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

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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

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

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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.

Disruption of stomatal lineage signaling or transcriptional regulators has differential effects on mesophyll development, but maintains coordination of gas exchange.

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Dow, Graham J; Berry, Joseph A; Bergmann, Dominique C

2017-10-01

Stomata are simultaneously tasked with permitting the uptake of carbon dioxide for photosynthesis while limiting water loss from the plant. This process is mainly regulated by guard cell control of the stomatal aperture, but recent advancements have highlighted the importance of several genes that control stomatal development. Using targeted genetic manipulations of the stomatal lineage and a combination of gas exchange and microscopy techniques, we show that changes in stomatal development of the epidermal layer lead to coupled changes in the underlying mesophyll tissues. This coordinated response tends to match leaf photosynthetic potential (V cmax ) with gas-exchange capacity (g smax ), and hence the uptake of carbon dioxide for water lost. We found that different genetic regulators systematically altered tissue coordination in separate ways: the transcription factor SPEECHLESS (SPCH) primarily affected leaf size and thickness, whereas peptides in the EPIDERMAL PATTERNING FACTOR (EPF) family altered cell density in the mesophyll. It was also determined that interlayer coordination required the cell-surface receptor TOO MANY MOUTHS (TMM). These results demonstrate that stomata-specific regulators can alter mesophyll properties, which provides insight into how molecular pathways can organize leaf tissues to coordinate gas exchange and suggests new strategies for improving plant water-use efficiency. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

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.

A novel bHLH transcription factor PebHLH35 from Populus euphratica confers drought tolerance through regulating stomatal development, photosynthesis and growth in Arabidopsis

Energy Technology Data Exchange (ETDEWEB)

Dong, Yan [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Liaoning Forestry Vocational-Technical College, Shenyang 110101 (China); Wang, Congpeng; Han, Xiao; Tang, Sha; Liu, Sha [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Xia, Xinli, E-mail: xiaxl@bjfu.edu.cn [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China); Yin, Weilun, E-mail: yinwl@bjfu.edu.cn [College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083 (China)

2014-07-18

Highlights: • PebHLH35 is firstly cloned from Populus euphratica and characterized its functions. • PebHLH35 is important for earlier seedling establishment and vegetative growth. • PebHLH35 enhances tolerance to drought by regulating growth. • PebHLH35 enhances tolerance to drought by regulating stomatal development. • PebHLH35 enhances tolerance to drought by regulating photosynthesis and transpiration. - Abstract: Plant basic helix-loop-helix (bHLH) transcription factors (TFs) are involved in a variety of physiological processes including the regulation of plant responses to various abiotic stresses. However, few drought-responsive bHLH family members in Populus have been reported. In this study, a novel bHLH gene (PebHLH35) was cloned from Populus euphratica. Expression analysis in P. euphratica revealed that PebHLH35 was induced by drought and abscisic acid. Subcellular localization studies using a PebHLH35-GFP fusion showed that the protein was localized to the nucleus. Ectopic overexpression of PebHLH35 in Arabidopsis resulted in a longer primary root, more leaves, and a greater leaf area under well-watered conditions compared with vector control plants. Notably, PebHLH35 overexpression lines showed enhanced tolerance to water-deficit stress. This finding was supported by anatomical and physiological analyses, which revealed a reduced stomatal density, stomatal aperture, transpiration rate, and water loss, and a higher chlorophyll content and photosynthetic rate. Our results suggest that PebHLH35 functions as a positive regulator of drought stress responses by regulating stomatal density, stomatal aperture, photosynthesis and growth.

A novel bHLH transcription factor PebHLH35 from Populus euphratica confers drought tolerance through regulating stomatal development, photosynthesis and growth in Arabidopsis

International Nuclear Information System (INIS)

Dong, Yan; Wang, Congpeng; Han, Xiao; Tang, Sha; Liu, Sha; Xia, Xinli; Yin, Weilun

2014-01-01

Highlights: • PebHLH35 is firstly cloned from Populus euphratica and characterized its functions. • PebHLH35 is important for earlier seedling establishment and vegetative growth. • PebHLH35 enhances tolerance to drought by regulating growth. • PebHLH35 enhances tolerance to drought by regulating stomatal development. • PebHLH35 enhances tolerance to drought by regulating photosynthesis and transpiration. - Abstract: Plant basic helix-loop-helix (bHLH) transcription factors (TFs) are involved in a variety of physiological processes including the regulation of plant responses to various abiotic stresses. However, few drought-responsive bHLH family members in Populus have been reported. In this study, a novel bHLH gene (PebHLH35) was cloned from Populus euphratica. Expression analysis in P. euphratica revealed that PebHLH35 was induced by drought and abscisic acid. Subcellular localization studies using a PebHLH35-GFP fusion showed that the protein was localized to the nucleus. Ectopic overexpression of PebHLH35 in Arabidopsis resulted in a longer primary root, more leaves, and a greater leaf area under well-watered conditions compared with vector control plants. Notably, PebHLH35 overexpression lines showed enhanced tolerance to water-deficit stress. This finding was supported by anatomical and physiological analyses, which revealed a reduced stomatal density, stomatal aperture, transpiration rate, and water loss, and a higher chlorophyll content and photosynthetic rate. Our results suggest that PebHLH35 functions as a positive regulator of drought stress responses by regulating stomatal density, stomatal aperture, photosynthesis and growth

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

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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.

Stomatal kinetics and photosynthetic gas exchange along a continuum of isohydric to anisohydric regulation of plant water status.

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Meinzer, Frederick C; Smith, Duncan D; Woodruff, David R; Marias, Danielle E; McCulloh, Katherine A; Howard, Ava R; Magedman, Alicia L

2017-08-01

Species' differences in the stringency of stomatal control of plant water potential represent a continuum of isohydric to anisohydric behaviours. However, little is known about how quasi-steady-state stomatal regulation of water potential may relate to dynamic behaviour of stomata and photosynthetic gas exchange in species operating at different positions along this continuum. Here, we evaluated kinetics of light-induced stomatal opening, activation of photosynthesis and features of quasi-steady-state photosynthetic gas exchange in 10 woody species selected to represent different degrees of anisohydry. Based on a previously developed proxy for the degree of anisohydry, species' leaf water potentials at turgor loss, we found consistent trends in photosynthetic gas exchange traits across a spectrum of isohydry to anisohydry. More anisohydric species had faster kinetics of stomatal opening and activation of photosynthesis, and these kinetics were closely coordinated within species. Quasi-steady-state stomatal conductance and measures of photosynthetic capacity and performance were also greater in more anisohydric species. Intrinsic water-use efficiency estimated from leaf gas exchange and stable carbon isotope ratios was lowest in the most anisohydric species. In comparisons between gas exchange traits, species rankings were highly consistent, leading to species-independent scaling relationships over the range of isohydry to anisohydry observed. © 2017 John Wiley & Sons Ltd.

Plant twitter: ligands under 140 amino acids enforcing stomatal patterning.

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Rychel, Amanda L; Peterson, Kylee M; Torii, Keiko U

2010-05-01

Stomata are an essential land plant innovation whose patterning and density are under genetic and environmental control. Recently, several putative ligands have been discovered that influence stomatal density, and they all belong to the epidermal patterning factor-like family of secreted cysteine-rich peptides. Two of these putative ligands, EPF1 and EPF2, are expressed exclusively in the stomatal lineage cells and negatively regulate stomatal density. A third, EPFL6 or CHALLAH, is also a negative regulator of density, but is expressed subepidermally in the hypocotyl. A fourth, EPFL9 or STOMAGEN, is expressed in the mesophyll tissues and is a positive regulator of density. Genetic evidence suggests that these ligands may compete for the same receptor complex. Proper stomatal patterning is likely to be an intricate process involving ligand competition, regional specificity, and communication between tissue layers. EPFL-family genes exist in the moss Physcomitrella patens, the lycophyte Selaginella moellendorffii, and rice, Oryza sativa, and their sequence analysis yields several genes some of which are related to EPF1, EPF2, EPFL6, and EPFL9. Presence of these EPFL family members in the basal land plants suggests an exciting hypothesis that the genetic components for stomatal patterning originated early in land plant evolution.

Quantitative Evaluation of Stomatal Cytoskeletal Patterns during the Activation of Immune Signaling in Arabidopsis thaliana.

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Masaki Shimono

Full Text Available Historically viewed as primarily functioning in the regulation of gas and water vapor exchange, it is now evident that stomata serve an important role in plant immunity. Indeed, in addition to classically defined functions related to cell architecture and movement, the actin cytoskeleton has emerged as a central component of the plant immune system, underpinning not only processes related to cell shape and movement, but also receptor activation and signaling. Using high resolution quantitative imaging techniques, the temporal and spatial changes in the actin microfilament array during diurnal cycling of stomatal guard cells has revealed a highly orchestrated transition from random arrays to ordered bundled filaments. While recent studies have demonstrated that plant stomata close in response to pathogen infection, an evaluation of stimulus-induced changes in actin cytoskeletal dynamics during immune activation in the guard cell, as well as the relationship of these changes to the function of the actin cytoskeleton and stomatal aperture, remains undefined. In the current study, we employed quantitative cell imaging and hierarchical clustering analyses to define the response of the guard cell actin cytoskeleton to pathogen infection and the elicitation of immune signaling. Using this approach, we demonstrate that stomatal-localized actin filaments respond rapidly, and specifically, to both bacterial phytopathogens and purified pathogen elicitors. Notably, we demonstrate that higher order temporal and spatial changes in the filament array show distinct patterns of organization during immune activation, and that changes in the naïve diurnal oscillations of guard cell actin filaments are perturbed by pathogens, and that these changes parallel pathogen-induced stomatal gating. The data presented herein demonstrate the application of a highly tractable and quantifiable method to assign transitions in actin filament organization to the activation of

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

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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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Mapping ‘hydroscapes’ along the iso- to anisohydric continuum of stomatal regulation of plant water status

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Frederick C. Meinzer; David R. Woodruff; Danielle E. Marias; Duncan D. Smith; Katherine A. McCulloh; Ava R. Howard; Alicia L. Magedman; Josep Penuelas

2016-01-01

The concept of iso- vs. anisohydry has been used to describe the stringency of stomatal regulation of plant water potential (ψ). However, metrics that accurately and consistently quantify species’ operating ranges along a continuum of iso- to anisohydry have been elusive. Additionally, most approaches to quantifying iso/anisohydry require labour-intensive measurements...

Plant water potential improves prediction of empirical stomatal models.

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William R L Anderegg

Full Text Available Climate change is expected to lead to increases in drought frequency and severity, with deleterious effects on many ecosystems. Stomatal responses to changing environmental conditions form the backbone of all ecosystem models, but are based on empirical relationships and are not well-tested during drought conditions. Here, we use a dataset of 34 woody plant species spanning global forest biomes to examine the effect of leaf water potential on stomatal conductance and test the predictive accuracy of three major stomatal models and a recently proposed model. We find that current leaf-level empirical models have consistent biases of over-prediction of stomatal conductance during dry conditions, particularly at low soil water potentials. Furthermore, the recently proposed stomatal conductance model yields increases in predictive capability compared to current models, and with particular improvement during drought conditions. Our results reveal that including stomatal sensitivity to declining water potential and consequent impairment of plant water transport will improve predictions during drought conditions and show that many biomes contain a diversity of plant stomatal strategies that range from risky to conservative stomatal regulation during water stress. Such improvements in stomatal simulation are greatly needed to help unravel and predict the response of ecosystems to future climate extremes.

Positive and negative peptide signals control stomatal density.

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

2011-06-01

The stoma is a micro valve found on aerial plant organs that promotes gas exchange between the atmosphere and the plant body. Each stoma is formed by a strict cell lineage during the early stages of leaf development. Molecular genetics research using the model plant Arabidopsis has revealed the genes involved in stomatal differentiation. Cysteine-rich secretory peptides of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family play crucial roles as extracellular signaling factors. Stomatal development is orchestrated by the positive factor STOMAGEN/EPFL9 and the negative factors EPF1, EPF2, and CHALLAH/EPFL6 in combination with multiple receptors. EPF1 and EPF2 are produced in the stomatal lineage cells of the epidermis, whereas STOMAGEN and CHALLAH are derived from the inner tissues. These findings highlight the complex cell-to-cell and intertissue communications that regulate stomatal development. To optimize gas exchange, particularly the balance between the uptake of carbon dioxide (CO(2)) and loss of water, plants control stomatal activity in response to environmental conditions. The CO(2) level and light intensity influence stomatal density. Plants sense environmental cues in mature leaves and adjust the stomatal density of newly forming leaves, indicating the involvement of long-distance systemic signaling. This review summarizes recent research progress in the peptide signaling of stomatal development and discusses the evolutionary model of the signaling machinery.

Combining sap flow and eddy covariance approaches to derive stomatal and non-stomatal O3 fluxes in a forest stand

International Nuclear Information System (INIS)

Nunn, A.J.; Cieslik, S.; Metzger, U.; Wieser, G.; Matyssek, R.

2010-01-01

Stomatal O 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 3 flux was 33% of the total O 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 3 flux and reflected stomatal regulation rather than O 3 exposure, paralleling the daily courses of canopy conductance for water vapor and eddy covariance-based total stand-level O 3 flux. The demonstrated combination of sap flow and eddy covariance approaches supports the development of O 3 risk assessment in forests from O 3 exposure towards flux-based concepts. - Combined tree sap flow and eddy covariance-based methodologies yield stomatal O 3 flux as 33% in total stand flux.

RIN4 functions with plasma membrane H+-ATPases to regulate stomatal apertures during pathogen attack

DEFF Research Database (Denmark)

Liu, Jun; Elmore, James M.; Fuglsang, Anja Thoe

2009-01-01

Abstract Pathogen perception by the plant innate immune system is of central importance to plant survival and productivity. The Arabidopsis protein RIN4 is a negative regulator of plant immunity. In order to identify additional proteins involved in RIN4- mediated immune signal transduction, we...... purified components of the RIN4 protein complex. We identified six novel proteins that had not previously been implicated in RIN4 signaling, including the plasma membrane (PM) H+-ATPases AHA1 and/or AHA2. RIN4 interacts with AHA1 and AHA2 both in vitro and in vivo. RIN4 overexpression and knockout lines...... exhibit differential PM H+-ATPase activity. PM H+-ATPase activation induces stomatal opening, enabling bacteria to gain entry into the plant leaf; inactivation induces stomatal closure thus restricting bacterial invasion. The rin4 knockout line exhibited reduced PM H+-ATPase activity and, importantly, its...

7 CFR 301.89-5 - Movement of regulated articles from regulated areas.

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2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of regulated articles from regulated areas. 301.89-5 Section 301.89-5 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL... § 301.89-5 Movement of regulated articles from regulated areas. (a) Any regulated article may be moved...

Drought responses of two gymnosperm species with contrasting stomatal regulation strategies under elevated [CO2] and temperature.

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Duan, Honglang; O'Grady, Anthony P; Duursma, Remko A; Choat, Brendan; Huang, Guomin; Smith, Renee A; Jiang, Yanan; Tissue, David T

2015-07-01

Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (C(a) (ambient, 400 μl l(-1)) and C(e) (elevated, 640 μl l(-1))) and two temperature (T(a) (ambient) and T(e) (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. C(e) did not delay the time-to-mortality in either species under drought or T(e) treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l(-1)) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought. �

CDPKs CPK6 and CPK3 function in ABA regulation of guard cell S-type anion- and Ca(2+-permeable channels and stomatal closure.

