partitioned into effects on mesophyll conductance (gm), the maximum Rubisco activity (Vcmax) and the maximum electron transport rate (Jmax). We found consistency among the drought responses of g1, gm, Vcmax and Jmax, suggesting that drought imposes limitations on Rubisco activity and RuBP regeneration capacity concurrently with declines in stomatal and mesophyll conductance. Within each experiment, the more xeric species showed relatively high g1 under moist conditions, low drought sensitivity of g1, gm, Vcmax and Jmax, and more negative values of the critical pre-dawn water potential at which Vcmax declines most steeply, compared with the more mesic species. These results indicate adaptive interspecific differences in drought responses that allow xeric tree species to continue transpiration and photosynthesis for longer during periods without rain.

  13. Delayed transmission selects for increased survival of vesicular stomatitis virus.

    Science.gov (United States)

    Wasik, Brian R; Bhushan, Ambika; Ogbunugafor, C Brandon; Turner, Paul E

    2015-01-01

    Life-history theory predicts that traits for survival and reproduction cannot be simultaneously maximized in evolving populations. For this reason, in obligate parasites such as infectious viruses, selection for improved between-host survival during transmission may lead to evolution of decreased within-host reproduction. We tested this idea using experimental evolution of RNA virus populations, passaged under differing transmission times in the laboratory. A single ancestral genotype of vesicular stomatitis virus (VSV), a negative-sense RNA Rhabdovirus, was used to found multiple virus lineages evolved in either ordinary 24-h cell-culture passage, or in delayed passages of 48 h. After 30 passages (120 generations of viral evolution), we observed that delayed transmission selected for improved extracellular survival, which traded-off with lowered viral fecundity (slower exponential population growth and smaller mean plaque size). To further examine the confirmed evolutionary trade-off, we obtained consensus whole-genome sequences of evolved virus populations, to infer phenotype-genotype associations. Results implied that increased virus survival did not occur via convergence; rather, improved virion stability was gained via independent mutations in various VSV structural proteins. Our study suggests that RNA viruses can evolve different molecular solutions for enhanced survival despite their limited genetic architecture, but suffer generalized reproductive trade-offs that limit overall fitness gains. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  14. A review on the oxidative stress in recurrent aphtous stomatitis

    Directory of Open Access Journals (Sweden)

    Mehryari Mahsa

    2015-01-01

    Full Text Available   Background and Aims: The purpose of the present study was to review the studies regarding serological and salivary oxidant / antioxidant status in patients with recurrent aphthous stomatitis (RAS.   Materials and Methods: The literature was searched using key words RAS, Antioxidants, Saliva, Hematinic (s and Hematinic Acid in the last 10 years, particularly the recent 3 years (2010-2013. At total of 37 clinical trials, 18 case-control articles were selected and evaluated; fulfilling the requirements as the RAS patients having at least 3 oral aphthous attack per year. The exclusion criteria included systemic as well as periodontal diseases, iron deficiency associated anemia, medication usage and smoking.   Conclusion: Almost all lipid-peroxidation studies in serum and saliva were manifested by an increase of malondialdehyde (MDA concentration in RAS patients compared with controls. This would indicate the role of reactive oxygen species (ROS in the etiology of the disease. Serum trace elements (Zn, Se were reduced and Cu was increased in RAS patients in comparison with control individuals. A decreased serum superoxide dismutase (SOD and an increased salivary SOD were observed in all RAS patients. Catalase (CAT and uric acid (UA analyses were non-inclusive. Levels of paraoxonase and arylesterase as well as antioxidant vitamins (A, E, C were lower in RAS patients than that of controls.

  15. A photosynthesis-based two-leaf canopy stomatal ...

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorology and air quality modeling system—WRF/CMAQ (Weather Research and Forecast model and Community Multiscale Air Quality model). The photosynthesis-based model for PX LSM (PX PSN) is evaluated at a FLUXNET site for implementation against different parameterizations and the current PX LSM approach with a simple Jarvis function (PX Jarvis). Latent heat flux (LH) from PX PSN is further evaluated at five FLUXNET sites with different vegetation types and landscape characteristics. Simulated ozone deposition and flux from PX PSN are evaluated at one of the sites with ozone flux measurements. Overall, the PX PSN simulates LH as well as the PX Jarvis approach. The PX PSN, however, shows distinct advantages over the PX Jarvis approach for grassland that likely result from its treatment of C3 and C4 plants for CO2 assimilation. Simulations using Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) rather than LAI measured at each site assess how the model would perform with grid averaged data used in WRF/CMAQ. MODIS LAI estimates degrade model performance at all sites but one site having exceptionally old and tall trees. Ozone deposition velocity and ozone flux along with LH

  16. A photosynthesis-based two-leaf canopy stomatal ...

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorology and air quality modeling system—WRF/CMAQ (Weather Research and Forecast model and Community Multiscale Air Quality model). The photosynthesis-based model for PX LSM (PX PSN) is evaluated at a FLUXNET site for implementation against different parameterizations and the current PX LSM approach with a simple Jarvis function (PX Jarvis). Latent heat flux (LH) from PX PSN is further evaluated at five FLUXNET sites with different vegetation types and landscape characteristics. Simulated ozone deposition and flux from PX PSN are evaluated at one of the sites with ozone flux measurements. Overall, the PX PSN simulates LH as well as the PX Jarvis approach. The PX PSN, however, shows distinct advantages over the PX Jarvis approach for grassland that likely result from its treatment of C3 and C4 plants for CO2 assimilation. Simulations using Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) rather than LAI measured at each site assess how the model would perform with grid averaged data used in WRF/CMAQ. MODIS LAI estimates degrade model performance at all sites but one site having exceptionally old and tall trees. Ozone deposition velocity and ozone flux along with LH

  17. Recurrent aphthous stomatitis: a case report

    Directory of Open Access Journals (Sweden)

    Xiomara Serpa-Romero

    2016-07-01

    Full Text Available Recurrent aphthosus stomatitis is an alteration of the oral mucosa in some cases associated with depression of the immune system that affects the tissue response at the level of the epithelium, triggering repetitive clinical picture of small and medium ulcers (3-5 mm which necrotic presented erythematous background and lasting no more than 15 days. The picture becomes recurrent, symptomatic, compromising the health of the patient who consults again with the same characteristics in oral cavity. The literature associates the process with hormonal changes, trauma, prolonged intake of medications, and stress. A case of female patient 53, who attends the service of dentistry to present multiple oral thrush that hard to swallow, drooling and feverish marked presents in Santa Marta, at the Center for Implantology and Oral Rehabilitation. According to the interrogation and clinical examination it is associated with a reactive inflammatory process caused by the intake of drugs to treat infectious or viral process, which is given the presumptive diagnosis of erythema drug. Any medication intake was suspended and additional tests are ordered antinuclear antibodies

  18. Drought effects on hydraulic conductivity and xylem vulnerability to embolism in diverse species and provenances of Mediterranean cedars.

    Science.gov (United States)

    Ladjal, Mehdi; Huc, Roland; Ducrey, Michel

    2005-09-01

    We studied hydraulic traits of young plants of the Mediterranean cedar species Cedrus atlantica (Endl.) G. Manetti ex Carrière (Luberon, France), C. brevifolia (Hook. f.) Henry (Cyprus), C. libani A. Rich (Hadeth El Jebbe, Lebanon) and C. libani (Armut Alani, Turkey). With an optimum water supply, no major differences were observed among species or provenances in either stem hydraulic conductivity (Ks) or leaf specific conductivity (Kl) measured on the main shoot. A moderate soil drought applied for 10 weeks induced marked acclimation through a reduction in Ks, particularly in the Lebanese provenance of C. libani, and a decrease in tracheid lumen size in all species. Cedrus atlantica, which had the smallest tracheids, was the species most vulnerable to embolism: a 50% loss in hydraulic conductivity (PsiPLC50) occurred at a water potential of -4.4 MPa in the well-watered treatment, and at -6.0 MPa in the moderate drought treatment. In the other species, PsiPLC50 was unaffected by moderate soil drought, and only declined sharply at water potentials between -6.4 and -7.5 MPa in both irrigation treatments. During severe drought, Ks of twigs and stomatal conductance (g(s)) were measured simultaneously as leaf water potential declined. For all species, lower vulnerability to embolism based on loss of Ks was recorded on current-year twigs. The threshold for stomatal closure (10% of maximum g(s)) was reached at a predawn water potential (Psi(pd)) of -2.5 MPa in C. atlantica (Luberon) and at -3.1 MPa in C. libani (Lebanon), whereas the other provenance and species had intermediate Psi(pd) values. Cedrus brevifolia, with a Psi(pd) (-3.0 MPa) close to that of C. libani (Lebanon), had the highest stomatal conductance of the study species. The importance of a margin of safety between water potential causing stomatal closure and that causing xylem embolism induction is discussed.

  19. Stomatal or non-stomatal limitation of photosynthesis of spring wheat flag leaf at late growth stages under natural conditions in semiarid rainfed regions%自然条件下半干旱雨养春小麦生育后期旗叶光合的气孔和非气孔限制

    Institute of Scientific and Technical Information of China (English)

    杨泽粟; 张强; 郝小翠

    2015-01-01

    . Ci decreased in the forenoon and slowly increased in the afternoon. This was attributed not only to photosynthetic consumption and stomatal conductance limitation, but also to mesophyll conductance limitation. Pn and gs were highly correlated at both growth stages, with correlation coefficients (R2) of 0.916 and 0.945, respectively. gs generally limited Pn at both heading and filling stages, with stomatal limitation indexes of 0.64 and 0.63, respectively. At heading stage, gs was highly sensitive to VPD. For this reason, there was obvious stomatal limitation in the afternoon due to induced water deficit by high transpiration rate. At filling stage, midday depression was mainly caused by stomatal closure due to strong radiation and high VPD. Besides this, there was somewhat non-stomatal limitation during midday depression. Due to declining sensitivity of gs to VPD and midday depression strategy, stomatal limitation decreased from heading stage to filling stage. This contributed to higher Pn of flag leaves of spring wheat in semiarid regions and thereby guaranteed good harvest.

  20. Plasticity in maximum stomatal conductance constrained by negative correlation between stomatal size and density: an analysis using Eucalyptus globulus

    National Research Council Canada - National Science Library

    Franks, Peter J; Drake, Paul L; Beerling, David J

    2009-01-01

    .... However, using basic equations for gas diffusion through stomata of different sizes, we show that a negative correlation between S and D offers several advantages, including plasticity in gwmax...

  1. 水分胁迫对水稻叶片气孔密度、大小 及净光合速率的影响%Effect of Water Stress on Stomatal Density, Length width and Net Rate in Rice Leaves

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The expperiment results showed that water stress made stomatal density of flag leaves increase and stomatal length, stomatal width decrease obviously. The stomatal density had a significant negative correlation with the stomatal length and the stomatal width. And the stomatal length was positively correlated with the stomatal width. The net photosynthetic rate of flag leaves also decreased under the water stress and had a significant negative correlation with stomatal dcnsity.%在水分胁迫下,水稻叶片的气孔密度明量增大,气孔的长、宽明量减小。气孔密度与气孔长度、宽度呈量著的负相关(r=-0.90*,n=7)、而气孔长度和宽度呈显著的正相关(r=0.71*,n=7)。在水分胁迫下,水稻叶片的净光合速率也量著下降,并表现出与气孔密度呈量著负相关(r=-0.89.n=7)。

  2. Chronic gingivitis and aphthous stomatitis relationship hypothesis: A neuroimmunobiological approach

    Directory of Open Access Journals (Sweden)

    Chiquita Prahasanti

    2009-03-01

    Full Text Available Background: Traumatic injuries to the oral mucosa in fixed orthodontic patients are common, especially in the first week of bracket placement, and occasionally lead to the development of aphthous stomatitis or ulcers. Nevertheless, these lesions are selflimiting. Purpose: The objective of this study is to reveal the connection between chronic gingivitis and aphthous stomatitis which is still unclear. Case: A patient with a persistent lesion for more than six months. Case Management: RAS was treated with scaling procedure, the gingival inflammation was healed. However, in this case report, despite the appropriate management procedures had been done, the lesion still worsen and became more painful. Moreover, the symptoms did not heal for more than two weeks. Actually, they had been undergone orthodontic treatment more than six months and rarely suffered from aphthous stomatitis. Coincidentally, at that time they also suffered from chronic gingivitis. It was interesting that after scaling procedures, the ulcer subsides in two days. Conclusion: Recently, the neuroimmunobiological researches which involved neurotransmitters and cytokines on cell-nerve signaling, and heat shock proteins in gingivitis and stomatitis are in progress. Nevertheless, they were done separately, thus do not explain the interrelationship. This proposed new concept which based on an integrated neuroimmunobiological approach could explain the benefit of periodontal treatment, especially scaling procedures, for avoiding prolonged painful episodes and unnecessary medications in aphthous stomatitis. However, for widely acceptance of the chronic gingivitis and aphthous stomatitis relationship, further clinical and laboratory study should be done. Regarding to the relatively fast healing after scaling procedures in this case report; it was concluded that the connection between chronic gingivitis and aphthous stomatitis is possible.

  3. Mucosal and salivary microbiota associated with recurrent aphthous stomatitis.

    Science.gov (United States)

    Kim, Yun-Ji; Choi, Yun Sik; Baek, Keum Jin; Yoon, Seok-Hwan; Park, Hee Kyung; Choi, Youngnim

    2016-04-01

    Recurrent aphthous stomatitis (RAS) is a common oral mucosal disorder of unclear etiopathogenesis. Although recent studies of the oral microbiota by high-throughput sequencing of 16S rRNA genes have suggested that imbalances in the oral microbiota may contribute to the etiopathogenesis of RAS, no specific bacterial species associated with RAS have been identified. The present study aimed to characterize the microbiota in the oral mucosa and saliva of RAS patients in comparison with control subjects at the species level. The bacterial communities of the oral mucosa and saliva from RAS patients with active lesions (RAS, n = 18 for mucosa and n = 8 for saliva) and control subjects (n = 18 for mucosa and n = 7 for saliva) were analyzed by pyrosequencing of the 16S rRNA genes. There were no significant differences in the alpha diversity between the controls and the RAS, but the mucosal microbiota of the RAS patients showed increased inter-subject variability. A comparison of the relative abundance of each taxon revealed decreases in the members of healthy core microbiota but increases of rare species in the mucosal and salivary microbiota of RAS patients. Particularly, decreased Streptococcus salivarius and increased Acinetobacter johnsonii in the mucosa were associated with RAS risk. A dysbiosis index, which was developed using the relative abundance of A. johnsonii and S. salivarius and the regression coefficients, correctly predicted 83 % of the total cases for the absence or presence of RAS. Interestingly, A. johnsonii substantially inhibited the proliferation of gingival epithelial cells and showed greater cytotoxicity against the gingival epithelial cells than S. salivarius. RAS is associated with dysbiosis of the mucosal and salivary microbiota, and two species associated with RAS have been identified. This knowledge may provide a diagnostic tool and new targets for therapeutics for RAS.

  4. Evolutionary Conservation of ABA Signaling for Stomatal Closure in Ferns.

    Science.gov (United States)

    Cai, Shengguan; Chen, Guang; Wang, Yuanyuan; Huang, Yuqing; Marchant, Blaine; Wang, Yizhou; Yang, Qian; Dai, Fei; Hills, Adrian; Franks, Peter J; Nevo, Eviatar; Soltis, Doug; Soltis, Pamela; Sessa, Emily; Wolf, Paul G; Xue, Dawei; Zhang, Guoping; Pogson, Barry J; Blatt, Mike R; Chen, Zhong-Hua

    2017-02-23

    ABA-driven stomatal regulation reportedly evolved after the divergence of ferns, during the early evolution of seed plants approximately 360 Mya. This hypothesis is based on the observation that the stomata of certain fern species are unresponsive to ABA, but exhibit passive hydraulic control. However, ABA-induced stomatal closure was detected in some mosses and lycophytes. Here, we observed that a number of ABA signaling and membrane transporter protein families diversified over the evolutionary history of land plants. The aquatic ferns Azolla filiculoides and Salvinia cucullata have representatives of 23 families of proteins orthologous to those of Arabidopsis thaliana and all other land plant species studied. Phylogenetic analysis of the key ABA signaling proteins indicates an evolutionarily conserved stomatal response to ABA. Moreover, comparative transcriptomic analysis has identified a suite of ABA responsive genes that differentially expressed in a terrestrial fern species, Polystichum proliferum. These genes encode proteins associated with ABA biosynthesis, transport, reception, transcription, signaling, and ion and sugar transport, which fit the general ABA signaling pathway constructed from Arabidopsis thaliana and Hordeum vulgare. The retention of these key ABA-responsive genes could have had a profound effect on the adaptation of ferns to dry conditions. Furthermore, stomatal assays have shown the primary evidence for ABA-induced closure of stomata in two terrestrial fern species P. proliferum and Nephrolepis exaltata. In summary, we report new molecular and physiological evidence for the presence of active stomatal control in ferns.

  5. Stomatal density and stomatal index as indicators of paleoatmospheric CO(2) concentration.

    Science.gov (United States)

    Royer, D L.

    2001-03-01

    A growing number of studies use the plant species-specific inverse relationship between atmospheric CO(2) concentration and stomatal density (SD) or stomatal index (SI) as a proxy for paleo-CO(2) levels. A total of 285 previously published SD and 145 SI responses to variable CO(2) concentrations from a pool of 176 C(3) plant species are analyzed here to test the reliability of this method. The percentage of responses inversely responding to CO(2) rises from 40 and 36% (for SD and SI, respectively) in experimental studies to 88 and 94% (for SD and SI, respectively) in fossil studies. The inconsistent experimental responses verify previous concerns involving this method, however the high percentage of fossil responses showing an inverse relationship clearly validates the method when applied over time scales of similar length. Furthermore, for all groups of observations, a positive relationship between CO(2) and SD/SI is found in only stomatal initiation, although the mechanism may involve genetic adaptation and therefore is often not clearly expressed under short CO(2) exposure times.Experimental responses of SD and SI based on open-top chambers (OTCs) inversely relate to CO(2) less often than greenhouse-based responses (P<0.01 for both SD and SI), and should be avoided when experimental responses are required for CO(2) reconstructions. In the combined data set, hypostomatous species follow the inverse relationship more often than amphistomatous species (56 vs. 44% for SD; 69 vs. 32% for SI; P<0.03 for both comparisons). Both the SD and SI of fossil responses are equally likely to inversely relate to CO(2) when exposed to elevated versus subambient CO(2) concentrations (relative to today). This result casts doubt on previous claims that stomata cannot respond to CO(2) concentrations above present-day levels. Although the proportion of SD and SI responses inversely relating to CO(2) are similar, SD is more

  6. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    Science.gov (United States)

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S

    2010-06-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests.

  7. Oral hygiene habits, denture plaque, presence of yeasts and stomatitis in institutionalised elderly in Lothian, Scotland

    DEFF Research Database (Denmark)

    Schou, L; Wight, C; Cumming, C

    1987-01-01

    The purpose of the present study was to examine the relation between oral hygiene habits, denture plaque, presence of yeasts and stomatitis in institutionalised elderly. A sample of 201 residents, 48-99 yr of age (mean age 82 yr), was selected from four different institutions in Lothian, Scotland....... Clinical recordings were carried out under standardised circumstances using well recognised indices. Information about oral hygiene habits was obtained through structured interviews conducted immediately before the clinical examination. A multivariate analysis, principal component, was carried out...

  8. A wilty mutant of rice has impaired hydraulic conductance.

    Science.gov (United States)

    Koizumi, Koji; Ookawa, Taiichiro; Satoh, Hikaru; Hirasawa, Tadashi

    2007-08-01

    The rice CM2088 mutant is the wilty phenotype and wilts markedly under well-watered sunny conditions. The leaf water potential and epidermal (mainly stomatal) conductance of CM2088 plants decreased significantly under conditions that induced intense transpiration, as compared with those of wild-type plants, revealing that the wilty phenotype was not the result of abnormal stomatal behavior but was due to an increase in resistance to water transport. The resistance to water transport was dramatically elevated in the node and the sheath and blade of a leaf of the mutant, but not in the root or stem. The diameter of xylem vessels in the large vascular bundles of the leaf sheath and the internode tended to be small, and the numbers of vessel elements with narrowed or scalariform perforation plates in the leaf blade and sheath were greater in the mutant than in the wild type. Most xylem vessels were occluded, with air bubbles in the leaf sheath of the mutant during the midday hours under intense transpiration conditions, while no bubbles were observed in plants that were barely transpiring, revealing that the significant increase in resistance to water transport was a result of the cavitation. The additive effects of cavitation in xylem vessels and the decreased diameter and deformed plates of vessel elements might be responsible for the wilty phenotype of CM2088.

  9. Native root xylem embolism and stomatal closure in stands of Douglas-fir and ponderosa pine: mitigation by hydraulic redistribution.

    Science.gov (United States)

    Domec, J-C; Warren, J M; Meinzer, F C; Brooks, J R; Coulombe, R

    2004-09-01

    Hydraulic redistribution (HR), the passive movement of water via roots from moist to drier portions of the soil, occurs in many ecosystems, influencing both plant and ecosystem-water use. We examined the effects of HR on root hydraulic functioning during drought in young and old-growth Douglas-fir [ Pseudotsuga menziesii (Mirb.) Franco] and ponderosa pine ( Pinus ponderosa Dougl. Ex Laws) trees growing in four sites. During the 2002 growing season, in situ xylem embolism, water deficit and xylem vulnerability to embolism were measured on medium roots (2-4-mm diameter) collected at 20-30 cm depth. Soil water content and water potentials were monitored concurrently to determine the extent of HR. Additionally, the water potential and stomatal conductance ( g(s)) of upper canopy leaves were measured throughout the growing season. In the site with young Douglas-fir trees, root embolism increased from 20 to 55 percent loss of conductivity (PLC) as the dry season progressed. In young ponderosa pine, root embolism increased from 45 to 75 PLC. In contrast, roots of old-growth Douglas-fir and ponderosa pine trees never experienced more than 30 and 40 PLC, respectively. HR kept soil water potential at 20-30 cm depth above -0.5 MPa in the old-growth Douglas-fir site and -1.8 MPa in the old-growth ponderosa pine site, which significantly reduced loss of shallow root function. In the young ponderosa pine stand, where little HR occurred, the water potential in the upper soil layers fell to about -2.8 MPa, which severely impaired root functioning and limited recovery when the fall rains returned. In both species, daily maximum g(s) decreased linearly with increasing root PLC, suggesting that root xylem embolism acted in concert with stomata to limit water loss, thereby maintaining minimum leaf water potential above critical values. HR appears to be an important mechanism for maintaining shallow root function during drought and preventing total stomatal closure.

  10. Use of sap flow measurements to validate stomatal functions for mature beech (Fagus sylvatica) in view of ozone uptake calculations

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Sabine, E-mail: sabine.braun@iap.c [Institute for Applied Plant Biology, Sangrubenstrasse 25, CH-4124 Schoenenbuch (Switzerland); Schindler, Christian [Swiss Tropical and Public Health Institute, University of Basel, Socinstrasse 57, CH-4051 Basel (Switzerland); Leuzinger, Sebastian [Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstr. 16, 8092 Zuerich (Switzerland)

    2010-09-15

    For a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. Because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. This technique was applied in three beech (Fagus sylvatica) stands in Switzerland. A canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. It represents mainly stomatal conductance as the boundary layer resistance in forests is usually small. Based on this relative conductance, stomatal functions to describe the dependence on light, temperature, vapour pressure deficit and soil moisture were derived using multivariate nonlinear regression. These functions were validated by comparison with conductance values directly estimated from sap flow. The results corroborate the current flux parameterization for beech used in the DO{sub 3}SE model. - A method was developed to derive stomatal functions and ozone uptake calculation from sap flow.

  11. Evaluation of Hematologic Status in Patients with Recurrent Aphthous Stomatitis

    Directory of Open Access Journals (Sweden)

    Tahereh Nosratzehi

    2014-07-01

    Full Text Available Background: The aim of the present study was to compare hematologic problems in patients with recurrent aphthous stomatitis, with a control group. Materials and Methods: In this cross sectional study, 30 subjects with recurrent aphthous stomatitis and 30 healthy individuals were included as the case and control groups, respectively. After diagnosis was established a 10 ml sample of the subjects' blood was used to determine serum levels of iron, ferritin, vitamin B12, folic acid and zinc in each subject. Independent t-test was used to analyze data. Results: The average serum iron, serum ferritin, vitamin B12, folic acid and serum zinc levels in the case and control groups were assessment, demonstrating no statistically significant differences between the two groups (p>0.05. Conclusion: According to the results of the present study, hematologic deficiencies cannot play a role in etiology of aphthous stomatitis.

  12. Treatment of radiation- and chemotherapy-induced stomatitis

    Energy Technology Data Exchange (ETDEWEB)

    Carnel, S.B.; Blakeslee, D.B.; Oswald, S.G.; Barnes, M. (Fitzsimons Army Medical Center, Aurora, CO (USA))

    1990-04-01

    Severe stomatitis is a common problem encountered during either radiation therapy or chemotherapy. Most therapeutic regimens are empirical, with no scientific basis. The purpose of this study is to determine the efficacy of various topical solutions in the treatment of radiation- or chemotherapy-induced stomatitis. Eighteen patients were entered into a prospective double-blinded study to test several topical solutions: (1) viscous lidocaine with 1% cocaine; (2) dyclonine hydrochloride 1.0% (Dyclone); (3) kaolin-pectin solution, diphenhydramine plus saline (KBS); and (4) a placebo solution. Degree of pain relief, duration of relief, side effects, and palatability were evaluated. The results showed that Dyclone provided the most pain relief. Dyclone and viscous lidocaine with 1% cocaine provided the longest pain relief, which averaged 50 minutes This study provides objective data and defines useful guidelines for treatment of stomatitis.

  13. [Preventive effect of polaprezinc suspension dispersed in sodium alginate solution (P-AG) for stomatitis induced by Docetaxel/Cisplatin/Fluorouracil (DCF) chemotherapy in patients with head and neck cancer].

    Science.gov (United States)

    Sugisaki, Takahito; Kawakami, Kazuyoshi; Nemoto, Maki; Kawata, Keiji; Ishibashi, Michiko; Fujiki, Yukako; Mishima, Yuko; Yokoyama, Masahiro; Takahashi, Shunji; Hatake, Kiyohiko; Hama, Toshihiro

    2011-05-01

    We measured the effectiveness of the prophylactic administration of a polaprezinc suspension dispersed in sodium alginate solution (P-AG) by dividing it into two courses in the same patients, and measured the stomatitis induced by Docetaxel/Cisplatin/Fluorouracil (DCF) chemotherapy. We then evaluated the results. We defined the therapeutic course as the course where P-AG was given therapeutically for stomatitis induced after DCF chemotherapy. We defined the prophylactic course as when P-AG was prophylactically given before any incidences of stomatitis after the therapeutic course. We compared the incidences of stomatitis in the prophylactic courses with those of the therapeutic courses. The incidences of stomatitis that were higher than Grade 1 were 17 out of 17 patients (100%) in the therapeutic course. On the other hand, they were 15 out of 17 patients (88. 2%) in the prophylactic course. Compared with the mean of the Grade of Stomatitis by the Common Terminology Criteria for Adverse Events version 3. 0 (CTCAE v. 3. 0), the maximal Grade of stomatitis significantly decreased in the prophylactic courses compared to those of the therapeutic courses(pstomatitis by using P-AG prophylactically, as opposed to using P-AG therapeutically.

  14. Overexpression of the Mg-chelatase H subunit in guard cells confers drought tolerance via promotion of stomatal closure in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Tomo eTsuzuki

    2013-10-01

    Full Text Available The Mg-chelatase H subunit (CHLH has been shown to mediate chlorophyll biosynthesis, as well as plastid-to-nucleus and abscisic acid (ABA-mediated signaling. A recent study using a novel CHLH mutant, rtl1, indicated that CHLH specifically affects ABA-induced stomatal closure, but also that CHLH did not serve as an ABA receptor in Arabidopsis thaliana. However, the molecular mechanism by which CHLH engages in ABA-mediated signaling in guard cells remains largely unknown. In the present study, we examined CHLH function in guard cells and explored whether CHLH expression might influence stomatal aperture. Incubation of rtl1 guard cell protoplasts with ABA induced expression of the ABA-responsive genes RAB18 and RD29B, as also observed in wild-type (WT cells, indicating that CHLH did not affect the expression of ABA-responsive genes. Earlier, ABA was reported to inhibit blue light (BL-mediated stomatal opening, at least in part through dephosphorylating/inhibiting guard cell H+-ATPase (which drives opening. Therefore, we immunohistochemically examined the phosphorylation status of guard cell H+-ATPase. Notably, ABA inhibition of BL-induced phosphorylation of H+-ATPase was impaired in rtl1 cells, suggesting that CHLH influences not only ABA-induced stomatal closure but also inhibition of BL-mediated stomatal opening by ABA. Next, we generated CHLH-GFP-overexpressing plants using CER6 promoter, which induces gene expression in the epidermis including guard cells. CHLH-transgenic plants exhibited a closed stomata phenotype even when brightly illuminated. Moreover, plant growth experiments conducted under water-deficient conditions showed that CHLH transgenic plants were more tolerant of drought than WT plants. In summary, we show that CHLH is involved in the regulation of stomatal aperture in response to ABA, but not in ABA-induced gene expression, and that manipulation of stomatal aperture via overexpression of CHLH in guard cells improves plant

  15. RNAi-directed downregulation of vacuolar H(+) -ATPase subunit a results in enhanced stomatal aperture and density in rice.