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Izumi C Mori

2006-10-01

Full Text Available Abscisic acid (ABA signal transduction has been proposed to utilize cytosolic Ca(2+ in guard cell ion channel regulation. However, genetic mutants in Ca(2+ sensors that impair guard cell or plant ion channel signaling responses have not been identified, and whether Ca(2+-independent ABA signaling mechanisms suffice for a full response remains unclear. Calcium-dependent protein kinases (CDPKs have been proposed to contribute to central signal transduction responses in plants. However, no Arabidopsis CDPK gene disruption mutant phenotype has been reported to date, likely due to overlapping redundancies in CDPKs. Two Arabidopsis guard cell-expressed CDPK genes, CPK3 and CPK6, showed gene disruption phenotypes. ABA and Ca(2+ activation of slow-type anion channels and, interestingly, ABA activation of plasma membrane Ca(2+-permeable channels were impaired in independent alleles of single and double cpk3cpk6 mutant guard cells. Furthermore, ABA- and Ca(2+-induced stomatal closing were partially impaired in these cpk3cpk6 mutant alleles. However, rapid-type anion channel current activity was not affected, consistent with the partial stomatal closing response in double mutants via a proposed branched signaling network. Imposed Ca(2+ oscillation experiments revealed that Ca(2+-reactive stomatal closure was reduced in CDPK double mutant plants. However, long-lasting Ca(2+-programmed stomatal closure was not impaired, providing genetic evidence for a functional separation of these two modes of Ca(2+-induced stomatal closing. Our findings show important functions of the CPK6 and CPK3 CDPKs in guard cell ion channel regulation and provide genetic evidence for calcium sensors that transduce stomatal ABA signaling.

Improving stomatal functioning at elevated growth air humidity: A review.

Science.gov (United States)

Fanourakis, Dimitrios; Bouranis, Dimitrios; Giday, Habtamu; Carvalho, Dália R A; Rezaei Nejad, Abdolhossein; Ottosen, Carl-Otto

2016-12-01

Plants grown at high relative air humidity (RH≥85%) are prone to lethal wilting upon transfer to conditions of high evaporative demand. The reduced survival of these plants is related to (i) increased cuticular permeability, (ii) changed anatomical features (i.e., longer pore length and higher stomatal density), (iii) reduced rehydration ability, (iv) impaired water potential sensitivity to leaf dehydration and, most importantly, (v) compromised stomatal closing ability. This review presents a critical analysis of the strategies which stimulate stomatal functioning during plant development at high RH. These include (a) breeding for tolerant cultivars, (b) interventions with respect to the belowground environment (i.e., water deficit, increased salinity, nutrient culture and grafting) as well as (c) manipulation of the aerial environment [i.e., increased proportion of blue light, increased air movement, temporal temperature rise, and spraying with abscisic acid (ABA)]. Root hypoxia, mechanical disturbance, as well as spraying with compounds mimicking ABA, lessening its inactivation or stimulating its within-leaf redistribution are also expected to improve stomatal functioning of leaves expanded in humid air. Available evidence leaves little doubt that genotypic and phenotypic differences in stomatal functioning following cultivation at high RH are realized through the intermediacy of ABA. Copyright © 2016 Elsevier GmbH. All rights reserved.

Adaxial/abaxial specification in the regulation of photosynthesis and stomatal opening with respect to light orientation and growth with CO2 enrichment in the C4 species Paspalum dilatatum.

Science.gov (United States)

Soares, Ana Sofia; Driscoll, Simon P; Olmos, Enrique; Harbinson, Jeremy; Arrabaça, Maria Celeste; Foyer, Christine H

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 microl l(-1) CO(2). Plant biomass was doubled as a result of growth at high CO(2) and the shoot:root ratio was decreased. Stomatal density was increased in the leaves of the high CO(2)-grown plants, which had greater numbers of smaller stomata and more epidermal cells on the abaxial surface. An asymmetric surface-specific regulation of photosynthesis and stomatal conductance was observed with respect to light orientation. This was not caused by dorso-ventral variations in leaf structure, the distribution of phosphoenolpyruvate carboxylase (PEPC) and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) proteins or light absorptance, transmittance or reflectance. Adaxial/abaxial specification in the regulation of photosynthesis results from differential sensitivity of stomatal opening to light orientation and fixed gradients of enzyme activation across the leaf.

Aquaporins Contribute to ABA-Triggered Stomatal Closure through OST1-Mediated Phosphorylation

Science.gov (United States)

Grondin, Alexandre; Rodrigues, Olivier; Verdoucq, Lionel; Merlot, Sylvain; Leonhardt, Nathalie; Maurel, Christophe

2015-01-01

Stomatal movements in response to environmental stimuli critically control the plant water status. Although these movements are governed by osmotically driven changes in guard cell volume, the role of membrane water channels (aquaporins) has remained hypothetical. Assays in epidermal peels showed that knockout Arabidopsis thaliana plants lacking the Plasma membrane Intrinsic Protein 2;1 (PIP2;1) aquaporin have a defect in stomatal closure, specifically in response to abscisic acid (ABA). ABA induced a 2-fold increase in osmotic water permeability (Pf) of guard cell protoplasts and an accumulation of reactive oxygen species in guard cells, which were both abrogated in pip2;1 plants. Open stomata 1 (OST1)/Snf1-related protein kinase 2.6 (SnRK2.6), a protein kinase involved in guard cell ABA signaling, was able to phosphorylate a cytosolic PIP2;1 peptide at Ser-121. OST1 enhanced PIP2;1 water transport activity when coexpressed in Xenopus laevis oocytes. Upon expression in pip2;1 plants, a phosphomimetic form (Ser121Asp) but not a phosphodeficient form (Ser121Ala) of PIP2;1 constitutively enhanced the Pf of guard cell protoplasts while suppressing its ABA-dependent activation and was able to restore ABA-dependent stomatal closure in pip2;1. This work supports a model whereby ABA-triggered stomatal closure requires an increase in guard cell permeability to water and possibly hydrogen peroxide, through OST1-dependent phosphorylation of PIP2;1 at Ser-121. PMID:26163575

Stomatal Blue Light Response Is Present in Early Vascular Plants.

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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. © 2015 American Society of Plant Biologists. All Rights Reserved.

Mix-and-match: ligand-receptor pairs in stomatal development and beyond.

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Torii, Keiko U

2012-12-01

Stomata are small valves on the plant epidermis balancing gas exchange and water loss. Stomata are formed according to positional cues. In Arabidopsis, two EPIDERMAL PATTERNING FACTOR (EPF) peptides, EPF1 and EPF2, are secreted from stomatal precursors enforcing proper stomatal patterning. Here, I review recent studies revealing the ligand-receptor pairs and revising the previously predicted relations between receptors specifying stomatal patterning: ERECTA-family and TOO MANY MOUTHS (TMM). Furthermore, EPF-LIKE9 (EPFL9/Stomagen) promotes stomatal differentiation from internal tissues. Two EPFL peptides specify inflorescence architecture, a process beyond stomatal development, as ligands for ERECTA. Thus, broadly expressed receptor kinases may regulate multiple developmental processes through perceiving different peptide ligands, each with a specialized expression pattern. TMM in the epidermis may fine-tune multiple EPF/EPFL signals to prevent signal interference. Copyright © 2012 Elsevier Ltd. All rights reserved.

Organ-specific effects of brassinosteroids on stomatal production coordinate with the action of Too Many Mouths.

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Wang, Ming; Yang, Kezhen; Le, Jie

2015-03-01

In Arabidopsis, stomatal development initiates after protodermal cells acquire stomatal lineage cell fate. Stomata or their precursors communicate with their neighbor epidermal cells to ensure the "one cell 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 cell fate determination and asymmetric entry divisions, and SPCH activity is regulated by YODA MAPK cascade. Brassinosteroid (BR) signaling, one of the most well 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 controlled 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 coordinate with the TMM organ-specific actions. © 2014 Institute of Botany, Chinese Academy of Sciences.

Natural variation in stomatal response to closing stimuli among Arabidopsis thaliana accessions after exposure to low VPD as a tool to recognize the mechanism of disturbed stomatal functioning.

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Aliniaeifard, Sasan; van Meeteren, Uulke

2014-12-01

Stomatal responses to closing stimuli are disturbed after long-term exposure of plants to low vapour pressure deficit (VPD). The mechanism behind this disturbance is not fully understood. Genetic variation between naturally occurring ecotypes can be helpful to elucidate the mechanism controlling stomatal movements in different environments. We characterized the stomatal responses of 41 natural accessions of Arabidopsis thaliana to closing stimuli (ABA and desiccation) after they had been exposed for 4 days to moderate VPD (1.17 kPa) or low VPD (0.23 kPa). A fast screening system was used to test stomatal response to ABA using chlorophyll fluorescence imaging under low O2 concentrations of leaf discs floating on ABA solutions. In all accessions stomatal conductance (gs) was increased after prior exposure to low VPD. After exposure to low VPD, stomata of 39 out of 41 of the accessions showed a diminished ABA closing response; only stomata of low VPD-exposed Map-42 and C24 were as responsive to ABA as moderate VPD-exposed plants. In response to desiccation, most of the accessions showed a normal stomata closing response following low VPD exposure. Only low VPD-exposed Cvi-0 and Rrs-7 showed significantly less stomatal closure compared with moderate VPD-exposed plants. Using principle component analysis (PCA), accessions could be categorized to very sensitive, moderately sensitive, and less sensitive to closing stimuli. In conclusion, we present evidence for different stomatal responses to closing stimuli after long-term exposure to low VPD across Arabidopsis accessions. The variation can be a useful tool for finding the mechanism of stomatal malfunctioning. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

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

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

2016-01-01

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...

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. Published 2015. This article is a US Government work and is in the public domain in the USA.

Functional Analysis of Cellulose and Xyloglucan in the Walls of Stomatal Guard Cells of Arabidopsis1[OPEN

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Rui, Yue; Anderson, Charles T.

2016-01-01

Stomatal guard cells are pairs of specialized epidermal cells that control water and CO2 exchange between the plant and the environment. To fulfill the functions of stomatal opening and closure that are driven by changes in turgor pressure, guard cell walls must be both strong and flexible, but how the structure and dynamics of guard cell walls enable stomatal function remains poorly understood. To address this question, we applied cell biological and genetic analyses to investigate guard cell walls and their relationship to stomatal function in Arabidopsis (Arabidopsis thaliana). Using live-cell spinning disk confocal microscopy, we measured the motility of cellulose synthase (CESA)-containing complexes labeled by green fluorescent protein (GFP)-CESA3 and observed a reduced proportion of GFP-CESA3 particles colocalizing with microtubules upon stomatal closure. Imaging cellulose organization in guard cells revealed a relatively uniform distribution of cellulose in the open state and a more fibrillar pattern in the closed state, indicating that cellulose microfibrils undergo dynamic reorganization during stomatal movements. In cesa3je5 mutants defective in cellulose synthesis and xxt1 xxt2 mutants lacking the hemicellulose xyloglucan, stomatal apertures, changes in guard cell length, and cellulose reorganization were aberrant during fusicoccin-induced stomatal opening or abscisic acid-induced stomatal closure, indicating that sufficient cellulose and xyloglucan are required for normal guard cell dynamics. Together, these results provide new insights into how guard cell walls allow stomata to function as responsive mediators of gas exchange at the plant surface. PMID:26729799

The Arabidopsis lectin receptor kinase LecRK-V.5 represses stomatal immunity induced by Pseudomonas syringae pv. tomato DC3000.

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Marie Desclos-Theveniau

2012-02-01

Full Text Available Stomata play an important role in plant innate immunity by limiting pathogen entry into leaves but molecular mechanisms regulating stomatal closure upon pathogen perception are not well understood. Here we show that the Arabidopsis thaliana L-type lectin receptor kinase-V.5 (LecRK-V.5 negatively regulates stomatal immunity. Loss of LecRK-V.5 function increased resistance to surface inoculation with virulent bacteria Pseudomonas syringae pv tomato DC3000. Levels of resistance were not affected after infiltration-inoculation, suggesting that LecRK-V.5 functions at an early defense stage. By contrast, lines overexpressing LecRK-V.5 were more susceptible to Pst DC3000. Enhanced resistance in lecrk-V.5 mutants was correlated with constitutive stomatal closure, while increased susceptibility phenotypes in overexpression lines were associated with early stomatal reopening. Lines overexpressing LecRK-V.5 also demonstrated a defective stomatal closure after pathogen-associated molecular pattern (PAMP treatments. LecRK-V.5 is rapidly expressed in stomatal guard cells after bacterial inoculation or treatment with the bacterial PAMP flagellin. In addition, lecrk-V.5 mutants guard cells exhibited constitutive accumulation of reactive oxygen species (ROS and inhibition of ROS production opened stomata of lecrk-V.5. LecRK-V.5 is also shown to interfere with abscisic acid-mediated stomatal closure signaling upstream of ROS production. These results provide genetic evidences that LecRK-V.5 negatively regulates stomatal immunity upstream of ROS biosynthesis. Our data reveal that plants have evolved mechanisms to reverse bacteria-mediated stomatal closure to prevent long-term effect on CO(2 uptake and photosynthesis.

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

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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.

7 CFR 330.200 - Movement of plant pests regulated; permits required.

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2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of plant pests regulated; permits required... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.200 Movement of...

Analysis of Stomatal Patterning in Selected Mutants of MAPK Pathways

KAUST Repository

Felemban, Abrar

2016-01-01

-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

Stomatal structure and physiology do not explain differences in water use among montane eucalypts.

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Gharun, Mana; Turnbull, Tarryn L; Pfautsch, Sebastian; Adams, Mark A

2015-04-01

Understanding the regulation of water use at the whole-tree scale is critical to advancing the utility of physiological ecology, for example in its role in predictive hydrology of forested catchments. For three eucalypt species that dominate high-elevation catchments in south-eastern Australia, we examined if whole-tree water use could be related to three widely discussed regulators of water use: stomatal anatomy, sensitivity of stomata [i.e. stomatal conductance (g(s))] to environmental influences, and sapwood area. While daily tree water use varied sixfold among species, sap velocity and sapwood area varied in parallel. Combined, stomatal structure and physiology could not explain differences in species-specific water use. Species which exhibited the fastest (Eucalyptus delegatensis) and slowest (Eucalyptus pauciflora) rates of water use both exhibited greater capacity for physiological control of g(s) [indicated by sensitivity to vapour pressure deficit (VPD)] and a reduced capacity to limit g(s) anatomically [indicated by greater potential g(s) (g(max))]. Conversely, g(s) was insensitive to VPD and g(max) was lowest for Eucalyptus radiata, the species showing intermediate rates of water use. Improved knowledge of stomatal anatomy will help us to understand the capacity of species to regulate leaf-level water loss, but seems likely to remain of limited use for explaining rates of whole-tree water use in montane eucalypts at the catchment scale.

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).

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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. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

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Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

2016-07-01

Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. © 2016 Federation of European Biochemical Societies.

Arabidopsis YAK1 regulates abscisic acid response and drought resistance

KAUST Repository

Kim, Dongjin

2016-06-06

Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. © 2016 Federation of European Biochemical Societies.

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

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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.

Ion Exchangers NHX1 and NHX2 Mediate Active Potassium Uptake into Vacuoles to Regulate Cell Turgor and Stomatal Function in Arabidopsis[W][OA

Science.gov (United States)

Barragán, Verónica; Leidi, Eduardo O.; Andrés, Zaida; Rubio, Lourdes; De Luca, Anna; Fernández, José A.; Cubero, Beatriz; Pardo, José M.

2012-01-01

Intracellular NHX proteins are Na+,K+/H+ antiporters involved in K+ homeostasis, endosomal pH regulation, and salt tolerance. Proteins NHX1 and NHX2 are the two major tonoplast-localized NHX isoforms. Here, we show that NHX1 and NHX2 have similar expression patterns and identical biochemical activity, and together they account for a significant amount of the Na+,K+/H+ antiport activity in tonoplast vesicles. Reverse genetics showed functional redundancy of NHX1 and NHX2 genes. Growth of the double mutant nhx1 nhx2 was severely impaired, and plants were extremely sensitive to external K+. By contrast, nhx1 nhx2 mutants showed similar sensitivity to salinity stress and even greater rates of Na+ sequestration than the wild type. Double mutants had reduced ability to create the vacuolar K+ pool, which in turn provoked greater K+ retention in the cytosol, impaired osmoregulation, and compromised turgor generation for cell expansion. Genes NHX1 and NHX2 were highly expressed in guard cells, and stomatal function was defective in mutant plants, further compromising their ability to regulate water relations. Together, these results show that tonoplast-localized NHX proteins are essential for active K+ uptake at the tonoplast, for turgor regulation, and for stomatal function. PMID:22438021

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

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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

Predicting photosynthesis and transpiration responses to ozone: decoupling modeled photosynthesis and stomatal conductance

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D. Lombardozzi

2012-08-01

Full Text Available Plants exchange greenhouse gases carbon dioxide and water with the atmosphere through the processes of photosynthesis and transpiration, making them essential in climate regulation. Carbon dioxide and water exchange are typically coupled through the control of stomatal conductance, and the parameterization in many models often predict conductance based on photosynthesis values. Some environmental conditions, like exposure to high ozone (O₃ concentrations, alter photosynthesis independent of stomatal conductance, so models that couple these processes cannot accurately predict both. The goals of this study were to test direct and indirect photosynthesis and stomatal conductance modifications based on O₃ damage to tulip poplar (Liriodendron tulipifera in a coupled Farquhar/Ball-Berry model. The same modifications were then tested in the Community Land Model (CLM to determine the impacts on gross primary productivity (GPP and transpiration at a constant O₃ concentration of 100 parts per billion (ppb. Modifying the V_cmax parameter and directly modifying stomatal conductance best predicts photosynthesis and stomatal conductance responses to chronic O₃ over a range of environmental conditions. On a global scale, directly modifying conductance reduces the effect of O₃ on both transpiration and GPP compared to indirectly modifying conductance, particularly in the tropics. The results of this study suggest that independently modifying stomatal conductance can improve the ability of models to predict hydrologic cycling, and therefore improve future climate predictions.

Effects of SO/sub 2/ pollution on stomatal movements in Vicia faba

Energy Technology Data Exchange (ETDEWEB)

Majernik, O; Mansfield, T A

1971-01-01

Leaves of broad bean Vicia faba L. exposed to controlled levels of SO/sub 2/ pollution in the range 0.25 to 9.0 ppm had much wider stomatal openings than control plants. The stimulation of opening relative to the controls was proportional to SO/sub 2/ concentration over the range 0.25 to 1.0 ppm. The ability of the stomata to close at night was not appreciably affected. The possible implications of this unnatural reaction of the stomata are discussed. Abnormal opening could lead to the plant's losing its usual control over transpiration, with resulting water stress. The main disadvantage, however, is that SO/sub 2/ will gain easier access to the interior of the leaf.

The BIG protein distinguishes the process of CO2 -induced stomatal closure from the inhibition of stomatal opening by CO2.

Science.gov (United States)

He, Jingjing; Zhang, Ruo-Xi; Peng, Kai; Tagliavia, Cecilia; Li, Siwen; Xue, Shaowu; Liu, Amy; Hu, Honghong; Zhang, Jingbo; Hubbard, Katharine E; Held, Katrin; McAinsh, Martin R; Gray, Julie E; Kudla, Jörg; Schroeder, Julian I; Liang, Yun-Kuan; Hetherington, Alistair M

2018-04-01

We conducted an infrared thermal imaging-based genetic screen to identify Arabidopsis mutants displaying aberrant stomatal behavior in response to elevated concentrations of CO 2 . This approach resulted in the isolation of a novel allele of the Arabidopsis BIG locus (At3g02260) that we have called CO 2 insensitive 1 (cis1). BIG mutants are compromised in elevated CO 2 -induced stomatal closure and bicarbonate activation of S-type anion channel currents. In contrast with the wild-type, they fail to exhibit reductions in stomatal density and index when grown in elevated CO 2 . However, like the wild-type, BIG mutants display inhibition of stomatal opening when exposed to elevated CO 2 . BIG mutants also display wild-type stomatal aperture responses to the closure-inducing stimulus abscisic acid (ABA). Our results indicate that BIG is a signaling component involved in the elevated CO 2 -mediated control of stomatal development. In the control of stomatal aperture by CO 2 , BIG is only required in elevated CO 2 -induced closure and not in the inhibition of stomatal opening by this environmental signal. These data show that, at the molecular level, the CO 2 -mediated inhibition of opening and promotion of stomatal closure signaling pathways are separable and BIG represents a distinguishing element in these two CO 2 -mediated responses. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

14-3-3 Proteins in Guard Cell Signaling.

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Cotelle, Valérie; Leonhardt, Nathalie

2015-01-01

Guard cells are specialized cells located at the leaf surface delimiting pores which control gas exchanges between the plant and the atmosphere. To optimize the CO2 uptake necessary for photosynthesis while minimizing water loss, guard cells integrate environmental signals to adjust stomatal aperture. The size of the stomatal pore is regulated by movements of the guard cells driven by variations in their volume and turgor. As guard cells perceive and transduce a wide array of environmental cues, they provide an ideal system to elucidate early events of plant signaling. Reversible protein phosphorylation events are known to play a crucial role in the regulation of stomatal movements. However, in some cases, phosphorylation alone is not sufficient to achieve complete protein regulation, but is necessary to mediate the binding of interactors that modulate protein function. Among the phosphopeptide-binding proteins, the 14-3-3 proteins are the best characterized in plants. The 14-3-3s are found as multiple isoforms in eukaryotes and have been shown to be involved in the regulation of stomatal movements. In this review, we describe the current knowledge about 14-3-3 roles in the regulation of their binding partners in guard cells: receptors, ion pumps, channels, protein kinases, and some of their substrates. Regulation of these targets by 14-3-3 proteins is discussed and related to their function in guard cells during stomatal movements in response to abiotic or biotic stresses.

Sensitivity of stomatal conductance to soil moisture: implications for tropospheric ozone

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A. Anav

2018-04-01

Full Text Available Soil moisture and water stress play a pivotal role in regulating stomatal behaviour of plants; however, in the last decade, the role of water availability has often been neglected in atmospheric chemistry modelling studies as well as in integrated risk assessments, despite the fact that plants remove a large amount of atmospheric compounds from the lower troposphere through stomata. The main aim of this study is to evaluate, within the chemistry transport model CHIMERE, the effect of soil water limitation on stomatal conductance and assess the resulting changes in atmospheric chemistry testing various hypotheses of water uptake by plants in the rooting zone. Results highlight how dry deposition significantly declines when soil moisture is used to regulate the stomatal opening, mainly in the semi-arid environments: in particular, over Europe the amount of ozone removed by dry deposition in one year without considering any soil water limitation to stomatal conductance is about 8.5 TgO3, while using a dynamic layer that ensures that plants maximize the water uptake from soil, we found a reduction of about 10 % in the amount of ozone removed by dry deposition ( ∼  7.7 TgO3. Although dry deposition occurs from the top of canopy to ground level, it affects the concentration of gases remaining in the lower atmosphere, with a significant impact on ozone concentration (up to 4 ppb extending from the surface to the upper troposphere (up to 650 hPa. Our results shed light on the importance of improving the parameterizations of processes occurring at plant level (i.e. from the soil to the canopy as they have significant implications for concentration of gases in the lower troposphere and resulting risk assessments for vegetation or human health.

Sensitivity of stomatal conductance to soil moisture: implications for tropospheric ozone

Science.gov (United States)

Anav, Alessandro; Proietti, Chiara; Menut, Laurent; Carnicelli, Stefano; De Marco, Alessandra; Paoletti, Elena

2018-04-01

Soil moisture and water stress play a pivotal role in regulating stomatal behaviour of plants; however, in the last decade, the role of water availability has often been neglected in atmospheric chemistry modelling studies as well as in integrated risk assessments, despite the fact that plants remove a large amount of atmospheric compounds from the lower troposphere through stomata. The main aim of this study is to evaluate, within the chemistry transport model CHIMERE, the effect of soil water limitation on stomatal conductance and assess the resulting changes in atmospheric chemistry testing various hypotheses of water uptake by plants in the rooting zone. Results highlight how dry deposition significantly declines when soil moisture is used to regulate the stomatal opening, mainly in the semi-arid environments: in particular, over Europe the amount of ozone removed by dry deposition in one year without considering any soil water limitation to stomatal conductance is about 8.5 TgO3, while using a dynamic layer that ensures that plants maximize the water uptake from soil, we found a reduction of about 10 % in the amount of ozone removed by dry deposition ( ˜ 7.7 TgO3). Although dry deposition occurs from the top of canopy to ground level, it affects the concentration of gases remaining in the lower atmosphere, with a significant impact on ozone concentration (up to 4 ppb) extending from the surface to the upper troposphere (up to 650 hPa). Our results shed light on the importance of improving the parameterizations of processes occurring at plant level (i.e. from the soil to the canopy) as they have significant implications for concentration of gases in the lower troposphere and resulting risk assessments for vegetation or human health.

Churchill regulates cell movement and mesoderm specification by repressing Nodal signaling

Directory of Open Access Journals (Sweden)

Mentzer Laura

2007-11-01

Full Text Available Abstract Background Cell movements are essential to the determination of cell fates during development. The zinc-finger transcription factor, Churchill (ChCh has been proposed to regulate cell fate by regulating cell movements during gastrulation in the chick. However, the mechanism of action of ChCh is not understood. Results We demonstrate that ChCh acts to repress the response to Nodal-related signals in zebrafish. When ChCh function is abrogated the expression of mesodermal markers is enhanced while ectodermal markers are expressed at decreased levels. In cell transplant assays, we observed that ChCh-deficient cells are more motile than wild-type cells. When placed in wild-type hosts, ChCh-deficient cells often leave the epiblast, migrate to the germ ring and are later found in mesodermal structures. We demonstrate that both movement of ChCh-compromised cells to the germ ring and acquisition of mesodermal character depend on the ability of the donor cells to respond to Nodal signals. Blocking Nodal signaling in the donor cells at the levels of Oep, Alk receptors or Fast1 inhibited migration to the germ ring and mesodermal fate change in the donor cells. We also detect additional unusual movements of transplanted ChCh-deficient cells which suggests that movement and acquisition of mesodermal character can be uncoupled. Finally, we demonstrate that ChCh is required to limit the transcriptional response to Nodal. Conclusion These data establish a broad role for ChCh in regulating both cell movement and Nodal signaling during early zebrafish development. We show that chch is required to limit mesodermal gene expression, inhibit Nodal-dependant movement of presumptive ectodermal cells and repress the transcriptional response to Nodal signaling. These findings reveal a dynamic role for chch in regulating cell movement and fate during early development.

A banana NAC transcription factor (MusaSNAC1) impart drought tolerance by modulating stomatal closure and H2O2 content.

Science.gov (United States)

Negi, Sanjana; Tak, Himanshu; Ganapathi, T R

2018-03-01

MusaSNAC1 function in H 2 O 2 mediated stomatal closure and promote drought tolerance by directly binding to CGT[A/G] motif in regulatory region of multiple stress-related genes. Drought is a abiotic stress-condition, causing reduced plant growth and diminished crop yield. Guard cells of the stomata control photosynthesis and transpiration by regulating CO 2 exchange and water loss, thus affecting growth and crop yield. Roles of NAC (NAM, ATAF1/2 and CUC2) protein in regulation of stress-conditions has been well documented however, their control over stomatal aperture is largely unknown. In this study we report a banana NAC protein, MusaSNAC1 which induced stomatal closure by elevating H 2 O 2 content in guard cells during drought stress. Overexpression of MusaSNAC1 in banana resulted in higher number of stomata closure causing reduced water loss and thus elevated drought-tolerance. During drought, expression of GUS (β-glucuronidase) under P MusaSNAC1 was remarkably elevated in guard cells of stomata which correlated with its function as a transcription factor regulating stomatal aperture closing. MusaSNAC1 is a transcriptional activator belonging to SNAC subgroup and its 5'-upstream region contain multiple Dof1 elements as well as stress-associated cis-elements. Moreover, MusaSNAC1 also regulate multiple stress-related genes by binding to core site of NAC-proteins CGT[A/G] in their 5'-upstream region. Results indicated an interesting mechanism of drought tolerance through stomatal closure by H 2 O 2 generation in guard cells, regulated by a NAC-protein in banana.

The Ecophysiology Of A Pinus Ponderosa Ecosystem Exposed To High Tropospheric Ozone: Implications For Stomatal And Non-Stomatal Ozone Fluxes

Science.gov (United States)

Fares, S.; McKay, M.; Goldstein, A.

2008-12-01

Ecosystems remove ozone from the troposphere through both stomatal and non-stomatal deposition. The portion of ozone taken up through stomata has an oxidative effect causing damage. We used a multi-year dataset to assess the physiological controls over ozone deposition. Environmental parameters, CO2 and ozone fluxes were measured continuously from January 2001 to December 2006 above a ponderosa pine plantation near Blodgett Forest, Georgetown, California. We studied the dynamic of NEE (Net Ecosystem Exchange, -838 g C m-2 yr-1) and water evapotranspiration on an annual and daily basis. These processes are tightly coupled to stomatal aperture which also controlled ozone fluxes. High levels of ozone concentrations (~ 100 ppb) were observed during the spring-summer period, with corresponding high levels of ozone fluxes (~ 30 μmol m-2 h-1). During the summer season, a large portion of the total ozone flux was due to non-stomatal processes, and we propose that a plant physiological control, releasing BVOC (Biogenic Volatile Organic Compounds), is mainly responsible. We analyzed the correlations of common ozone exposure metrics based on accumulation of concentrations (AOT40 and SUM0) with ozone fluxes (total, stomatal and non-stomatal). Stomatal flux showed poorer correlation with ozone concentrations than non-stomatal flux during summer and fall seasons, which largely corresponded to the growing period. We therefore suggest that AOT40 and SUM0 are poor predictors of ozone damage and that a physiologically based metric would be more effective.

Stomatal characteristics of Eucalyptus grandis clonal hybrids in ...

African Journals Online (AJOL)

This study describes the stomatal response occurring during water stress and subsequent recovery of three Eucalyptus grandis clonal hybrids. The aim was to investigate the degree to which stomatal conductance (gs) and stomatal density differ between the clonal hybrids across seasons and in response to water stress.

Separating active and passive influences on stomatal control of transpiration.

Science.gov (United States)

McAdam, Scott A M; Brodribb, Timothy J

2014-04-01

Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior.

Emotion Regulation through Movement: Unique Sets of Movement Characteristics are Associated with and Enhance Basic Emotions.

Science.gov (United States)

Shafir, Tal; Tsachor, Rachelle P; Welch, Kathleen B

2015-01-01

We have recently demonstrated that motor execution, observation, and imagery of movements expressing certain emotions can enhance corresponding affective states and therefore could be used for emotion regulation. But which specific movement(s) should one use in order to enhance each emotion? This study aimed to identify, using Laban Movement Analysis (LMA), the Laban motor elements (motor characteristics) that characterize movements whose execution enhances each of the basic emotions: anger, fear, happiness, and sadness. LMA provides a system of symbols describing its motor elements, which gives a written instruction (motif) for the execution of a movement or movement-sequence over time. Six senior LMA experts analyzed a validated set of video clips showing whole body dynamic expressions of anger, fear, happiness and sadness, and identified the motor elements that were common to (appeared in) all clips expressing the same emotion. For each emotion, we created motifs of different combinations of the motor elements common to all clips of the same emotion. Eighty subjects from around the world read and moved those motifs, to identify the emotion evoked when moving each motif and to rate the intensity of the evoked emotion. All subjects together moved and rated 1241 motifs, which were produced from 29 different motor elements. Using logistic regression, we found a set of motor elements associated with each emotion which, when moved, predicted the feeling of that emotion. Each emotion was predicted by a unique set of motor elements and each motor element predicted only one emotion. Knowledge of which specific motor elements enhance specific emotions can enable emotional self-regulation through adding some desired motor qualities to one's personal everyday movements (rather than mimicking others' specific movements) and through decreasing motor behaviors which include elements that enhance negative emotions.