    Science.gov (United States)

    Zhang, Huiying; Niu, Xiangli; Liu, Jia; Xiao, Fangming; Cao, Shuqing; Liu, Yongsheng

    2013-01-01

    Stomatal movement plays a key role in plant development and response to drought and salt stress by regulating gas exchange and water loss. A number of genes have been demonstrated to be involved in the regulation of this process. Using inverse genetics approach, we characterized the function of a rice (Oryza sativa L.) vacuolar H(+)-ATPase subunit A (OsVHA-A) gene in stomatal conductance regulation and physiological response to salt and osmotic stress. OsVHA-A was constitutively expressed in different rice tissues, and the fusion protein of GFP-OsVHA-A was exclusively targeted to tonoplast when transiently expressed in the onion epidermal cells. Heterologous expression of OsVHA-A was able to rescue the yeast mutant vma1Δ (lacking subunit A activity) phenotype, suggesting that it partially restores the activity of V-ATPase. Meanwhile, RNAi-directed knockdown of OsVHA-A led to a reduction of vacuolar H(+)-ATPase activity and an enhancement of plasma membrane H(+)-ATPase activity, thereby increasing the concentrations of extracellular H(+) and intracellular K(+) and Na(+) under stress conditions. Knockdown of OsVHA-A also resulted in the upregulation of PAM3 (plasma membrane H(+)-ATPase 3) and downregulation of CAM1 (calmodulin 1), CAM3 (calmodulin 3) and YDA1 (YODA, a MAPKK gene). Altered level of the ion concentration and the gene expression by knockdown of OsVHA-A probably resulted in expanded aperture of stomatal pores and increased stomatal density. In addition, OsVHA-A RNAi plants displayed significant growth inhibition under salt and osmotic stress conditions. Taken together, our results suggest that OsVHA-A takes part in regulating stomatal density and opening via interfering with pH value and ionic equilibrium in guard cells and thereby affects the growth of rice plants.

  16. RNAi-directed downregulation of vacuolar H(+ -ATPase subunit a results in enhanced stomatal aperture and density in rice.

    Directory of Open Access Journals (Sweden)

    Huiying Zhang

    Full Text Available Stomatal movement plays a key role in plant development and response to drought and salt stress by regulating gas exchange and water loss. A number of genes have been demonstrated to be involved in the regulation of this process. Using inverse genetics approach, we characterized the function of a rice (Oryza sativa L. vacuolar H(+-ATPase subunit A (OsVHA-A gene in stomatal conductance regulation and physiological response to salt and osmotic stress. OsVHA-A was constitutively expressed in different rice tissues, and the fusion protein of GFP-OsVHA-A was exclusively targeted to tonoplast when transiently expressed in the onion epidermal cells. Heterologous expression of OsVHA-A was able to rescue the yeast mutant vma1Δ (lacking subunit A activity phenotype, suggesting that it partially restores the activity of V-ATPase. Meanwhile, RNAi-directed knockdown of OsVHA-A led to a reduction of vacuolar H(+-ATPase activity and an enhancement of plasma membrane H(+-ATPase activity, thereby increasing the concentrations of extracellular H(+ and intracellular K(+ and Na(+ under stress conditions. Knockdown of OsVHA-A also resulted in the upregulation of PAM3 (plasma membrane H(+-ATPase 3 and downregulation of CAM1 (calmodulin 1, CAM3 (calmodulin 3 and YDA1 (YODA, a MAPKK gene. Altered level of the ion concentration and the gene expression by knockdown of OsVHA-A probably resulted in expanded aperture of stomatal pores and increased stomatal density. In addition, OsVHA-A RNAi plants displayed significant growth inhibition under salt and osmotic stress conditions. Taken together, our results suggest that OsVHA-A takes part in regulating stomatal density and opening via interfering with pH value and ionic equilibrium in guard cells and thereby affects the growth of rice plants.

  17. Mucosal microbiome in patients with recurrent aphthous stomatitis.

    Science.gov (United States)

    Hijazi, K; Lowe, T; Meharg, C; Berry, S H; Foley, J; Hold, G L

    2015-03-01

    Recurrent aphthous stomatitis (RAS) is the most common disease affecting oral mucosae. Etiology is unknown, but several factors have been implicated, all of which influence the composition of microbiota residing on oral mucosae, which in turn modulates immunity and thereby affects disease progression. Although no individual pathogens have been conclusively shown to be causative agents of RAS, imbalanced composition of the oral microbiota may play a key role. In this study, we sought to determine composition profiles of bacterial microbiota in the oral mucosa associated with RAS. Using high-throughput 16S rRNA gene sequencing, we characterized the most abundant bacterial populations residing on healthy and ulcerated mucosae in patients with RAS (recruited using highly stringent criteria) and no associated medical conditions; we also compared these to the bacterial microbiota of healthy controls (HCs). Phylum-level diversity comparisons revealed decreased Firmicutes and increased Proteobacteria in ulcerated sites, as compared with healthy sites in RAS patients, and no differences between RAS patients with healthy sites and HCs. Genus-level analysis demonstrated higher abundance of total Bacteroidales in RAS patients with healthy sites over HCs. Porphyromonadaceae comprising species associated with periodontal disease and Veillonellaceae predominated in ulcerated sites over HCs, while no quantitative differences of these families were observed between healthy sites in RAS patients and HCs. Streptococcaceae comprising species associated with oral health predominated in HCs over ulcerated sites but not in HCs over healthy sites in RAS patients. This study demonstrates that mucosal microbiome changes in patients with idiopathic RAS--namely, increased Bacteroidales species in mucosae of RAS patients not affected by active ulceration. While these changes suggest a microbial role in initiation of RAS, this study does not provide data on causality. Within this limitation

  18. Stomatal characterization of five species of the genus Vanilla.

    Directory of Open Access Journals (Sweden)

    Delfino Reyes-López

    2015-06-01

    Full Text Available The objective was to characterize the stomata of five species of vanilla. Throughout 2012, leaf samples of V. planifolia G. Jackson, V. pompona Schiede, V. indora Schiede, V. insignis Ames and V. odorota Presl were taken from the vanilla germplasm bank at the Benemérita Universidad Autónoma de Puebla. The stomata size was obtained considering their length and width, as well as the index and stomata number of the abaxial and adaxial leaf surfaces in a randomized complete block design with three replications. V. pompona Schiede and V. inodora Schiede showed the highest stomatal index with 8713 and 8246 stomata per mm2, respectively, followed by V. odorata Presl with 4412 stomata per mm2. V. insignis Ames and V. planifolia G. Jackson showed the lowest stomata index with 2968 and 1378 stomata per mm2, respectively, in the abaxial leaf surface, these differences were statistically significant (P≤0.05. According to the position of the leaf stomata, V. planifolia G. Jackson and V. inodora Schiede can be considered to be hypostomatics since they showed stomata only in the abaxial leaf surface. V. insignis Ames, V. inodora Schiede and V. odorata Presl. can be considered to be anfiestomatic because they showed stomata in both the abaxial and adaxial leaf surfaces. V. inodora Schiede had smaller stomata compared with the other species.That is an important feature to be included in the genetic improvement of the genus Vanilla, because due to climate change, temperature will increase and precipitation will decrease, so Vainilla will require more efficient genotypes for water use.

  19. Eradication of Helicobacter pylori in patients without gastric symptoms suffering from recurrent aphthous stomatitis: A pilot study

    OpenAIRE

    Latković Marina; Ranin Lazar; Teodorović Nevenka; Anđelković Marko

    2017-01-01

    Background/Aim. Helicobacter (H.) pylori is a widespread bacterium and its involvement in pathogenesis of gastric diseases is well-known. However, H. pylori role in etiology of other histologically similar conditions, especially recurrent aphthous stomatitis (RAS) is still controversial. Research regarding H. pylori and its association with RAS, as well as the treatment options were always conducted on patients with diagnosed gastric problems. The aim of th...

  20. Are fern stomatal responses to different stimuli coordinated? Testing responses to light, vapor pressure deficit, and CO2 for diverse species grown under contrasting irradiances.

    Science.gov (United States)

    Creese, Chris; Oberbauer, Steve; Rundel, Phil; Sack, Lawren

    2014-10-01

    The stomatal behavior of ferns provides an excellent system for disentangling responses to different environmental signals, which balance carbon gain against water loss. Here, we measured responses of stomatal conductance (gs ) to irradiance, CO2 , and vapor pressure deficit (VPD) for 13 phylogenetically diverse species native to open and shaded habitats, grown under high- and low-irradiance treatments. We tested two main hypotheses: that plants adapted and grown in high-irradiance environments would have greater responsiveness to all stimuli given higher flux rates; and that species' responsiveness to different factors would be correlated because of the relative simplicity of fern stomatal control. We found that species with higher light-saturated gs had larger responses, and that plants grown under high irradiance were more responsive to all stimuli. Open habitat species showed greater responsiveness to irradiance and CO2 , but lower responsiveness to VPD; a case of plasticity and adaptation tending in different directions. Responses of gs to irradiance and VPD were positively correlated across species, but CO2 responses were independent and highly variable. The novel finding of correlations among stomatal responses to different stimuli suggests coordination of hydraulic and photosynthetic signaling networks modulating fern stomatal responses, which show distinct optimization at growth and evolutionary time-scales.

  1. Stomatal Regulation on the Gas Exchange of Eupatorium adenophorum:Implication on Its Invasive Ability%紫茎泽兰叶片气体交换的气孔调节特性:对其入侵能力的意义

    Institute of Scientific and Technical Information of China (English)

    祖元刚; 王文杰; 杨逢建; 赵则海; 曹建国

    2005-01-01

    species grown in different regions of China and Japan was also done. For finding the possible implication for its invasive ability, the stomatal regulation on gas exchange in diurnal changing microenvironment and long term acclimation to xeric and hygric habitats as well as water use efficiency were examined.Generally, net photosynthetic rate at noon was only about one third of that in the morning and with time onward in the afternoon,photosynthetic capacities partially recovered but cannot reach that in the morning. Stomatal and non-stomatal regulations ware responsible for this diurnal pattern, i.e. stomata regulated the photosynthesis by decreasing the intercellular CO2 concentration and increasing the value of stomatal limitation, whereas biochemical regulation adjusted the photosynthetic capacity by decreasing the carboxylation efficiency and apparent quantum yield. With considering the relative importance of stomatal and non-stomatal regulation, stomatal regulation control more on this diurnal pattern. This type of strategy was similar to other common species,showing limited implication on its rampancy. However, after long term acclimation in xeric and hygric habitats, stomatal regulation functioned with plasticity. Different from a wide range of 20 species, net photosynthetic rate and transpiration rate were dramatically higher in hygric habitats than those in xeric habitats. Moreover, leaf nitrogen in hygric habitats was significant higher than that in xeric habitats although soil organic matter, soil pH value and soil available nitrogen were slightly different.Furthermore, water use efficiency increased with stomatal conductance decrease when stomatal conductance was low for the wide range of species. E. adenophorum grown in xeric habitats also showed this type strategy on water utilization. However, it increased the water use efficiency with stomatal conductance increase in hygric habitats, indicating that the water use strategy of this weed included both

  2. Inhibition of various steps in the replication cycle of vesicular stomatitis virus contributes to its photoinactivation by AlPcS4 or Pc4 and red light

    NARCIS (Netherlands)

    Moor, ACE; Wagenaars-van Gompel, AE; Hermanns, RCA; van der Meulen, J; Smit, J; Wilschut, J; Brand, A; Dubbelman, TMAR; VanSteveninck, J

    1999-01-01

    Vesicular stomatitis virus (VSV) was used as a model virus to study the processes involved in photoinactivation by aluminum phthalocyanine tetrasulfonate (AIPcS(4),) or silicon phthalocyanine HOSiPcOSi(CH3)(2)(CH2)(3)N(CH3)(2) (Pc4) and red light. Previously a very rapid decrease in the intracellula

  3. Linking stomatal sensitivity and whole-tree hydraulic architecture

    Science.gov (United States)

    Katherine A. McCulloh; David R. Woodruff

    2012-01-01

    Despite the complexity of the relationship between stomatal sensitivity, water loss and vulnerability to embolism, the goal of teasing apart the subtleties is a necessary one. As Litvak et al. (2012) mention, determining transpiration patterns based on vulnerability to embolism would be much easier than the lengthy and potentially expensive processes involved in sap...

  4. Stomatal Closure: The Old Guard Takes Up the SLAC

    OpenAIRE

    Chater, C.; Gray, J E

    2015-01-01

    Flowering plant stomata close through passive dehydration or by active pumping of anions through SLAC, a phospho-activated membrane channel. A new study reports that moss likely utilise this same mechanism, and thus supports an early origin for SLAC-mediated active stomatal control.

  5. Stomatal closure: the old guard takes up the SLAC.

    Science.gov (United States)

    Chater, Caspar; Gray, Julie E

    2015-03-30

    Flowering plant stomata close through passive dehydration or by active pumping of anions through SLAC, a phospho-activated membrane channel. A new study reports that moss likely utilise this same mechanism, and thus supports an early origin for SLAC-mediated active stomatal control.

  6. Mammalian target of rapamycin inhibitor-associated stomatitis

    NARCIS (Netherlands)

    Boers-Doets, C.B.; Raber-Durlacher, J.E.; Treister, N.S.; Epstein, J.B.; Arends, A.B.P.; Wiersma, D.R.; Lalla, R.V.; Logan, R.M.; van Erp, N.R.P.; Gelderblom, H.

    2013-01-01

    With the recent introduction of inhibitors of mammalian target of rapamycin (mTOR) in oncology, distinct cutaneous and oral adverse events have been identified. In fact, stomatitis and rash are documented as the most frequent and potentially dose-limiting side effects. Clinically, mTOR inhibitor-ass

  7. Reconstitution of the fusogenic activity of vesicular stomatitis virus

    NARCIS (Netherlands)

    Metsikkö, K.; van Meer, G.; Simons, K.

    1986-01-01

    Enveloped virus glycoproteins exhibit membrane fusion activity. We have analysed whether the G protein of vesicular stomatitis virus, reconstituted into liposomes, is able to fuse nucleated cells in a pH-dependent fashion. Proteoliposomes produced by octylglucoside dialysis did not exhibit cell fusi

  8. Burdock fructooligosaccharide induces stomatal closure in Pisum sativum.

    Science.gov (United States)

    Guo, Yanling; Guo, Moran; Zhao, Wenlu; Chen, Kaoshan; Zhang, Pengying

    2013-09-12

    Burdock fructooligosaccharide (BFO) isolated from the root tissue of Arctium lappa is a reserve carbohydrate that can induce resistance against a number of plant diseases. Stomatal closure is a part of plant innate immune response to restrict bacterial invasion. In this study, the effects of BFO on stomata movement in Pisum sativum and the possible mechanisms were studied with abscisic acid (ABA) as a positive control. The results showed that BFO could induce stomatal closure accompanied by ROS and NO production, as is the case with ABA. BFO-induced stomatal closure was inhibited by pre-treatment with L-NAME (N(G)-nitro-L-arginine methyl ester, hydrochloride; nitric oxide synthase inhibitor) and catalase (hydrogen peroxide scavenger). Exogenous catalase completely restricted BFO-induced production of ROS and NO in guard cells. In contrast, L-NAME prevented the rise in NO levels but only partially restricted the ROS production. These results indicate that BFO-induced stomatal closure is mediated by ROS and ROS-dependent NO production.

  9. Nitric oxide induces stomatal closure and enhances the adaptive plant responses against drought stress.

    Science.gov (United States)

    García-Mata, C; García Mata, C; Lamattina, L

    2001-07-01

    Nitric oxide (NO) is a very active molecule involved in many and diverse biological pathways where it has proved to be protective against damages provoked by oxidative stress conditions. In this work, we studied the effect of two NO donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine SNP-treated on the response of wheat (Triticum aestivum) to water stress conditions. After 2 and 3 h of drought, detached wheat leaves pretreated with 150 microM SNP retained up to 15% more water than those pretreated with water or NO(2)(-)/NO(3)(-). The effect of SNP treatment on water retention was also found in wheat seedlings after 7 d of drought. These results were consistent with a 20% decrease in the transpiration rate of SNP-treated detached wheat leaves for the same analyzed time. In parallel experiments, NO was also able to induce a 35%, 30%, and 65% of stomatal closure in three different species, Tradescantia sp. (monocotyledonous) and two dicotyledonous, Salpichroa organifolia and fava bean (Vicia faba), respectively. In SNP-treated leaves of Tradescantia sp., the stomatal closure was correlated with a 10% increase on RWC. Ion leakage, a cell injury index, was 25% lower in SNP-treated wheat leaves compared with control ones after the recovery period. Carboxy-PTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), a specific NO scavenger, reverted SNP action by restoring the transpiration rate, stomatal aperture, and the ion leakage to the level found in untreated leaves. Northern-blot analysis showed that SNP-treated wheat leaves display a 2-fold accumulation of a group three late embryogenesis abundant transcript with respect to control leaves both after 2 and 4 h of drought periods. All together, these results suggest that the exogenous application of NO donors might confer an increased tolerance to severe drought stress conditions in plants.

  10. Changes in root hydraulic conductivity facilitate the overall hydraulic response of rice (Oryza sativa L.) cultivars to salt and osmotic stress.

    Science.gov (United States)

    Meng, Delong; Fricke, Wieland

    2017-04-01

    The aim of the present work was to assess the significance of changes in root AQP gene expression and hydraulic conductivity (Lp) in the regulation of water balance in two hydroponically-grown rice cultivars (Azucena, Bala) which differ in root morphology, stomatal regulation and aquaporin (AQP) isoform expression. Plants were exposed to NaCl (25 mM, 50 mM) and osmotic stress (5%, 10% PEG6000). Root Lp was determined for exuding root systems (osmotic forces driving water uptake; 'exudation Lp') and transpiring plants (hydrostatic forces dominating; 'transpiration-Lp'). Gene expression was analysed by qPCR. Stress treatments caused a consistent and significant decrease in plant growth, transpirational water loss, stomatal conductance, shoot-to-root surface area ratio and root Lp. Comparison of exudation-with transpiration-Lp supported a significant contribution of AQP-facilitated water flow to root water uptake. Changes in root Lp in response to treatments were correlated much stronger with root morphological characteristics, such as the number of main and lateral roots, surface area ratio of root to shoot and plant transpiration rate than with AQP gene expression. Changes in root Lp, involving AQP function, form an integral part of the plant hydraulic response to stress and facilitate changes in the root-to-shoot surface area ratio, transpiration and stomatal conductance.

  11. Cultivar Differences in Plant Transpiration Rate at High Relative Air Humidity Are Not Related to Genotypic Variation in Stomatal Responsiveness

    DEFF Research Database (Denmark)

    Gebraegziabher, Habtamu Giday; Kjær, Katrine Heinsvig; Ottosen, Carl-Otto

    2015-01-01

    a given cultivar, Tleaf was generally higher, (1.5-3.7°C) at high as compared to moderate RH. Following desiccation, leaf weight loss was differentially enhanced (8-66%) in high RH-grown plants, indicating a wide variation in high RH tolerance. High RH mainly decreased plant water loss during the light......Plants grown at high relative air humidity (RH) often show disturbed water relations due to less responsive stomata. The attenuation of stomatal responsiveness as a result of high RH during leaf expansion depends on the cultivar. We hypothesized that tolerant cultivars to high RH experience a lower...... decline in plant transpiration by high RH, and that the variation in plant transpiration rate can be reflected by differences in leaf temperature (Tleaf). Plant leaf area, stomatal responsiveness to desiccation, together with plant transpiration and leaf temperature at growth conditions were analyzed...

  12. Stomatal malfunctioning under low VPD conditions: induced by alterations in stomatal morphology and leaf anatomy or in the ABA signaling?

    NARCIS (Netherlands)

    Ali Niaei Fard, S.; Malcolm Matamoros, P.; Meeteren, van U.

    2014-01-01

    Exposing plants to low VPD reduces leaf capacity to maintain adequate water status thereafter. To find the impact of VPD on functioning of stomata, stomatal morphology and leaf anatomy, fava bean plants were grown at low (L, 0.23 kPa) or moderate (M, 1.17 kPa) VPDs and some plants that developed the

  13. Variable conductivity and embolism in roots, trunks and branches of tree species growing under future atmospheric CO2 concentration (DUKE FACE site): impacts on whole-plant hydraulic performance and carbon assimilation

    Science.gov (United States)

    domec, J.; Palmroth, S.; Oren, R.; Johnson, D. M.; Ward, E. J.; McCulloh, K.; Gonzalez, C.; Warren, J.

    2013-12-01

    Anatomical and physiological acclimation to water stress of the tree hydraulic system involves tradeoffs between maintenance of stomatal conductance and loss of hydraulic conductivity, with short-term impacts on photosynthesis and long-term consequences to survival and growth. Here we study the role of variations in root, trunk and branch maximum hydraulic specific conductivity (Ks-max) under high and low soil moisture in determining whole-tree hydraulic conductance (Ktree) and in mediating stomatal control of gas exchange in loblolly pine trees growing under ambient and elevated CO2 (CO2a and CO2e). We hypothesized that Ktree would adjust to CO2e, through an increase in root and branch Ks-max in response to anatomical adjustments. Embolism in roots explained the loss of Ktree and therefore indirectly constituted a hydraulic signal involved in stomatal regulation and in the reduction of canopy conductance and carbon assimilation. Across roots, trunk and branches, the increase in Ks-max was associated with a decrease resistance to drought, a consequence of structural acclimation such as larger conduits and lower wood density. In loblolly pine, higher xylem dysfunction under CO2e might impact tree performance in a future climate when increased evaporative demand could cause a greater loss of hydraulic function. The results contributed to our knowledge of the physiological and morphological mechanisms underpinning the responses of tree species to drought and more generally to global change.

  14. ABA-Mediated Stomatal Response in Regulating Water Use during the Development of Terminal Drought in Wheat

    Directory of Open Access Journals (Sweden)

    Renu Saradadevi

    2017-07-01

    Full Text Available End-of-season drought or “terminal drought,” which occurs after flowering, is considered the most significant abiotic stress affecting crop yields. Wheat crop production in Mediterranean-type environments is often exposed to terminal drought due to decreasing rainfall and rapid increases in temperature and evapotranspiration during spring when wheat crops enter the reproductive stage. Under such conditions, every millimeter of extra soil water extracted by the roots benefits grain filling and yield and improves water use efficiency (WUE. When terminal drought develops, soil dries from the top, exposing the top part of the root system to dry soil while the bottom part is in contact with available soil water. Plant roots sense the drying soil and produce signals, which on transmission to shoots trigger stomatal closure to regulate crop water use through transpiration. However, transpiration is linked to crop growth and productivity and limiting transpiration may reduce potential yield. While an early and high degree of stomatal closure affects photosynthesis and hence biomass production, a late and low degree of stomatal closure exhausts available soil water rapidly which results in yield losses through a reduction in post-anthesis water use. The plant hormone abscisic acid (ABA is considered the major chemical signal involved in stomatal regulation. Wheat genotypes differ in their ability to produce ABA under drought and also in their stomatal sensitivity to ABA. In this viewpoint article we discuss the possibilities of exploiting genotypic differences in ABA response to soil drying in regulating the use of water under terminal drought. Root density distribution in the upper drying layers of the soil profile is identified as a candidate trait that can affect ABA accumulation and subsequent stomatal closure. We also examine whether leaf ABA can be designated as a surrogate characteristic for improved WUE in wheat to sustain grain yield under

  15. The Denture-Associated Oral Microbiome in Health and Stomatitis.

    Science.gov (United States)

    Shi, Baochen; Wu, Tingxi; McLean, Jeffrey; Edlund, Anna; Young, Youngik; He, Xuesong; Lv, Hongyang; Zhou, Xuedong; Shi, Wenyuan; Li, Huiying; Lux, Renate

    2016-01-01

    While investigation of the microbiome on natural oral surfaces has generated a wealth of information, few studies have examined the microbial communities colonizing dentures and their relationship to oral health. To address this knowledge gap, we characterized the bacterial community associated with dentures and remaining teeth in healthy individuals and patients with denture stomatitis. The microbiome compositions of matched denture and tooth plaque samples of 10 healthy individuals and 9 stomatitis patients were determined by 16S rRNA gene pyrosequencing. The microbial communities colonizing dentures and remaining teeth in health and disease were very similar to each other. Matched denture and tooth samples from the same individuals shared a significantly higher percentage of identical phylotypes than random pairs of samples from different study participants. Despite these overall similarities, several bacterial phylotypes displayed discrete health- and stomatitis-associated denture colonization, while others were distinct in health and disease independently of the surface. Certain phylotypes exhibited differential colonization of dentures and teeth independently of denture health status. In conclusion, denture and natural tooth surfaces in health and stomatitis harbor similar bacterial communities. Individual-related rather than surface-specific factors play a significant role in the bacterial phylotype composition colonizing dentures and teeth. This individual-specific mutual influence on denture and tooth surface colonization could be an important factor in maintaining oral health in denture wearers. Discrete differences in colonization patterns for distinct genera and phylotypes warrant further studies regarding their potential involvement or utility as specific indicators of health and disease development in denture-wearing individuals. IMPORTANCE Denture stomatitis is a prevalent inflammatory condition of the mucosal tissue in denture wearers that is

  16. Sensitivity of grassland productivity to aridity controlled by stomatal and xylem regulation

    Science.gov (United States)

    Konings, A. G.; Williams, A. P.; Gentine, P.

    2017-03-01

    The terrestrial water and carbon cycles are coupled through plant regulation of stomatal closure. Both soil moisture and vapour pressure deficit--the amount of moisture in the air relative to its potential maximum--can govern stomatal closure, which reduces plant carbon uptake. However, plants vary in the degree to which they regulate their stomata--and in association, xylem conductance--in response to increasing aridity: isohydric plants exert tight regulation of stomata and the water content of the plant, whereas anisohydric plants do not. Here we use remote-sensing data sets of anisohydricity and vegetation greenness to show that productivity in United States grasslands--especially anisohydric ones--is far more sensitive to variations in vapour pressure deficit than to variations in precipitation. Anisohydric ecosystem productivity is over three times more sensitive to vapour pressure deficit than isohydric ecosystem productivity. The precipitation sensitivity of summer productivity increases with anisohydricity only for the most anisohydric ecosystems. We conclude that increases in vapour pressure deficit rather than changes in precipitation--both of which are expected impacts of climate change--will be a dominant influence on future grassland productivity.

  17. Baobab trees (Adansonia) in Madagascar use stored water to flush new leaves but not to support stomatal opening before the rainy season.

    Science.gov (United States)

    Chapotin, Saharah Moon; Razanameharizaka, Juvet H; Holbrook, N Michele

    2006-01-01

    Baobab trees (Adansonia, Bombacaceae) are widely thought to store water in their stems for use when water availability is low. We tested this hypothesis by assessing the role of stored water during the dry season in three baobab species in Madagascar. In the dry season, leaves are present only during and after leaf flush. We quantified the relative contributions of stem and soil water during this period through measures of stem water content, sap flow and stomatal conductance. Rates of sap flow at the base of the trunk were near zero, indicating that leaf flushing was almost entirely dependent on stem water. Stem water content declined by up to 12% during this period, yet stomatal conductance and branch sap flow rates remained very low. Stem water reserves were used to support new leaf growth and cuticular transpiration, but not to support stomatal opening before the rainy season. Stomatal opening coincided with the onset of sap flow at the base of the trunk and occurred only after significant rainfall.

  18. Within-catchment variation in regulation of water use by eucalypts, and the roles of stomatal anatomy and physiology

    Science.gov (United States)

    Gharun, Mana; Turnbull, Tarryn; Adams, Mark

    2014-05-01

    Understanding how environmental cues impact water use of forested catchments is crucial for accurate calculation of water balance and effective catchment management in terrestrial ecosystems. We characterised structural and physiological properties of leaves and canopies of Eucalyptus delegatensis, E. pauciflora and E. radiata, the most common species in high-country catchments in temperate Australia. These properties were related to whole-tree water transport to assess differences in water use strategies among the three species. Stomatal conductance, instantaneous transpiration efficiency, stomatal occlusion (through cuticular ledges) and leaf area index differed significantly among species. Whole-tree water use of all species was strongly coupled to changes in vapour pressure deficit (VPD) and photosynthetically active radiation (Q), yet stomatal closure reduced water transport at VPD > 1 kPa in all species, even when soil water was not limiting. The observed differences in leaf traits and related water use strategies reflect species-specific adaptations to dominant environmental conditions within the landscape matrix of catchments. The generalist E. radiata seems to follow an opportunistic, while the two more spatially restricted species have adopted a pessimistic water use strategy. Catchment-scale models of carbon and water fluxes will need to reflect such variation in structure and function, if they are to fully capture species effects on water balance and yield.

  19. GID1 modulates stomatal response and submergence tolerance involving abscisic acid and gibberellic acid signaling in rice.

    Science.gov (United States)

    Du, Hao; Chang, Yu; Huang, Fei; Xiong, Lizhong

    2015-11-01

    Plant responses to abiotic stresses are coordinated by arrays of growth and developmental programs. Gibberellic acid (GA) and abscisic acid (ABA) play critical roles in the developmental programs and environmental responses, respectively, through complex signaling and metabolism networks. However, crosstalk between the two phytohormones in stress responses remains largely unknown. In this study, we report that GIBBERELLIN-INSENSITIVE DWARF 1 (GID1), a soluble receptor for GA, regulates stomatal development and patterning in rice (Oryza sativa L.). The gid1 mutant showed impaired biosynthesis of endogenous ABA under drought stress conditions, but it exhibited enhanced sensitivity to exogenous ABA. Scanning electron microscope and infrared thermal image analysis indicated an increase in the stomatal conductance in the gid1 mutant under drought conditions. Interestingly, the gid1 mutant had increased levels of chlorophyll and carbohydrates under submergence conditions, and showed enhanced reactive oxygen species (ROS)-scavenging ability and submergence tolerance compared with the wild-type. Further analyses suggested that the function of GID1 in submergence responses is partially dependent on ABA, and GA signaling by GID1 is involved in submergence tolerance by modulating carbohydrate consumption. Taken together, these findings suggest GID1 plays distinct roles in stomatal response and submergence tolerance through both the ABA and GA signaling pathways in rice.

  20. Evaluation of Denture Stomatitis in Croatian Adult Population

    OpenAIRE

    Ćelić, R.; Knezović Zlatarić, D.; Baučić, I.

    2001-01-01

    Denture stomatitis (DS) is often found under the removable partial dentures (RPDs). There are many factors influencing it, such as patient’s age and gender, smoking habits, denture age, denture material, denture wearing habits, denture hygiene habits, oral hygiene instruction, denture cleanness and denture plaque accumulation. The aim of this study was to find out the influence these factors have on the prevalence of DS under RPDs and complete dentures (CDs). A total of 200 pat...

  1. Oral exfoliative cytology in female reverse smokers having stomatitis nicotina.

    Science.gov (United States)

    Reddy, C R; Sarma, P R; Kameswari, V R

    1975-01-01

    1. The Karyopyknotic index of the palatal and lingual mucosa is increased in female reverse smokers when compared to non-smoking females. 2. The Karyopyknotic index of the buccal mucosa did not show any change in female reverse smokers when compared to non-smoking females. 3. The Karyopyknotic index did not show any change with age in the non-smoking females. 4. Very few cases show epithelial atypia in palatal smears from female reverse smokers having stomatitis nicotina.

  2. Original findings associated with two cases of bovine papular stomatitis.

    Science.gov (United States)

    Dal Pozzo, F; Martinelle, L; Gallina, L; Mast, J; Sarradin, P; Thiry, E; Scagliarini, A; Büttner, M; Saegerman, C

    2011-12-01

    Bovine papular stomatitis virus was isolated from two calves in an animal house with biosafety level 3 confinement. The hypotheses on the origin of the infection, the interesting features of the partial amino acid sequences of the major envelope viral protein, and the importance of diagnostic tools available for animal diseases that are not listed by the World Organization for Animal Health (OIE) are discussed.

  3. A reduced order model to analytically infer atmospheric CO2 concentration from stomatal and climate data

    Science.gov (United States)

    Konrad, Wilfried; Katul, Gabriel; Roth-Nebelsick, Anita; Grein, Michaela

    2017-06-01

    To address questions related to the acceleration or deceleration of the global hydrological cycle or links between the carbon and water cycles over land, reliable data for past climatic conditions based on proxies are required. In particular, the reconstruction of palaeoatmospheric CO2 content (Ca) is needed to assist the separation of natural from anthropogenic Ca variability and to explore phase relations between Ca and air temperature Ta time series. Both Ta and Ca are needed to fingerprint anthropogenic signatures in vapor pressure deficit, a major driver used to explain acceleration or deceleration phases in the global hydrological cycle. Current approaches to Ca reconstruction rely on a robust inverse correlation between measured stomatal density in leaves (ν) of many plant taxa and Ca. There are two methods that exploit this correlation: The first uses calibration curves obtained from extant species assumed to represent the fossil taxa, thereby restricting the suitable taxa to those existing today. The second is a hybrid eco-hydrological/physiological approach that determines Ca with the aid of systems of equations based on quasi-instantaneous leaf-gas exchange theories and fossil stomatal data collected along with other measured leaf anatomical traits and parameters. In this contribution, a reduced order model (ROM) is proposed that derives Ca from a single equation incorporating the aforementioned stomatal data, basic climate (e.g. temperature), estimated biochemical parameters of assimilation and isotope data. The usage of the ROM is then illustrated by applying it to isotopic and anatomical measurements from three extant species. The ROM derivation is based on a balance between the biochemical demand and atmospheric supply of CO2 that leads to an explicit expression linking stomatal conductance to internal CO2 concentration (Ci) and Ca. The resulting expression of stomatal conductance from the carbon economy of the leaf is then equated to another

  4. Physiology and Regulation of Calcium Channels in Stomatal Guard Cells

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Julian I.

    2007-05-02

    Stomatal pores in the epidermis of leaves regulate the diffusion of CO2 into leaves for photosynthetic carbon fixation and control water loss of plants during drought periods. Guard cells sense CO2, water status, light and other environmental conditions to regulate stomatal apertures for optimization of CO2 intake and plant growth under drought stress. The cytosolic second messenger calcium contributes to stomatal movements by transducing signals and regulating ion channels in guard cells. Studies suggest that both plasma membrane Ca2+ influx channels and vacuolar/organellar Ca2+ release channels contribute to ABA-induced Ca2+ elevations in guard cells. Recent research in the P.I.'s laboratory has led to identification of a novel major cation-selective Ca2+-permeable influx channel (Ica) in the plasma membrane of Arabidopsis guard cells. These advances will allow detailed characterization of Ica plasma membrane Ca2+ influx channels in guard cells. The long term goal of this research project is to gain a first detailed characterization of these novel plasma membrane Ca2+-permeable channel currents in Arabidopsis guard cells. The proposed research will investigate the hypothesis that Ica represents an important Ca2+ influx pathway for ABA and CO2 signal transduction in Arabidopsis guard cells. These studies will lead to elucidation of key signal transduction mechanisms by which plants balance CO2 influx into leaves and transpirational water loss and may contribute to future strategies for manipulating gas exchange for improved growth of crop plants and for biomass production.

  5. Ozone exposure and stomatal sluggishness in different plant physiognomic classes

    Energy Technology Data Exchange (ETDEWEB)

    Paoletti, Elena, E-mail: e.paoletti@ipp.cnr.i [IPP-CNR, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Florence (Italy); Grulke, Nancy E. [US Forest Service, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States)

    2010-08-15

    Gas exchange responses to static and variable light were tested in three species: snap bean (Phaseolus vulgaris, two cultivars), California black oak (Quercus kelloggii), and blue oak (Q. douglasii). The effects of 1-month (snap beans) and 2-month (oaks) O{sub 3} (ozone) exposure (70 ppb over 8 h per day in open-top chambers) were investigated. A delay in stomatal responses (i.e., 'sluggish' responses) to variable light was found to be both an effect of O{sub 3} exposure and a reason for increased O{sub 3} sensitivity in snap bean cultivars, as it implied higher O{sub 3} uptake during times of disequilibrium. Sluggishness increased the time to open (thus limiting CO{sub 2} uptake) and close stomata (thus increasing transpirational water loss) after abrupt changes in light level. Similar responses were shown by snap beans and oaks, suggesting that O{sub 3}-induced stomatal sluggishness is a common trait among different plant physiognomic classes. - Sluggish stomatal responses are suggested to be both an effect of O{sub 3} exposure and a reason of increased O{sub 3} sensitivity in plants.

  6. Acquired changes in stomatal characteristics in response to ozone during plant growth and leaf development of bush beans (Phaseolus vulgaris L.) indicate phenotypic plasticity

    Energy Technology Data Exchange (ETDEWEB)

    Elagoez, Vahram [Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003 (United States)]. E-mail: velagoz@nsm.umass.edu; Han, Susan S. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States); Manning, William J. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2006-04-15

    Bush bean (Phaseolus vulgaris L.) lines 'S156' (O{sub 3}-sensitive)/'R123' (O{sub 3}-tolerant) and cultivars 'BBL 290' (O{sub 3}-sensitive)/'BBL 274' (O{sub 3}-tolerant) were used to study the effects of O{sub 3} on stomatal conductance (g {sub s}), density, and aperture size on leaf and pod surfaces with the objective of establishing links between the degree of plant sensitivity to O{sub 3} and plasticity of stomatal properties in response to O{sub 3}. Studies in open-top chambers (OTCs) and in continuously stirred tank reactors (CSTRs) established a clear relationship between plant developmental stages, degrees of O{sub 3} sensitivity and g {sub s}: while 'S156' had higher g {sub s} rates than 'R123' earlier in development, similar differences between 'BBL 290' and 'BBL 274' were observed at later stages. G {sub s} rates on the abaxial leaf surfaces of 'S156' and 'BBL 290', accompanied by low leaf temperatures, were significantly higher than their O{sub 3}-tolerant counterparts. Exposure to O{sub 3} in CSTRs had greater and more consistent impacts on both stomatal densities and aperture sizes of O{sub 3}-sensitive cultivars. Stomatal densities were highest on the abaxial leaf surfaces of 'S156' and 'BBL 290' at higher O{sub 3} concentrations (60 ppb), but the largest aperture sizes were recorded on the adaxial leaf surfaces at moderate O{sub 3} concentrations (30 ppb). Exposure to O{sub 3} eliminated aperture size differences on the adaxial leaf surfaces between sensitive and tolerant cultivars. Regardless of sensitivity to O{sub 3} and treatment regimes, the smallest aperture sizes and highest stomatal densities were found on the abaxial leaf surface. Our studies showed that O{sub 3} has the potential to affect stomatal plasticity and confirmed the presence of different control mechanisms for stomatal development on each leaf surface. This

  7. Effect of SO/sub 2/ on stomatal aperture and sulfur uptake of woody angiosperm seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Noland, T.L.; Kozlowski, T.T.

    1979-01-01

    Effects of SO/sub 2/ pollution on stomatal aperture and sulfur uptake varied with SO/sub 2/ dosage and plant species. Fumigation of Ulmus americana L. seedlings with 1 ppm SO/sub 2/ for 8 h inhibited stomatal closure and fumigation with 2 ppm SO/sub 2/ for 12 h induced stomatal closure. Sulfur uptake of fumigated Ulmus americana seedlings depended on stomatal aperture and was much higher in the light than in the dark. Fumigation of water-stressed Ginkgo biloba L. seedlings with 2 ppm SO/sub 2/ for 6.5 h tended to prevent stomatal closure. However, the effects of SO/sub 2/ on stomatal aperture were modulated and often overridden by environmental stresses such as low light intensity and drought.

  8. [The role of nitric oxide in ethylene-induced stomatal closure in Vicia faba L].

    Science.gov (United States)

    Li, Jie; Qiu, Li-Yan; Zhao, Fang-Gui; Hou, Li-Xia; Liu, Xin

    2007-08-01

    The effects of nitric oxide (NO) and ethylene on Vicia faba L. stomatal movement were studied. The results showed that NO donor SNP (sodium nitroprusside) 10 micromol/L and ethylene 0.04% could induce stomatal closure distinctly and they could promote stomatal closure when treated together. When treated with AVG (an inhibitor of ethylene synthesis), c-PTIO (a specific scavenger of NO) and NaN(3) (an inhibitor of NR), the effects of NO- and ethylene-induced stomatal closure were inhibited but the inhibitor of nitric oxide synthase (NOS) had little effect. We presumed that there was coordinative effect between NO and ethylene in regulation of stomatal closure; ethylene could induce stomatal closure by regulating the production of nitrate reductase (NR)-dependent NO.

  9. Chloroplastic and stomatal aspects of ozone-induced reduction of net photosynthesis in plants

    Energy Technology Data Exchange (ETDEWEB)

    Torsethaugen, Gro

    1998-09-01

    The present thesis relates to ozone-induced reduction of photosynthesis in plants. As a photochemical oxidant O{sub 3} is formed by the interaction of hydrocarbons, nitrogen oxides and oxygen in sunlight. Ozone (O{sub 3}) is the most phytotoxic of all the air pollutants and is known to reduce plant growth and net photosynthesis, cause stomatal closure, induce visible injury, accelerate senescence and induce or inhibit transcription of a variety of genes with a corresponding increase/decrease in protein products. The underlying cellular mechanisms for many of these changes are unknown. Following fields are investigated: Ozone-induced reduction of net photosynthesis; ozone and the photosynthetic apparatus in the chloroplasts; ozone and stomata; ozone effects on plant membranes; protection against ozone injury in plants. 249 refs., 22 figs., 4 tabs.

  10. Uji Klinik Efektifitas Pasta Gigi Antiplaque™ terhadap Kesembuhan Lesi dan Rekurensi Sariawan (Stomatitis Aftosa Minor

    Directory of Open Access Journals (Sweden)

    Siti Aliyah Pradono

    2015-10-01

    Full Text Available Treatment of Recurrent Aphthous Stomatitis (RAS often becomes a problem until now. It is because of the RAS characteristic that has a high recurrence, unclear etiology and has a lot of predisposing factors. Antiplaque™ tooth paste with active ingredients of Sodium monophosphate, Arnica tincture, Cloxiphenol and Oleum cariofill, has been used in this study to accelerate healing and to reduce the recurrence of RAS. Ninety one students and employees of Faculty of Dentistry, University of Indonesia who have minor RAS as subjects were divided into study group and control group. Regarding of healing the results of 58.7% from study group compared to 35.9% from control group, implies that the lesions healed faster. RAS recurrence of 83.3% from study group compared to 42.9% from control group states that recurrence had decreased.

  11. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Taiz, L.; Zeiger, E.; Mawson, B. T.; Cornish, K.; Radin, J. W.; Turcotte, E. L.; Hercovitz, S.; Tallman, G.; Karlsson, P. E.; Bogomolni, R. A.; Talbott, L. D.; Srivastava, A.

    1992-01-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  12. The effect of Purslane in the treatment of recurrent aphthous stomatitis

    Directory of Open Access Journals (Sweden)

    Najafi Sh

    2013-05-01

    Full Text Available Background: Recurrent aphthous stomatitis (RAS is a common disease with unknown etiology. There is no curative treatment. Purslane is considered as a rich source of antioxidants with anti-inflammatory effects. The purpose of this study is to evaluate the effect of Purslane in the treatment of RAS.Methods: A total of 50 patients were selected for this randomized triple-blind placebo-controlled clinical trial from School of Dentistry of Tehran University of Medical Sciences in 2011. All subjects were randomly divided into two groups. Groups A and B received placebo and Purslane, respectively, for three months. Pain intensity based on the visual analogue scale (VAS, the mean intervals of lesions occurrence, number of lesions and the mean duration of complete healing at baseline and at months 1, 2 and 3 were recorded.  Results: While no patient complained from increased severity of pain, decreased severity of pain for 4, 3, 2, and 1 grades were recorded in %16, %20, 20%, and 40%, respectively, which were much higher than 4%, 8%, 8%, and 28%, respectively, in the control group. A significant decrease in pain intensity in VAS scores were seen after treatment in group B (P<0.001. The mean duration of complete healing showed significant differences (P<0.001 between groups A (-1.52±4.07 days and group B (-6.56±4.50 days. The mean intervals between lesions also showed significant differences (P<0.001 between group A (17.88 days and group B (33.12 days. No significant differences were found between group A and group B regarding to number of lesions. No serious side-effects occurred in either group.Conclusion: According to our study, Purslane is clinically effective in treatment of RAS and considering the lack of side-effects during the study period, this medicine may be a favorable alternative treatment for recurrent aphthous stomatitis.

  13. Stomatal dynamics are limited by leaf hydraulics in ferns and conifers: results from simultaneous measurements of liquid and vapour fluxes in leaves.

    Science.gov (United States)

    Martins, Samuel C V; McAdam, Scott A M; Deans, Ross M; DaMatta, Fábio M; Brodribb, Tim J

    2016-03-01

    Stomatal responsiveness to vapour pressure deficit (VPD) results in continuous regulation of daytime gas-exchange directly influencing leaf water status and carbon gain. Current models can reasonably predict steady-state stomatal conductance (gs ) to changes in VPD but the gs dynamics between steady-states are poorly known. Here, we used a diverse sample of conifers and ferns to show that leaf hydraulic architecture, in particular leaf capacitance, has a major role in determining the gs response time to perturbations in VPD. By using simultaneous measurements of liquid and vapour fluxes into and out of leaves, the in situ fluctuations in leaf water balance were calculated and appeared to be closely tracked by changes in gs thus supporting a passive model of stomatal control. Indeed, good agreement was found between observed and predicted gs when using a hydropassive model based on hydraulic traits. We contend that a simple passive hydraulic control of stomata in response to changes in leaf water status provides for efficient stomatal responses to VPD in ferns and conifers, leading to closure rates as fast or faster than those seen in most angiosperms.

  14. Stomatal Blue Light Response Is Present in Early Vascular Plants1[OPEN

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-01-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K+ accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum. PMID:26307440

  15. The secretory peptide gene EPF1 enforces the stomatal one-cell-spacing rule.

    Science.gov (United States)

    Hara, Kenta; Kajita, Ryoko; Torii, Keiko U; Bergmann, Dominique C; Kakimoto, Tatsuo

    2007-07-15

    Stomata are innovations of land plants that allow regulated gas exchange. Stomatal precursor cells are produced by asymmetric cell division, and once formed, signal their neighbors to inhibit the formation of stomatal precursors in direct contact. We report a gene of Arabidopsis thaliana, EPIDERMAL PATTERNING FACTOR 1 (EPF1) that encodes a small secretory peptide expressed in stomatal cells and precursors and that controls stomatal patterning through regulation of asymmetric cell division. EPF1 activity is dependent on the TOO MANY MOUTHS receptor-like protein and ERECTA family receptor kinases, suggesting that EPF1 may provide a positional cue interpreted by these receptors.

  16. [Three cases of stomatitis caused by chemotherapy for gastrointestinal cancer that responded well to lafutidine].

    Science.gov (United States)

    Uchida, Kazumi; Hayashi, Kazuhiko; Kuramochi, Hidekazu; Nakajima, Go; Yamamoto, Masakazu

    2008-08-01

    We described 3 cases of stomatitis caused by chemotherapy with the fluoropyrimidine preparation S-1, alone or combined with other anticancer drugs. The stomatitis did not respond to conventional oral mucosal treatment such as triamcinolone acetonide(Kenalog)or allopurinol, but improved after treatment with the histamine H2-receptor antagonist lafutidine. The concurrent use of lafutidine allowed these 3 patients to continue chemotherapy with no recurrence of stomatitis. We concluded that lafutidine may be a viable treatment option for chemotherapy-induced stomatitis, allowing treatment to be continued.

  17. Cultivar Differences in Plant Transpiration Rate at High Relative Air Humidity Are Not Related to Genotypic Variation in Stomatal Responsiveness

    DEFF Research Database (Denmark)

    Gebraegziabher, Habtamu Giday; Kjær, Katrine Heinsvig; Ottosen, Carl-Otto;

    2015-01-01

    Plants grown at high relative air humidity (RH) often show disturbed water relations due to less responsive stomata. The attenuation of stomatal responsiveness as a result of high RH during leaf expansion depends on the cultivar. We hypothesized that tolerant cultivars to high RH experience a lower...... a given cultivar, Tleaf was generally higher, (1.5-3.7°C) at high as compared to moderate RH. Following desiccation, leaf weight loss was differentially enhanced (8-66%) in high RH-grown plants, indicating a wide variation in high RH tolerance. High RH mainly decreased plant water loss during the light...

  18. Effectiveness of microwave disinfection of complete dentures on the treatment of Candida-related denture stomatitis.

    Science.gov (United States)

    Neppelenbroek, K H; Pavarina, A C; Palomari Spolidorio, D M; Sgavioli Massucato, E M; Spolidorio, L C; Vergani, C E

    2008-11-01

    The effectiveness of microwave disinfection of maxillary complete dentures on the treatment of Candida-related denture stomatitis was evaluated. Patients (n = 60) were randomly assigned to one of four treatment groups of 15 subjects each; patients performed the routine denture care; Mw group: patients had their upper denture microwaved (650 W per 6 min) three times per week for 30 days; group MwMz: patients received the treatment of Mw group in conjunction with topical application of miconazole three times per day for 30 days; group Mz: patients received the antifungal therapy of group MwMz. Cytological smears and mycological cultures were taken from the dentures and the palates of all patients before treatment at day 15 and 30 of treatment and at follow-up (days 60 and 90). The effectiveness of the treatments was evaluated by Kruskal-Wallis and Mann-Whitney tests. Microbial and clinical analysis of the control group demonstrated no significant decrease in the candidal infection over the clinical trial. Smears and cultures of palates and dentures of the groups Mw and MwMz exhibited absence of Candida at day 15 and 30 of treatment. On day 60 and 90, few mycelial forms were observed on 11 denture smears (36.6%) from groups Mw and MwMz, but not on the palatal smears. Miconazole (group Mz) neither caused significant reduction of palatal inflammation nor eradicated Candida from the dentures and palates. Microwaving dentures was effective for the treatment of denture stomatitis. The recurrence of Candida on microwaved dentures at follow-up was dramatically reduced.

  19. Denture-Related Stomatitis Is Associated with Endothelial Dysfunction

    Directory of Open Access Journals (Sweden)

    Joanna Maciąg

    2014-01-01

    Full Text Available Oral inflammation, such as periodontitis, can lead to endothelial dysfunction, accelerated atherosclerosis, and vascular dysfunction. The relationship between vascular dysfunction and other common forms of oral infections such as denture-related stomatitis (DRS is unknown. Similar risk factors predispose to both conditions including smoking, diabetes, age, and obesity. Accordingly, we aimed to investigate endothelial function and major vascular disease risk factors in 44 consecutive patients with dentures with clinical and microbiological features of DRS (n=20 and without DRS (n=24. While there was a tendency for higher occurrence of diabetes and smoking, groups did not differ significantly in respect to major vascular disease risk factors. Groups did not differ in main ambulatory blood pressure, total cholesterol, or even CRP. Importantly, flow mediated dilatation (FMD was significantly lower in DRS than in non-DRS subjects, while nitroglycerin induced vasorelaxation (NMD or intima-media thickness (IMT was similar. Interestingly, while triglyceride levels were normal in both groups, they were higher in DRS subjects, although they did not correlate with either FMD or NMD. Conclusions. Denture related stomatitis is associated with endothelial dysfunction in elderly patients with dentures. This is in part related to the fact that diabetes and smoking increase risk of both DRS and cardiovascular disease.

  20. Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome.

    Science.gov (United States)

    Ali, Nora S; Sartori-Valinotti, Julio C; Bruce, Alison J

    2016-01-01

    Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome, the most common periodic disorder of childhood, presents with the cardinal symptoms of periodic fever, aphthous stomatitis, pharyngitis, and adenitis typically before age 5. This review presents the recent literature on PFAPA and summarizes key findings in the pathogenesis, evaluation, and treatment of the disease. Theories surrounding the pathogenesis of PFAPA include a faulty innate immunologic response in conjunction with dysregulated T-cell activation. A potential genetic link is also under consideration. Mediterranean fever (MEFV) gene variants have been implicated and appear to modify disease severity. In individuals with the heterozygous variant, PFAPA episodes are milder and shorter in duration. Diagnostic criteria include the traditional clinical signs, in addition to the following biomarkers: elevated C-reactive protein in the absence of elevated procalcitonin, vitamin D, CD64, mean corpuscular volume, and other nonspecific inflammatory mediators in the absence of an infectious explanation for fever. Treatment of PFAPA includes tonsillectomy, a single dose of corticosteroids, and, most recently, interleukin 1 blockers such as anakinra, rilonacept, and canakinumab. Tonsillectomy remains the only permanent treatment modality. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Risk factors associated with denture stomatitis in the United States.

    Science.gov (United States)

    Shulman, J D; Rivera-Hidalgo, F; Beach, M M

    2005-07-01

    This study reports denture stomatitis (DS) prevalence from a large USA probability sample from the National Health and Nutrition Examination Survey, 1988-1994 (NHANES III). Oral examinations were performed on 3450 individuals 18-90+ years of age (mean: 59.2; SD: 0.50 years), 57.7% male and 42.3% female. Multivariable logistic regression models were fitted for DS using sociodemographic, denture quality, blood analytes, alcohol and tobacco use, history of diabetes, and current antibiotic use as covariates. Odds ratios (OR), adjusted for other covariates in each model (AOR) are presented. Of 3450 removable denture wearers, 963 (27.9%) had DS. DS prevalence was associated with wearing maxillary (AOR: 6.20) and mandibular (AOR: 5.21) complete dentures continuously; smoking >/=15 cigarettes day (maxillary complete: AOR = 1.31; mandibular complete: AOR = 1.50; maxillary partial: AOR = 2.04); vitamin A deficiency (mandibular complete: AOR = 5.97; maxillary partial: AOR = 5.67; mandibular partial: AOR = 24.42). Maxillary dentures with inadequate relines had approximately half the OR of DS than those with adequate relines (maxillary complete: AOR = 0.42; mandibular complete: AOR = 0.50). Denture stomatitis prevalence is associated with the amount of tissue covered by dentures, low vitamin A levels, cigarette smoking, and constant denture wear.

  2. Triamcinolone Acetonide Oromucoadhesive Paste for Treatment of Aphthous Stomatitis

    Directory of Open Access Journals (Sweden)

    Hamed Hamishehkar

    2015-06-01

    Full Text Available Purpose: The aim of this study was to prepare the optimized oral paste formulation of Triamcinolone acetonide intended to be used in aphtous stomatitis. Methods: Plastibases were prepared using mineral oil and polyethylene (95:5. Oral paste formulations were prepared with different mixtures of three hydrocolloids solids, including gelatin, pectin and sodium carboxymethylcellulose, with different ratios, as well as Plastibase. Long-term and short-term stability of prepared formulations were studied in the case of color and consistency of pastes. Franz diffusion cell and dialysis membrane were employed for release study. Release data were fitted in the kinetic models to find out the mechanism of drug release. Results: Formulation containing 60% plastibase, 3.3% pectin, 6.6% gelatin and 30% carboxymethylcellulose showed desired durability of adhesion, spreadability and rheology property in healthy volunteers and was compared with reference formulation (Adcortyl® in the case of release profile. Although, optimized formulation and Adcortyl followed the Higuchi and first order release kinetics respectively, optimized formulation showed similar release profile to reference formulation. Conclusion: Optimized oral paste formulation of Triamcinolone Acetonide showed similar characteristics with reference formulation and could be used as an effective drug delivery system for the treatment of recurrent aphthous stomatitis.

  3. Modelling of root ABA synthesis, stomatal conductance, transpiration and potato production under water saving irrigation regimes

    DEFF Research Database (Denmark)

    Plauborg, Finn; Abrahamsen, Per; Gjettermann, Birgitte

    2010-01-01

    a central role in reducing crop transpiration. This paper presented a mechanistic model (Daisy) developed based on data obtained in the SAFIR project on measured leaf gas exchange and soil water dynamics in irrigated potato crops grown in a semi-field environment subjected to different irrigation regimes...... Daisy model is capable of simulating the mechanisms underlying the water saving effects of the partial root-zone drying (PRD) irrigation as compared with the conventional full irrigation (FI). However the simulated effect on both crop yield and water use in this particular experiment was negligible......Application of water saving irrigation strategies in agriculture has become increasingly important. Both modelling and experimental work are needed to gain more insights into the biological and physical mechanisms in the soil-plant system, which regulates water flow in the system and plays...