Emotion regulation through movement: Unique sets of movement characteristics are associated with and enhance basic emotions

Directory of Open Access Journals (Sweden)

Tal eShafir

2016-01-01

Full Text Available We have recently demonstrated that motor execution, observation and imagery of movements expressing certain emotions can enhance corresponding affective states and therefore could be used for emotion regulation. But which specific movement(s should one use in order to enhance each emotion? This study aimed to identify, using Laban Movement Analysis (LMA, the Laban motor elements (motor characteristics that characterize movements whose execution enhances each of the basic emotions: anger, fear happiness, and sadness. LMA provides a system of symbols describing its motor elements, which gives a written instruction (motif for the execution of a movement or movement-sequence over time. Six senior LMA experts analyzed a validated set of video clips showing whole body dynamic expressions of anger, fear, happiness and sadness, and identified the motor elements that were common to (appeared in all clips expressing the same emotion. For each emotion, we created motifs of different combinations of the motor elements common to all clips of the same emotion. Eighty subjects from around the world read and moved those motifs, to identify the emotion evoked when moving each motif and to rate the intensity of the evoked emotion. All subjects together moved and rated 1241 motifs, which were produced from 29 different motor elements. Using logistic regression, we found a set of motor elements associated with each emotion which, when moved, predicted the feeling of that emotion. Each emotion was predicted by a unique set of motor elements and each motor element predicted only one emotion. Knowledge of which specific motor elements enhance specific emotions can enable emotional self-regulation through adding some desired motor qualities to one’s personal everyday movements (rather than mimicking others’ specific movements and through decreasing motor behaviors which include elements that enhance negative emotions.

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

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

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...

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.

7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Interstate movement of regulated nursery stock from a... Citrus Canker Notice of Quarantine and Regulations § 301.75-6 Interstate movement of regulated nursery stock from a quarantined area. (a) Regulated nursery stock may not be moved interstate from a...

Separating Active and Passive Influences on Stomatal Control of Transpiration[OPEN

Science.gov (United States)

McAdam, Scott A.M.; Brodribb, Timothy J.

2014-01-01

Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior. PMID:24488969

Optimal stomatal behaviour around the world

Science.gov (United States)

Lin, Yan-Shih; Medlyn, Belinda E.; Duursma, Remko A.; Prentice, I. Colin; Wang, Han; Baig, Sofia; Eamus, Derek; de Dios, Victor Resco; Mitchell, Patrick; Ellsworth, David S.; de Beeck, Maarten Op; Wallin, Göran; Uddling, Johan; Tarvainen, Lasse; Linderson, Maj-Lena; Cernusak, Lucas A.; Nippert, Jesse B.; Ocheltree, Troy W.; Tissue, David T.; Martin-Stpaul, Nicolas K.; Rogers, Alistair; Warren, Jeff M.; de Angelis, Paolo; Hikosaka, Kouki; Han, Qingmin; Onoda, Yusuke; Gimeno, Teresa E.; Barton, Craig V. M.; Bennie, Jonathan; Bonal, Damien; Bosc, Alexandre; Löw, Markus; Macinins-Ng, Cate; Rey, Ana; Rowland, Lucy; Setterfield, Samantha A.; Tausz-Posch, Sabine; Zaragoza-Castells, Joana; Broadmeadow, Mark S. J.; Drake, John E.; Freeman, Michael; Ghannoum, Oula; Hutley, Lindsay B.; Kelly, Jeff W.; Kikuzawa, Kihachiro; Kolari, Pasi; Koyama, Kohei; Limousin, Jean-Marc; Meir, Patrick; Lola da Costa, Antonio C.; Mikkelsen, Teis N.; Salinas, Norma; Sun, Wei; Wingate, Lisa

2015-05-01

Stomatal conductance (gs) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of gs in predictions of global water and carbon cycle changes, a global-scale 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 differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model and the leaf and wood economics spectrum. We also demonstrate a global relationship with climate. These findings provide a robust theoretical framework for understanding and predicting the behaviour of gs across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.

Impaired Malate and Fumarate Accumulation Due to the Mutation of the Tonoplast Dicarboxylate Transporter Has Little Effects on Stomatal Behavior.

Science.gov (United States)

Medeiros, David B; Barros, Kallyne A; Barros, Jessica Aline S; Omena-Garcia, Rebeca P; Arrivault, Stéphanie; Sanglard, Lílian M V P; Detmann, Kelly C; Silva, Willian Batista; Daloso, Danilo M; DaMatta, Fábio M; Nunes-Nesi, Adriano; Fernie, Alisdair R; Araújo, Wagner L

2017-11-01

Malate is a central metabolite involved in a multiplicity of plant metabolic pathways, being associated with mitochondrial metabolism and playing significant roles in stomatal movements. Vacuolar malate transport has been characterized at the molecular level and is performed by at least one carrier protein and two channels in Arabidopsis ( Arabidopsis thaliana ) vacuoles. The absence of the Arabidopsis tonoplast Dicarboxylate Transporter (tDT) in the tdt knockout mutant was associated previously with an impaired accumulation of malate and fumarate in leaves. Here, we investigated the consequences of this lower accumulation on stomatal behavior and photosynthetic capacity as well as its putative metabolic impacts. Neither the stomatal conductance nor the kinetic responses to dark, light, or high CO 2 were highly affected in tdt plants. In addition, we did not observe any impact on stomatal aperture following incubation with abscisic acid, malate, or citrate. Furthermore, an effect on photosynthetic capacity was not observed in the mutant lines. However, leaf mitochondrial metabolism was affected in the tdt plants. Levels of the intermediates of the tricarboxylic acid cycle were altered, and increases in both light and dark respiration were observed. We conclude that manipulation of the tonoplastic organic acid transporter impacted mitochondrial metabolism, while the overall stomatal and photosynthetic capacity were unaffected. © 2017 American Society of Plant Biologists. All Rights Reserved.

Tumor Necrosis Factor-Mediated Survival of CD169+ Cells Promotes Immune Activation during Vesicular Stomatitis Virus Infection

DEFF Research Database (Denmark)

Shinde, Prashant V; Xu, Haifeng C; Maney, Sathish Kumar

2018-01-01

Innate immune activation is essential to mount an effective antiviral response and to prime adaptive immunity. Although a crucial role of CD169(+) cells during vesicular stomatitis virus (VSV) infections is increasingly recognized, factors regulating CD169(+) cells during viral infections remain...... stomatitis virus infection, phagocytes produce tumor necrosis factor (TNF) which signals via TNFR1 and promote "enforced virus replication" in CD169(+) macrophages. Consequently, lack of TNF or TNFR1 resulted in defective immune activation and VSV clearance....

Linking stomatal traits and expression of slow anion channel genes HvSLAH1 2 HvSLAC1 with grain yield for increasing salinity tolerance in barley

Directory of Open Access Journals (Sweden)

Xiaohui eLiu

2014-11-01

Full Text Available Soil salinity is an environmental and agricultural problem in many parts of the world. One of the keys to breeding barley for adaptation to salinity lies in a better understanding of the genetic control of stomatal regulation. We have employed a range of physiological and molecular techniques (stomata assay, gas exchange, phylogenetic analysis, QTL analysis, and gene expression to investigate stomatal behaviour and genotypic variation in barley cultivars and a genetic population in four experimental trials. A set of relatively efficient and reliable methods were developed for the characterisation of stomatal behaviour of large numbers of varieties and genetic lines. Furthermore, we have found a large genetic variation of gas exchange and stomatal traits in barley in response to salinity stress. Salt-tolerant CM72 showed significantly larger stomatal aperture in 200 mM NaCl treatment than that of salt-sensitive Gairdner. Stomatal traits such as aperture width/length were found to significantly correlate with grain yield in salt treatment. Phenotypic characterisation and QTL analysis of a segregating double haploid population of the CM72/Gairdner resulted in the identification of significant stomatal traits-related QTLs for salt tolerance. Moreover, expression analysis of the slow anion channel genes HvSLAH1 and HvSLAC1 demonstrated that their up-regulation is linked to high barley grain yield in the field.

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...

Effect of nitrogen supply on transpiration and stomatal behaviour of beans (Phaseolus vulgaris L. )

Energy Technology Data Exchange (ETDEWEB)

Shimshi, D

1970-01-01

The effect of nitrogen supply on the transpiration rate and stomatal opening of potted bean plants was studied in a series of experiments. The transpiration rates of N-supplied plants were higher than those of N-deficient plants when soil moisture was relatively high; as soil moisture approached the wilting range, the transpiration rates of N-supplied plants dropped to below those of N-deficient plants. In spite of the marked differences in transpiration rates, as influenced by soil moisture and nitrogen supply, the stomata appeared closed. By coating the upper or lower surfaces of the leaves with a vapor-impervious compound it was shown that stomatal apertures below the limit of microscopic resolution control the rate of transpiration. Under conditions that encourage stomatal opening (covering the plants with transparent plastic bags), the stomata of the N-deficient plants opened to a lesser degree than those of N-supplied plants. There was some evidence that when stomata were visibly open, transpiration rates were regulated by the degree of plant hydration rather than by the degree of stomatal opening. It is concluded that N-deficient plants fail to open their stomata as widely and to close them as tightly as N-supplied plants. 8 references, 2 tables.

Stomatal uptake and stomatal deposition of ozone in isoprene and monoterpene emitting plants.

Science.gov (United States)

Fares, S; Loreto, F; Kleist, E; Wildt, J

2008-01-01

Volatile isoprenoids were reported to protect plants against ozone. To understand whether this could be the result of a direct scavenging of ozone by these molecules, the stomatal and non-stomatal uptake of ozone was estimated in plants emitting isoprene or monoterpenes. Ozone uptake by holm oak (Quercus ilex, a monoterpene emitter) and black poplar (Populus nigra, an isoprene emitter) was studied in whole plant enclosures (continuously stirred tank reactors, CSTR). The ozone uptake by plants was estimated measuring ozone concentration at the inlet and outlet of the reactors, after correcting for the uptake of the enclosure materials. Destruction of ozone at the cuticle or at the plant stems was found to be negligible compared to the ozone uptake through the stomata. For both plant species, a relationship between stomatal conductance and ozone uptake was found. For the poplar, the measured ozone losses were explained by the uptake of ozone through the stomata only, and ozone destruction by gas phase reactions with isoprene was negligible. For the oak, gas phase reactions of ozone with the monoterpenes emitted by the plants contributed significantly to ozone destruction. This was confirmed by two different experiments showing a) that in cases of high stomatal conductance but under low CO(2) concentration, a reduction of monoterpene emission was still associated with reduced O(3) uptake; and b) that ozone losses due to the gas phase reactions only can be measured when using the exhaust from a plant chamber to determine the gas phase reactivity in an empty reaction chamber. Monoterpenes can therefore relevantly scavenge ozone at leaf level contributing to protection against ozone.

Ecology of Candida-associated Denture Stomatitis

OpenAIRE

Budtz-Jørgensen, Ejvind

2011-01-01

Introduction of a prosthesis into the oral cavity results in profound alterations of the environmental conditions as the prosthesis and the underlying mucosa become colonized with oral microorganisms, including Candida spp. This may lead to denture stomatitis, a non-specific inflammatory reaction against microbial antigens, toxins and enzymes produced by the colonizing microorganisms. The role of Candida in the etiology of denture stomatitis is indicated by an increased number of yeasts on th...

Optimal Stomatal Behaviour Around the World: Synthesis of a Global Stomatal Conductance Database and Scaling from Leaf to Ecosystem

Science.gov (United States)

Lin, Y. S.; Medlyn, B. E.; Duursma, R.; Prentice, I. C.; Wang, H.

2014-12-01

Stomatal conductance (gs) is a key land surface attribute as it links transpiration, the dominant component of global land evapotranspiration and a key element of the global water cycle, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of gs in predictions of global water and carbon cycles, a global scale database and an associated globally applicable model of gs that allow predictions of stomatal behaviour are lacking. We present a unique database of globally distributed gs obtained in the field for a wide range of plant functional types (PFTs) and biomes. We employed a model of optimal stomatal conductance to assess differences in stomatal behaviour, and estimated the model slope coefficient, g1, which is directly related to the marginal carbon cost of water, for each dataset. We found that g1 varies considerably among PFTs, with evergreen savanna trees having the largest g1 (least conservative water use), followed by C3 grasses and crops, angiosperm trees, gymnosperm trees, and C4 grasses. Amongst angiosperm trees, species with higher wood density had a higher marginal carbon cost of water, as predicted by the theory underpinning the optimal stomatal model. There was an interactive effect between temperature and moisture availability on g1: for wet environments, g1 was largest in high temperature environments, indicated by high mean annual temperature during the period when temperature above 0oC (Tm), but it did not vary with Tm across dry environments. We examine whether these differences in leaf-scale behaviour are reflected in ecosystem-scale differences in water-use efficiency. These findings provide a robust theoretical framework for understanding and predicting the behaviour of stomatal conductance across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of productivity and ecohydrological processes in a future changing climate.

Compound stress response in stomatal closure: a mathematical model of ABA and ethylene interaction in guard cells

Directory of Open Access Journals (Sweden)

Beguerisse-Dıaz Mariano

2012-11-01

Full Text Available Abstract Background Stomata are tiny pores in plant leaves that regulate gas and water exchange between the plant and its environment. Abscisic acid and ethylene are two well-known elicitors of stomatal closure when acting independently. However, when stomata are presented with a combination of both signals, they fail to close. Results Toshed light on this unexplained behaviour, we have collected time course measurements of stomatal aperture and hydrogen peroxide production in Arabidopsis thaliana guard cells treated with abscisic acid, ethylene, and a combination of both. Our experiments show that stomatal closure is linked to sustained high levels of hydrogen peroxide in guard cells. When treated with a combined dose of abscisic acid and ethylene, guard cells exhibit increased antioxidant activity that reduces hydrogen peroxide levels and precludes closure. We construct a simplified model of stomatal closure derived from known biochemical pathways that captures the experimentally observed behaviour. Conclusions Our experiments and modelling results suggest a distinct role for two antioxidant mechanisms during stomatal closure: a slower, delayed response activated by a single stimulus (abscisic acid ‘or’ ethylene and another more rapid ‘and’ mechanism that is only activated when both stimuli are present. Our model indicates that the presence of this rapid ‘and’ mechanism in the antioxidant response is key to explain the lack of closure under a combined stimulus.

Solar-induced chlorophyll fluorescence tracks the trend of canopy stomatal conductance and transpiration at diurnal and seasonal scales

Science.gov (United States)

Zhang, Y.; Shan, N.; Ju, W.; Chen, J.

2017-12-01

Transpiration is the process of plant water loss through the stomata on the leaf surface and plays a key role in the energy and water balance of the land surface. Plant stomata function as a control interface for regulating photosynthetic uptake of CO2 and transpiration, strongly linked to plant productivity. Stomatal conductance is fundamental to larger-scale regional prediction of carbon-water cycles and their feedbacks to climate. The widely used Ball-Berry model coupled photosynthesis to a semi-empirical model of stomatal conductance. However large uncertainties remain in simulation of carbon assimilation rate in ecosystem and regional scales. The strong correlations of solar-induced fluorescence (SIF) and GPP have been demonstrated and provides an important opportunity to accurately monitor photosynthetic activity and water exchange. In this presentation, we compared both canopy-observed SIF and satellite-derived SIF with tower-based canopy stomatal conductance from hourly to 8-day scales in forest and cropland ecosystem. Using the model of stomatal conductance based on SIF, the transpiration was estimated at hourly and daily scales and compared with flux tower measurements. The results showed that the seasonal pattern of canopy stomatal conductance agreed better with SIF compared to NDVI and their relationship was higher during sunny days for forest ecosystem. Canopy stomatal conductance correlated with both tower-observed SIF and SIF from the Global Ozone Monitoring Experiment-2. Estimation of transpiration from SIF performed well in both forest and cropland ecosystem. This remotely sensed approaches from SIF for modelling stomatal conductance opens a new era to analysis and simulation of coupled carbon and water cycles under climate change.