  4. Cultivar Differences in the Stomatal Characteristics of Cut Roses Grown at High Relative Humidity

    NARCIS (Netherlands)

    Fanourakis, D.; Tapia, A.; Heuvelink, E.; Pinto De Carvalho, S.M.

    2009-01-01

    High relative air humidity (RH>85%) during cultivation is known to reduce the vase life of cut roses, but the magnitude of such effect is cultivar dependent. The reasons behind this genotypic variation are not yet known. In this study, the stomatal density and stomatal responses to two closing

  5. [The laser therapy and laser acupunture of patients with chronic recurrent aphthous stomatitis].

    Science.gov (United States)

    Mikhaĭlova, R I; Terekhova, N V; Zemskaia, E A; Melkadze, N

    1992-01-01

    Laser therapy and laser acupuncture of the biologically active sites were administered to 24 patients with chronic recurrent aphthous stomatitis. The biologically active sites were selected individually with due consideration for the underlying somatic condition. Good results were achieved in the patients with the fibrous form of chronic aphthous stomatitis. Secretory and serum immunoglobulin levels were monitored over the course of laser treatment.

  6. Guard cell chloroplasts are essential for blue light-dependent stomatal opening in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Noriyuki Suetsugu

    Full Text Available Blue light (BL induces stomatal opening through the activation of H+-ATPases with subsequent ion accumulation in guard cells. In most plant species, red light (RL enhances BL-dependent stomatal opening. This RL effect is attributable to the chloroplasts of guard cell, the only cells in the epidermis possessing this organelle. To clarify the role of chloroplasts in stomatal regulation, we investigated the effects of RL on BL-dependent stomatal opening in isolated epidermis, guard cell protoplasts, and intact leaves of Arabidopsis thaliana. In isolated epidermal tissues and intact leaves, weak BL superimposed on RL enhanced stomatal opening while BL alone was less effective. In guard cell protoplasts, RL enhanced BL-dependent H+-pumping and DCMU, a photosynthetic electron transport inhibitor, eliminated this effect. RL enhanced phosphorylation levels of the H+-ATPase in response to BL, but this RL effect was not suppressed by DCMU. Furthermore, DCMU inhibited both RL-induced and BL-dependent stomatal opening in intact leaves. The photosynthetic rate in leaves correlated positively with BL-dependent stomatal opening in the presence of DCMU. We conclude that guard cell chloroplasts provide ATP and/or reducing equivalents that fuel BL-dependent stomatal opening, and that they indirectly monitor photosynthetic CO2 fixation in mesophyll chloroplasts by absorbing PAR in the epidermis.

  7. Viral Surveillance during the 2006 Vesicular Stomatitis Outbreak in Natrona County, Wyoming

    Science.gov (United States)

    In 2006, we collected 12203 biting flies from a vesicular stomatitis outbreak in Natrona County, Wyoming. Flies were identified to the species level and viruses were isolated and identified by RT-PCR. We detected vesicular stomatitis virus-New Jersey serotype in two pools of Simulium bivittatum, W...

  8. Experimental infection of Didelphis marsupialis with Vesicular Stomatitis New Jersey Virus

    Science.gov (United States)

    Although vesicular stomatitis has been present for many years in the Americas, many aspects of its natural history remain undefined. In this study we challenged five adult Virginia opossums (Didelphis marsupialis) with vesicular stomatitis New Jersey serotype virus (VSNJV). Opossums had no detecta...

  9. Time to seroconversion to vesicular stomatitis virus in sentinel cows in Southern Mexico

    Science.gov (United States)

    Vesicular stomatitis (VS) is a disease of livestock and some wildlife species caused by vesicular stomatitis virus (VSV). VS epidemics are frequent in certain regions of the United States and such epidemics inflict severe economic losses to affected regions of the country. In this study, a prospecti...

  10. Genetic and antigenic relationships of veicular stomatitis viruses from South America

    Science.gov (United States)

    Vesicular stomatitis (VS) viruses have beenclassified into two serotypes: New Jersey (VSNJV) and Indiana (VSIV). Here, we have characterized field isolates causing vesicular stomatitis in Brazil and Argentina over a 35-year span. Cluster analysis based on either serological relatedness, as inferred ...

  11. Role of salivary and candidal proteins in denture stomatitis: an exploratory proteomic analysis.

    Science.gov (United States)

    Byrd, Warren C; Schwartz-Baxter, Sarah; Carlson, Jim; Barros, Silvana; Offenbacher, Steven; Bencharit, Sompop

    2014-07-29

    Denture stomatitis, inflammation and redness beneath a denture, affects nearly half of all denture wearers. Candidal organisms, the presence of a denture, saliva, and host immunity are the key etiological factors for the condition. The role of salivary proteins in denture stomatitis is not clear. In this study 30 edentulous subjects wearing a maxillary complete denture were recruited. Unstimulated whole saliva from each subject was collected and pooled into two groups (n = 15 each), healthy and stomatitis (Newton classification II and III). Label-free multidimensional liquid chromatography/tandem mass spectrometry (2D-LC-MS/MS) proteomics on two mass spectrometry platforms were used to determine peptide mass differences between control and stomatitis groups. Cluster analysis and principal component analysis were used to determine the differential expression among the groups. The two proteomic platforms identified 97 and 176 proteins (ANOVA; p stomatitis groups. Three proteins including carbonic anhydrase 6, cystatin C, and cystatin SN were found to be the same as previous study. Salivary proteomic profiles of patients with denture stomatitis were found to be uniquely different from controls. Analysis of protein components suggests that certain salivary proteins may predispose some patients to denture stomatitis while others are believed to be involved in the reaction to fungal infection. Analysis of candidal proteins suggests that multiple species of candidal organisms play a role in denture stomatitis.

  12. Development and Characterization of Oral Spray for Stomatitis Containing Irsogladine Maleate.

    Science.gov (United States)

    Kawano, Yayoi; Imamura, Ayano; Nakamura, Tomoe; Akaishi, Mio; Satoh, Mitsutoshi; Hanawa, Takehisa

    2016-12-01

    The stomatitis caused by anticancer agents and radiation therapy deteriorates patient QOL, potentially causing eating disorders as a result of pain. Although gargling and ointments can be used in the treatment of stomatitis, patients must spit out mouthwash after use, while ointment application requires a finger to be inserted into the oral cavity. In contrast, sprays eliminate these potential compliance problems. Therefore, we developed a stomatitis spray that remains on the oral mucosa. It has been reported that irsogladine maleate (IM) is effective against stomatitis via oral administration. IM is water insoluble; thus, it was dissolved with various cyclodextrins (CDs). Furthermore, we examined combination with gum ghatti (GG), a mucoadhesive polymer. The interaction between mucin and GG was examined by Quartz Crystal Microbalance with Dissipation monitoring. We found that GG exhibited mucoadhesion. Furthermore, we examined the healing effects of IM on stomatitis in a stomatitis model hamster. We found that stomatitis healed after direct application of IM. However, the model used in this experiment is not based on stomatitis caused by anticancer agents. Further study is therefore necessary.

  13. Grasses use an alternatively wired bHLH transcription factor network to establish stomatal identity.

    Science.gov (United States)

    Raissig, Michael T; Abrash, Emily; Bettadapur, Akhila; Vogel, John P; Bergmann, Dominique C

    2016-07-19

    Stomata, epidermal valves facilitating plant-atmosphere gas exchange, represent a powerful model for understanding cell fate and pattern in plants. Core basic helix-loop-helix (bHLH) transcription factors regulating stomatal development were identified in Arabidopsis, but this dicot's developmental pattern and stomatal morphology represent only one of many possibilities in nature. Here, using unbiased forward genetic screens, followed by analysis of reporters and engineered mutants, we show that stomatal initiation in the grass Brachypodium distachyon uses orthologs of stomatal regulators known from Arabidopsis but that the function and behavior of individual genes, the relationships among genes, and the regulation of their protein products have diverged. Our results highlight ways in which a kernel of conserved genes may be alternatively wired to produce diversity in patterning and morphology and suggest that the stomatal transcription factor module is a prime target for breeding or genome modification to improve plant productivity.

  14. Does Size Matter? Atmospheric CO2 May Be a Stronger Driver of Stomatal Closing Rate Than Stomatal Size in Taxa That Diversified under Low CO2

    Science.gov (United States)

    Elliott-Kingston, Caroline; Haworth, Matthew; Yearsley, Jon M.; Batke, Sven P.; Lawson, Tracy; McElwain, Jennifer C.

    2016-01-01

    One strategy for plants to optimize stomatal function is to open and close their stomata quickly in response to environmental signals. It is generally assumed that small stomata can alter aperture faster than large stomata. We tested the hypothesis that species with small stomata close faster than species with larger stomata in response to darkness by comparing rate of stomatal closure across an evolutionary range of species including ferns, cycads, conifers, and angiosperms under controlled ambient conditions (380 ppm CO2; 20.9% O2). The two species with fastest half-closure time and the two species with slowest half-closure time had large stomata while the remaining three species had small stomata, implying that closing rate was not correlated with stomatal size in these species. Neither was response time correlated with stomatal density, phylogeny, functional group, or life strategy. Our results suggest that past atmospheric CO2 concentration during time of taxa diversification may influence stomatal response time. We show that species which last diversified under low or declining atmospheric CO2 concentration close stomata faster than species that last diversified in a high CO2 world. Low atmospheric [CO2] during taxa diversification may have placed a selection pressure on plants to accelerate stomatal closing to maintain adequate internal CO2 and optimize water use efficiency. PMID:27605929

  15. Hydraulic conductance as well as nitrogen accumulation plays a role in the higher rate of leaf photosynthesis of the most productive variety of rice in Japan

    Science.gov (United States)

    Taylaran, Renante D.; Adachi, Shunsuke; Ookawa, Taiichiro; Usuda, Hideaki; Hirasawa, Tadashi

    2011-01-01

    An indica variety Takanari is known as one of the most productive rice varieties in Japan and consistently produces 20–30% heavier dry matter during ripening than Japanese commercial varieties in the field. The higher rate of photosynthesis of individual leaves during ripening has been recognized in Takanari. By using pot-grown plants under conditions of minimal mutual shading, it was confirmed that the higher rate of leaf photosynthesis is responsible for the higher dry matter production after heading in Takanari as compared with a japonica variety, Koshihikari. The rate of leaf photosynthesis and shoot dry weight became larger in Takanari after the panicle formation and heading stages, respectively, than in Koshihikari. Roots grew rapidly in the panicle formation stage until heading in Takanari compared with Koshihikari. The higher rate of leaf photosynthesis in Takanari resulted not only from the higher content of leaf nitrogen, which was caused by its elevated capacity for nitrogen accumulation, but also from higher stomatal conductance. When measured under light-saturated conditions, stomatal conductance was already decreased due to the reduction in leaf water potential in Koshihikari even under conditions of a relatively small difference in leaf–air vapour pressure difference. In contrast, the higher stomatal conductance was supported by the maintenance of higher leaf water potential through the higher hydraulic conductance in Takanari with the larger area of root surface. However, no increase in root hydraulic conductivity was expected in Takanari. The larger root surface area of Takanari might be a target trait in future rice breeding for increasing dry matter production. PMID:21527630

  16. Hydraulic conductance as well as nitrogen accumulation plays a role in the higher rate of leaf photosynthesis of the most productive variety of rice in Japan.

    Science.gov (United States)

    Taylaran, Renante D; Adachi, Shunsuke; Ookawa, Taiichiro; Usuda, Hideaki; Hirasawa, Tadashi

    2011-07-01

    An indica variety Takanari is known as one of the most productive rice varieties in Japan and consistently produces 20-30% heavier dry matter during ripening than Japanese commercial varieties in the field. The higher rate of photosynthesis of individual leaves during ripening has been recognized in Takanari. By using pot-grown plants under conditions of minimal mutual shading, it was confirmed that the higher rate of leaf photosynthesis is responsible for the higher dry matter production after heading in Takanari as compared with a japonica variety, Koshihikari. The rate of leaf photosynthesis and shoot dry weight became larger in Takanari after the panicle formation and heading stages, respectively, than in Koshihikari. Roots grew rapidly in the panicle formation stage until heading in Takanari compared with Koshihikari. The higher rate of leaf photosynthesis in Takanari resulted not only from the higher content of leaf nitrogen, which was caused by its elevated capacity for nitrogen accumulation, but also from higher stomatal conductance. When measured under light-saturated conditions, stomatal conductance was already decreased due to the reduction in leaf water potential in Koshihikari even under conditions of a relatively small difference in leaf-air vapour pressure difference. In contrast, the higher stomatal conductance was supported by the maintenance of higher leaf water potential through the higher hydraulic conductance in Takanari with the larger area of root surface. However, no increase in root hydraulic conductivity was expected in Takanari. The larger root surface area of Takanari might be a target trait in future rice breeding for increasing dry matter production.

  17. Denture Stomatitis and Candida Albicans in Iranian Population: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Mahmood Moosazadeh

    2016-09-01

    Full Text Available Statement of the Problem: Denture stomatitis is the common form of oral candidiasis, which is seen in the form of diffused inflammation in the areas covered by dentures. Many primary studies report the prevalence of denture stomatitis and candida albicans among patients in the Iranian population; therefore, using meta-analysis is valuable for health policy makers. Purpose: The purpose of the present study is to determine the prevalence of denture stomatitis and candida albicans in Iran. Materials and Method: Using relevant keywords, national and international databases were searched. After limiting the search strategy and deleting the duplicates, the remaining papers were screened by examining the title and abstract. In order to increase the sensitivity of search reference lists of papers were examined. Finally the index of heterogeneity between studies was defined using Cochran test (Q and I-squared (I2. According to heterogeneity, the random effects model was used to estimate the prevalence of denture stomatitis and candida albicans in Iran. Result: The prevalence of denture stomatitis in 12 studies, and the prevalence of candida albicans in patients with denture stomatitis have been reported in 6 studies. The number of sample under investigated and its age range among primary studies included meta- analysis was 2271 individuals and 32.7 till 87.5 years respectively. The prevalence of denture stomatitis in preliminary studies imported to a meta-analysis varied from 1.9% to 54.6%, and its rate in Iran using the meta-analysis was estimated 28.9 % (CI 95%: 18.2-39.6. Also the overall prevalence of candida albicans in patients with denture stomatitis in Iran was estimated 60.6% (CI 95%:50.1-71.2. Conclusion: This study showed that the prevalence of denture stomatitis and candida albicans among patient infected denture stomatitis is relatively significant in Iran.

  18. Adaxial/abaxial specification in the regulation of photosynthesis and stomatal opening with respect to light orentation and growth with CO2 enrichment in the C4 species Paspalum dilatatum

    NARCIS (Netherlands)

    Soares, A.S.; Discoll, S.P.; Olmos, E.; Harbinson, J.; Arrabaca, M.C.

    2008-01-01

    Whole-plant morphology, leaf structure and composition were studied together with the effects of light orientation on the dorso-ventral regulation of photosynthesis and stomatal conductance in Paspalum dilatatum cv. Raki plants grown for 6 wk at either 350 or 700 µl l¿1 CO2. Plant biomass was double

  19. Understanding Decreases in Land Relative Humidity with Global Warming: Conceptual Model and GCM Simulations

    Science.gov (United States)

    Byrne, Michael P.; O'Gorman, Paul A.

    2016-12-01

    Climate models simulate a strong land-ocean contrast in the response of near-surface relative humidity to global warming: relative humidity tends to increase slightly over oceans but decrease substantially over land. Surface energy balance arguments have been used to understand the response over ocean but are difficult to apply over more complex land surfaces. Here, a conceptual box model is introduced, involving moisture transport between the land and ocean boundary layers and evapotranspiration, to investigate the decreases in land relative humidity as the climate warms. The box model is applied to idealized and full-complexity (CMIP5) general circulation model simulations, and it is found to capture many of the features of the simulated changes in land relative humidity. The box model suggests there is a strong link between fractional changes in specific humidity over land and ocean, and the greater warming over land than ocean then implies a decrease in land relative humidity. Evapotranspiration is of secondary importance for the increase in specific humidity over land, but it matters more for the decrease in relative humidity. Further analysis shows there is a strong feedback between changes in surface-air temperature and relative humidity, and this can amplify the influence on relative humidity of factors such as stomatal conductance and soil moisture.

  20. Opportunistic microorganisms in individuals with lesions of denture stomatitis.

    Science.gov (United States)

    Pereira, Cristiane Aparecida; Toledo, Bruna Costa; Santos, Camila Teles; Pereira Costa, Anna Carolina Borges; Back-Brito, Graziella Nuernberg; Kaminagakura, Estela; Jorge, Antonio Olavo Cardoso

    2013-08-01

    The aim of this study was to isolate, quantify, identify, and compare opportunistic microorganisms (Candida and Staphylococcus genera and Enterobacteriaceae/Pseudomonadaceae families) from prosthesis-fitting surfaces, the hard palate, and mouth rinses of individuals wearing removable maxillary prosthesis with (50) and without (50) lesions of denture stomatitis (DS). The strains were collected and identified using phenotypic, biochemical and molecular tests. The counts of microorganisms were significantly higher in the group of individuals with DS (P < 0.05). C. albicans was the most frequently isolated yeast species in both groups, following by C. tropicalis and C. glabrata. Six isolates were identified as C. dubliniensis. S. aureus and S. epidermidis were the most frequent Staphylococcus species in both groups. Klebsiella pneumoniae was the predominant species in both groups. The association between Candida spp. and bacteria isolated in this study with DS suggests that these microorganisms may play important roles in the establishment and persistence of this disease.

  1. Periodic fevers with aphthous stomatitis, pharyngitis, and adenitis (PFAPA).

    Science.gov (United States)

    Vigo, Giulia; Zulian, Francesco

    2012-11-01

    PFAPA syndrome (acronym of periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis) is the most common cause of periodic fever in childhood. Nowadays, it is considered part of the wide family of the autoinflammatory diseases, but a genetic or molecular marker hasn't been identified yet, therefore, its etiology is still unknown. Diagnosis is essentially based on clinical criteria but, especially in younger children, it is sometimes difficult to differentiate it from other hereditary periodic fever syndromes. Fever attacks in PFAPA have a spontaneous resolution and in a high rate of patients the syndrome ends spontaneously over time. Treatment is still a matter of debate. Usually a single administration of oral corticosteroids aborts attacks. Tonsillectomy may be an alternative option but its role remains to be clarified. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. AMLEXANOX 5% SEBAGAI MODALITAS TERAPI STOMATITIS AFTOSA REKUREN TERKINI

    Directory of Open Access Journals (Sweden)

    Rusmawati Rusmawati

    2015-07-01

    Full Text Available Recurrent Aphthous Stomatitis (RAS is characterized by painful recurring ulceration of oral mucosa and is the most common oral ulcerative disease. The specific etiology of the disease remains unknown. This situation makes the therapy of RAS difficult and uncertain. This article will discuss the effectiveness and the safety of amlexanox 5% in relieving the symptoms and accelerate heling in RAS lesions. Amlexanox 5% is a new drug used topically in treatment of RAS. The mechanism of action by which alexanox accelerates healing of RAS in unknown. Clnincal study of efficacy amlexanox 5% has been demonstrated significantly accelerate healing and reduce pain of RAS, compared to amlexanox 1% vehicle and no treatment. 5% amlexanox oral paste has an advantageous pharmacological activity to accelerate healing and reduce the pain of RAS, thus it can be used as one of the modality in this therapy.

  3. Methemoglobinemia in postchemotherapy stomatitis topical treatment: 2 pediatric cases.

    Science.gov (United States)

    Kaczorowska-Hac, Barbara; Stefanowicz, Joanna; Stachowicz-Stencel, Teresa; Kozlowska, Marta; Adamkiewicz-Drozynska, Elzbieta; Balcerska, Anna

    2012-03-01

    Methemoglobinemia is a rare congenital or acquired disease of increased blood methemoglobin concentration. We documented 2 cases of children suffering from neuroblastoma whose postchemotherapy anemia, leucopenia, and stomatitis were complicated by methemoglobinemia after using a formulary oral gel (7.5% benzocaine, doxycycline, nystatin, glycerin). The complication resulted in hospital treatment. Percutaneous oxygen saturation remained at 85% and 87% despite administration of 100% oxygen through a nonrebreather mask. Arterial blood gas analysis showed an oxygen saturation of 98% and 97%, respectively. Spectroscopic measurement showed methemoglobin concentration of 42% and 35.5%, respectively. After red blood cell transfusion and oral ascorbic acid in case 1 and methylene blue in case 2, the patients' condition improved. Although the benzocaine gel is not in use in several medical systems, it should be considered as a possible reason for methemoglobinemia.

  4. Stomatal distribution, stomatal density and daily leaf movement in Acacia aroma (Leguminosae Distribución y densidad estomática y movimiento diario de la hoja en Acacia aroma (Leguminosae

    Directory of Open Access Journals (Sweden)

    Marcelo P. Hernández

    2010-12-01

    Full Text Available Acacia aroma Gillies ex Hook. & Arn. grows in the Chacoan and Yungas Biogeographic Provinces, Argentina. It has numerous medicinal applications, sweet and edible fruits, and it may be used as forage. The objective of the present contribution was to analyse the stomatal distribution and stomatal density on the secondary leaflet surfaces, in different parts of the leaf, and at different tree crown levels, establishing the leaf movement and environmental condition relationships. The work was performed with fresh material and herbarium specimens, using conventional anatomical techniques. Stomatal distribution on the secondary leaflet surfaces was established, and differences in stomatal density among basal, medium and apical leaflets were found. A decrease in stomatal density from the lower level to the upper level of the tree crown would be connected with that. The stomatal distribution and density appear related to the secondary leaflet shape and its position on the secondary rachis, interacting with the daily secondary leaflets and leaf movement, and the weather conditions. It is interesting that the medium value of stomata density were found in the middle part of the leaf and at the middle level of the tree crown. Original illustrations are given.Acacia aroma crece en las Provincias Biogeográficas Chaqueña y de las Yungas, Argentina. Este árbol posee numerosas aplicaciones en medicina popular, sus frutos son comestibles y puede ser usada como forraje. Los objetivos de la presente contribución fueron: establecer la distribución y densidad de los estomas en el folíolo secundario, en distintos folíolos secundarios de la misma hoja y en los folíolos secundarios de las hojas de la parte basal, media y superior de la copa del árbol, estableciendo relaciones con el movimiento diario de las hojas y condiciones ambientales. Para el estudio se utilizó material fresco y ejemplares de herbario empleando técnicas de anatomía convencionales. Se

  5. Depolymerization of actin cytoskeleton is involved in stomatal closure-induced by extracellular calmodulin in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Extracellular calmodulin(CaM)plays significant roles in many physiological processes,but little is known about its mechanism of regulating stomatal movements.In this paper,whether CaM exists in the guard cell walls of Arabidopsis and whether depolymerization of actin cytoskeleton is involved in extracellular CaM-induced stomatal closing are investigated.It is found that CaM exists in guard cell walls of Arabidopsis,and its molecular weight is about 17 kD.Bioassay using CaM antagonists W7-agarose and anti-CaM serum shows that the endogenous extracellular CaM promotes stomatal closure and delays stomatal opening.The long radial actin filaments in guard cells undergo disruption in a time-dependent manner during exogenous CaM-induced stomatal closing.Pharmacological experiments show that depolymerization of actin cytoskeleton enhances the effect of exogenous CaM-induced stomatal closing and polymerization reduces the effect.We also find that exogenous CaM triggers an increase in [Ca2+]cyt of guard cells.If [Ca2+]cyt increase is blocked with EGTA,exogenous CaM-induced stomatal closure is inhibited.These results indicate that extracellular CaM causes elevation of [Ca2+]cyt in guard cells,subsequently resulting in disruption of actin filaments and finally leading to guard cells closure.

  6. Water Channels Are Involved in Stomatal Oscillations Encoded by Parameter-Specific Cytosolic Calcium Oscillations

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Earlier studies have shown that various stimuli can induce specific cytosolic calcium ([Ca2+]cyt) oscillations in guard cells and various oscillations in stomatal apertures. Exactly how [Ca2+]cyt oscillation signaling functions in stomatal oscillation is not known. In the present study, the epidermis of broad bean (Vicia faba L.)was used and a rapid ion-exchange treatment with two shifting buffers differing in K+ and Ca2+ concentrations was applied. The treatment for five transients at a 10-min transient period induced clear and regular stomatal oscillation. However, for other transient numbers and periods, the treatments induced some irregular oscillations or even no obvious oscillations in stomatal aperture. The results indicate that stomatal oscillation is encoded by parameter-specific [Ca2+]cyt oscillation: the parameters of [Ca2+]cyt oscillation affected the occurrence rate and the parameters of stomatal oscillation. The water channel inhibitor HgCl2 completely inhibited stomatal oscillation and the inhibitory effect could be partially reversed by β-mercaptoethanol (an agent capable of reversing water channel inhibition by HgCl2). Other inhibitory treatments against ion transport (i.e. the application of LaCl3, EGTA, or tetraethylammonium chloride (TEACl))weakly impaired stomatal oscillation when the compounds were added after rapid ion-exchange treatment.If these compounds were added before rapid-ion exchange treatment, the inhibitory effect was much more apparent (except in the case of TEACI). The results of the present study suggest that water channels are involved in stomatal oscillation as a downstream element of [Ca2+]cyt oscillation signaling.

  7. Transpiration and stomatal resistance variations of perennial tropical crops under soil water availability conditions and water deficit

    Directory of Open Access Journals (Sweden)

    José Ozinaldo Alves de Sena

    2007-03-01

    Full Text Available During the dry and rainy seasons, determinations of stomatal resistance and transpiration of five tropical crops were carried out: guarana (Paullinia cupana Kunth, coffee (Coffea arabica L., cashew (Anacardium occidentale L., guava (Psidium guajava L. and rubber (Hevea brasiliensis Muell. - Arg. trees. Experimental design was done at randomized complete blocks with five replications. During the dry season there was a decrease in values of stomatal resistance in the following order: guarana > coffee> cashew> guava > rubber, with values from 2.5 to 30.0 s.cm-1. During the rainy season the stomatal resistance values varied from 1.5 to 3.0 s.cm-1. The guarana and coffee crops showed higher resistance to water transpiration when compared to other crops. During the rainy season, the rubber tree continued to present lower stomatal resistance and, consequently, higher transpiration.O experimento foi realizado no Departamento de Produção Vegetal da Escola Superior de Agricultura "Luiz de Queiroz", ESALQ/USP, Piracicaba, São Paulo, Brasil, utilizando-se as culturas de guaranazeiro (Paullinia cupana Kunth, cafeeiro (Coffea arabica L., cajueiro (Anacardium occidentale L., goiabeira (Psidium guajava L. e seringueira (Hevea brasiliensis Muell. - Arg.. No período de seca (setembro/94 e de chuvas (novembro/94, realizaram-se determinações de resistência estomática (RE (s cm-1 e transpiração (T (µg cm-1 s-1 nas diferentes espécies. O delineamento experimental foi em blocos casualizados com cinco repetições. A partir das análises dos dados pode-se concluir: 1. diferenças significativas entre espécies, em termos das variáveis avaliadas no período de deficiência hídrica, com valores decrescentes de resistência estomática e crescente de transpiração na seguinte ordem: guaranazeiro > cafeeiro > cajueiro > goiabeira > seringueira; 2. Nas águas as diferenças entre espécies, para ambas as variáveis, foram menos evidentes, continuando a

  8. Everolimus-associated stomatitis in a patient who had renal transplant.

    Science.gov (United States)

    Ji, Yisi D; Aboalela, Ali; Villa, Alessandro

    2016-10-19

    Everolimus is used as an immunosuppressant in renal allograft transplant rejection and in metastatic breast cancer treatment. One side effect of everolimus is stomatitis, referred to as mammalian target of rapamycin inhibitor-associated stomatitis. This side effect can affect treatment course and contribute to discontinuation of therapy or dose reduction, previously reported in the treatment of metastatic breast cancer. Here, we present a case of everolimus-associated stomatitis with a novel management method with intralesional triamcinolone that allows for continuous course of everolimus.

  9. Ozone decreases soybean productivity and water use efficiency

    Science.gov (United States)

    Betzelberger, A. M.; VanLoocke, A. D.; Ainsworth, E. A.; Bernacchi, C. J.

    2011-12-01

    The combination of population growth and climate change will increase pressure on agricultural and water resources throughout this century. An additional consequence of this growth is an increase in anthropogenic emissions that lead to the formation of tropospheric ozone (O3), which in concert with climate change, poses a significant threat to human health and nutrition. In addition to being an important greenhouse gas, O3 reduces plant productivity, an effect that has been particularly pronounced in soybean, which provides over half of the world's oilseed production. Plant productivity is linked to feedbacks in the climate system, indirectly through the carbon cycle, as well as directly through the partitioning of radiation into heat and moisture fluxes. Soybean, along with maize, comprises the largest ecosystem in the contiguous U.S. Therefore, changes in productivity and water use under increasing O3 could impact human nutrition as well as the regional climate. Soybean response to increasing O3 concentrations was tested under open-air agricultural conditions at the SoyFACE research site. During the 2009 growing season, eight 20 m diameter FACE plots were exposed to different O3 concentrations, ranging from 40 to 200 ppb. Canopy growth (leaf area index) and physiological measurements of leaf photosynthesis and stomatal conductance were taken regularly throughout the growing season. Canopy fluxes of heat and moisture were measured using the residual energy balance micrometeorological technique. Our results indicate that as O3 increased from 40 to 200 ppb, rates of photosynthesis and stomatal conductance decreased significantly. Further, the seed yield decreased by over 60%, while water use decreased by 30% and the water-use-efficiency (yield/water-use) declined by 50%. The growing season average canopy temperatures increased by 1°C and midday temperatures increased by 2°C compared to the control. Warmer and drier canopies may result in a positive feedback on O3

  10. The Lateglacial and Postglacial vegetation history of the northwestern limits of Beringia, based on pollen, stomate and tree stump evidence

    Science.gov (United States)

    Pisaric, M. F. J.; MacDonald, G. M.; Velichko, A. A.; Cwynar, L. C.

    2001-01-01

    In order to reconstruct the Late- and Postglacial vegetation history of the northwestern edge of Beringia, a sediment core was collected from a lake north of the present treeline along the lower Lena River of northeastern Siberia, and analysed for fossil pollen and stomates. In addition, fossil tree stumps were collected in the vicinity of the lake. Eight radiocarbon dates indicate that the lake sediment record spans at least the past 12,300 yr BP. The early vegetation at this site was dominated by herb and shrub tundra. Possible evidence of Younger Dryas cooling, consisting of a decrease in shrub birch and increases in grass and herbaceous plants, occurs between 11,000 and 10,000 yr BP. Forests, dominated by Larix dahurica and including Picea obovata, extended northward to the site between 8500 and 3500 yr BP. There is an agreement between the pollen, stomate and tree stump evidence for this advance. The modern vegetation of shrub tundra was established after 3500 yr BP.

  11. Activated expression of an Arabidopsis HD-START protein confers drought tolerance with improved root system and reduced stomatal density.

    Science.gov (United States)

    Yu, Hong; Chen, Xi; Hong, Yuan-Yuan; Wang, Yao; Xu, Ping; Ke, Sheng-Dong; Liu, Hai-Yan; Zhu, Jian-Kang; Oliver, David J; Xiang, Cheng-Bin

    2008-04-01

    Drought is one of the most important environmental constraints limiting plant growth and agricultural productivity. To understand the underlying mechanism of drought tolerance and to identify genes for improving this important trait, we conducted a gain-of-function genetic screen for improved drought tolerance in Arabidopsis thaliana. One mutant with improved drought tolerance was isolated and designated as enhanced drought tolerance1. The mutant has a more extensive root system than the wild type, with deeper roots and more lateral roots, and shows a reduced leaf stomatal density. The mutant had higher levels of abscisic acid and Pro than the wild type and demonstrated an increased resistance to oxidative stress and high levels of superoxide dismutase. Molecular genetic analysis and recapitulation experiments showed that the enhanced drought tolerance is caused by the activated expression of a T-DNA tagged gene that encodes a putative homeodomain-START transcription factor. Moreover, overexpressing the cDNA of the transcription factor in transgenic tobacco also conferred drought tolerance associated with improved root architecture and reduced leaf stomatal density. Therefore, we have revealed functions of the homeodomain-START factor that were gained upon altering its expression pattern by activation tagging and provide a key regulator that may be used to improve drought tolerance in plants.

  12. Yeast elicitor-induced stomatal closure and peroxidase-mediated ROS production in Arabidopsis.

    Science.gov (United States)

    Khokon, Md Atiqur Rahman; Hossain, Mohammad Anowar; Munemasa, Shintaro; Uraji, Misugi; Nakamura, Yoshimasa; Mori, Izumi C; Murata, Yoshiyuki

    2010-11-01

    Yeast elicitor (YEL) induces stomatal closure. We investigated reactive oxygen species (ROS) production, nitric oxide (NO) production and [Ca(2+)](cyt) oscillations to clarify YEL signaling in Arabidopsis guard cells. YEL induced ROS accumulation in guard cells. A peroxidase inhibitor [salicylhydroxamic acid (SHAM)] inhibited the stomatal closure and the ROS accumulation, but neither the atrbohD atrbohF mutation nor an NADPH oxidase inhibitor [diphenylene iodonium chloride (DPI)] had any effect. An NO scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO)] inhibited the YEL-induced stomatal closure and SHAM abolished NO production. YEL-elicited [Ca(2+)](cyt) oscillations were inhibited by SHAM but not by the atrbohD atrbohF mutation. These results indicate that YEL induces stomatal closure accompanied by ROS production mediated by peroxidases and NO production.

  13. [Experience in irradiating with helium-neon lasers to treat patients with relapsing aphthous stomatitis].

    Science.gov (United States)

    Prikuls, V F

    2000-01-01

    Seventy-five patients with relapsing aphthous stomatitis (41 with the fibrinous form, 25 with glandular form, and 9 with necrotic form) were treated using He-Ne laser and a photosensitizer. A good therapeutic effect was attained.

  14. Involvement of Ca2+/CaM in the signal transduction of acetylcholine regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It has been known that the neurotransmitter acetylcholine (ACh) also exists in plants and is able to regulate the movement of stomata. In another aspect, Ca2+/CaM as the second messengers have a critical role of signal transduction in stomatal guard-cell. Here we showed that Ca2+/CaM were also involved in theACh regulated stomatal movement. In the medium containing Ca2+, the Ca2+ channel blockers (NIF and Ver) and CaM inhibitors (TFP and W7) could neutralize the ACh induced stomatal opening, however, they are ineffective in the medium containing K+. Those results indicated that Ca2+/CaM were involved in the signal transduction pathway of ACh regulating stomatal movement.

  15. Behaviour of Sub Prosthesis Stomatitis in Patients with Upper Dental Prosthesis

    National Research Council Canada - National Science Library

    Yoel González Beriau; Arelys Dumenigo Soler; Julia R. Fuguet Boullón

    2017-01-01

    Foundation: Sub prosthesis stomatitis is one of the most frequent affections in patients who wear dental prosthesis and constitutes a risk factor for the appearance of pre malignant and malignant lesions in the oral cavity. Objective...

  16. Anamnestic findings from patients with recurrent aphthous stomatitis.

    Science.gov (United States)

    Bratel, John; Hakeberg, Magnus

    2014-01-01

    Recurrent aphthous stomatitis (RAS) is a common oral disorder with a prevalence varying between 5% and 66%. RAS appears in three forms; minor, major and herpetiform. The aetiology is unknown.The aim of this study was to evaluate associations between specific anamnestic information and different types of recurrent aphthous stomatitis (RAS). A group of 177 patients (mean age = 42.8 years; SD = 14.3; range 17-79 years) participated. Data were collected from a structured interview, consisting of 22 questions. Information about i) health status and medication, ii) predisposing factors, iii) RAS experience, iv) previous treatment methods and v) brand of toothpaste was collected. Sixty-eight per cent of the patients were healthy and 44% of the patients were not taking any medication. Forty-one per cent of the patients did not have any apprehension of the reason for their RAS, while stress (15.8%) was the most common apprehended aetiological factor. Sixty-two per cent had one to three minor ulcers at one time. Forty-eight per cent reported having had a major aphthous ulcer at least once.The most frequent symptom reported was pain (53.7%), followed by a smarting sensation (18.6%) and tenderness (4%). The most common treatment for RAS was Zendium™ toothpaste/mouthrinse (28%), followed by corticosteroids (25%). Fifty-four per cent of the patients experienced no relief from the treatment. When toothpaste habits were investigated, Zendium™ was used by 32% of the patients and toothpaste containing sodium-lauryl-sulfatase was used by 32%.There was no positive correlation between the use of Zendium™ toothpaste and the relief of symptoms or the size, number or frequency of the aphthous ulcers. Sixty-four per cent of the patients had never smoked, while 7% were smokers. No positive correlation was found when age, gender, allergy, medication and smoking were correlated to the frequency, number and size of the aphthous ulcers. In conclusion, we found that the aetiology behind

  17. PFAPA syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis, Adenitis).

    Science.gov (United States)

    Lee, W I; Yang, M H; Lee, K F; Chen, L C; Lin, S J; Yeh, K W; Huang, J L

    1999-01-01

    This paper aims to remind paediatric clinicians to suspect and confirm 'PFAPA' syndrome (Periodic Fever, Aphthous stomatitis, Pharyngitis and cervical Adenitis syndrome). We report two cases of PFAPA syndrome: a 3-year-old healthy boy with atopic rhinitis and a boy aged 8 years 5 months who simultaneously had lymphocytic vasculitis syndrome treated with immunosuppressive drugs. Both met Marshall's criteria. The literature regarding PFAPA syndrome was complied using a Medline search for articles published between 1963 and 1998 and we then reviewed the reference lists of the articles. The Medline search revealed 28 cases with available clinical manifestations, management and prognosis. Our study describes two additional cases. We divided the cases into typical (28 cases) and atypical (two cases) PFAPA syndrome. In typical PFAPA, the age of onset was less than 5 years in most cases and the patients presented 4.9 +/- 1.4 days of fever (100%), pharyngitis (89.3%), cervical adenitis (72.1%), stomatitis (71.4%), malaise (64.3%), headache (60.7%), abdominal pain (53.6%) and nausea/vomiting (17.9%). Afebrile intervals were 3.2 +/- 2.4 months and increased with age. The time from initial onset to final episode was 3 years 7 months +/- 3 years 6 months. The total number of episodes was 8.3 +/- 2.5 (range 6-14). Effective treatment included steroids, tonsillectomy/adenoidectomy and cimetidine. The general outcome was good. In atypical PFAPF, the clinical manifestations were similar to those of typical PFAPA except that the age of onset was more than 5 years, and life-threatening intestinal perforation happened once in a patient with underlying Fanconi's anaemia. It was concluded that typical PFAPA syndrome is benign and can be diagnosed by detailed history-taking and from physical findings during repeated febrile episodes with tests to rule out other periodic fever syndromes. A review of the literatures since the first report in 1987 has shown that typical PFAPA syndrome is

  18. Maxillary osteomyelitis in two Scottish terrier dogs with chronic ulcerative paradental stomatitis.

    Science.gov (United States)

    Boutoille, Florian; Hennet, Philippe

    2011-01-01

    Two Scottish terrier dogs were presented for recurrent oral problems. They were diagnosed with refractory chronic ulcerative paradental stomatitis and necrosis of the incisive and maxillary bones. Both dogs were treated with a combination of bilateral rostral maxillectomy and tooth extractions. The ostectomy was performed with a specific cutting device using piezoelectric bone surgery technology. These two cases show that a precise evaluation of dogs is essential for the diagnose of chronic ulcerative paradental stomatitis and its differentiation from mucocutaneous autoimmune diseases.

  19. Level of Denture Cleanliness Influences the Presence of Denture Stomatitis on Maxillary Denture Bearing-Mucosa

    OpenAIRE

    Winatty Krisma; Martha Mozartha; Rani Purba

    2014-01-01

    Plaque accumulation on internal surface of denture is a common problem among removable denture wearers. Poor denture cleanliness can increase colonization of Candida albicans and cause inflammatory reaction of denture-bearing mucosa, i.e. denture stomatitis. Objective: To find out the effect of denture cleanliness level on denture stomatitis on maxillary denture-bearing mucosa in a group of removable denture wearers who received prosthodontic treatment at Poliklinik Gigi RSMH Palembang and to...

  20. Tobacco guard cells fix CO2 by both Rubisco and PEPcase while sucrose acts as a substrate during light-induced stomatal opening.

    Science.gov (United States)

    Daloso, Danilo M; Antunes, Werner C; Pinheiro, Daniela P; Waquim, Jardel P; Araújo, Wagner L; Loureiro, Marcelo E; Fernie, Alisdair R; Williams, Thomas C R

    2015-11-01

    Transcriptomic and proteomic studies have improved our knowledge of guard cell function; however, metabolic changes in guard cells remain relatively poorly understood. Here we analysed metabolic changes in guard cell-enriched epidermal fragments from tobacco during light-induced stomatal opening. Increases in sucrose, glucose and fructose were observed during light-induced stomatal opening in the presence of sucrose in the medium while no changes in starch were observed, suggesting that the elevated fructose and glucose levels were a consequence of sucrose rather than starch breakdown. Conversely, reduction in sucrose was observed during light- plus potassium-induced stomatal opening. Concomitant with the decrease in sucrose, we observed an increase in the level as well as in the (13) C enrichment in metabolites of, or associated with, the tricarboxylic acid cycle following incubation of the guard cell-enriched preparations in (13) C-labelled bicarbonate. Collectively, the results obtained support the hypothesis that sucrose is catabolized within guard cells in order to provide carbon skeletons for organic acid production. Furthermore, they provide a qualitative demonstration that CO2 fixation occurs both via ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPcase). The combined data are discussed with respect to current models of guard cell metabolism and function.

  1. Stomatal ozone flux and visible leaf injury in native juvenile trees of Fagus sylvatica L.: a field study from the Jizerske hory Mts., the Czech Republic.

    Science.gov (United States)

    Vlasáková-Matoušková, Leona; Hůnová, Iva

    2015-07-01

    The study was carried out at six sites in the Jizerskehory Mts. in the north of the Czech Republic. At all these sites, ranging in altitude between 460 and 962 m a. s. l., and during the period from June to September in 2008, O3 concentrations and environmental parameters important for accumulated stomatal O3 flux (AFst) into Fagus sylvatica leaves were measured. At five sites, visible injury on Fagus sylvatica L. juvenile tree leaves was observed. A combination of actual O3 levels in the Jizerkehory Mts. and environmental conditions, though relative air humidity and air temperature significantly limited stomatal conductance, has been sufficient enough to cause O3 uptake exceeding the critical level (CL) for forest ecosystems. The AFst values ranged between 13.4 and 22.3 mmol O3 m(-2). The CL for the accumulated stomatal flux of O3 above a flux threshold 1.6 nmol m(-2) s(-1) (AFst1.6) was exceeded at all sites from ca 45 to 270% (160% on average). The CL of 5 ppm h(-1) for AOT40 (accumulated O3 exposure above threshold of 40 ppb) was exceeded at four sites. The relationship between visible injury on O3 indices was found. The conclusions based on AOT40 and AFSt are not the same. AFSt has been determined as better predictor of visible injury than AOT40.

  2. Validation of the stomatal flux approach for the assessment of ozone visible injury in young forest trees. Results from the TOP (transboundary ozone pollution) experiment at Curno, Italy

    Energy Technology Data Exchange (ETDEWEB)

    Gerosa, G., E-mail: giacomo.gerosa@unicatt.i [Department of Mathematics and Physics, Catholic University, via dei Musei 41, 25125 Brescia (Italy); Marzuoli, R. [Department of Mathematics and Physics, Catholic University, via dei Musei 41, 25125 Brescia (Italy); Desotgiu, R.; Bussotti, F. [Department of Plant Biology, University of Florence, Piazzale delle Cascine 28, 50144 Florence (Italy); Ballarin-Denti, A. [Department of Mathematics and Physics, Catholic University, via dei Musei 41, 25125 Brescia (Italy)

    2009-05-15

    This paper summarises some of the main results of a two-year experiment carried out in an Open-Top Chambers facility in Northern Italy. Seedlings of Populus nigra, Fagus sylvatica, Quercus robur and Fraxinus excelsior have been subjected to different ozone treatments (charcoal-filtered and non-filtered air) and soil moisture regimes (irrigated and non-irrigated plots). Stomatal conductance models were applied and parameterised under South Alpine environmental conditions and stomatal ozone fluxes have been calculated. The flux-based approach provided a better performance than AOT40 in predicting the onset of foliar visible injuries. Critical flux levels, related to visible leaf injury, are proposed for P. nigra and F. sylvatica (ranging between 30 and 33 mmol O{sub 3} m{sup -2}). Soil water stress delayed visible injury appearance and development by limiting ozone uptake. Data from charcoal-filtered treatments suggest the existence of an hourly flux threshold, below which may occur a complete ozone detoxification. - The stomatal uptake of ozone is an important factor to evaluate visible injury appearance and evolution in plants.

  3. Chloroplast downsizing under nitrate nutrition restrained mesophyll conductance and photosynthesis in rice (Oryza sativa L.) under drought conditions.

    Science.gov (United States)

    Li, Yong; Ren, Binbin; Yang, Xiuxia; Xu, Guohua; Shen, Qirong; Guo, Shiwei

    2012-05-01

    The phenomenon whereby ammonium enhances the tolerance of rice seedlings (Oryza sativa L., cv. 'Shanyou 63' hybrid indica China) to water stress has been reported in previous studies. To study the intrinsic mechanism of biomass synthesis related to photosynthesis, hydroponic experiments supplying different nitrogen (N) forms were conducted; water stress was simulated by the addition of polyethylene glycol. Water stress decreased leaf water potential (Ψ(leaf)) under nitrate nutrition, while it had no negative effect under ammonium nutrition. The decreased Ψ(leaf) under nitrate nutrition resulted in chloroplast downsizing and subsequently decreased mesophyll conductance to CO(2) (g(m)). The decreased g(m) and stomatal conductance (g(s)) under nitrate nutrition with water stress restrained the CO(2) supply to the chloroplast and Rubisco. The relatively higher distribution of leaf N to Rubisco under ammonium nutrition might also be of benefit for photosynthesis under water stress. In conclusion, chloroplast downsizing induced a decline in g(m), a relatively higher decrease in g(s) under nitrate nutrition with water stress, restrained the CO(2) supply to Rubisco and finally decreased the photosynthetic rate.

  4. Involvement of nitric oxide in the signal transduction of salicylic acid regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The effects and the relationship between salicylic acid (SA) and nitric oxide (NO) on Vicia faba L. stomatal movement were studied. The results here showed that exogenous SA and NO induced stomatal closure, 100 μmol/L SA induced a rapid and striking NO increase in the cytosol of guard cells. This phenomenon was largely pre-vented by 200 μmol/L 2-phenyl-4,4,5,5-tetramethylimida-zoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, and 25 μmol/L NG-nitro-L-Arg-methyl eater (L-NAME), an in-hibitor of NO synthase (NOS) in mammalian cells that also inhibits plant NOS. In addition, SA-induced stomatal closure was largely prevented by PTIO and L-NAME. These results provide evidence that guard cells generate NO in response to SA via NOS-like activity, and that such NO production is required for full stomatal closure in response to SA. H-(1,2,4)-oxadiazole-[4,3-α]quinoxalin-1-one (ODQ), an inhibitor of guanylate cyclase, and nicotinamide, an antago-nist of cADPR production, inhibited the effects of SA- and NO-induced stomatal closure. It suggests that both cGMP and cADPR might mediate the signal transduction of SA and NO-induced stomatal closure.

  5. Is ginger (Zingiber officinale mouthwash a convenient therapeutic for denture stomatitis?

    Directory of Open Access Journals (Sweden)

    Hosein Eslami

    2015-07-01

    Full Text Available Introduction: Denture stomatitis is the most common type of chronic oral candidiasis. Ginger (Zingiber officinale is an herbal plant with profound antioxidant, antibacterial, anti-inflammatory and antifungal effects with possible effects on Candida albicans. In this study, we aimed at comparing the efficacy of ginger and nystatin mouthwashes on denture stomatitis.Materials and Methods: In this randomized clinical trial, 30 patients with type II denture stomatitis were randomly assigned into two groups. Group 1 received ginger mouthwash (20 ml, 3 times a day for 20 days, while group 2 used nystatin mouthwash (500000 IU, 3 times a day for 20 days. The patients were visited on days 5, 10, 15, 20. In each follow-up visit, the length and width of erythema were measured using a digital caliper. Patients’ satisfaction with the treatment was evaluated at the end of the study.Results: During a 20-day treatment period, both treatments significantly reduced the width and length of the erythema (P<0.001; but the changes between groups were not significant (P=0.9 for both measurements. Patients receiving ginger mouthwash were significantly more satisfied with the outcome compared to those receiving nystatin mouthwash (86.7% vs. 13.3%, P<0.001.Conclusion: Although both mouthwashes have acceptable efficacy on denture stomatitis, patients were more satisfied with ginger use. Therefore, ginger mouthwash is recommended as an alternative to nystatin mouthwash in treatment of denture stomatitis. Keywords: Denture stomatitis; Ginger; Nystatin; Mouthwash

  6. Brazilian Green Propolis Compared to Miconazole Gel in the Treatment of Candida-Associated Denture Stomatitis

    Directory of Open Access Journals (Sweden)

    Hermínia Marques Capistrano

    2013-01-01

    Full Text Available Aim. To evaluate the efficacy of Brazilian green propolis in comparison to miconazole gel in the treatment of Candida-associated denture stomatitis. Methods. Forty-five denture stomatitis patients, with palatal mucosa erythema levels classified according to Newtons’s criteria and with positive culture to Candida spp., were randomly divided into three treatment groups: 15 received miconazole gel 2%, 15 received propolis gel 2,5%, and 15 received propolis 24% for mouthwash. After four daily use lasting two weeks, they were reexamined for the denture stomatitis degree and for a second culture of Candida. The Wilcoxon’s test was applied to compare the results of clinical classification of the denture stomatitis and the Candida spp. colonies numbers, before and after each treatment. The Kruskall-Wallis’s test was used to compare efficacy among the three treatment groups. Results. There were a significant reduction or complete remission of denture stomatitis (P0.05. Conclusion. Brazilian green propolis has a similar effect as miconazole in the treatment of Candida-associated denture stomatitis being an alternative in the therapeutics of this condition.

  7. Brazilian green propolis compared to miconazole gel in the treatment of Candida-associated denture stomatitis.

    Science.gov (United States)

    Capistrano, Hermínia Marques; de Assis, Eliene Magda; Leal, Rosana Maria; Alvarez-Leite, Maria Eugênia; Brener, Sylvie; Bastos, Esther Margarida Alves Ferreira

    2013-01-01

    Aim. To evaluate the efficacy of Brazilian green propolis in comparison to miconazole gel in the treatment of Candida-associated denture stomatitis. Methods. Forty-five denture stomatitis patients, with palatal mucosa erythema levels classified according to Newtons's criteria and with positive culture to Candida spp., were randomly divided into three treatment groups: 15 received miconazole gel 2%, 15 received propolis gel 2,5%, and 15 received propolis 24% for mouthwash. After four daily use lasting two weeks, they were reexamined for the denture stomatitis degree and for a second culture of Candida. The Wilcoxon's test was applied to compare the results of clinical classification of the denture stomatitis and the Candida spp. colonies numbers, before and after each treatment. The Kruskall-Wallis's test was used to compare efficacy among the three treatment groups. Results. There were a significant reduction or complete remission of denture stomatitis (P 0.05). Conclusion. Brazilian green propolis has a similar effect as miconazole in the treatment of Candida-associated denture stomatitis being an alternative in the therapeutics of this condition.

  8. Ancestral stomatal control results in a canalization of fern and lycophyte adaptation to drought.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J

    2013-04-01

    Little is known about how a predominantly passive hydraulic stomatal control in ferns and lycophytes might impact water use under stress. Ferns and lycophytes occupy a diverse array of habitats, from deserts to rainforest canopies, raising the question of whether stomatal behaviour is the same under all ecological strategies and imposes ecological or functional constraints on ferns and lycophytes. We examined the stomatal response of a diverse sample of fern and lycophyte species to both soil and atmospheric water stress, assessing the foliar level of the hormone abscisic acid (ABA) over drought and recovery and the critical leaf water potential (Ψl) at which photosynthesis in droughted leaves failed to recover. The stomata of all ferns and lycophytes showed very predictable responses to soil and atmospheric water deficit via Ψl, while stomatal closure was poorly correlated with changes in ABA. We found that all ferns closed stomata at very low levels of water stress and their survival afterwards was limited only by their capacitance and desiccation tolerance. Ferns and lycophytes have constrained stomatal responses to soil and atmospheric water deficit as a consequence of a predominantly passive stomatal regulation. This results in a monotypic strategy in ferns and lycophytes under water stress.

  9. Stomatal vs. genome size in angiosperms: the somatic tail wagging the genomic dog?

    Science.gov (United States)

    Hodgson, J G; Sharafi, M; Jalili, A; Díaz, S; Montserrat-Martí, G; Palmer, C; Cerabolini, B; Pierce, S; Hamzehee, B; Asri, Y; Jamzad, Z; Wilson, P; Raven, J A; Band, S R; Basconcelo, S; Bogard, A; Carter, G; Charles, M; Castro-Díez, P; Cornelissen, J H C; Funes, G; Jones, G; Khoshnevis, M; Pérez-Harguindeguy, N; Pérez-Rontomé, M C; Shirvany, F A; Vendramini, F; Yazdani, S; Abbas-Azimi, R; Boustani, S; Dehghan, M; Guerrero-Campo, J; Hynd, A; Kowsary, E; Kazemi-Saeed, F; Siavash, B; Villar-Salvador, P; Craigie, R; Naqinezhad, A; Romo-Díez, A; de Torres Espuny, L; Simmons, E

    2010-04-01

    Genome size is a function, and the product, of cell volume. As such it is contingent on ecological circumstance. The nature of 'this ecological circumstance' is, however, hotly debated. Here, we investigate for angiosperms whether stomatal size may be this 'missing link': the primary determinant of genome size. Stomata are crucial for photosynthesis and their size affects functional efficiency. Stomatal and leaf characteristics were measured for 1442 species from Argentina, Iran, Spain and the UK and, using PCA, some emergent ecological and taxonomic patterns identified. Subsequently, an assessment of the relationship between genome-size values obtained from the Plant DNA C-values database and measurements of stomatal size was carried out. Stomatal size is an ecologically important attribute. It varies with life-history (woody species angiosperms. Correlation is not, however, proof of causality and here our interpretation is hampered by unexpected deficiencies in the scientific literature. Firstly, there are discrepancies between our own observations and established ideas about the ecological significance of stomatal size; very large stomata, theoretically facilitating photosynthesis in deep shade, were, in this study (and in other studies), primarily associated with vernal geophytes of unshaded habitats. Secondly, the lower size limit at which stomata can function efficiently, and the ecological circumstances under which these minute stomata might occur, have not been satisfactorally resolved. Thus, our hypothesis, that the optimization of stomatal size for functional efficiency is a major ecological determinant of genome size, remains unproven.

  10. Stomatitis-related pain in women with breast cancer undergoing autologous hematopoietic stem cell transplant.

    Science.gov (United States)

    Fall-Dickson, Jane M; Mock, Victoria; Berk, Ronald A; Grimm, Patricia M; Davidson, Nancy; Gaston-Johansson, Fannie

    2008-01-01

    The purpose of this cross-sectional, correlational study was to describe stomatitis-related pain in women with breast cancer undergoing autologous hematopoietic stem cell transplant. The hypotheses that significant, positive relationships would exist between oral pain and stomatitis, state anxiety, depression, and alteration in swallowing were tested. Stomatitis, sensory dimension of oral pain, and state anxiety were hypothesized to most accurately predict oral pain overall intensity. Thirty-two women were recruited at 2 East Coast comprehensive cancer centers. Data were collected on bone marrow transplantation day +7 +/- 24 hours using Painometer, Oral Mucositis Index-20, Oral Assessment Guide, State-Trait Anxiety Inventory, and Beck Depression Inventory. Data analysis included descriptive statistics, correlations, and stepwise multiple regression. All participants had stomatitis; 47% had oral pain, with a subset reporting continuous moderate to severe oral pain despite pain management algorithms. Significant, positive associations were seen between oral pain, stomatitis, and alteration in swallowing and between oral pain with swallowing and alteration in swallowing. Oral pain was not significantly correlated with state anxiety and depression. Oral sensory and affective pain intensity most accurately predicted oral pain overall intensity. Future research needs to explore factors that affect perception and response to stomatitis-related oropharyngeal pain and individual patient response to opioid treatment.