The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

Directory of Open Access Journals (Sweden)

Asako eUchiyama

2014-11-01

Full Text Available Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV and the Tobamovirus Tobacco mosaic virus (TMV through plasmodesmata (Lewis and Lazarowitz, 2010. To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV, the Caulimovirus Cauliflower mosaic virus (CaMV and the Tobamovirus Turnip vein clearing virus (TVCV, which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP, Tobamoviruses (TVCV and TMV 30K protein and Potyviruses (TuMV P3N-PIPO to alter PD and thereby mediate virus cell-to-cell spread.

Application of thermography for monitoring stomatal conductance of Coffea arabica under different shading systems.

Science.gov (United States)

Craparo, A C W; Steppe, K; Van Asten, P J A; Läderach, P; Jassogne, L T P; Grab, S W

2017-12-31

Stomatal regulation is a key process in the physiology of Coffea arabica (C. arabica). Intrinsically linked to photosynthesis and water relations, it provides insights into the plant's adaptive capacity, survival and growth. The ability to rapidly quantify this parameter for C. arabica under different agroecological systems would be an indispensable tool. Using a Flir E6 MIR Camera, an index that is equivalent to stomatal conductance (I g ) was compared with stomatal conductance measurements (g s ) in a mature coffee plantation. In order to account for varying meteorological conditions between days, the methods were also compared under stable meteorological conditions in a laboratory and I g was also converted to absolute stomatal conductance values (g 1 ). In contrast to typical plant-thermography methods which measure indices once per day over an extended time period, we used high resolution hourly measurements over daily time series with 9 sun and 9 shade replicates. Eight daily time series showed a strong correlation between methods, while the remaining 10 were not significant. Including several other meteorological parameters in the calculation of g 1 did not contribute to any stronger correlation between methods. Total pooled data (combined daily series) resulted in a correlation of ρ=0.66 (P≤2.2e-16), indicating that our approach is particularly useful for situations where absolute values of stomatal conductance are not required, such as for comparative purposes, screening or trend analysis. We use the findings to advance the protocol for a more accurate methodology which may assist in quantifying advantageous microenvironment designs for coffee, considering the current and future climates of coffee growing regions. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

7 CFR 301.75-10 - Interstate movement of regulated articles through a quarantined area.

Science.gov (United States)

2010-01-01

... articles being moved interstate, and the date the interstate movement began. (b) The regulated article is moved through the quarantined area without being unloaded, and no regulated article, except regulated... through a quarantined area. Any regulated article not produced in a quarantined area may be moved...

Differential Effects of Phosphatidylinositol 4-Kinase (PI4K and 3-Kinase (PI3K Inhibitors on Stomatal Responses to Environmental Signals

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Koh Iba

2017-05-01

Full Text Available Specific cellular components including products of phosphatidylinositol (PI metabolism play an important role as signaling molecules in stomatal responses to environmental signals. In this study, pharmacological inhibitors of a set of cellular components, including PI4-kinase (PI4K and PI3K, were used to investigate stomatal closure in response to CO2, darkness, and abscisic acid (ABA. Treatment with PAO, a specific inhibitor of PI4K, specifically inhibited the stomatal response to CO2 compared with that to darkness and ABA. In contrast, treatment with LY294002, a PI3K-specific inhibitor, specifically inhibited the stomatal response to darkness compared with that to CO2 and ABA. The specific inhibitory effects of PAO and LY294002 were also observed as changes in the spatial density of dot-like structures labeled by green fluorescent protein-tagged PATROL1, a protein that controls stomatal aperture possibly via regulation of H+-ATPase amount in guard cell plasma membranes. Our results suggest an important role for PI4K and PI3K in the CO2 and darkness signal transduction pathways, respectively, that mediate PATROL1 dynamics.

Guard cell zeaxanthin tracks photosynthetically active radiation and stomatal apertures in Vicia faba leaves

International Nuclear Information System (INIS)

Srivastava, A.; Zeiger, E.

1995-01-01

Zeaxanthin, antheraxanthin and violaxanthin concentrations in guard cells from sonicated abaxial epidermal peels of Vicia faba were measured from dawn to dusk, and compared with concentrations in mesophyll tissue of the same leaves. Measured changes in guard cell zeaxanthin and violaxanthin concentrations indicate that guard cells operate the xanthophyll cycle throughout the day. Mesophyll tissue had no detectable zeaxanthin at dawn, whereas guard cells had 30–50 mmol mol −1 chlorophyll a+b. On a chlorophyll basis, maximal zeaxanthin levels were 3–4 fold higher in guard cells than in mesophyll cells. Zeaxanthin concentrations tracked levels of photosynthetically active radiation (PAR) in both mesophyll and guard cells. In the mesophyll, most of the zeaxanthin changes occurred in mid-morning and mid-afternoon. In guard cells, zeaxanthin concentrations changed nearly linearly with PAR in the early morning and late afternoon, and closely tracked PAR levels throughout the day. Guard cell zeaxanthin concentrations were also closely correlated with stomatal apertures. The close relationship between zeaxanthin concentrations and PAR levels in guard cells indicates that zeaxanthin is well suited to function as a molecular photosensor in stomatal movements. (author)

Chronic gingivitis and aphthous stomatitis relationship hypothesis: A neuroimmunobiological approach

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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.

7 CFR 301.75-9 - Interstate movement of regulated articles from a quarantined area for experimental or scientific...

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2010-01-01

... Interstate movement of regulated articles from a quarantined area for experimental or scientific purposes. A... 7 Agriculture 5 2010-01-01 2010-01-01 false Interstate movement of regulated articles from a quarantined area for experimental or scientific purposes. 301.75-9 Section 301.75-9 Agriculture Regulations of...

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

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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

Does Size Matter? Atmospheric CO2 May Be a Stronger Driver of Stomatal Closing Rate Than Stomatal Size in Taxa That Diversified under Low CO2.

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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.

Phosphoinositides play differential roles in regulating phototropin1- and phototropin2-mediated chloroplast movements in Arabidopsis.

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Chhavi Aggarwal

Full Text Available Phototropins are UVA/blue-light receptors involved in controlling the light-dependent physiological responses which serve to optimize the photosynthetic activity of plants and promote growth. The phototropin-induced phosphoinositide (PI metabolism has been shown to be essential for stomatal opening and phototropism. However, the role of PIs in phototropin-induced chloroplast movements remains poorly understood. The aim of this work is to determine which PI species are involved in the control of chloroplast movements in Arabidopsis and the nature of their involvement. We present the effects of the inactivation of phospholipase C (PLC, PI3-kinase (PI3K and PI4-kinase (PI4K on chloroplast relocations in Arabidopsis. The inhibition of the phosphatidylinositol 4,5-bisphospahte [PI(4,5P2]-PLC pathway, using neomycin and U73122, suppressed the phot2-mediated chloroplast accumulation and avoidance responses, without affecting movement responses controlled by phot1. On the other hand, PI3K and PI4K activities are more restricted to phot1- and phot2-induced weak-light responses. The inactivation of PI3K and PI4K by wortmannin and LY294002 severely affected the weak blue-light-activated accumulation response but had little effect on the strong blue-light-activated avoidance response. The inhibitory effect observed with PI metabolism inhibitors is, at least partly, due to a disturbance in Ca(2+ ((c signaling. Using the transgenic aequorin system, we show that the application of these inhibitors suppresses the blue-light-induced transient Ca(2+ ((c rise. These results demonstrate the importance of PIs in chloroplast movements, with the PI(4,5P2-PLC pathway involved in phot2 signaling while PI3K and PI4K are required for the phot1- and phot2-induced accumulation response. Our results suggest that these PIs modulate cytosolic Ca(2+ signaling during movements.

Phosphoinositides play differential roles in regulating phototropin1- and phototropin2-mediated chloroplast movements in Arabidopsis.

Science.gov (United States)

Aggarwal, Chhavi; Labuz, Justyna; Gabryś, Halina

2013-01-01

Phototropins are UVA/blue-light receptors involved in controlling the light-dependent physiological responses which serve to optimize the photosynthetic activity of plants and promote growth. The phototropin-induced phosphoinositide (PI) metabolism has been shown to be essential for stomatal opening and phototropism. However, the role of PIs in phototropin-induced chloroplast movements remains poorly understood. The aim of this work is to determine which PI species are involved in the control of chloroplast movements in Arabidopsis and the nature of their involvement. We present the effects of the inactivation of phospholipase C (PLC), PI3-kinase (PI3K) and PI4-kinase (PI4K) on chloroplast relocations in Arabidopsis. The inhibition of the phosphatidylinositol 4,5-bisphospahte [PI(4,5)P2]-PLC pathway, using neomycin and U73122, suppressed the phot2-mediated chloroplast accumulation and avoidance responses, without affecting movement responses controlled by phot1. On the other hand, PI3K and PI4K activities are more restricted to phot1- and phot2-induced weak-light responses. The inactivation of PI3K and PI4K by wortmannin and LY294002 severely affected the weak blue-light-activated accumulation response but had little effect on the strong blue-light-activated avoidance response. The inhibitory effect observed with PI metabolism inhibitors is, at least partly, due to a disturbance in Ca(2+) ((c)) signaling. Using the transgenic aequorin system, we show that the application of these inhibitors suppresses the blue-light-induced transient Ca(2+) ((c)) rise. These results demonstrate the importance of PIs in chloroplast movements, with the PI(4,5)P2-PLC pathway involved in phot2 signaling while PI3K and PI4K are required for the phot1- and phot2-induced accumulation response. Our results suggest that these PIs modulate cytosolic Ca(2+) signaling during movements.

Nuclear movement regulated by non-Smad Nodal signaling via JNK is associated with Smad signaling during zebrafish endoderm specification.

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Hozumi, Shunya; Aoki, Shun; Kikuchi, Yutaka

2017-11-01

Asymmetric nuclear positioning is observed during animal development, but its regulation and significance in cell differentiation remain poorly understood. Using zebrafish blastulae, we provide evidence that nuclear movement towards the yolk syncytial layer, which comprises extraembryonic tissue, occurs in the first cells fated to differentiate into the endoderm. Nodal signaling is essential for nuclear movement, whereas nuclear envelope proteins are involved in movement through microtubule formation. Positioning of the microtubule-organizing center, which is proposed to be crucial for nuclear movement, is regulated by Nodal signaling and nuclear envelope proteins. The non-Smad JNK signaling pathway, which is downstream of Nodal signaling, regulates nuclear movement independently of the Smad pathway, and this nuclear movement is associated with Smad signal transduction toward the nucleus. Our study provides insight into the function of nuclear movement in Smad signaling toward the nucleus, and could be applied to the control of TGFβ signaling. © 2017. Published by The Company of Biologists Ltd.

Salicaceae Endophytes Modulate Stomatal Behavior and Increase Water Use Efficiency in Rice

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Hyungmin Rho

2018-03-01

Full Text Available Bacterial and yeast endophytes isolated from the Salicaceae family have been shown to promote growth and alleviate stress in plants from different taxa. To determine the physiological pathways through which endophytes affect plant water relations, we investigated leaf water potential, whole-plant water use, and stomatal responses of rice plants to Salicaceae endophyte inoculation under CO2 enrichment and water deficit. Daytime stomatal conductance and stomatal density were lower in inoculated plants compared to controls. Leaf ABA concentrations increased with endophyte inoculation. As a result, transpirational water use decreased significantly with endophyte inoculation while biomass did not change or slightly increased. This response led to a significant increase in cumulative water use efficiency at harvest. Different endophyte strains produced the same results in host plant water relations and stomatal responses. These stomatal responses were also observed under elevated CO2 conditions, and the increase in water use efficiency was more pronounced under water deficit conditions. The effect on water use efficiency was positively correlated with daily light integrals across different experiments. Our results provide insights on the physiological mechanisms of plant-endophyte interactions involving plant water relations and stomatal functions.

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

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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.

Improvement of herpetic stomatitis therapy in patients with chronic tonsillitis

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Lepilin А.V.

2011-12-01

Full Text Available The research goal is to determine the clinical and pathogenetic efficacy of Cycloferon liniment in the combined therapy in patients with herpetic stomatitis accompanied by chronic tonsillitis. Materials and methods: Medical examination and treatment of 60 patients have been carried out. The marker of endogenous intoxication, infectious severity and immunity has been investigated. Results. It has been established that use of Cycloferon liniment in the combined therapy in patients with herpetic stomatitis accompanied by chronic tonsillitis has allowed to decrease infectious severity in par-odontal recess and evidence of local inflammation, to normalize immunity indices and reduce the level of endogenous intoxication that has been liable for acceleration of recuperation processes and lowering of frequency of stomatitis recurrences. Conclusion. The clinical efficacy of Cycloferon liniment in the therapy in patients with herpetic stomatitis accompanied by chronic tonsillitis conditioned by the decreasing of activity of local inflammatory process according to the reducing of level pro-inflammatory cytokines, infectious burden of the mouth cavity, endogenous intoxication

Regulation of photosynthesis and stomatal and mesophyll conductance under water stress and recovery in olive trees: correlation with gene expression of carbonic anhydrase and aquaporins.

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Perez-Martin, Alfonso; Michelazzo, Chiara; Torres-Ruiz, Jose M; Flexas, Jaume; Fernández, José E; Sebastiani, Luca; Diaz-Espejo, Antonio

2014-07-01

The hypothesis that aquaporins and carbonic anhydrase (CA) are involved in the regulation of stomatal (g s) and mesophyll (g m) conductance to CO2 was tested in a short-term water-stress and recovery experiment in 5-year-old olive plants (Olea europaea) growing outdoors. The evolution of leaf gas exchange, chlorophyll fluorescence, and plant water status, and a quantitative analysis of photosynthesis limitations, were followed during water stress and recovery. These variables were correlated with gene expression of the aquaporins OePIP1.1 and OePIP2.1, and stromal CA. At mild stress and at the beginning of the recovery period, stomatal limitations prevailed, while the decline in g m accounted for up to 60% of photosynthesis limitations under severe water stress. However, g m was restored to control values shortly after rewatering, facilitating the recovery of the photosynthetic rate. CA was downregulated during water stress and upregulated after recovery. The use of structural equation modelling allowed us to conclude that both OePIP1.1 and OePIP2.1 expression could explain most of the variations observed for g s and g m. CA expression also had a small but significant effect on g m in olive under water-stress conditions. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Assessing urban habitat quality based on specific leaf area and stomatal characteristics of Plantago lanceolata L

International Nuclear Information System (INIS)

Kardel, F.; Wuyts, K.; Babanezhad, M.; Vitharana, U.W.A.; Wuytack, T.; Potters, G.; Samson, R.

2010-01-01

This study has evaluated urban habitat quality by studying specific leaf area (SLA) and stomatal characteristics of the common herb Plantago lanceolata L. SLA and stomatal density, pore surface and resistance were measured at 169 locations in the city of Gent (Belgium), distributed over four land use classes, i.e., sub-urban green, urban green, urban and industry. SLA and stomatal density significantly increased from sub-urban green towards more urbanised land use classes, while the reverse was observed for stomatal pore surface. Stomatal resistance increased in the urban and industrial land use class in comparison with the (sub-) urban green, but differences between land use classes were less pronounced. Spatial distribution maps for these leaf characteristics showed a high spatial variation, related to differences in habitat quality within the city. Hence, stomatal density and stomatal pore surface are assumed to be potentially good bio-indicators for urban habitat quality. - Stomatal characteristics of Plantago lanceolata can be used for biomonitoring of urban habitat quality.