  11. Level of Denture Cleanliness Influences the Presence of Denture Stomatitis on Maxillary Denture Bearing-Mucosa

    Directory of Open Access Journals (Sweden)

    Winatty Krisma

    2014-12-01

    Full Text Available Plaque accumulation on internal surface of denture is a common problem among removable denture wearers. Poor denture cleanliness can increase colonization of Candida albicans and cause inflammatory reaction of denture-bearing mucosa, i.e. denture stomatitis. Objective: To find out the effect of denture cleanliness level on denture stomatitis on maxillary denture-bearing mucosa in a group of removable denture wearers who received prosthodontic treatment at Poliklinik Gigi RSMH Palembang and to investigate the denture hygiene habits of removable denture wearers. Methods: Thirty subjects participated in this study. Denture cleanliness level was assessed with disclosing solution to disclose denture plaque on internal surface of maxillary denture. Cleanliness level was graded according to Budtz-Jorgensen. Intraoral examination was done to determine any visible signs of denture stomatitis. Data referring to denture hygiene habits of removable denture wearers was collected from interview using questionnaire. Data were analyzed using the Komolgorov-Smirnov test. Results: Result of the study showed that 40% subjects had poor upper denture cleanliness. Denture stomatitis was observed on maxillary denture-bearing mucosa in 43.3% subjects. Kolmogorov-Smirnov test showed that there was a significant effect of denture cleanliness level on denture stomatitis on maxillary denture-bearing mucosa (p<0.05. Conclusion: Denture cleanliness level influence the occurence of denture stomatitis on maxillary denture bearing-mucosa in a group of removable denture wearers who received prosthodontic treatment.

  12. Pharmacological activation of small conductance calcium-activated potassium channels with naphtho[1,2-d]thiazol-2-ylamine decreases guinea pig detrusor smooth muscle excitability and contractility.

    Science.gov (United States)

    Parajuli, Shankar P; Soder, Rupal P; Hristov, Kiril L; Petkov, Georgi V

    2012-01-01

    Small conductance Ca²⁺-activated K⁺ (SK) and intermediate conductance Ca(2+)-activated K⁺ (IK) channels are thought to be involved in detrusor smooth muscle (DSM) excitability and contractility. Using naphtho[1,2-d]thiazol-2-ylamine (SKA-31), a novel and highly specific SK/IK channel activator, we investigated whether pharmacological activation of SK/IK channels reduced guinea pig DSM excitability and contractility. We detected the expression of all known isoforms of SK (SK1-SK3) and IK channels at mRNA and protein levels in DSM by single-cell reverse transcription-polymerase chain reaction and Western blot. Using the perforated patch-clamp technique on freshly isolated DSM cells, we observed that SKA-31 (10 μM) increased SK currents, which were blocked by apamin (1 μM), a selective SK channel inhibitor. In current-clamp mode, SKA-31 (10 μM) hyperpolarized the cell resting membrane potential, which was blocked by apamin (1 μM) but not by 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34) (1 μM), a selective IK channel inhibitor. SKA-31 (10 nM-10 μM) significantly inhibited the spontaneous phasic contraction amplitude, frequency, duration, and muscle force in DSM isolated strips. The SKA-31 inhibitory effects on DSM contractility were blocked by apamin (1 μM) but not by TRAM-34 (1 μM), which did not per se significantly affect DSM spontaneous contractility. SK channel activation with SKA-31 reduced contractions evoked by electrical field stimulation. SKA-31 effects were reversible upon washout. In conclusion, SK channels, but not IK channels, mediate SKA-31 effects in guinea pig DSM. Pharmacological activation of SK channels reduces DSM excitability and contractility and therefore may provide a novel therapeutic approach for controlling bladder dysfunction.

  13. Potassium channel currents in intact stomatal guard cells: rapid enhancement by abscisic acid.

    Science.gov (United States)

    Blatt, M R

    1990-02-01

    Evidence of a role for abscisic acid (ABA) in signalling conditions of water stress and promoting stomatal closure is convincing, but past studies have left few clues as to its molecular mechanism(s) of action; arguments centred on changes in H(+)-pump activity and membrane potential, especially, remain ambiguous without the fundamental support of a rigorous electrophysiological analysis. The present study explores the response to ABA of K(+) channels at the membrane of intact guard cells of Vicia faba L. Membrane potentials were recorded before and during exposures to ABA, and whole-cell currents were measured at intervals throughout to quantitate the steady-state and time-dependent characteristics of the K(+) channels. On adding 10 μM ABA in the presence of 0.1, 3 or 10 mM extracellular K(+), the free-running membrane potential (V m) shifted negative-going (-)4-7 mV in the first 5 min of exposure, with no consistent effect thereafter. Voltage-clamp measurements, however, revealed that the K(+)-channel current rose to between 1.84- and 3.41-fold of the controls in the steady-state with a mean halftime of 1.1 ± 0.1 min. Comparable changes in current return via the leak were also evident and accounted for the minimal response in V m. Calculated at V m, the K(+) currents translated to an average 2.65-fold rise in K(+) efflux with ABA. Abscisic acid was not observed to alter either K(+)-current activation or deactivation.These results are consistent with an ABA-evoked mobilization of K(+) channels or channel conductance, rather than a direct effect of the phytohormone on K(+)-channel gating. The data discount notions that large swings in membrane voltage are a prerequisite to controlling guard-cell K(+) flux. Instead, thev highlight a rise in membrane capacity for K(+) flux, dependent on concerted modulations of K(+)-channel and leak currents, and sufficiently rapid to account generally for the onset of K(+) loss from guard cells and stomatal closure in ABA.

  14. Evaluation of the Effects of Chamomill Mouthrinse on Recurrent Aphthous Stomatitis

    Directory of Open Access Journals (Sweden)

    S. Sahba

    2005-12-01

    Full Text Available Statement of Problem: Recurrent aphthous stomatitis (RAS is one of the most common diseases affecting the oral mucosa. Many topical and systemic medications used to treat RAS have adverse local and systemic effects. Chamomill (kamillosan has been shown to be an effective drug, without any noticeable side effects.Purpose: The aim of present study was to assess the efficacy of a chamomill mouthrinse on RAS in comparison with a placebo mouthrinse.Materials and Methods: The study was designed as a double blind randomized placebo controlled clinical trial with participation of 50 patients diagnosed with RAS.They were randomly divided into two groups: 26 patients forming the test group,received chamomill mouthrinse and 24 patients constituting the control group received aplacebo rinse. All subjects were instructed to use the solutions three times a day until complete resolution of the lesions. Treatment outcome was assessed on days 3 and 5 and at the exact healing time. The ability of the solution to control the pain and burning sensation and the diameter of the ulcers was evaluated. Statistical analysis was performed using the χ2 and unpaired t test for comparison between the two groups.Results: The chamomill group showed a significant reduction in the time required for controlling the pain and burning sensation (P<0.01. Ulcer diameter and healing time were also decreased (P<0.01.Conclusion: Chamomill mouthrinse was effective in the treatment of RAS without producing adverse effect.

  15. Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome and IgA nephropathy.

    Science.gov (United States)

    Sugimoto, Keisuke; Fujita, Shinsuke; Miyazawa, Tomoki; Okada, Mitsuru; Takemura, Tsukasa

    2013-01-01

    A syndrome of periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA), as well as immunoglobulin A nephropathy (IgAN), may be caused by autoimmune reactivity nephropathy. A 10-year-old boy presented with periodic fever, exudative tonsillitis, oral aphthous ulcer, and cervical lymph node inflammation. These conditions had occurred at intervals of about 2-6 weeks since the age of 3 years. Microscopic hematuria, first detected at age 8 years, worsened during episodes of PFAPA-related fever; since 10 years of age, the hematuria was accompanied by sustained proteinuria. Examination of a kidney biopsy specimen led to a diagnosis of IgAN. In the kidney specimen, fractalkine immunoreactivity and heavy macrophage infiltration were prominent. Multi-drug cocktail therapy improved the urinalysis findings, and subsequent tonsillectomy succeeded in controlling recurrences of PFAPA and IgAN. In a post-treatment renal biopsy specimen, mesangial proliferation was decreased, and fractalkine immunoreactivity was absent. Immunologic reactions against certain antigens in local mucosa, including tonsils, may be impaired in PFAPA and IgAN, as evidenced by the suppression of both diseases in our patient by tonsillectomy. Accordingly, the concurrence of PFAPA and IgAN in our patient appeared to be a consequence of shared autoimmune mechanisms and systemic and local increases in cytokine concentrations, rather than coincidence.

  16. Photodynamic inactivation of virulence factors of Candida strains isolated from patients with denture stomatitis.

    Science.gov (United States)

    Pereira, Cristiane Aparecida; Domingues, Nádia; Silva, Michelle Peneluppi; Costa, Anna Carolina Borges Pereira; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

    2015-12-01

    Candida species are major microorganisms isolated in denture stomatitis (DS), an inflammatory process of the mucosa underlying removable dental prostheses, and express a variety of virulence factors that can increase their pathogenicity. The potential of Photodynamic inactivation (PDI) in planktonic culture, biofilms and virulence factors of Candida strains was evaluated. A total of 48 clinical Candida isolates from individuals wearing removable maxillary prostheses with DS were included in the study. The effects of erythrosine (ER, 200 μM) and a green LED (λ 532 ± 10 nm, 237 mW/cm(2) and 42.63 J/cm(2)) in a planktonic culture were evaluated. The effect of the addition of ER at a concentration of 400 μM together with a green LED was evaluated in biofilms. The virulence factors of all of the Candida strains were evaluated before and after the PDI process in cells derived from biofilm and planktonic assays. All of the Candida species were susceptible to ER and green LED. However, the biofilm structures were more resistant to PDI than the planktonic cultures. PDI also promoted slight reductions in most of the virulence factors of C. albicans and some of the Candida tropicalis strains. These results suggest that the addition of PDI is effective for reducing yeasts and may also reduce the virulence of certain Candida species and decrease their pathogenicity.

  17. Effectiveness of Laser Therapy in the Management of Recurrent Aphthous Stomatitis: A Systematic Review

    Science.gov (United States)

    Fang, Hui; Cao, Ying; Xia, Rong; Zhang, Zhi-Hong

    2016-01-01

    Objectives. Laser therapy is a promising new treatment for patients with recurrent aphthous stomatitis (RAS). However, the clinical effect and security issue of laser therapy remain controversial. This systematic review was conducted to evaluate the clinical effectiveness and security of laser treatment in RAS patients. Methods. Five electronic databases were searched (MEDLINE (PubMed), EMBASE, ScienceDirect, the Cochrane Library, and Web of Science) to identify all studies that were about randomized controlled clinical trials, involving the effect of laser therapy in RAS patients. Conclusion. Twenty-three studies were retained for full-text analysis after screening the titles and abstracts of potential articles, but only 10 studies satisfied the inclusion criteria after the full texts were reviewed. The included studies reported a comparison of the effectiveness between the laser treatment and placebo laser therapy (or conventional drug therapy) when managing the RAS patients. It can be concluded that laser therapy has the superiority in relieving ulcer pain and shortening healing time when compared with placebo group or medical treatment group. Although laser therapy is a promising effective treatment for RAS, high-quality clinical studies with large sample size must be further performed to confirm the effectiveness of this therapy. PMID:28078164

  18. Stomatal behaviour and gas exchange of Sedges ( Carex spp.) under different soil moisture regimes

    Science.gov (United States)

    Busch, J.; Lösch, R.

    Sedges ( Carex spec., Cyperaceae) are important members of different vegetation types in temperate zones nearly all over the world. For this, knowledge of gas exchange and stomata behaviour of sedges is significant for understanding the exchange of water vapour and carbon dioxide between such vegetation types and the atmosphere. The gas exchange of several Carex species was studied in an experimental site of the Botanical Garden Düsseldorf (Germany). Transpiration and netassimilation rates (A), leaf conductances (g) and microclimatic parameters were measured porometrically during two vegetation periods. Patterns of dependence of leaf gas exchange on microclimatic conditions were worked out for different species and culture regimes. The sedges differ in stomatal sensitivity to changing air humidity. Water loss through transpiration is therefore decoupled from evaporation in a species-specific degree. Resulting mathematical models of g and A are presented and the importance of these species-specific differences in modelling and upscaling water vapour, carbon dioxide and trace gas fluxes are pointed out.

  19. A single nucleotide polymorphism of porcine MX2 gene provides antiviral activity against vesicular stomatitis virus.

    Science.gov (United States)

    Sasaki, Keisuke; Tungtrakoolsub, Pullop; Morozumi, Takeya; Uenishi, Hirohide; Kawahara, Manabu; Watanabe, Tomomasa

    2014-01-01

    The objective was to determine if single nucleotide polymorphisms (SNPs) in porcine MX2 gene affect its antiviral potential. MX proteins are known to suppress the multiplication of several viruses, including influenza virus and vesicular stomatitis virus (VSV). In domestic animals possessing highly polymorphic genome, our previous research indicated that a specific SNP in chicken Mx gene was responsible for its antiviral function. However, there still has been no information about SNPs in porcine MX2 gene. In this study, we first conducted polymorphism analysis in 17 pigs of MX2 gene derived from seven breeds. Consequently, a total of 30 SNPs, of which 11 were deduced to cause amino acid variations, were detected, suggesting that the porcine MX2 is very polymorphic. Next, we classified MX2 into eight alleles (A1-A8) and subsequently carried out infectious experiments with recombinant VSVΔG*-G to each allele. In A1-A5 and A8, position 514 amino acid (514 aa) of MX2 was glycine (Gly), which did not inhibit VSV multiplication, whereas in A6 and A7, 514 aa was arginine (Arg), which exhibited the antiviral ability against VSV. These results demonstrate that a SNP at 514 aa (Gly-Arg) of porcine MX2 plays a pivotal role in the antiviral activity as well as that at 631 aa of chicken Mx.

  20. Randomized clinical trial of the effectiveness of complementary therapies for recurrent aphthous stomatitis.

    Science.gov (United States)

    Rodríguez-Archilla, Alberto; Raissouni, Tarik

    2017-07-21

    Despite the high prevalence of recurrent aphthous stomatitis (RAS), its etiology is not yet completely clear and there is no completely remedial treatment available at present. The objective of this study was to evaluate the clinical efficacy and safety of 4 treatments (silver nitrate, propolis, rhubarb and walnut) for RAS. A randomized clinical trial was conducted with 125 patients with minor aphthae, including 25 patients per group: cauterization with silver nitrate, propolis, rhubarb extract, walnut extract and placebo. No patient reported adverse effects related to the treatment received. There were significant (P<.001) differences in the time elapsed until symptom resolution. The fastest treatment was silver nitrate (1.16 days), followed by the 3 alternative treatments (1.60 days with propolis, 1.84 with rhubarb and 2.00 with walnut; with no differences between them), and finally the placebo (4.64 days). The mean healing time of the lesions was statistically higher (8.96 days) for the placebo than for the 4 treatments: silver nitrate (7.32 days), propolis (6.80), rhubarb (7.72) and walnut (8.00). Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  1. Uncaria tomentosa Gel against Denture Stomatitis: Clinical Report.

    Science.gov (United States)

    Tay, Lidia Y; Dos Santos, Fabio A; Jorge, Janaina H

    2015-02-09

    The objective of this study is to report the clinical use of 2% Uncaria tomentosa gel against denture stomatitis (DS) as an alternative treatment. The patient was a 65-year-old, denture-wearing woman. At the clinical examination, her palate showed hyperplasic and erythematous mucosa indicating DS type II. DS is a chronic oral disease that affects denture wearers. It occurs as an inflammatory reaction in denture-wearing patients under maxillary prostheses. Candida albicans has been reported as the principal etiological agent. An alternative treatment, the topical application of a gel of 2% U. tomentosa three times a day for 1 week was given to the patient. After 1 week of this treatment, she had significantly reduced signs of the disease. Despite the existence of a great number of antifungal agents, treatment failure is observed frequently. Phytotherapy is becoming more popular worldwide. Currently, the most promising medicinal Amazonian herb is U. tomentosa (Willd.) DC., known as Cat's Claw. Studies of the chemical and pharmacological properties of this medicinal plant have allowed researchers to develop indications for its use. This report demonstrates the effectiveness of U. tomentosa against DS. © 2015 by the American College of Prosthodontists.

  2. Understanding and altering cell tropism of vesicular stomatitis virus

    Science.gov (United States)

    Hastie, Eric; Cataldi, Marcela; Marriott, Ian; Grdzelishvili, Valery Z.

    2013-01-01

    Vesicular stomatitis virus (VSV) is a prototypic nonsegmented negative-strand RNA virus. VSV’s broad cell tropism makes it a popular model virus for many basic research applications. In addition, a lack of preexisting human immunity against VSV, inherent oncotropism and other features make VSV a widely used platform for vaccine and oncolytic vectors. However, VSV’s neurotropism that can result in viral encephalitis in experimental animals needs to be addressed for the use of the virus as a safe vector. Therefore, it is very important to understand the determinants of VSV tropism and develop strategies to alter it. VSV glycoprotein (G) and matrix (M) protein play major roles in its cell tropism. VSV G protein is responsible for VSV broad cell tropism and is often used for pseudotyping other viruses. VSV M affects cell tropism via evasion of antiviral responses, and M mutants can be used to limit cell tropism to cell types defective in interferon signaling. In addition, other VSV proteins and host proteins may function as determinants of VSV cell tropism. Various approaches have been successfully used to alter VSV tropism to benefit basic research and clinically relevant applications. PMID:23796410

  3. Periodic fever, apthous stomatitis, pharyngitis and adenitis syndrome.

    Science.gov (United States)

    Caorsi, Roberta; Pelagatti, Maria Antonietta; Federici, Silvia; Finetti, Martina; Martini, Alberto; Gattorno, Marco

    2010-09-01

    Periodic fever, apthous stomatitis, pharyngitis and adenitis (PFAPA) syndrome is the most common cause of periodic fever of unknown origin in childhood. During the last years a number of studies on large series of patients have shed more light on the actual clinical characterization, long-term outcome and response to treatment. Current PFAPA criteria have low specificity since they are positive in a considerable proportion of patients with inherited periodic fevers. We report on the findings coming from the analysis of large cohorts of PFAPA patients and the possible implication for the differential diagnosis. An update on the efficacy of possible prophylactic treatments and tonsillectomy is given. A diagnostic score developed in a large series of children identifies patients meeting PFAPA criteria and at higher risk to carry relevant mutations of genes associated with periodic fevers. Randomized studies on the efficacy of tonsillectomy give a more evidence-based justification to this possible therapeutic approach. The findings coming from the recent literature give new information to clinicians for the correct diagnostic approach to pediatric and adult patients presenting periodic fever of unknown origin and provide an updated overview on the therapeutic possibilities for patients presenting a persistence of fever attacks.

  4. Ozone treatment of recurrent aphthous stomatitis: a double blinded study.

    Science.gov (United States)

    Al-Omiri, Mahmoud K; Alhijawi, Mohannad; AlZarea, Bader K; Abul Hassan, Ra'ed S; Lynch, Edward

    2016-06-15

    This study aimed to evaluate the use of ozone to treat recurrent aphthous stomatitis (RAS). Consecutive sixty-nine participants with RAS were recruited into this non-randomized double blind, controlled cohort observational study (test group). A control group of 69 RAS patients who matched test group with age and gender was recruited. RAS lesions in test group were exposed to ozone in air for 60 seconds while controls received only air. Ulcer size and pain were recorded for each participant at baseline and daily for 15 days. Ulcer duration was determined by recording the time taken for ulcers to disappear. The main outcome measures were pain due to the ulcer, ulcer size and ulcer duration. 138 RAS participants (69 participants and 69 controls) were analyzed. Ulcer size was reduced starting from the second day in test group and from the fourth day in controls (p ≤ 0.004). Pain levels were reduced starting from the first day in the test group and from the third day in controls (p ≤ 0.001). Ulcer duration, ulcer size after day 2 and pain levels were more reduced in the test group. In conclusion, application of ozone on RAS lesions for 60 seconds reduced pain levels and enhanced ulcers' healing by reducing ulcers' size and duration.

  5. Asymmetric packaging of polymerases within vesicular stomatitis virus

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, Jeffery; Tang, Xiaolin; Landesman, Michael B. [Dept. of Physics and Astronomy, University of Utah (United States); Center for Cell and Genome Science, University of Utah (United States); Ruedas, John B. [Dept. of Biology, San Diego State University (United States); Ghimire, Anil [Dept. of Physics and Astronomy, University of Utah (United States); Gudheti, Manasa V. [Vutara, Inc., Salt Lake City, UT (United States); Dept. of Biology, University of Utah (United States); Perrault, Jacques [Dept. of Biology, San Diego State University (United States); Jorgensen, Erik M. [Howard Hughes Medical Institute (United States); Dept. of Biology, University of Utah (United States); Gerton, Jordan M. [Dept. of Physics and Astronomy, University of Utah (United States); Dept. of Bioengineering, University of Utah (United States); Saffarian, Saveez, E-mail: saffarian@physics.utah.edu [Dept. of Physics and Astronomy, University of Utah (United States); Center for Cell and Genome Science, University of Utah (United States); Dept. of Biology, University of Utah (United States)

    2013-10-18

    Highlights: •The VSV polymerases (L proteins) are localized to the blunt end of the virus. •The VSV phosphoproteins (P proteins) are localized to the blunt end of the virus. •Each VSV virion packages a variable number of P and L proteins. -- Abstract: Vesicular stomatitis virus (VSV) is a prototypic negative sense single-stranded RNA virus. The bullet-shape appearance of the virion results from tightly wound helical turns of the nucleoprotein encapsidated RNA template (N-RNA) around a central cavity. Transcription and replication require polymerase complexes, which include a catalytic subunit L and a template-binding subunit P. L and P are inferred to be in the cavity, however lacking direct observation, their exact position has remained unclear. Using super-resolution fluorescence imaging and atomic force microscopy (AFM) on single VSV virions, we show that L and P are packaged asymmetrically towards the blunt end of the virus. The number of L and P proteins varies between individual virions and they occupy 57 ± 12 nm of the 150 nm central cavity of the virus. Our finding positions the polymerases at the opposite end of the genome with respect to the only transcriptional promoter.

  6. A treatment of stomatitis and treatment in cats.

    Science.gov (United States)

    Ray, Jody D; Jordan, Dinah G; Eubanks, Diana L; Crosswhite, Megan E

    2009-01-01

    A three-year old spayed female Domestic Shorthair was diagnosed with chronic plasmacytic stomatitis involving the mandibular gingiva caudal to the canine teeth. The cat presented with excessive drooling and bleeding from the gums. The definitive diagnosis was made on oral tissue samples obtained by biopsy and submitted for histopathology. The management included bilateral extraction of the mandibular and maxillary premolars and molars with closure of the defects utilizing a single mucosal flap in each quadrant. Preoperative laboratory evaluation and negative feline leukemia virus and/or feline immunodeficiency virus testing were performed. Following surgical removal of the teeth, the inflammation improved for eight months before returning. The cat now maintains comfort with parenteral injections of corticosteroid approximately every three to five months. Compounding pharmacists play a vital role in the treatment of felines due to their small size concerns with toxicity and sensitivity to certain medications and their reluctance to be dosed. Even in medical cases where a surgical procedure is the final resolution to an issue, compounded preparations are often required prior to surgery, during surgery, and post surgery for the purpose of eliminating pain and discomfort in the feline patient.

  7. Increased NF-κB Activity and Decreased Wnt/β-Catenin Signaling Mediate Reduced Osteoblast Differentiation and Function in ΔF508 Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Mice.

    Science.gov (United States)

    Le Henaff, Carole; Mansouri, Rafik; Modrowski, Dominique; Zarka, Mylène; Geoffroy, Valérie; Marty, Caroline; Tarantino, Nadine; Laplantine, Emmanuel; Marie, Pierre J

    2015-07-17

    The prevalent human ΔF508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) is associated with reduced bone formation and bone loss in mice. The molecular mechanisms by which the ΔF508-CFTR mutation causes alterations in bone formation are poorly known. In this study, we analyzed the osteoblast phenotype in ΔF508-CFTR mice and characterized the signaling mechanisms underlying this phenotype. Ex vivo studies showed that the ΔF508-CFTR mutation negatively impacted the differentiation of bone marrow stromal cells into osteoblasts and the activity of osteoblasts, demonstrating that the ΔF508-CFTR mutation alters both osteoblast differentiation and function. Treatment with a CFTR corrector rescued the abnormal collagen gene expression in ΔF508-CFTR osteoblasts. Mechanistic analysis revealed that NF-κB signaling and transcriptional activity were increased in mutant osteoblasts. Functional studies showed that the activation of NF-κB transcriptional activity in mutant osteoblasts resulted in increased β-catenin phosphorylation, reduced osteoblast β-catenin expression, and altered expression of Wnt/β-catenin target genes. Pharmacological inhibition of NF-κB activity or activation of canonical Wnt signaling rescued Wnt target gene expression and corrected osteoblast differentiation and function in bone marrow stromal cells and osteoblasts from ΔF508-CFTR mice. Overall, the results show that the ΔF508-CFTR mutation impairs osteoblast differentiation and function as a result of overactive NF-κB and reduced Wnt/β-catenin signaling. Moreover, the data indicate that pharmacological inhibition of NF-κB or activation of Wnt/β-catenin signaling can rescue the abnormal osteoblast differentiation and function induced by the prevalent ΔF508-CFTR mutation, suggesting novel therapeutic strategies to correct the osteoblast dysfunctions in cystic fibrosis.

  8. A Comparative Clinical Trial of Topical Triamcinolone (Adcortyle and a Herbal Solution for the Treatment of Minor Aphthous Stomatitis

    Directory of Open Access Journals (Sweden)

    F Rad

    2010-10-01

    The aim of this study was to compare the therapeutic effect of topical Myrtus communis (myrtle solution with topical triamcinolone (Adcortyle in the treatment of minor apotheosis. Materials & Methods: This clinical-trial study was conducted at Kurdistan University of Medical Sciences in 2009. 100 patients were randomly assigned into 2 groups. The 1st group received topical myrtle solution. The 2nd group received topical trimcinolone (Adcortyle. After one week, patients' declaration about time of the recovery of the pain and deterioration of oral lesion was recorded. The gathered data was then analyzed using the SPSS statistical software using t-test and chi-square. Results: After treatment, both groups showed response to topical medications with no significant difference between them (p>0.05. Conclusion: results of this study showed that topical myrtle solution is effective in the treatment of minor aphthous stomatitis and its therapeutic effect is comparable with topical triamcinolone (Adcortyle.

  9. Introduction of cationic virosome derived from vesicular stomatitis virus as a novel gene delivery system for sf9 cells.

    Science.gov (United States)

    Mohammadzadeh, Yahya; Gholami, Shima; Rasouli, Narges; Sarrafzadeh, Sahar; Seyed Tabib, Nasim Sadat; Samiee Aref, Mohammad Hasan; Abdoli, Asghar; Biglari, Peyvand; Fotouhi, Fatemeh; Farahmand, Behrokh; Tavassoti Kheiri, Masoumeh; Jamali, Abbas

    2017-06-01

    Insect-derived cell lines are used extensively to produce recombinant proteins because they are capable of performing a range of post-translational modifications. Due to their significance in biotechnological applications, various methods have been developed to transfect them. In this study, we introduce a virosome constructed from vesicular stomatitis virus (VSV) as a new delivery system for sf9 cells. We labeled these VSV virosomes by fluorescent probe Rhodamine B chloride (R18). By fluorescence microscope observation and conducting a fusion assay, we confirmed the uptake of VSV virosomes via endocytosis by sf9 cells and their fusion with the endosomal membrane. Moreover, we incubated cationic VSV virosomes with a GFP-expressing bacmid and transfected sf9 cells, after 24 h some cells expressed GFP indicating the ability of VSV virosomes to deliver heterologous DNA to these cells. This is the first report of a virosome-based delivery system introduced for an insect cell line.

  10. Inhibition of inward K+ channels and stomatal response by abscisic acid: an intracellular locus of phytohormone action.

    OpenAIRE

    Schwartz, A; Wu, W. H.; Tucker, E B; Assmann, S M

    1994-01-01

    Abscisic acid (ABA), a plant hormone whose production is stimulated by water stress, reduces the apertures of stomatal pores in the leaf surface, thereby lessening transpirational water loss. It has been thought that inhibition of stomatal opening and promotion of stomatal closure by ABA are initiated by the binding of extracellular ABA to a receptor located in the guard-cell plasma membrane. However, in the present research, we employ three distinct experimental approaches to demonstrate tha...

  11. Inhibition, in anaerobiosis, of the reaction of stomatal closure of Pelargonium in the presence of SO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Bonte, J.; De Cormis, L.; Louguet, P.

    1977-01-01

    The temporary stomatal closing movement of Pelargonium x hortorum induced by exposure to an atmospheric concentration of sulfur dioxide (2 x 10/sup -6/ v/v) is completely inhibited in anaerobiosis, in light as in darkness. These results suggest that SO/sub 2/ has a direct action on the stomatal cells. The significance of these experiments on the theory of the mechanism of stomatal movement is emphasized.

  12. Ear Rachis Xylem Occlusion and Associated Loss in Hydraulic Conductance Coincide with the End of Grain Filling for Wheat.

    Science.gov (United States)

    Neghliz, Hayet; Cochard, Hervé; Brunel, Nicole; Martre, Pierre

    2016-01-01

    Seed dehydration is the normal terminal event in the development of orthodox seeds and is physiologically related to the cessation of grain dry mass accumulation and crop grain yield. For a better understanding of grain dehydration, we evaluated the hypothesis that hydraulic conductance of the ear decreases during the latter stages of development and that this decrease results from disruption or occlusion of xylem conduits. Whole ear, rachis, and stem nodes hydraulic conductance and percentage loss of xylem conductivity were measured from flowering to harvest-ripeness on bread wheat (Triticum aestivum L.) cv. Récital grown under controlled environments. Flag leaf transpiration, stomatal conductance, chlorophyll content and grain and ear water potentials were also measured during grain development. We show that grain dehydration was not related with whole plant physiology and leaf senescence, but closely correlated with the hydraulic properties of the xylem conduits irrigating the grains. Indeed, there was a substantial decrease in rachis hydraulic conductance at the onset of the grain dehydration phase. This hydraulic impairment was not caused by the presence of air embolism in xylem conduits of the stem internodes or rachis but by the occlusion of the xylem lumens by polysaccharides (pectins and callose). Our results demonstrate that xylem hydraulics plays a key role during grain maturation.

  13. Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups.

    Science.gov (United States)

    Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A; Bar-On, Benny; Harpaz-Saad, Smadar

    2017-04-01

    Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns ( Asplenium nidus and Platycerium bifurcatum ) and angiosperms ( Arabidopsis thaliana and Commelina erecta ) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata ( Sorghum bicolor and Triticum aestivum ). Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in

  14. Visualization of abscisic acid-perception sites on the plasma membrane of stomatal guard cells.

    Science.gov (United States)

    Yamazaki, Daiki; Yoshida, Shigeo; Asami, Tadao; Kuchitsu, Kazuyuki

    2003-07-01

    Abscisic acid (ABA) is a phytohormone that plays a key role as a stress signal, regulating water relations during drought conditions, by inducing stomatal closure. However, to date, no putative ABA receptor(s) has been reported at the protein sequence, gene family, or cellular localization levels. We used biotinylated ABA (bioABA) to characterize the ABA-perception sites in the stomatal guard cells of Vicia faba. Treatment with bioABA induced stomatal closure and shrinkage of guard cell protoplasts (GCPs). The ABA-perception sites were visualized by fluorescence microscopy and confocal laser scanning microscopy (CLSM), using bioABA and fluorescence-labeled avidin. Fluorescent particles were observed in patches on the surface of the GCPs. Fluorescence intensity was quantified by flow cytometry (FCM) as well as by CLSM. Binding of bioABA was inhibited by ABA in a dose-dependent manner. Pre-treatment of GCPs with proteinase K also blocked the binding of bioABA. Binding of bioABA was inhibited by RCA-7a, an ABA analog that induces stomatal closure, but not by RCA-16, which has no effect on stomatal aperture. Another ABA analog, PBI-51, inhibited ABA-induced stomatal closure. This ABA antagonist also inhibited binding of bioABA to the GCPs. These results suggest that ABA is perceived on the plasma membrane of stomatal guard cells, and that the present experimental methods constitute valuable tools for characterizing the nature of the ABA receptor(s) that perceives physiological ABA signals. These imaging studies allow us to demonstrate the spatial distribution of the ABA-perception sites. Visualization of the ABA-perception sites provides new insights into the nature of membrane-associated ABA receptor(s).

  15. Rearrangements of microtubule cytoskeleton in stomatal closure of Arabidopsis induced by nitric oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG YongMei; WU ZhongYi; WANG XueChen; YU Rong

    2008-01-01

    NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (ⅰ) In vivo stomatal aperture assays revealed that both vinblastine (microtubule-disrupting drug) and SNP (exogenous NO donor) prevented stomatal opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas taxol (a microtubule-stabilizing agent) was able to reduce this effect; (ⅱ) microtubules in the opening Arabi-dopsis guard cells expressing GFP:α-tubulin-6 (AtGFP:α-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (ⅲ) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be-came oblique or exhibited a random pattern; (ⅳ) furthermore, the involvement of cytosolic Ca2+ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca2+) greatly sup-pressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca2+]cyt (free Ca2+ concentration in the cy-toplasm), finally leading to stomatal closure.

  16. Conduct disorder

    Science.gov (United States)

    ... Conduct disorder is often linked to attention-deficit disorder . Conduct disorder also can be an early sign of ... child or teen has a history of conduct disorder behaviors. A physical examination and blood tests can help ...

  17. Development of Candida-associated denture stomatitis: new insights

    Directory of Open Access Journals (Sweden)

    Tatiana Pereira-Cenci

    2008-04-01

    Full Text Available Despite therapeutic progress, opportunistic oral fungal infectious diseases have increased in prevalence, especially in denture wearers. The combination of entrapment of yeast cells in irregularities in denture-base and denture-relining materials, poor oral hygiene and several systemic factors is the most probable cause for the onset of this infectious disease. Hence colonization and growth on prostheses by Candida species are of clinical importance. The purpose of this review is to critically discuss several key factors controlling the adhesion of Candida species which are relevant to denture-associated stomatitis. Although there is some consensus on the role of surface properties, studies on several other factors, as the use of denture liners, salivary properties and yeast-bacterial interactions, have shown contradictory findings. A comprehensive fundamental understanding is hampered by conflicting findings due to the large variations in experimental protocols, while other factors have never been thoroughly studied. Surface free energy and surface roughness control the initial adherence, but temporal changes have not been reported. Neither have in vivo studies shown if the substratum type is critical in dictating biofilm accumulation during longer periods in the oral environment. The contribution of saliva is unclear due to factors like variations in its collection and handling. Initial findings have disclosed that also bacteria are crucial for the successful establishment of Candida in biofilms, but the clinical significance of this observation is yet to be confirmed. In conclusion, there is a need to standardize experimental procedures, to bridge the gap between laboratory and in vivo methodologies and findings and - in general - to thoroughly investigate the factors that modulate the initial attachment and subsequent colonization of denture-base materials and the oral mucosa of patients subjected to Candida infections. Information on how

  18. A Retrospective Evaluation of Patients with Recurrent Aphthous Stomatitis

    Directory of Open Access Journals (Sweden)

    Filiz Topaloğlu Demir

    2017-03-01

    Full Text Available Aim: To determine the factors in the etiology of recurrent aphthous stomatitis (RAS and to evaluate patients in the terms of RAS associated systemic disorders especially Behçet’s disease. Methods: Patients with RAS, who were followed up in Bartın State Hospital Dermatology Clinic between July 2013 and April 2015, were retrospectively evaluated. Results: A total of 123 patients (86 female, 37 male were included in this study. Thirteen (106% patients were children. The mean age of patients was 34.5±14.7 years (range: 8-69 years. Minor aphthous somatitis was the most frequent clinical type (68.3%. Family history was positive in 52.8% of patients. The triggering factors in the etiology of RAS were stress (54.5%, trauma (40.2%, gingivitis (29.3%, food (9.8%, medicines (5.7%, menstruation in female patients (3.3%, and throat infections (2.4%. Nutritional deficiencies were found in 39% of patients. There was a statistically significant difference in attack frequency (p=0.017 and throat infection history (p=0.029 between adults and pediatric patients. Fourteen (11.4% patients were diagnosed with Behçet’s disease. When we compared the RAS patients diagnosed with Behçet’s disease and the other RAS patients, a significant difference was found in pathergy test (p<0.001 and ferritin levels (p=0.020. Conclusion: Patients with RAS should be followed up for a long time for systemic disorders, especially for Behçet’s disease, accompanying RAS.

  19. Sociodemographic and clinical characteristics of patients with recurrent aphthous stomatitis

    Directory of Open Access Journals (Sweden)

    Anıl Gülsel Bahalı

    2014-12-01

    Full Text Available Background and Design: The purpose of this study was to obtain data that may provide an insight into the etiopathogenesis of recurrent aphtous stomatitis (RAS by the way of analysing the sociodemographic and clinical characteristics of patients who had been diagnosed with RAS. Materials and Metods: The patients, who were diagnosed with RAS in the dermatology outpatient clinic, between May 2007 and May 2010, were evaluated retrospectively. The data including sociodemografic and clinical characteristics, and treatment options were recorded. Results: A hundred patients (68 women, 32 men were included in this study. The average age was 40±13.6 years. RAS was more common in patients with middle-income and low education. The most common type of RAS was minor aphtous ulcers (88%. The lesions were most frequently seen on the lateral side of the tongue (34% and cheek (34%. Sixty percent of patients had a positive family history. Some factors such as biting (12%, tooth brushing (18%, dental disease presence (82%, food (39%, menstruation (10.3%, stress (76%, iron deficiency (16.7%, vitamin B12 deficiency (22.4%, low serum ferritin levels (18%, and seasonal variability (32% showed positive correlation with RAS. A negative correlation was found between RAS and smoking. Forty-nine percent of patients had used alternative therapies in addition to drug therapy. The most frequently used alternative method was consumption of sumac (26.5%. Conlucions: In contrast to the literature, our study found that RAS is started in the third decade of life and, approximately 50% of patients prefered alternative treatment methods, particularly sumac. Nowadays, discussions about the etiopathogenesis of RAS continue. In this study, we found that different sociodemographic and clinical factors may be associated with the etiopathogenesis of the disease. Our study will be followed by further studies using prospective design to identify the the etiopathogenesis of RAS.

  20. Redistributive properties of the vesicular stomatitis virus polymerase

    Energy Technology Data Exchange (ETDEWEB)

    Helfman, W.B.; Perrault, J. (San Diego State Univ., CA (USA))

    1989-08-01

    The template for transcription of the vesicular stomatitis virus (VSV) genome consists of a negative-strand RNA (approximately 11 kb) tightly associated with approximately 1250 copies of the nucleocapsid or N protein (N-RNA template). The interaction between the virion-associated polymerase and this template was probed with a novel assay using purified N-RNA complexes added to detergent-disrupted uv-irradiated standard virions or unirradiated defective interfering (DI) particles. In contrast to the well-known stability of assembled cellular transcription complexes, the VSV polymerase copied exogenously added templates efficiently and yielded products indistinguishable from control virus transcription. Addition of uv-irradiated N-RNA templates to unirradiated virus effectively competed for transcription of endogenous template indicating that most or all of the polymerase can freely redistribute. Furthermore preincubation of virus and added templates at high ionic strength to solubilize L and NS polymerase proteins did not release additional active enzyme for redistribution. Pretranscription of virus also had little or no effect on redistributed activity indicating that polymerase complexes are capable of multiple rounds of synthesis beginning at the 3' end promoter. Unexpectedly, titration with saturating amounts of added N-RNA showed that active polymerase complexes are only in slight excess relative to template in standard or DI particles despite the large surplus of packaged L and NS polypeptides. Moreover, added standard virus templates competed equally well for the redistributing polymerase from DI particles or standard virus indicating no significant polymerase-binding preference for interfering templates. These findings bear important implications regarding mechanisms of VSV transcription and replication.

  1. Transcription co-activator Arabidopsis ANGUSTIFOLIA3 (AN3) regulates water-use efficiency and drought tolerance by modulating stomatal density and improving root architecture by the transrepression of YODA (YDA).

    Science.gov (United States)

    Meng, Lai-Sheng; Yao, Shun-Qiao

    2015-09-01

    One goal of modern agriculture is the improvement of plant drought tolerance and water-use efficiency (WUE). Although stomatal density has been linked to WUE, the causal molecular mechanisms and engineered alternations of this relationship are not yet fully understood. Moreover, YODA (YDA), which is a MAPKK kinase gene, negatively regulates stomatal development. BR-INSENSITIVE 2 interacts with phosphorylates and inhibits YDA. However, whether YDA is modulated in the transcriptional level is still unclear. Plants lacking ANGUSTIFOLIA3 (AN3) activity have high drought stress tolerance because of low stomatal densities and improved root architecture. Such plants also exhibit enhanced WUE through declining transpiration without a demonstrable reduction in biomass accumulation. AN3 negatively regulated YDA expression at the transcriptional level by target-gene analysis. Chromatin immunoprecipitation analysis indicated that AN3 was associated with a region of the YDA promoter in vivo. YDA mutation significantly decreased the stomatal density and root length of an3 mutant, thus proving the participation of YDA in an3 drought tolerance and WUE enhancement. These components form an AN3-YDA complex, which allows the integration of water deficit stress signalling into the production or spacing of stomata and cell proliferation, thus leading to drought tolerance and enhanced WUE.

  2. Stomatal area as an anatomical criterion for the determination of chromosome number in the Eragrostis curvula complex

    Directory of Open Access Journals (Sweden)

    J. J. Spies

    1982-12-01

    Full Text Available Twenty stomatal areas of each of 55 Eragrostis curvula (Schrad. Nees plants were determined. An increase in polyploid level is shown to be moderately correlated with an increase in stomatal area. However, the extent of overlap in stomatal areas between different polyploid levels is too great to use this character for the determination of the polyploid level above the diploid level. All diploid  E. curvula plants have an area of less than 280 µ2,  whereas the tetraploid plants have areas greater than 320 µ2. It is therefore possible to identify diploid E. curvula plants on the basis of their stomatal area.

  3. 盾叶秋海棠叶表皮气孔簇的发育及分布格局%Developmental Mechanism and Distribution Pattern of Stomatal Clusters in Begonia peltatifolia

    Institute of Scientific and Technical Information of China (English)

    唐敏; 胡玉熹; 林金星; 靳晓白

    2002-01-01

    The function of stomata in plants is controlling gas exchange and modul ating water balance. The distribution pattern of stomata in most vascular plants follows a certain regulation with at least one normal epidermal cell between tw o stomata. However, some plants restricted in several genera of vascular plants have stomatal clusters in which more than one stoma is adjacently arranged with no epidermal cells among them. The developmental process of stomatal clusters in plants, especially in non-mutant (wild type) vascular plants, has rarely been documented, and very few studies concerning the distribution pattern of stomata l clusters on leaf epidermis have been carried out. We reported the developmenta l mechanism and distribution pattern of stomatal clusters in Begonia peltatifo lia Li native to China. The results indicated that the clustered arrangement o f meris temoids at the juvenile stage of the leaf development contributed greatly to the pattern of stomatal clusters. Additionally, satellite meristemoids derived from subsidiary cells around the mature stomata also had an impact on the develop ment as well as the pattern of stomatal clusters. Regarding stomatal cluster and singly occurring stoma both as a stomatal unit, we found that the stomatal unit density (i.e., number of stomatal unit per area) increased gradually from the mi ddle part to the edge and the apex of the leaf, while stomatal unit size (i.e., number of stomata per stomatal unit) decreased. The possible reason of this pat tern was discussed.%气孔是植物控制气体交换和调节水分散失的门户.大部分高等植物气孔的分布格局是相邻气孔之间被一至多个表皮细胞所间隔.而在有限分布的几个科属的植物种中发现气孔成簇分布的现象,即由2至多个紧密相邻的气孔器组成相对独立的单元,称为气孔簇(stoma tal cluster).以中国原产的盾叶秋海棠(Begonia peltatifolia Li)为研究对象,探讨了叶表皮气孔簇的发育

  4. Algorithm developing of gross primary production from its capacity and a canopy conductance index using flux and global observing satellite data

    Science.gov (United States)

    Muramatsu, Kanako; Furumi, Shinobu; Daigo, Motomasa

    2015-10-01

    We plan to estimate gross primary production (GPP) using the SGLI sensor on-board the GCOM-C1 satellite after it is launched in 2017 by the Japan Aerospace Exploration Agency, as we have developed a GPP estimation algorithm that uses SGLI sensor data. The characteristics of this GPP estimation method correspond to photosynthesis. The rate of plant photosynthesis depends on the plant's photosynthesis capacity and the degree to which photosynthesis is suppressed. The photosynthesis capacity depends on the chlorophyll content of leaves, which is a plant physiological parameter, and the degree of suppression of photosynthesis depends on weather conditions. The framework of the estimation method to determine the light-response curve parameters was developed using ux and satellite data in a previous study[1]. We estimated one of the light-response curve parameters based on the linear relationship between GPP capacity at 2000 (μmolm-2s-1) of photosynthetically active radiation and a chlorophyll index (CIgreen [2;3] ). The relationship was determined for seven plant functional types. Decreases in the photosynthetic rate are controlled by stomatal opening and closing. Leaf stomatal conductance is maximal during the morning and decreases in the afternoon. We focused on daily changes in leaf stomatal conductance. We used open shrub flux data and MODIS reflectance data to develop an algorithm for a canopy. We first evaluated the daily changes in GPP capacity estimated from CIgreen and photosynthesis active radiation using light response curves, and GPP observed during a flux experiment. Next, we estimated the canopy conductance using flux data and a big-leaf model using the Penman-Monteith equation[4]. We estimated GPP by multiplying GPP capacity by the normalized canopy conductance at 10:30, the time of satellite observations. The results showed that the estimated daily change in GPP was almost the same as the observed GPP. From this result, we defined a normalized canopy

  5. Behaviour of Sub Prosthesis Stomatitis in Patients with Upper Dental Prosthesis

    Directory of Open Access Journals (Sweden)

    Yoel González Beriau

    2017-02-01

    Full Text Available Foundation: Sub prosthesis stomatitis is one of the most frequent affections in patients who wear dental prosthesis and constitutes a risk factor for the appearance of pre malignant and malignant lesions in the oral cavity.Objective: To describe the behaviour of sub prosthesis stomatitis in patients with upper dental prosthesis.Methods: A descriptive study was carried out, of all the patients who wear upper dental prosthesis (N=61 who came to the consultation due to sub prosthesis stomatitis, in the period from September 2014 to September 2015. The variables analyzed were: Age groups, sex, degree of the lesion, state of the prosthesis, toxic habits, location of the lesion and frequency of visits to the dentist.Results: Old adults predominated (54.1% and sub prosthesis Stomatitis degree II, represented by 77%. Unadjusted prosthesis was observed in most patients and the lesions were located more frequently in mix zones. The most frequent toxic habits were continuous use and deficient oral hygiene. 85.2% of the patients reported to have visited the dentist only when they felt discomforts.Conclusion: Some results show patients ignorance about this ailment, among them a high frequency of toxic habits so as the use of continuous use of prosthesis and deficient oral hygiene, factors which condition the appearance of sub prosthesis stomatitis.

  6. Carbonic anhydrases are upstream regulators of CO2-controlled stomatal movements in guard cells

    KAUST Repository

    Hu, Honghong

    2009-12-13

    The continuing rise in atmospheric CO2 causes stomatal pores in leaves to close and thus globally affects CO2 influx into plants, water use efficiency and leaf heat stress. However, the CO2-binding proteins that control this response remain unknown. Moreover, which cell type responds to CO2, mesophyll or guard cells, and whether photosynthesis mediates this response are matters of debate. We demonstrate that Arabidopsis thaliana double-mutant plants in the beta-carbonic anhydrases betaCA1 and betaCA4 show impaired CO2-regulation of stomatal movements and increased stomatal density, but retain functional abscisic-acid and blue-light responses. betaCA-mediated CO2-triggered stomatal movements are not, in first-order, linked to whole leaf photosynthesis and can function in guard cells. Furthermore, guard cell betaca-overexpressing plants exhibit instantaneous enhanced water use efficiency. Guard cell expression of mammalian alphaCAII complements the reduced sensitivity of ca1 ca4 plants, showing that carbonic anhydrase-mediated catalysis is an important mechanism for betaCA-mediated CO2-induced stomatal closure and patch clamp analyses indicate that CO2/HCO3- transfers the signal to anion channel regulation. These findings, together with ht1-2 (ref. 9) epistasis analysis demonstrate that carbonic anhydrases function early in the CO2 signalling pathway, which controls gas-exchange between plants and the atmosphere.

  7. A Study of Factors Contributing to Denture Stomatitis in a North Indian Community

    Directory of Open Access Journals (Sweden)

    Amit Vinayak Naik

    2011-01-01

    Full Text Available Factors like oral and denture hygiene, presence of saliva, age of the denture, and degree of colonization with Candida albicans are to be evaluated as local contributing factors for causing denture stomatitis. 100 patients aged 30 to 70 years were selected for the study. Among these, 70 patients were labeled test group showing signs of stomatitis and 30 patients as control group as they showed no inflammatory signs. Clinical tests included oral and denture hygiene evaluation, salivary measurements, and age of the dentures, and microscopic investigations were done. Results showed no significant differences between the two groups in terms of saliva, oral and denture hygiene habits, and denture age. Test group showed stomatitis in patients who were wearing dentures for 5 to 10 years compared to control group who were wearing dentures for 10 years and above. Denture age was proportional to Candida colonization and not to degree of inflammation. Significant differences were found in Candida colonization of the fitting surface of the denture between stomatitis and control groups. Poor denture hygiene habits are the most prominent contributing factor for denture stomatitis and colonization.

  8. Methylglyoxal-induced stomatal closure accompanied by peroxidase-mediated ROS production in Arabidopsis.

    Science.gov (United States)

    Hoque, Tahsina Sharmin; Uraji, Misugi; Ye, Wenxiu; Hossain, Mohammad Anowar; Nakamura, Yoshimasa; Murata, Yoshiyuki

    2012-07-01

    Methylglyoxal (MG) is an oxygenated short aldehyde and a glycolytic intermediate that accumulates in plants under environmental stresses. Being a reactive α-oxoaldehyde, MG may act as a signaling molecule in plants during stresses. We investigated whether MG induces stomatal closure, reactive oxygen species (ROS) production, and cytosolic free calcium concentration ([Ca²⁺](cyt)) to clarify roles of MG in Arabidopsis guard cells. MG induced production of ROS and [Ca²⁺](cyt) oscillations, leading to stomatal closure. The MG-induced stomatal closure and ROS production were completely inhibited by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), but were not affected by an NAD(P)H oxidase mutation, atrbohD atrbohF. Furthermore, the MG-elicited [Ca²⁺](cyt) oscillations were significantly suppressed by SHAM but not by the atrbohD atrbohF mutation. Neither endogenous abscisic acid nor endogenous methyl jasmonate was involved in MG-induced stomatal closure. These results suggest that intrinsic metabolite MG can induce stomatal closure in Arabidopsis accompanied by extracellular ROS production mediated by SHAM-sensitive peroxidases, intracellular ROS accumulation, and [Ca²⁺](cyt) oscillations. Copyright © 2012 Elsevier GmbH. All rights reserved.

  9. Protein Tyrosine Phosphatases Mediate the Signaling Pathway of Stomatal Closure of Vicia faba L.

    Institute of Scientific and Technical Information of China (English)

    Wu-Liang SHI; Xin LIU; Wen-Suo JIA; Shu-Qiu ZHANG

    2005-01-01

    The regulation of stomatal movement is one of the most important signaling networks in plants.The H+-ATPase at the plasma membrane of guard cells plays a critical role in the stomata opening, while there are some conflicting results regarding the effectiveness of the plasma membrane H+-ATPase inhibitor,vanadate, in inhibiting stomata opening. We observed that 2 mmol/L vanadate hardly inhibited light-stimulated stomata opening in epidermal peels of Viciafaba L., but significantly inhibited dark- and ABA-induced stomatal closure. These results cannot be explained with the previous findings that H+-ATPase was inhibited by vanadate. In view of the fact that vanadate is an inhibitor of protein tyrosine phosphatases (PTPases),we investigated whether the stomatal movement regulated by vanadate is through the regulation of PTPase.As expected, phenylarsine oxide (PAO), a specific inhibitor of PTPase, has very similar effects and even more effective than vanadate. Typical PTPase activity was found in guard cells of V. faba; moreover, the phosphatase activity could be inhibited by both vanadate and PAO. These results not only provide a novel explanation for conflicting results about vanadate modulating stomatal movement, but also provide further evidence for the involvement of PTPases in modulating signal transduction of stomatal movement.

  10. Ultrastructure of stomatal development in early-divergent angiosperms reveals contrasting patterning and pre-patterning.

    Science.gov (United States)

    Rudall, Paula J; Knowles, Emma V W

    2013-10-01

    Angiosperm stomata consistently possess a pair of guard cells, but differ between taxa in the patterning and developmental origin of neighbour cells. Developmental studies of phylogenetically pivotal taxa are essential as comparative yardsticks for understanding the evolution of stomatal development. We present a novel ultrastructural study of developing stomata in leaves of Amborella (Amborellales), Nymphaea and Cabomba (Nymphaeales), and Austrobaileya and Schisandra (Austrobaileyales), representing the three earliest-divergent lineages of extant angiosperms (the ANITA-grade). Alternative developmental pathways occur in early-divergent angiosperms, resulting partly from differences in pre-patterning and partly from the presence or absence of highly polarized (asymmetric) mitoses in the stomatal cell lineage. Amplifying divisions are absent from ANITA-grade taxa, indicating that ostensible similarities with the stomatal patterning of Arabidopsis are superficial. In Amborella, 'squared' pre-patterning occurs in intercostal regions, with groups of four protodermal cells typically arranged in a rectangle; most guard-mother cells are formed by asymmetric division of a precursor cell (the mesoperigenous condition) and are typically triangular or trapezoidal. In contrast, water-lily stomata are always perigenous (lacking asymmetric divisions). Austrobaileya has occasional 'giant' stomata. Similar mature stomatal phenotypes can result from contrasting morphogenetic factors, although the results suggest that paracytic stomata are invariably the product of at least one asymmetric division. Loss of asymmetric divisions in stomatal development could be a significant factor in land plant evolution, with implications for the diversity of key structural and physiological pathways.

  11. Stochastic dynamics of actin filaments in guard cells regulating chloroplast localization during stomatal movement.

    Science.gov (United States)

    Wang, Xiu-Ling; Gao, Xin-Qi; Wang, Xue-Chen

    2011-08-01

    Actin filaments and chloroplasts in guard cells play roles in stomatal function. However, detailed actin dynamics vary, and the roles that they play in chloroplast localization during stomatal movement remain to be determined. We examined the dynamics of actin filaments and chloroplast localization in transgenic tobacco expressing green fluorescent protein (GFP)-mouse talin in guard cells by time-lapse imaging. Actin filaments showed sliding, bundling and branching dynamics in moving guard cells. During stomatal movement, long filaments can be severed into small fragments, which can form longer filaments by end-joining activities. With chloroplast movement, actin filaments near chloroplasts showed severing and elongation activity in guard cells during stomatal movement. Cytochalasin B treatment abolished elongation, bundling and branching activities of actin filaments in guard cells, and these changes of actin filaments, and as a result, more chloroplasts were localized at the centre of guard cells. However, chloroplast turning to avoid high light, and sliding of actin fragments near the chloroplast, was unaffected following cytochalasin B treatment in guard cells. We suggest that the sliding dynamics of actin may play roles in chloroplast turning in guard cells. Our results indicate that the stochastic dynamics of actin filaments in guard cells regulate chloroplast localization during stomatal movement.

  12. Relationships between Stomatal Behavior and Internal Carbon Dioxide Concentration in Crassulacean Acid Metabolism Plants.

    Science.gov (United States)

    Cockburn, W

    1979-06-01

    Measurements of internal gas phase CO(2) concentration, stomatal resistance, and acid content were made in Crassulacean acid metabolism plants growing under natural conditions. High CO(2) concentrations, sometimes in excess of 2%, were observed during the day in a range of taxonomically widely separated plants (Opuntia ficus-indica L., Opuntia basilaris Engelm. and Bigel., Agave desertii Engelm., Yucca schidigera Roezl. ex Ortiges, Ananas comosus [L.] Merr., Aloe vera L., Cattleya sp. and Phalanopsis sp.) and below ambient air concentrations were observed at night.Stomatal resistance was always high when CO(2) concentration was high and experiments in which attempts were made to manipulate internal CO(2) concentrations gave data consistent with stomatal behavior in Crassulacean acid metabolism being controlled by internal CO(2) concentration. Exogenous CO(2) applied in darkness at a concentration similar to those observed in the light caused stomatal resistance to increase.In pads of Opuntia basilaris Engelm. and Bigel. subjected to severe water stress internal gas phase CO(2) concentrations exhibited fluctuations opposite in phase to fluctuations in acid content. Stomatal resistance remained high and the opening response to low CO(2) concentration was almost entirely eliminated.

  13. Lineage-specific stem cells, signals and asymmetries during stomatal development.

    Science.gov (United States)

    Han, Soon-Ki; Torii, Keiko U

    2016-04-15

    Stomata are dispersed pores found in the epidermis of land plants that facilitate gas exchange for photosynthesis while minimizing water loss. Stomata are formed from progenitor cells, which execute a series of differentiation events and stereotypical cell divisions. The sequential activation of master regulatory basic-helix-loop-helix (bHLH) transcription factors controls the initiation, proliferation and differentiation of stomatal cells. Cell-cell communication mediated by secreted peptides, receptor kinases, and downstream mitogen-activated kinase cascades enforces proper stomatal patterning, and an intrinsic polarity mechanism ensures asymmetric cell divisions. As we review here, recent studies have provided insights into the intrinsic and extrinsic factors that control stomatal development. These findings have also highlighted striking similarities between plants and animals with regards to their mechanisms of specialized cell differentiation. © 2016. Published by The Company of Biologists Ltd.