Preventive effects of Ancer 20 injection against radiation stomatitis

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Naohiko; Nomura, Yasuya; Takano, Shinya (Showa Univ., Tokyo (Japan). School of Medicine) (and others)

1993-10-01

Ancer 20 was injected subcutaneously twice a day into 23 patients during the couse of radiation therapy for head and neck cancer, with the aim of preventing radiation stomatitis. Oral mucosa was assessed both subjectively and objectively, in addition to white blood cell counts. Objective findings of oral mucosa revealed grade I in 71%, grade II in 52%, grade III in 14%, and grade IV in 5%. The dose of irradiation needed to produce grade I in 50% was 22.8 Gy. Subjective findings revealed grade I in 67%, grade II in 33%, and grade III in 10%. Irradiation dose needed to produce grade I in 50% was 23.9 Gy. Mucosous damage was slight when the white blood cell count of 6,000/mm[sup 3] was maintained. According to the rate of leukopenia, this drug was effective in 86.4%. These findings showed that Ancer 20 injection is useful in maintaining white blood cell counts and in preventing radiation stomatitis associated with radiation therapy especially to the field of mucous membrane. There was inverse correlation between white blood cell counts and both the occurrence rate and degree of radiation stomatitis. It seemed necessary to maintain white blood cell counts to prevent radiation stomatitis. (N.K.).

Using Movement to Regulate Emotion: Neurophysiological Findings and Their Application in Psychotherapy

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Tal Shafir

2016-09-01

Full Text Available Emotion regulation is a person’s active attempt to manage their emotional state by enhancing or decreasing specific feelings. Peripheral theories of emotion argue that the origins of emotions stem from bodily responses. This notion has been reformulated in neurophysiological terms by Damasio, who claimed that emotions are generated by conveying the current state of the body to the brain through interoceptive and proprioceptive afferent input. The resulting brain activation patterns represent unconscious emotions and correlate with conscious feelings. This proposition implies that through deliberate control of motor behavior and its consequent proprioception and interoception, one could regulate his emotions and affect his feelings. This concept is used in dance/movement (psychotherapy where, by guiding to move in a certain way, the therapist helps the client to evoke, process, and regulate specific emotions. Exploration and practice of new and unfamiliar motor patterns can help the client to experience new unaccustomed feelings. The idea that certain motor qualities enhance specific emotions is utilized by the therapist also when she mirrors the client’s movements or motor qualities in order to feel what the client feels, and empathize with them. Because of the mirror neurons, feeling what the client feels is enabled also through observation and imagination of their movements and posture. This principle can be used by verbal therapists as well, who should be aware of its bi-directionality: clients seeing the therapist’s motor behavior are unconsciously affected by the therapist’s bodily expressions. Additional implications for psychotherapy, of findings regarding mirror neurons activation, are discussed.

Aquaporins facilitate hydrogen peroxide entry into guard cells to mediate ABA- and pathogen-triggered stomatal closure.

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Rodrigues, Olivier; Reshetnyak, Ganna; Grondin, Alexandre; Saijo, Yusuke; Leonhardt, Nathalie; Maurel, Christophe; Verdoucq, Lionel

2017-08-22

Stomatal movements are crucial for the control of plant water status and protection against pathogens. Assays on epidermal peels revealed that, similar to abscisic acid (ABA), pathogen-associated molecular pattern (PAMP) flg22 requires the At PIP2;1 aquaporin to induce stomatal closure. Flg22 also induced an increase in osmotic water permeability ( P f ) of guard cell protoplasts through activation of At PIP2;1. The use of HyPer, a genetic probe for intracellular hydrogen peroxide (H 2 O 2 ), revealed that both ABA and flg22 triggered an accumulation of H 2 O 2 in wild-type but not pip2;1 guard cells. Pretreatment of guard cells with flg22 or ABA facilitated the influx of exogenous H 2 O 2 Brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) and open stomata 1 (OST1)/Snf1-related protein kinase 2.6 (SnRK2.6) were both necessary to flg22-induced P f and both phosphorylated At PIP2;1 on Ser121 in vitro. Accumulation of H 2 O 2 and stomatal closure as induced by flg22 was restored in pip2;1 guard cells by a phosphomimetic form (Ser121Asp) but not by a phosphodeficient form (Ser121Ala) of At PIP2;1. We propose a mechanism whereby phosphorylation of At PIP2;1 Ser121 by BAK1 and/or OST1 is triggered in response to flg22 to activate its water and H 2 O 2 transport activities. This work establishes a signaling role of plasma membrane aquaporins in guard cells and potentially in other cellular context involving H 2 O 2 signaling.

Regulation of stomatal tropism and infection by light in Cercospora zeae-maydis: evidence for coordinated host/pathogen responses to photoperiod?

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Hun Kim

2011-07-01

Full Text Available Cercospora zeae-maydis causes gray leaf spot of maize, which has become one of the most widespread and destructive diseases of maize in the world. C. zeae-maydis infects leaves through stomata, which is predicated on the ability of the pathogen to perceive stomata and reorient growth accordingly. In this study, the discovery that light was required for C. zeae-maydis to perceive stomata and infect leaves led to the identification of CRP1, a gene encoding a putative blue-light photoreceptor homologous to White Collar-1 (WC-1 of Neurospora crassa. Disrupting CRP1 via homologous recombination revealed roles in multiple aspects of pathogenesis, including tropism of hyphae to stomata, the formation of appressoria, conidiation, and the biosynthesis of cercosporin. CRP1 was also required for photoreactivation after lethal doses of UV exposure. Intriguingly, putative orthologs of CRP1 are central regulators of circadian clocks in other filamentous fungi, raising the possibility that C. zeae-maydis uses light as a key environmental input to coordinate pathogenesis with maize photoperiodic responses. This study identified a novel molecular mechanism underlying stomatal tropism in a foliar fungal pathogen, provides specific insight into how light regulates pathogenesis in C. zeae-maydis, and establishes a genetic framework for the molecular dissection of infection via stomata and the integration of host and pathogen responses to photoperiod.

Regulation of stomatal tropism and infection by light in Cercospora zeae-maydis: evidence for coordinated host/pathogen responses to photoperiod?

Science.gov (United States)

Kim, Hun; Ridenour, John B; Dunkle, Larry D; Bluhm, Burton H

2011-07-01

Cercospora zeae-maydis causes gray leaf spot of maize, which has become one of the most widespread and destructive diseases of maize in the world. C. zeae-maydis infects leaves through stomata, which is predicated on the ability of the pathogen to perceive stomata and reorient growth accordingly. In this study, the discovery that light was required for C. zeae-maydis to perceive stomata and infect leaves led to the identification of CRP1, a gene encoding a putative blue-light photoreceptor homologous to White Collar-1 (WC-1) of Neurospora crassa. Disrupting CRP1 via homologous recombination revealed roles in multiple aspects of pathogenesis, including tropism of hyphae to stomata, the formation of appressoria, conidiation, and the biosynthesis of cercosporin. CRP1 was also required for photoreactivation after lethal doses of UV exposure. Intriguingly, putative orthologs of CRP1 are central regulators of circadian clocks in other filamentous fungi, raising the possibility that C. zeae-maydis uses light as a key environmental input to coordinate pathogenesis with maize photoperiodic responses. This study identified a novel molecular mechanism underlying stomatal tropism in a foliar fungal pathogen, provides specific insight into how light regulates pathogenesis in C. zeae-maydis, and establishes a genetic framework for the molecular dissection of infection via stomata and the integration of host and pathogen responses to photoperiod.

Stomatal Conductance, Plant Hydraulics, and Multilayer Canopies: A New Paradigm for Earth System Models or Unnecessary Uncertainty

Science.gov (United States)

Bonan, G. B.

2016-12-01

Soil moisture stress is a key regulator of canopy transpiration, the surface energy budget, and land-atmosphere coupling. Many land surface models used in Earth system models have an ad-hoc parameterization of soil moisture stress that decreases stomatal conductance with soil drying. Parameterization of soil moisture stress from more fundamental principles of plant hydrodynamics is a key research frontier for land surface models. While the biophysical and physiological foundations of such parameterizations are well-known, their best implementation in land surface models is less clear. Land surface models utilize a big-leaf canopy parameterization (or two big-leaves to represent the sunlit and shaded canopy) without vertical gradients in the canopy. However, there are strong biometeorological and physiological gradients in plant canopies. Are these gradients necessary to resolve? Here, I describe a vertically-resolved, multilayer canopy model that calculates leaf temperature and energy fluxes, photosynthesis, stomatal conductance, and leaf water potential at each level in the canopy. In this model, midday leaf water stress manifests in the upper canopy layers, which receive high amounts of solar radiation, have high leaf nitrogen and photosynthetic capacity, and have high stomatal conductance and transpiration rates (in the absence of leaf water stress). Lower levels in the canopy become water stressed in response to longer-term soil moisture drying. I examine the role of vertical gradients in the canopy microclimate (solar radiation, air temperature, vapor pressure, wind speed), structure (leaf area density), and physiology (leaf nitrogen, photosynthetic capacity, stomatal conductance) in determining above canopy fluxes and gradients of transpiration and leaf water potential within the canopy.

Carbon and hydrogen isotopic effects of stomatal density in Arabidopsis thaliana

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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.

Stomatal Function Requires Pectin De-methyl-esterification of the Guard Cell Wall.

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Amsbury, Sam; Hunt, Lee; Elhaddad, Nagat; Baillie, Alice; Lundgren, Marjorie; Verhertbruggen, Yves; Scheller, Henrik V; Knox, J Paul; Fleming, Andrew J; Gray, Julie E

2016-11-07

Stomatal opening and closure depends on changes in turgor pressure acting within guard cells to alter cell shape [1]. The extent of these shape changes is limited by the mechanical properties of the cells, which will be largely dependent on the structure of the cell walls. Although it has long been observed that guard cells are anisotropic due to differential thickening and the orientation of cellulose microfibrils [2], our understanding of the composition of the cell wall that allows them to undergo repeated swelling and deflation remains surprisingly poor. Here, we show that the walls of guard cells are rich in un-esterified pectins. We identify a pectin methylesterase gene, PME6, which is highly expressed in guard cells and required for stomatal function. pme6-1 mutant guard cells have walls enriched in methyl-esterified pectin and show a decreased dynamic range in response to triggers of stomatal opening/closure, including elevated osmoticum, suggesting that abrogation of stomatal function reflects a mechanical change in the guard cell wall. Altered stomatal function leads to increased conductance and evaporative cooling, as well as decreased plant growth. The growth defect of the pme6-1 mutant is rescued by maintaining the plants in elevated CO 2 , substantiating gas exchange analyses, indicating that the mutant stomata can bestow an improved assimilation rate. Restoration of PME6 rescues guard cell wall pectin methyl-esterification status, stomatal function, and plant growth. Our results establish a link between gene expression in guard cells and their cell wall properties, with a corresponding effect on stomatal function and plant physiology. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

The alpha-subunit of the Arabidopsis heterotrimeric G protein, GPA1, is a regulator of transpiration efficiency.

Science.gov (United States)

Nilson, Sarah E; Assmann, Sarah M

2010-04-01

Land plants must balance CO2 assimilation with transpiration in order to minimize drought stress and maximize their reproductive success. The ratio of assimilation to transpiration is called transpiration efficiency (TE). TE is under genetic control, although only one specific gene, ERECTA, has been shown to regulate TE. We have found that the alpha-subunit of the heterotrimeric G protein in Arabidopsis (Arabidopsis thaliana), GPA1, is a regulator of TE. gpa1 mutants, despite having guard cells that are hyposensitive to abscisic acid-induced inhibition of stomatal opening, have increased TE under ample water and drought stress conditions and when treated with exogenous abscisic acid. Leaf-level gas-exchange analysis shows that gpa1 mutants have wild-type assimilation versus internal CO2 concentration responses but exhibit reduced stomatal conductance compared with ecotype Columbia at ambient and below-ambient internal CO2 concentrations. The increased TE and reduced whole leaf stomatal conductance of gpa1 can be primarily attributed to stomatal density, which is reduced in gpa1 mutants. GPA1 regulates stomatal density via the control of epidermal cell size and stomata formation. GPA1 promoter::beta-glucuronidase lines indicate that the GPA1 promoter is active in the stomatal cell lineage, further supporting a function for GPA1 in stomatal development in true leaves.

Plant, cell, and molecular mechanisms of abscisic-acid regulation of stomatal apertures. A new mechanism for the regulation of stomatal-aperture size in intact leaves: Accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba L.

Energy Technology Data Exchange (ETDEWEB)

Lu, P.; Outlaw, W.H. Jr.; Smith, B.G.; Freed, G.A.

1996-12-31

At various times after pulse labeling Vicia faba L. leaflets with {sup 14}CO{sub 2}, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents whereas those from rinsed peels contained only cytoplastic contents. Sucrose specific radioactivity peaked in palisade cells, 111 GBq{center_dot}mol{sup {minus}1}, at 20 min. In contrast, the {sup 14}C content and sucrose specific radioactivity were very low in guard cells for 20 min, implying little CO{sub 2} incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum sucrose specific radioactivity and a high sucrose influx rate. These and other comparisons implied the presence of (a) multiple sucrose pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived sucrose in guard-cell walls sufficient to diminish stomatal opening by {approximately} 4 {micro}m. Factors expected to enhance sucrose accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic sucrose concentration, which is elevated when mesophyll-sucrose efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal-aperture size by this previously unrecognized mechanism.

Overexpression of StNF-YB3.1 reduces photosynthetic capacity and tuber production, and promotes ABA-mediated stomatal closure in potato (Solanum tuberosum L.).

Science.gov (United States)

Xuanyuan, Guochao; Lu, Congming; Zhang, Ruofang; Jiang, Jiming

2017-08-01

Nuclear factor Y (NF-Y) is one of the most ubiquitous transcription factors (TFs), comprising NF-YA, NF-YB and NF-YC subunits, and has been identified and reported in various aspects of development for plants and animals. In this work, StNF-YB3.1, a putative potato NF-YB subunit encoding gene, was isolated from Solanum tuberosum by rapid amplification of cDNA ends (RACE). Overexpression of StNF-YB3.1 in potato (cv. Atlantic) resulted in accelerated onset of flowering, and significant increase in leaf chlorophyll content in field trials. However, transgenic potato plants overexpressing StNF-YB3.1 (OEYB3.1) showed significant decreases in photosynthetic rate and stomatal conductance both at tuber initiation and bulking stages. OEYB3.1 lines were associated with significantly fewer tuber numbers and yield reduction. Guard cell size and stomatal density were not changed in OEYB3.1 plants, whereas ABA-mediated stomatal closure was accelerated compared to that of wild type plants because of the up-regulation of genes for ABA signaling, such as StCPK10-like, StSnRK2.6/OST1-like, StSnRK2.7-like and StSLAC1-like. We speculate that the acceleration of stomatal closure was a possible reason for the significantly decreased stomatal conductance and photosynthetic rate. Copyright © 2017 Elsevier B.V. All rights reserved.

Stomatal vs. genome size in angiosperms: the somatic tail wagging the genomic dog?

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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 < herbaceous species < vernal geophytes) and contributes to ecologically and physiologically important axes of leaf specialization. Moreover, it is positively correlated with genome size across a wide range of major taxa. Stomatal size predicts genome size within 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.

A comparison of two stomatal conductance models for ozone flux modelling using data from two Brassica species

International Nuclear Information System (INIS)

Op de Beeck, M.; De Bock, M.; Vandermeiren, K.; Temmerman, L. de; Ceulemans, R.

2010-01-01

In this study we tested and compared a multiplicative stomatal model and a coupled semi-empirical stomatal-photosynthesis model in their ability to predict stomatal conductance to ozone (g st ) using leaf-level data from oilseed rape (Brassica napus L.) and broccoli (Brassica oleracea L. var. italica Plenck). For oilseed rape, the multiplicative model and the coupled model were able to explain 72% and 73% of the observed g st variance, respectively. For broccoli, the models were able to explain 53% and 51% of the observed g st variance, respectively. These results support the coupled semi-empirical stomatal-photosynthesis model as a valid alternative to the multiplicative stomatal model for O 3 flux modelling, in terms of predictive performance. - A multiplicative stomatal model and a coupled semi-empirical stomatal-photosynthesis model performed equally well when tested against leaf-level data for oilseed rape and broccoli.

Vesicular stomatitis forecasting based on Google Trends.

Science.gov (United States)

Wang, JianYing; Zhang, Tong; Lu, Yi; Zhou, GuangYa; Chen, Qin; Niu, Bing

2018-01-01

Vesicular stomatitis (VS) is an important viral disease of livestock. The main feature of VS is irregular blisters that occur on the lips, tongue, oral mucosa, hoof crown and nipple. Humans can also be infected with vesicular stomatitis and develop meningitis. This study analyses 2014 American VS outbreaks in order to accurately predict vesicular stomatitis outbreak trends. American VS outbreaks data were collected from OIE. The data for VS keywords were obtained by inputting 24 disease-related keywords into Google Trends. After calculating the Pearson and Spearman correlation coefficients, it was found that there was a relationship between outbreaks and keywords derived from Google Trends. Finally, the predicted model was constructed based on qualitative classification and quantitative regression. For the regression model, the Pearson correlation coefficients between the predicted outbreaks and actual outbreaks are 0.953 and 0.948, respectively. For the qualitative classification model, we constructed five classification predictive models and chose the best classification predictive model as the result. The results showed, SN (sensitivity), SP (specificity) and ACC (prediction accuracy) values of the best classification predictive model are 78.52%,72.5% and 77.14%, respectively. This study applied Google search data to construct a qualitative classification model and a quantitative regression model. The results show that the method is effective and that these two models obtain more accurate forecast.

Vesicular stomatitis forecasting based on Google Trends

Science.gov (United States)

Lu, Yi; Zhou, GuangYa; Chen, Qin

2018-01-01

Background Vesicular stomatitis (VS) is an important viral disease of livestock. The main feature of VS is irregular blisters that occur on the lips, tongue, oral mucosa, hoof crown and nipple. Humans can also be infected with vesicular stomatitis and develop meningitis. This study analyses 2014 American VS outbreaks in order to accurately predict vesicular stomatitis outbreak trends. Methods American VS outbreaks data were collected from OIE. The data for VS keywords were obtained by inputting 24 disease-related keywords into Google Trends. After calculating the Pearson and Spearman correlation coefficients, it was found that there was a relationship between outbreaks and keywords derived from Google Trends. Finally, the predicted model was constructed based on qualitative classification and quantitative regression. Results For the regression model, the Pearson correlation coefficients between the predicted outbreaks and actual outbreaks are 0.953 and 0.948, respectively. For the qualitative classification model, we constructed five classification predictive models and chose the best classification predictive model as the result. The results showed, SN (sensitivity), SP (specificity) and ACC (prediction accuracy) values of the best classification predictive model are 78.52%,72.5% and 77.14%, respectively. Conclusion This study applied Google search data to construct a qualitative classification model and a quantitative regression model. The results show that the method is effective and that these two models obtain more accurate forecast. PMID:29385198

Vesicular stomatitis forecasting based on Google Trends.

Directory of Open Access Journals (Sweden)

JianYing Wang

Full Text Available Vesicular stomatitis (VS is an important viral disease of livestock. The main feature of VS is irregular blisters that occur on the lips, tongue, oral mucosa, hoof crown and nipple. Humans can also be infected with vesicular stomatitis and develop meningitis. This study analyses 2014 American VS outbreaks in order to accurately predict vesicular stomatitis outbreak trends.American VS outbreaks data were collected from OIE. The data for VS keywords were obtained by inputting 24 disease-related keywords into Google Trends. After calculating the Pearson and Spearman correlation coefficients, it was found that there was a relationship between outbreaks and keywords derived from Google Trends. Finally, the predicted model was constructed based on qualitative classification and quantitative regression.For the regression model, the Pearson correlation coefficients between the predicted outbreaks and actual outbreaks are 0.953 and 0.948, respectively. For the qualitative classification model, we constructed five classification predictive models and chose the best classification predictive model as the result. The results showed, SN (sensitivity, SP (specificity and ACC (prediction accuracy values of the best classification predictive model are 78.52%,72.5% and 77.14%, respectively.This study applied Google search data to construct a qualitative classification model and a quantitative regression model. The results show that the method is effective and that these two models obtain more accurate forecast.

Common and unique elements of the ABA-regulated transcriptome of Arabidopsis guard cells

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Zhao Zhixin

2011-05-01

Full Text Available Abstract Background In the presence of drought and other desiccating stresses, plants synthesize and redistribute the phytohormone abscisic acid (ABA. ABA promotes plant water conservation by acting on specialized cells in the leaf epidermis, guard cells, which border and regulate the apertures of stomatal pores through which transpirational water loss occurs. Following ABA exposure, solute uptake into guard cells is rapidly inhibited and solute loss is promoted, resulting in inhibition of stomatal opening and promotion of stomatal closure, with consequent plant water conservation. There is a wealth of information on the guard cell signaling mechanisms underlying these rapid ABA responses. To investigate ABA regulation of gene expression in guard cells in a systematic genome-wide manner, we analyzed data from global transcriptomes of guard cells generated with Affymetrix ATH1 microarrays, and compared these results to ABA regulation of gene expression in leaves and other tissues. Results The 1173 ABA-regulated genes of guard cells identified by our study share significant overlap with ABA-regulated genes of other tissues, and are associated with well-defined ABA-related promoter motifs such as ABREs and DREs. However, we also computationally identified a unique cis-acting motif, GTCGG, associated with ABA-induction of gene expression specifically in guard cells. In addition, approximately 300 genes showing ABA-regulation unique to this cell type were newly uncovered by our study. Within the ABA-regulated gene set of guard cells, we found that many of the genes known to encode ion transporters associated with stomatal opening are down-regulated by ABA, providing one mechanism for long-term maintenance of stomatal closure during drought. We also found examples of both negative and positive feedback in the transcriptional regulation by ABA of known ABA-signaling genes, particularly with regard to the PYR/PYL/RCAR class of soluble ABA receptors and

Common and unique elements of the ABA-regulated transcriptome of Arabidopsis guard cells

Science.gov (United States)

2011-01-01

Background In the presence of drought and other desiccating stresses, plants synthesize and redistribute the phytohormone abscisic acid (ABA). ABA promotes plant water conservation by acting on specialized cells in the leaf epidermis, guard cells, which border and regulate the apertures of stomatal pores through which transpirational water loss occurs. Following ABA exposure, solute uptake into guard cells is rapidly inhibited and solute loss is promoted, resulting in inhibition of stomatal opening and promotion of stomatal closure, with consequent plant water conservation. There is a wealth of information on the guard cell signaling mechanisms underlying these rapid ABA responses. To investigate ABA regulation of gene expression in guard cells in a systematic genome-wide manner, we analyzed data from global transcriptomes of guard cells generated with Affymetrix ATH1 microarrays, and compared these results to ABA regulation of gene expression in leaves and other tissues. Results The 1173 ABA-regulated genes of guard cells identified by our study share significant overlap with ABA-regulated genes of other tissues, and are associated with well-defined ABA-related promoter motifs such as ABREs and DREs. However, we also computationally identified a unique cis-acting motif, GTCGG, associated with ABA-induction of gene expression specifically in guard cells. In addition, approximately 300 genes showing ABA-regulation unique to this cell type were newly uncovered by our study. Within the ABA-regulated gene set of guard cells, we found that many of the genes known to encode ion transporters associated with stomatal opening are down-regulated by ABA, providing one mechanism for long-term maintenance of stomatal closure during drought. We also found examples of both negative and positive feedback in the transcriptional regulation by ABA of known ABA-signaling genes, particularly with regard to the PYR/PYL/RCAR class of soluble ABA receptors and their downstream targets

A steady-state stomatal model of balanced leaf gas exchange, hydraulics and maximal source-sink flux.

Science.gov (United States)

Hölttä, Teemu; Lintunen, Anna; Chan, Tommy; Mäkelä, Annikki; Nikinmaa, Eero

2017-07-01

Trees must simultaneously balance their CO2 uptake rate via stomata, photosynthesis, the transport rate of sugars and rate of sugar utilization in sinks while maintaining a favourable water and carbon balance. We demonstrate using a numerical model that it is possible to understand stomatal functioning from the viewpoint of maximizing the simultaneous photosynthetic production, phloem transport and sink sugar utilization rate under the limitation that the transpiration-driven hydrostatic pressure gradient sets for those processes. A key feature in our model is that non-stomatal limitations to photosynthesis increase with decreasing leaf water potential and/or increasing leaf sugar concentration and are thus coupled to stomatal conductance. Maximizing the photosynthetic production rate using a numerical steady-state model leads to stomatal behaviour that is able to reproduce the well-known trends of stomatal behaviour in response to, e.g., light, vapour concentration difference, ambient CO2 concentration, soil water status, sink strength and xylem and phloem hydraulic conductance. We show that our results for stomatal behaviour are very similar to the solutions given by the earlier models of stomatal conductance derived solely from gas exchange considerations. Our modelling results also demonstrate how the 'marginal cost of water' in the unified stomatal conductance model and the optimal stomatal model could be related to plant structural and physiological traits, most importantly, the soil-to-leaf hydraulic conductance and soil moisture. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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. © 2014 Institute of Botany, Chinese Academy of Sciences.

Virus-induced down-regulation of GmERA1A and GmERA1B genes enhances the stomatal response to abscisic acid and drought resistance in soybean.

Directory of Open Access Journals (Sweden)

Takuya Ogata

Full Text Available Drought is a major threat to global soybean production. The limited transformation potential and polyploid nature of soybean have hindered functional analysis of soybean genes. Previous research has implicated farnesylation in the plant's response to abscisic acid (ABA and drought tolerance. We therefore used virus-induced gene silencing (VIGS to evaluate farnesyltransferase genes, GmERA1A and GmERA1B (Glycine max Enhanced Response to ABA1-A and -B, as potential targets for increasing drought resistance in soybean. Apple latent spherical virus (ALSV-mediated GmERA1-down-regulated soybean leaves displayed an enhanced stomatal response to ABA and reduced water loss and wilting under dehydration conditions, suggesting that GmERA1A and GmERA1B negatively regulate ABA signaling in soybean guard cells. The findings provide evidence that the ALSV-VIGS system, which bypasses the need to generate transgenic plants, is a useful tool for analyzing gene function using only a single down-regulated leaf. Thus, the ALSV-VIGS system could constitute part of a next-generation molecular breeding pipeline to accelerate drought resistance breeding in soybean.

Les caractéristiques des stomates des feuilles de Ficus benjamina L ...

African Journals Online (AJOL)

Objective: The main objective of this study is to assess the potential of Ficus benjamina stomata to be used as indicators of local air pollution. Methodology: Stomatal prints were taken from the species of study in the vicinity of roads, in residential and industrial areas and parks. Density, pore surface and stomatal resistance ...

7 CFR 301.55-4 - Conditions governing the interstate movement of regulated articles from quarantined areas.

Science.gov (United States)

2010-01-01

... from outside the quarantined area that are being moved in accordance with the protocols described in a... movement of regulated articles from quarantined areas. Any regulated article may be moved interstate from a quarantined area 3 only if moved under the following conditions: 3 Requirements under all other applicable...

OsPRX2 contributes to stomatal closure and improves potassium deficiency tolerance in rice.

Science.gov (United States)

Mao, Xiaohui; Zheng, Yanmei; Xiao, Kaizhuan; Wei, Yidong; Zhu, Yongsheng; Cai, Qiuhua; Chen, Liping; Xie, Huaan; Zhang, Jianfu

2018-01-01

Peroxiredoxins (Prxs) which are thiol-based peroxidases have been implicated in the toxic reduction and intracellular concentration regulation of hydrogen peroxide. In Arabidopsis thaliana At2-CysPrxB (At5g06290) has been demonstrated to be essential in maintaining the water-water cycle for proper H 2 O 2 scavenging. Although the mechanisms of 2-Cys Prxs have been extensively studied in Arabidopsis thaliana, the function of 2-Cys Prxs in rice is unclear. In this study, a rice homologue gene of At2-CysPrxB, OsPRX2 was investigated aiming to characterize the effect of 2-Cys Prxs on the K + -deficiency tolerance in rice. We found that OsPRX2 was localized in the chloroplast. Overexpressed OsPRX2 causes the stomatal closing and K + -deficiency tolerance increasing, while knockout of OsPRX2 lead to serious defects in leaves phenotype and the stomatal opening under the K + -deficiency tolerance. Detection of K + accumulation, antioxidant activity of transgenic plants under the starvation of potassium, further confirmed that OsPRX2 is a potential target for engineering plants with improved potassium deficiency tolerance. Copyright © 2017 Elsevier Inc. All rights reserved.

Contrasting responses of leaf stomatal characteristics to climate change: a considerable challenge to predict carbon and water cycles.

Science.gov (United States)

Yan, Weiming; Zhong, Yangquanwei; Shangguan, Zhouping

2017-09-01

Stomata control the cycling of water and carbon between plants and the atmosphere; however, no consistent conclusions have been drawn regarding the response of stomatal frequency to climate change. Here, we conducted a meta-analysis of 1854 globally obtained data series to determine the response of stomatal frequency to climate change, which including four plant life forms (over 900 species), at altitudes ranging from 0 to 4500 m and over a time span of more than one hundred thousand years. Stomatal frequency decreased with increasing CO 2 concentration and increased with elevated temperature and drought stress; it was also dependent on the species and experimental conditions. The response of stomatal frequency to climate change showed a trade-off between stomatal control strategies and environmental factors, such as the CO 2 concentration, temperature, and soil water availability. Moreover, threshold effects of elevated CO 2 and temperature on stomatal frequency were detected, indicating that the response of stomatal density to increasing CO 2 concentration will decrease over the next few years. The results also suggested that the stomatal index may be more reliable than stomatal density for determination of the historic CO 2 concentration. Our findings indicate that the contrasting responses of stomata to climate change bring a considerable challenge in predicting future water and carbon cycles. © 2017 John Wiley & Sons Ltd.