  14. Nitric oxide suppresses stomatal opening by inhibiting inward-rectifying Kin channels in Arabidopsis guard cells

    Institute of Scientific and Technical Information of China (English)

    XUE ShaoWu; YANG Pin; HE YiKun

    2008-01-01

    We explore nitric oxide (NO) effect on K+in channels in Arabidopsis guard cells. We observed NO inhib-ited K+in currents when Ca2+ chelator EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N',N'tetraacetic acid) was not added in the pipette solution; K+in currents were not sensitive to NO when cytosolic Ca2+ was chelated by EGTA. NO inhibited the Arabidopsis stomatal opening, but when EGTA was added in the bath solution, inhibition effect of NO on stomatal opening vanished. Thus, it implies that NO ele-vates cytosolic Ca2+ by activating plasma membrane Ca2+ channels firstly, then inactivates K+in chan-nels, resulting in stomatal opening suppressed subsequently.

  15. Effect of shading treatment on stomatal behavior of Adenophora lo-bophylla at different ages

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stomatal behavior of Adenophora lobophylla of different age structures was studied in July 1995 in greenhouse of the Harbin Forest Farm of Northeast Forestry University by means of shading experiment. The effects of different shading treatments on the stomatal physiological character and ecological adaptation of A. lo-bophylla of different ages were compared. The results showed that the morphological characters of annual A. lo-bophylla were more obvious than that of the perennial, but the stomatal density of annual was less than that of perennial. Growth of annual A. lobophylla was more sensitive to the change of environment than that of the peren-nial. The ecological adaptation of annual was weak, which was one of the main causes of endangered population.

  16. Stimulation of Vesicular Stomatitis Virus in vitro RNA Synthesis by Microtubule-Associated Proteins

    Science.gov (United States)

    Hill, Virginia M.; Harmon, Shirley A.; Summers, Donald F.

    1986-08-01

    Microtubule-associated proteins purified from bovine brains stimulated the in vitro transcription and replication reactions of vesicular stomatitis virus. The products of these reactions were intact messenger or genome-sized RNA species. A preparation from HeLa cells containing tubulin and microtubule-associated proteins also stimulated vesicular stomatitis virus transcription in vitro. This observation is in accord with previous studies, which suggested that a host cell factor was involved with the function of the vesicular stomatitis virus RNA polymerase, and others that indicated that several animal viruses displayed an association with host cell cytoskeletal elements during their replication cycles. We show evidence in this report of a host cell protein that seems to have a functional role in interacting with the virion polymerase.

  17. Ulcerative Uremic Stomatitis - Review of the Literature and A Rare Case Report

    Directory of Open Access Journals (Sweden)

    Shantala Arunkumar

    2015-01-01

    Full Text Available Uremic Stomatitis (US represents a comparatively uncommon intraoral complication seen, mostly, in cases of end-stage renal disease or undiagnosed or untreated chronic renal failure. Its frequency has diminished due to the advent of renal dialysis. Clinically uremic stomatitis is characterized by the presence of painful plaques and crusts that are usually distributed on the buccal and labial mucosa, dorsal or ventral surface of the tongue, gingiva, and floor of the mouth. Ultimate treatment consists of improvement of blood urea concentration and underlying renal failure is supported by enhancement of oral hygiene with antiseptic mouthwashes and antimicrobial/antifungal agents, if necessary. Here we report a rare case of ulcerative type of uremic stomatitis occurring in a patient of chronic renal failure due to sudden relapse of uremia and reviewed the possible pathophysiology of oral symptoms of chronic renal failure.

  18. Feline lymphoplasmacytic stomatitis associated with monoclonal gammopathy and Bence-Jones proteinuria.

    Science.gov (United States)

    Lyon, K F

    1994-03-01

    Lymphoplasmacytic stomatitis and gingivitis was diagnosed in an 8-year old female domestic shorthair. The cat had evidence of severe generalized inflammation of the oral cavity. Biopsy samples were evaluated and displayed a lichenoid, interface stomatitis which was predominantly lymphoplasmacytic. Serum protein electrophoresis confirmed a monoclonal gammopathy. Urine protein electrophoresis confirmed Bence-Jones proteinuria. Protein electrophoresis was used to diagnose monoclonal gammopathy (the production of a monoclonal immunoglobulin, or paraprotein, which is associated with a characteristic "M" protein spike on serum electrophoresis). Diseases associated with monoclonal gammopathy are similar in the dog and cat. Alkylating agent chemotherapy is used to rapidly reduce paraprotein concentrations in multiple myeloma. Multiple myeloma is the most common disorder associated with monoclonal gammopathy. This condition is less common in the cat, compared to the dog. This report examines the diagnosis and treatment of multiple myeloma in a cat presenting with severe stomatitis.

  19. Hydrogen Sulfide Regulates Ethylene-induced Stomatal Closure in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Zhihui Hou; Lanxiang Wang; Jing Liu; Lixia Hou; Xin Liu

    2013-01-01

    Hydrogen sulfide (H2S) is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years,but its function in stomatal movement is unclear.In plants,H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase (D-/L-CDes).AtD-/L-CDes::GUS transgenic Arabidopsis thaliana (L.) Heynh.plants were generated and used to investigate gene expression patterns,and results showed that AtD-/L-CDes can be expressed in guard cells.We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes::GFP,and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm,respectively.The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure.Among these factors,ACC,a precursor of ethylene,has the most significant effect,which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure.Meanwhile,H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis.Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves.AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however,the effect was not observed in the Atd-cdes and Atl-cdes mutants.In conclusion,our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.

  20. Carbon and hydrogen isotopic effects of stomatal density in Arabidopsis thaliana

    Science.gov (United States)

    Lee, Hyejung; Feakins, Sarah J.; Sternberg, Leonel da S. L.

    2016-04-01

    Stomata are key gateways mediating carbon uptake and water loss from plants. Varied stomatal densities in fossil leaves raise the possibility that isotope effects associated with the openness of exchange may have mediated plant wax biomarker isotopic proxies for paleovegetation and paleoclimate in the geological record. Here we use Arabidopsis thaliana, a widely used model organism, to provide the first controlled tests of stomatal density on carbon and hydrogen isotopic compositions of cuticular waxes. Laboratory grown wildtype and mutants with suppressed and overexpressed stomatal densities allow us to directly test the isotope effects of stomatal densities independent of most other environmental or biological variables. Hydrogen isotope (D/H) measurements of both plant waters and plant wax n-alkanes allow us to directly constrain the isotopic effects of leaf water isotopic enrichment via transpiration and biosynthetic fractionations, which together determine the net fractionation between irrigation water and n-alkane hydrogen isotopic composition. We also measure carbon isotopic fractionations of n-alkanes and bulk leaf tissue associated with different stomatal densities. We find offsets of +15‰ for δD and -3‰ for δ13C for the overexpressed mutant compared to the suppressed mutant. Since the range of stomatal densities expressed is comparable to that found in extant plants and the Cenozoic fossil record, the results allow us to consider the magnitude of isotope effects that may be incurred by these plant adaptive responses. This study highlights the potential of genetic mutants to isolate individual isotope effects and add to our fundamental understanding of how genetics and physiology influence plant biochemicals including plant wax biomarkers.

  1. The efficacy of a paste containing Myrtus communis (Myrtle) in the management of recurrent aphthous stomatitis: a randomized controlled trial.

    Science.gov (United States)

    Babaee, Neda; Mansourian, Arash; Momen-Heravi, Fatemeh; Moghadamnia, Aliakbar; Momen-Beitollahi, Jalil

    2010-02-01

    Recurrent aphthous stomatitis (RAS) is a common, painful, and ulcerative disorder of the oral cavity with unknown etiology. Treatment is a highly controversial topic. The aim of this study was to evaluate the clinical efficacy of a novel paste containing Myrtus communis (Myrtle) in the treatment of recurrent aphthous stomatitis. Myrtle is a particular herb used in some cultures as treatment for mouth ulcers. The study was a randomized, double-blind, controlled before-after clinical trial. Forty-five patients with RAS randomly participated in this study. The subjects were treated with placebo paste and myrtle oral paste in two consecutive episodes. The paste was applied by subjects themselves four times a day for 6 days. Five parameters (size change, pain scale, erythema and exudation level, oral health impact profile, and patient overall assessment of their treatment) were recorded both before (baseline) and during each episodes of treatment (on the morning of days 2, 4, and 6). There were no statistically significant differences between baseline parameters (p > 0.05). The data indicated a statistically significant reduction of ulcer size (p < 0.001), pain severity (p < 0.05), and erythema and exudation level (p < 0.001). Oral Health Impact Profile improved significantly in the treatment group (p < 0.001). Patient overall assessment of their treatment improved after applying paste containing myrtle (p < 0.05). No side effects were reported. This study has shown myrtle to be effective in decreasing the size of ulcers, pain severity and the level of erythema and exudation, and improving the quality of life in patients who suffer from RAS.

  2. Sensitivity difference of Streptococcus viridans on 35% Piper betle linn extract and 10% povidone iodine towards recurrent apthous stomatitis

    Directory of Open Access Journals (Sweden)

    Maharani Laillyza Apriasari

    2011-09-01

    Full Text Available Background: Oral ulceration often becomes the main reason for the patients to see a dentist. Therapy of the oral ulceration is by giving the palliative therapy with topical antiseptic. Nowadays, there are many researches concerning with the traditional medicines as alternative therapy. One of them is Piper betle linn which contains the antiseptic agent. Purpose: This research is aimed to observe the sensitivity difference of Streptococcus viridans on 35% Piper betle linn extract and 10%povidone iodine. Methods: This laboratory research was conducted by the post test only design with random complete design. The research sampel is Streptococcus viridans culture that was scrapped from the ulcer of the recurrent aphthous stomatitis patient, then it was replicated by using the Federer theory. Results: Inhibitory zone of 35% Piper betle linn extract is bigger than 10% povidone iodine. Conclusion: Streptococcus viridans are more sensitive to 35% Piper bittle linn extract than 10% povidone iodine. 35% Piper betle linn extract has more antibacterial effect than 10% povidone iodine.Latar belakang: Ulserasi rongga mulut seringkali menjadi alasan utama bagi pasien untuk memeriksakan diri ke dokter gigi. Terapi ulserasi rongga mulut adalah pemberian terapi paliatif kepada penderita, seperti: pemberian obat topikal yang mengandung antiseptik. Saat ini banyak penelitian dalam pengembangan obat tradisional yang dapat dijadikan sebagai obat alternatif. Salah satu diantaranya adalah daun sirih yang mengandung zat antiseptik. Tujuan: Penelitian ini bertujuan mengetahui perbedaan sensitivitas Streptococcus viridans terhadap ekstrak daun sirih 35% jika dibandingkan dengan povidone iodine 10%. Metode: Penelitian laboratoris yang dilakukan dengan post test only design dengan rancangan acak lengkap. Sampel penelitian adalah kultur Streptococcus viridans yang diambil melalui swab dari hapusan ulser pada pasien yang menderita stomatitis aftosa rekuren, kemudian dilakukan

  3. Cell type mediated resistance of vesicular stomatitis virus and Sendai virus to ribavirin.

    Science.gov (United States)

    Shah, Nirav R; Sunderland, Amanda; Grdzelishvili, Valery Z

    2010-06-22

    Ribavirin (RBV) is a synthetic nucleoside analog with broad spectrum antiviral activity. Although RBV is approved for the treatment of hepatitis C virus, respiratory syncytial virus, and Lassa fever virus infections, its mechanism of action and therapeutic efficacy remains highly controversial. Recent reports show that the development of cell-based resistance after continuous RBV treatment via decreased RBV uptake can greatly limit its efficacy. Here, we examined whether certain cell types are naturally resistant to RBV even without prior drug exposure. Seven different cell lines from various host species were compared for RBV antiviral activity against two nonsegmented negative-strand RNA viruses, vesicular stomatitis virus (VSV, a rhabdovirus) and Sendai virus (SeV, a paramyxovirus). Our results show striking differences between cell types in their response to RBV, ranging from virtually no antiviral effect to very effective inhibition of viral replication. Despite differences in viral replication kinetics for VSV and SeV in the seven cell lines, the observed pattern of RBV resistance was very similar for both viruses, suggesting that cellular rather than viral determinants play a major role in this resistance. While none of the tested cell lines was defective in RBV uptake, dramatic variations were observed in the long-term accumulation of RBV in different cell types, and it correlated with the antiviral efficacy of RBV. While addition of guanosine neutralized RBV only in cells already highly resistant to RBV, actinomycin D almost completely reversed the RBV effect (but not uptake) in all cell lines. Together, our data suggest that RBV may inhibit the same virus via different mechanisms in different cell types depending on the intracellular RBV metabolism. Our results strongly point out the importance of using multiple cell lines of different origin when antiviral efficacy and potency are examined for new as well as established drugs in vitro.

  4. Cell type mediated resistance of vesicular stomatitis virus and Sendai virus to ribavirin.

    Directory of Open Access Journals (Sweden)

    Nirav R Shah

    Full Text Available Ribavirin (RBV is a synthetic nucleoside analog with broad spectrum antiviral activity. Although RBV is approved for the treatment of hepatitis C virus, respiratory syncytial virus, and Lassa fever virus infections, its mechanism of action and therapeutic efficacy remains highly controversial. Recent reports show that the development of cell-based resistance after continuous RBV treatment via decreased RBV uptake can greatly limit its efficacy. Here, we examined whether certain cell types are naturally resistant to RBV even without prior drug exposure. Seven different cell lines from various host species were compared for RBV antiviral activity against two nonsegmented negative-strand RNA viruses, vesicular stomatitis virus (VSV, a rhabdovirus and Sendai virus (SeV, a paramyxovirus. Our results show striking differences between cell types in their response to RBV, ranging from virtually no antiviral effect to very effective inhibition of viral replication. Despite differences in viral replication kinetics for VSV and SeV in the seven cell lines, the observed pattern of RBV resistance was very similar for both viruses, suggesting that cellular rather than viral determinants play a major role in this resistance. While none of the tested cell lines was defective in RBV uptake, dramatic variations were observed in the long-term accumulation of RBV in different cell types, and it correlated with the antiviral efficacy of RBV. While addition of guanosine neutralized RBV only in cells already highly resistant to RBV, actinomycin D almost completely reversed the RBV effect (but not uptake in all cell lines. Together, our data suggest that RBV may inhibit the same virus via different mechanisms in different cell types depending on the intracellular RBV metabolism. Our results strongly point out the importance of using multiple cell lines of different origin when antiviral efficacy and potency are examined for new as well as established drugs in vitro.

  5. Impact of elevated temperatures on specific leaf weight, stomatal density, photosynthesis and chlorophyll fluorescence in soybean.

    Science.gov (United States)

    Jumrani, Kanchan; Bhatia, Virender Singh; Pandey, Govind Prakash

    2017-03-01

    High-temperature stress is a major environmental stress and there are limited studies elucidating its impact on soybean (Glycine max L. Merril.). The objectives of present study were to quantify the effect of high temperature on changes in leaf thickness, number of stomata on adaxial and abaxial leaf surfaces, gas exchange, chlorophyll fluorescence parameters and seed yield in soybean. Twelve soybean genotypes were grown at day/night temperatures of 30/22, 34/24, 38/26 and 42/28 °C with an average temperature of 26, 29, 32 and 35 °C, respectively, under greenhouse conditions. One set was also grown under ambient temperature conditions where crop season average maximum, minimum and mean temperatures were 28.0, 22.4 and 25.2 °C, respectively. Significant negative effect of temperature was observed on specific leaf weight (SLW) and leaf thickness. Rate of photosynthesis, stomatal conductance and water use efficiency declined as the growing temperatures increased; whereas, intercellular CO2 and transpiration rate were increased. With the increase in temperature chlorophyll fluorescence parameters such as Fv/Fm, qP and PhiPSII declined while there was increase in qN. Number of stomata on both abaxial and adaxial surface of leaf increased significantly with increase in temperatures. The rate of photosynthesis, PhiPSII, qP and SPAD values were positively associated with leaf thickness and SLW. This indicated that reduction in photosynthesis and associated parameters appears to be due to structural changes observed at higher temperatures. The average seed yield was maximum (13.2 g/pl) in plants grown under ambient temperature condition and declined by 8, 14, 51 and 65% as the temperature was increased to 30/22, 34/24, 38/26 and 42/28 °C, respectively.

  6. Serious stomatitis and esophagitis: a peculiar mucous reaction induced by pegylated liposomal doxorubicin.

    Science.gov (United States)

    Ma, Han; Chen, Meilan; Liu, Junru; Li, Ying; Li, Juan

    2015-01-01

    Pegylated liposomal doxorubicin is an important antineoplastic agent with activity in a variety of solid tumors. It has a totally different profile of pharmacokinetics and toxicity compared with doxorubicin. It rarely causes side-effects like cardiotoxicity or hair loss, but frequently results in many kinds of mucocutaneous reactions, including palmar-plantar erythrodysesthesia, diffuse follicular rash, intertrigo-like eruption, new formation of melanotic macules, stomatitis and radiation recall dermatitis. We present a rare case of multiple myeloma who immediately developed serious stomatitis and esophatitis associated with minor palmar-plantar erythrodysesthesia after a single course of pegylated liposomal doxorubicin.

  7. Inhibition of inward K+ channels and stomatal response by abscisic acid: an intracellular locus of phytohormone action.

    Science.gov (United States)

    Schwartz, A; Wu, W H; Tucker, E B; Assmann, S M

    1994-04-26

    Abscisic acid (ABA), a plant hormone whose production is stimulated by water stress, reduces the apertures of stomatal pores in the leaf surface, thereby lessening transpirational water loss. It has been thought that inhibition of stomatal opening and promotion of stomatal closure by ABA are initiated by the binding of extracellular ABA to a receptor located in the guard-cell plasma membrane. However, in the present research, we employ three distinct experimental approaches to demonstrate that ABA can act from within guard cells to regulate stomatal apertures. (i) The extent to which ABA inhibits stomatal opening and promotes stomatal closure in Commelina communis L. is proportional to the extent of ABA uptake, as assayed with [3H]ABA. (ii) Direct microinjection of ABA into the cytoplasm of Commelina guard cells precipitates stomatal closure. (iii) Application of ABA to the cytosol of Vicia faba L. guard-cell protoplasts via patch-clamp techniques inhibits inward K+ currents, an effect sufficient to inhibit stomatal opening. These results demonstrate an intracellular locus of phytohormone action and imply that the search for hormone receptor proteins should be extended to include intracellular compartments.

  8. Effects of a Rebamipide Mouthwash on Stomatitis Caused by Cancer Chemotherapy-Evaluation of the Efficacy by Patients Themselves.

    Science.gov (United States)

    Ishii, Naoko; Kawano, Yayoi; Sakai, Hideki; Hayashi, Seitaku; Akizuki, Norikazu; Komoda, Masayo; Hanawa, Takehisa

    2017-08-01

     Anticancer drug-induced stomatitis develops in 30% to 40% of cancer cases that undergo chemotherapy. However, medications for this condition are not commercially available in Japan. Upon obtaining approval of the ethics committee, a mouthwash containing rebamipide as the active ingredient (rebamipide mouthwash) was administered to one inpatient and four outpatients, who had developed stomatitis caused by cancer chemotherapy. Starting from 14 d after the administration of the rebamipide mouthwash, the patients scored a stomatitis survey on oral state, pain level, and diet and recorded the number of times they gargled, as well as any stomatitis observations, in a stomatitis diary. The total scores for the points for each of the three types of survey sections were classified into Grades 0 to 4 and evaluated as a stomatitis evaluation score (SES). The SES became "0" in three out of the five patients within 14 d of treatment. No change in SES was found in one patient. In the remaining patients, SES became "0" once but increased again later. Using image analysis software (ImageJ), the area at which the stomatitis was observed was measured. When comparing SES and change in the area in patients who agreed to participate, gradual reductions in the extent of stomatitis was observed even during the period when SES did not change. Having patients fill in an observation chart was effective for grasping changes in symptoms in outpatients.

  9. Organ-specific effects of brassinosteroids on stomatal production coordinate with the action of TOO MANY MOUTHS

    Institute of Scientific and Technical Information of China (English)

    Ming Wang; Kezhen Yang; Jie Le

    2015-01-01

    In Arabidopsis, stomatal development initiates after protodermal cel s acquire stomatal lineage cel fate. Stomata or their precursors communicate with their neighbor epidermal cel s to ensure the“one cel spacing”rule. The signals from EPF/EPFL peptide ligands received by TOO MANY MOUTHS (TMM) and ERECTA‐family receptors are supposed to be transduced by YODA MAPK cascade. A basic helix‐loop‐helix transcription factor SPEECHLESS (SPCH) is another key regulator of stomatal cel fate determination and asymmetric entry divisions, and SPCH activity is regulated by YODA MAPK cascade. Brassinos-teroid (BR) signaling, one of the most wel characterized signal transduction pathways in plants, contributes to the control of stomatal production. But opposite organ‐specific effects of BR on stomatal production were reported. Here we confirm that stomatal production in hypocotyls is control ed by BR levels. YODA and CYCD4 are not essential for BR stomata‐promoting function. Furthermore, we found that BR could confer tmm hypocotyls clustered stomatal phenotype, indicating that the BR organ‐specific effects on stomatal production might coordi-nate with the TMM organ‐specific actions.

  10. Carbon Monoxide-induced Stomatal Closure Involves Generation of Hydrogen Peroxide in Vicia faba Guard Cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ping She; Xi-Gui Song

    2008-01-01

    Here the regulatory role of CO during stomatal movement In Vicla faba L. was surveyed. Results Indicated that, like hydrogen peroxide (H2O2), CO donor Hematin induced stomatal closure in dose- and time-dependent manners. These responses were also proven by the addition of gaseous CO aqueous solution with different concentrations, showing the first time that CO and H2O2 exhibit the similar regulation role in the atomatal movement. Moreover, our data showed that ascorbic acid (ASA, an important reducing substrate for H2O2 removal) and diphenylene iodonium (DPI, an inhibitor of the H2O2-generating enzyme NADPH oxidase) not only reversed stomatal closure by CO, but also suppressed the H2O2 fluorescence induced by CO, implying that CO induced-atomatal closure probably involves H2O2 signal. Additionally, the CO/NO scavenger hemoglobin (Hb) and CO specific synthetic inhibitor ZnPPIX, ASA and DPI reversed the darkness-induced stomatal closure and H2O2 fluorescence. These results show that, perhaps like H2O2, the levels of CO in guard cells of V. faba are higher In the dark than in light, HO-1 and NADPH oxidase are the enzyme systems responsible for generating endogenous CO and H2O2 in darkness respectively, and that CO is involved in darkness-induced H2O2 synthesis in V. faba guard cells.

  11. In situ observation of stomatal movements and gas exchange of Aegopodium podagraria L. in the understorey.

    Science.gov (United States)

    Kaiser, H; Kappen, L

    2000-10-01

    Observations of stomata in situ while simultaneously measuring CO(2) gas exchange and transpiration were made in field experiments with Aegopodium podagraria in a highly variable light climate in the understorey of trees. The low background photosynthetic photon flux density (PPFD) caused a slight opening of the stomata and no visible response to sporadic lightflecks. However, if lightflecks were frequent and brighter, slow opening movements were observed. Small apertures were sufficient to allow maximal photosynthetic rates. Therefore, the small apertures observed in low light usually only caused minor stomatal limitations of lightfleck photosynthesis. The response of stomata to step-wise changes in PPFD under different levels of leaf to air vapour pressure difference (Delta(W)) was observed under controlled conditions. High Delta(W) influenced the stomatal response only slightly by reducing stomatal aperture in low light and causing a slight reduction in the initial capacity to utilize high PPFD levels. Under continuous high PPFD, however, stomata opened to the same degree irrespective of Delta(W). Under high Delta(W), opening and closing responses to PPFD-changes were faster, which enabled a rapid removal of the small stomatal limitations of photosynthesis initially present in high Delta(W) after longer periods in low light. It is concluded that A. podagraria maintains a superoptimal aperture in low light which leads to a low instantaneous water use efficiency, but allows an efficient utilization of randomly occurring lightflecks.

  12. Vesicular stomatitis virus-based vaccines against Lassa and Ebola viruses.

    Science.gov (United States)

    Marzi, Andrea; Feldmann, Friederike; Geisbert, Thomas W; Feldmann, Heinz; Safronetz, David

    2015-02-01

    We demonstrated that previous vaccination with a vesicular stomatitis virus (VSV)-based Lassa virus vaccine does not alter protective efficacy of subsequent vaccination with a VSV-based Ebola virus vaccine. These findings demonstrate the utility of VSV-based vaccines against divergent viral pathogens, even when preexisting immunity to the vaccine vector is present.

  13. RECURRENT ASEPTIC ENCEPHALITIS IN PERIODIC FEVER, APHTHOUS STOMATITIS, PHARYNGITISAND ADENOPATHY (PFAPA) SYNDROME

    Science.gov (United States)

    Frye, Richard E.

    2008-01-01

    An 11-year-old boy with episodes of periodic fever, aphthous stomatitis, pharyngitis and adenopathy (PFAPA) is reported. Two PFAPA episodes were associated with aseptic encephalitis and seizures. Recurrent acute aseptic encephalitis or seizures have never been reported during the febrile episodes of PFAPA. This possible association is discussed within the context of the etiology of PFAPA. PMID:16645518

  14. Two siblings with periodic fever, aphthous stomatitis, pharyngitis, adenitis (PFAPA) syndrome.

    Science.gov (United States)

    Sampaio, Isabel Cristina Ramos Melo; Rodrigo, Maria João; Monteiro Marques, José Gonçalo Duque Pereira

    2009-03-01

    PFAPA syndrome (periodic fever, aphthous stomatitis, pharyngitis, adenitis) is a benign sporadic syndrome of unknown cause. We report 2 siblings diagnosed with this syndrome. The second case started crisis simultaneously with recurrence of crisis after a 3-year free interval in her brother. This temporal relation suggests environmental factor acting in genetically predisposed children.

  15. Spontaneous mutation 7B-1 in tomato impairs blue light-induced stomatal opening.

    Science.gov (United States)

    Hlavinka, Jan; Nauš, Jan; Fellner, Martin

    2013-08-01

    It was reported earlier that 7B-1 mutant in tomato (Solanum lycopersicum L.), an ABA overproducer, is defective in blue light (BL) signaling leading to BL-specific resistance to abiotic and biotic stresses. In this work, we examine responses of stomata to blue, red and white lights, fusicoccin, anion channel blockers (anthracene-9-carboxylic acid; 9-AC and niflumic acid; NIF) and ABA. Our results showed that the aperture of 7B-1 stomata does not increase in BL, suggesting that 7B-1 mutation impairs an element of BL signaling pathway involved in stomatal opening. Similar stomatal responses of 7B-1 and wild type (WT) to fusicoccin or 9-AC points out that activity of H(+)-ATPase and 9-AC-sensitive anion channels per se is not likely affected by the mutation. Since 9-AC restored stomatal opening of 7B-1 in BL, it seems that 9-AC and BL could block similar type of anion channels. The stomata of both genotypes did not respond to NIF neither in darkness nor in any light conditions tested. In light, 9-AC but not NIF restored stomatal opening inhibited by ABA in WT and 7B-1. We suggest that in comparison to WT, the activity of S-type anion channels in 7B-1 is more promoted by increased ABA content, and less reduced by BL, because of the mutant resistance to BL.

  16. Comparison of arabidopsis stomatal density mutants indicates variation in water stress responses and potential epistatic effects

    Science.gov (United States)

    Shaneka S. Lawson; Paula M. Pijut; Charles H. Michler

    2014-01-01

    Recent physiological analysis of Arabidopsis stomatal density (SD) mutants indicated that SD was not the major factor controlling aboveground biomass accumulation. Despite the general theory that plants with fewer stomata have limited biomass acquisition capabilities, epf1 and several other Arabidopsis mutants varied significantly in leaf fresh...

  17. Can prolonged exposure to low VPD disturb the ABA signalling in stomatal guard cells?

    NARCIS (Netherlands)

    Ali Niaei Fard, S.; Meeteren, van U.

    2013-01-01

    The response of stomata to many environmental factors is well documented. Multiple signalling pathways for abscisic acid (ABA)-induced stomatal closure have been proposed over the last decades. However, it seems that exposure of a leaf for a long time (several days) to some environmental conditions

  18. Function of ABA in Stomatal Defense against Biotic and Drought Stresses

    Directory of Open Access Journals (Sweden)

    Chae Woo Lim

    2015-07-01

    Full Text Available The plant hormone abscisic acid (ABA regulates many