Phenotype-gene: 458 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available onsivity in organ named stomatal complex during process named stomatal movement for AT1G20090 Jeon Byeong Wo...69i increased responsivity in organ named stomatal complex during process named stomatal movement

Phenotype-gene: 396 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available ciency in organ named stomatal complex during process named stomatal movement for AT5G13680 Chen Zhizhong et...943431i increased efficiency in organ named stomatal complex during process named stomatal movement

Nitric oxide in guard cells as an important secondary messenger during stomatal closure

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Gunja eGayatri

2013-10-01

Full Text Available he modulation of guard cell function is the basis of stomatal closure, essential for optimizing water use and CO2 uptake by leaves. Nitric oxide (NO in guard cells plays a very important role as a secondary messenger during stomatal closure induced by effectors, including hormones. For example, exposure to abscisic acid (ABA triggers a marked increase in NO of guard cells, well before stomatal closure. In guard cells of multiple species, like Arabidopsis, Vicia and pea, exposure to ABA or methyl jasmonate or even microbial elicitors (e.g. chitosan induces production of NO as well as reactive oxygen species (ROS. The role of NO in stomatal closure has been confirmed by using NO donors (e.g. SNP and NO scavengers (like cPTIO and inhibitors of NOS (L-NAME or NR (tungstate. Two enzymes: a L-NAME-sensitive, nitric oxide synthase (NOS-like enzyme and a tungstate-sensitive nitrate reductase (NR, can mediate ABA-induced NO rise in guard cells. However, the existence of true NOS in plant tissues and its role in guard cell NO-production are still a matter of intense debate. Guard cell signal transduction leading to stomatal closure involves the participation of several components, besides NO, such as cytosolic pH, ROS, free Ca2+ and phospholipids. Use of fluorescent dyes has revealed that the rise in NO of guard cells occurs after the increase in cytoplasmic pH and ROS. The rise in NO causes an elevation in cytosolic free Ca2+ and promotes the efflux of cations as well as anions from guard cells. Stomatal guard cells have become a model system to study the signalling cascade mechanisms in plants, particularly with NO as a dominant component. The interrelationships and interactions of NO with cytosolic pH, ROS, and free Ca2+ are quite complex and need further detailed examination. While assessing critically the available literature, the present review projects possible areas of further work related to NO-action in stomatal guard cells.

The Cell Adhesion Molecule Necl-4/CADM4 Serves as a Novel Regulator for Contact Inhibition of Cell Movement and Proliferation.

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Shota Yamana

Full Text Available Contact inhibition of cell movement and proliferation is critical for proper organogenesis and tissue remodeling. We show here a novel regulatory mechanism for this contact inhibition using cultured vascular endothelial cells. When the cells were confluently cultured, Necl-4 was up-regulated and localized at cell-cell contact sites where it cis-interacted with the vascular endothelial growth factor (VEGF receptor. This interaction inhibited the tyrosine-phosphorylation of the VEGF receptor through protein-tyrosine phosphatase, non-receptor type 13 (PTPN13, eventually reducing cell movement and proliferation. When the cells were sparsely cultured, Necl-4 was down-regulated but accumulated at leading edges where it inhibited the activation of Rho-associated protein kinase through PTPN13, eventually facilitating the VEGF-induced activation of Rac1 and enhancing cell movement. Necl-4 further facilitated the activation of extracellular signal-regulated kinase 1/2, eventually enhancing cell proliferation. Thus, Necl-4 serves as a novel regulator for contact inhibition of cell movement and proliferation cooperatively with the VEGF receptor and PTPN13.

Elevated-CO2 Response of Stomata and Its Dependence on Environmental Factors

Science.gov (United States)

Xu, Zhenzhu; Jiang, Yanling; Jia, Bingrui; Zhou, Guangsheng

2016-01-01

Stomata control the flow of gases between plants and the atmosphere. This review is centered on stomatal responses to elevated CO2 concentration and considers other key environmental factors and underlying mechanisms at multiple levels. First, an outline of general responses in stomatal conductance under elevated CO2 is presented. Second, stomatal density response, its development, and the trade-off with leaf growth under elevated CO2 conditions are depicted. Third, the molecular mechanism regulating guard cell movement at elevated CO2 is suggested. Finally, the interactive effects of elevated CO2 with other factors critical to stomatal behavior are reviewed. It may be useful to better understand how stomata respond to elevated CO2 levels while considering other key environmental factors and mechanisms, including molecular mechanism, biochemical processes, and ecophysiological regulation. This understanding may provide profound new insights into how plants cope with climate change. PMID:27242858

Constitutive activation of a plasma membrane H+-ATPase prevents abscisic acid-mediated stomatal closure

Science.gov (United States)

Merlot, Sylvain; Leonhardt, Nathalie; Fenzi, Francesca; Valon, Christiane; Costa, Miguel; Piette, Laurie; Vavasseur, Alain; Genty, Bernard; Boivin, Karine; Müller, Axel; Giraudat, Jérôme; Leung, Jeffrey

2007-01-01

Light activates proton (H+)-ATPases in guard cells, to drive hyperpolarization of the plasma membrane to initiate stomatal opening, allowing diffusion of ambient CO2 to photosynthetic tissues. Light to darkness transition, high CO2 levels and the stress hormone abscisic acid (ABA) promote stomatal closing. The overall H+-ATPase activity is diminished by ABA treatments, but the significance of this phenomenon in relationship to stomatal closure is still debated. We report two dominant mutations in the OPEN STOMATA2 (OST2) locus of Arabidopsis that completely abolish stomatal response to ABA, but importantly, to a much lesser extent the responses to CO2 and darkness. The OST2 gene encodes the major plasma membrane H+-ATPase AHA1, and both mutations cause constitutive activity of this pump, leading to necrotic lesions. H+-ATPases have been traditionally assumed to be general endpoints of all signaling pathways affecting membrane polarization and transport. Our results provide evidence that AHA1 is a distinct component of an ABA-directed signaling pathway, and that dynamic downregulation of this pump during drought is an essential step in membrane depolarization to initiate stomatal closure. PMID:17557075

Effects of a Heat Wave on Nocturnal Stomatal Conductance in Eucalyptus camaldulensis

Directory of Open Access Journals (Sweden)

Víctor Resco de Dios

2018-06-01

Full Text Available Nocturnal transpiration constitutes a significant yet poorly understood component of the global water cycle. Modeling nocturnal transpiration has been complicated by recent findings showing that stomata respond differently to environmental drivers over day- vs. night-time periods. Here, we propose that nocturnal stomatal conductance depends on antecedent daytime conditions. We tested this hypothesis across six genotypes of Eucalyptus camaldulensis Dehnh. growing under different CO2 concentrations (ambient vs. elevated and exposed to contrasting temperatures (ambient vs. heat wave for four days prior to the night of measurements, when all plants experienced ambient temperature conditions. We observed significant effects after the heat wave that led to 36% reductions in nocturnal stomatal conductance. The response was partly driven by changes in daytime stomatal behavior but additional factors may have come into play. We also observed significant differences in response to the heat wave across genotypes, likely driven by local adaptation to their climate of origin, but CO2 played no effect. Stomatal models may need to incorporate the role of antecedent effects to improve projections particularly after drastic changes in the environment such as heat waves.

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.

Stomatal responses to carbon dioxide of isolated epidermis from a C/sub 3/ plant, the Argenteum mutant of Pisum sativum L. , and a crassulacean-acid-metabolism plant Kalanchoe daigremontiana Hamet et Perr

Energy Technology Data Exchange (ETDEWEB)

Jewer, P.C.; Neales, T.F.; Incoll, L.D.

1985-01-01

The response of stomata in isolated epidermis to the concentration of CO/sub 2/ in the gaseous phase was examined in a C/sub 3/ species, the Argenteum mutant of Pisum sativum, and a crassulacean-acid-metabolism (CAM) species, Kalanchoe daigremontiana. Epidermis from leaves of both species was incubated on buffer solutions in the presence of air containing various volume fractions of CO/sub 2/ (0 to 10,000 x 10/sup -6/). In both species and in the light and in darkness, the effect of CO/sub 2/ was to inhibit stomatal opening, the maximum inhibition of opening occurring in the range 0 to 360 x 10/sup -6/. The inhibition of opening per unit change in concentration was greatest between volume fractions of 0 and 240 x 10/sup -6/. There was little further closure above the volume fraction of 360 x 10/sup -6/, i.e. approximately ambient concentration of CO/sub 2/. Thus, although leaves of CAM species may experience much higher internal concentrations of CO/sub 2/ in the light than those of C/sub 3/ plants, this does not affect the sensitivity of their stomata to CO/sub 2/ concentration or the range over which they respond. Stomatal responses to CO/sub 2/ were similar in both the light and the dark, indicating that effects of CO/sub 2/ on stomata occur via mechanisms which are independent of light. The responses of stomata to CO/sub 2/ in the gaseous phase took place without the treatments changing the pH of the buffered solutions. Thus, it is unlikely that CO/sub 2/ elicited stomatal movement by changing either the pH or the HCO/sub 3//sup -//CO/sub 3//sup 2 -/ equilibria. It is suggested that the concentration of dissolved unhydrated CO/sub 2/ may be the effector of stomatal movement and that its activity is related to its reactivity with amines.

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo.

Science.gov (United States)

Paoletti, Elena

2005-04-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol(-1) O3) on stomatal conductance (gs) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state gs compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury gs levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O3 exposure ("memory effect") and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O3 exposure. Nevertheless, measurements of steady-state gs at midday may not account for altered stomatal responses to stressors.

Movement and personality development

Directory of Open Access Journals (Sweden)

Aida M. Aylamazyan

2017-06-01

Full Text Available The paper discusses the role of the movement in the process of shaping the personality, its importance as a mechanism for personality development is considered. The issue of the movement has always occupied a central place in Russian psychology. However, subsequently the movement began to be considered primarily as an executive action in human life. The role of movement in personality development can vary depending on the level it occupies in the hierarchical structure of activity, and also on the type of movement, its character, and the way it is constructed. Under certain conditions, the movement can express the attitude of the subject to the surrounding world and people. Many foreign and Russian psychologists point to a special place of the postural tonic component of the motor movement, the posture in personal regulation. The posture reflects his/her personal attitudes, the system of relationships, and, above all, the emotional attitude or emotional assessment of the current situation, the interest in the actions performed. Mastering the tonic level of motor management is based on the emotional regulation, so the ability to regulate one’s own pose is an important stage in the personality development. Posture tonic regulation of motor movements in humans reveals a qualitatively different character than in animals, this being due to the person’s facing the task of mastering his’her posture, arbitrary retention of the body in one or another position. Maintaining a vertical posture requires constant activity at an arbitrary and involuntary level of mental regulation. Mastering the posture of an unstable equilibrium presupposes the emergence of the «I» and is the last stage of the development. The way a person solves the motor task of maintaining the vertical position of the body reflects his/her specific personal strategy or attitude.

Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

Science.gov (United States)

Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

2013-10-01

The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency. © 2013 John Wiley & Sons Ltd.

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. © 2011 Blackwell Publishing Ltd.

Loss of nitrate reductases NIA1 and NIA2 impairs stomatal closure by altering genes of core ABA signaling components in Arabidopsis.

Science.gov (United States)

Zhao, Chenchen; Cai, Shengguan; Wang, Yizhou; Chen, Zhong-Hua

2016-06-02

Nitrate reductases NIA1 and NIA2 determine NO production in plants and are critical to abscisic acid (ABA)-induced stomatal closure. However, the role for NIA1 and NIA2 in ABA signaling has not been paid much attention in nitrate reductase loss-of-function mutant nia1nia2. Recently, we have demonstrated that ABA-inhibited K(+)in current and ABA-enhanced slow anion current were absent in nia1nia2. Exogenous NO restored regulation of these channels for stomatal closure in nia1nia2. In this study, we found that mutating NIA1 and NIA2 impaired nearly all the key components of guard cell ABA signaling pathway in Arabidopsis. We also propose a simplified model for ABA signaling in the nia1nia2 mutant.

Stomatal design principles in synthetic and real leaves

DEFF Research Database (Denmark)

Zwieniecki, Maciej A.; Haaning, Katrine S; Boyce, C. Kevin

2016-01-01

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 the geometrical properties of the stoma pores. The link between...... 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 stoma geometry. We show that the observed correlations between stoma size and density are consistent with the hypothesis that plants favour...... efficient use of space and maximum control of dynamic gas conductivity, and that the capacity for gas exchange in plants has remained constant over at least the last 325 Myr. Our analysis provides a new measure to gauge the relative performance of species based on their stomatal characteristics....

Seasonal ozone uptake by a warm-temperate mixed deciduous and evergreen broadleaf forest in western Japan estimated by the Penman–Monteith approach combined with a photosynthesis-dependent stomatal model

International Nuclear Information System (INIS)

Kitao, Mitsutoshi; Komatsu, Masabumi; Hoshika, Yasutomo; Yazaki, Kenichi; Yoshimura, Kenichi; Fujii, Saori; Miyama, Takafumi; Kominami, Yuji

2014-01-01

Canopy-level stomatal conductance over a warm-temperate mixed deciduous and evergreen broadleaf forest in Japan was estimated by the Penman–Monteith approach, as compensated by a semi-empirical photosynthesis-dependent stomatal model, where photosynthesis, relative humidity, and CO 2 concentration were assumed to regulate stomatal conductance. This approach, using eddy covariance data and routine meteorological observations at a flux tower site, permits the continuous estimation of canopy-level O 3 uptake, even when the Penman–Monteith approach is unavailable (i.e. in case of direct evaporation from soil or wet leaves). Distortion was observed between the AOT40 exposure index and O 3 uptake through stomata, as AOT40 peaked in April, but with O 3 uptake occurring in July. Thus, leaf pre-maturation in the predominant deciduous broadleaf tree species (Quercus serrata) might suppress O 3 uptake in springtime, even when the highest O 3 concentrations were observed. -- Highlights: • We estimate canopy-level O 3 uptake in a warm-temperate mixed forest in Japan. • The Penman–Monteith approach is compensated by a photosynthesis-dependent model. • Stomatal conductance can be estimated, even in a partly-opened or wet canopy. • The estimated O 3 dose peaks in summer though O 3 exposure peaks in spring. -- Estimation of seasonal O 3 uptake over a mixed-temperate forest compensated by a photosynthesis-dependent stomatal model

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.

Self-Regulated Learning from Illustrated Text: Eye Movement Modelling to Support Use and Regulation of Cognitive Processes during Learning from Multimedia

Science.gov (United States)

Scheiter, Katharina; Schubert, Carina; Schüler, Anne

2018-01-01

Background: When learning with text and pictures, learners often fail to adequately process the materials, which can be explained as a failure to self-regulate one's learning by choosing adequate cognitive learning processes. Eye movement modelling examples (EMME) showing how to process multimedia instruction have improved elementary school…

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.

Daya Hambat Infusum Daun Sirih Terhadap Pertumbuhan Staphylococcus aureus Yang Diisolasi Dari Denture Stomatitis ; Penelitian In Vitro.

OpenAIRE

bin Abdullah, Muhammad Naim

2011-01-01

Denture Stomatitis merupakan lesi mukosa oral berwarna merah, sakit, dan bengkak, kondisi ini karena kebiasaan jelek pada pemakai gigitiruan yang tidak mumbuka protesa pada malam hari dan jarang dibersihkan. Faktor sistemik yang mendukung terjadinya Denture Stomatitis dapat disebabkan oleh beberapa bakteri, salah satunya Staphylococcus aureus. Pencegahan Denture Stomatitis dapat dilakukan dengan sering membersihkan gigitiruan dan pemakaian obat kumur. Tujuan penelitian ini adalah untuk menguj...

A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.

Directory of Open Access Journals (Sweden)

Weiqing Zeng

2011-10-01

Full Text Available Bacterial infection of plants often begins with colonization of the plant surface, followed by entry into the plant through wounds and natural openings (such as stomata, multiplication in the intercellular space (apoplast of the infected tissues, and dissemination of bacteria to other plants. Historically, most studies assess bacterial infection based on final outcomes of disease and/or pathogen growth using whole infected tissues; few studies have genetically distinguished the contribution of different host cell types in response to an infection. The phytotoxin coronatine (COR is produced by several pathovars of Pseudomonas syringae. COR-deficient mutants of P. s. tomato (Pst DC3000 are severely compromised in virulence, especially when inoculated onto the plant surface. We report here a genetic screen to identify Arabidopsis mutants that could rescue the virulence of COR-deficient mutant bacteria. Among the susceptible to coronatine-deficient Pst DC3000 (scord mutants were two that were defective in stomatal closure response, two that were defective in apoplast defense, and four that were defective in both stomatal and apoplast defense. Isolation of these three classes of mutants suggests that stomatal and apoplastic defenses are integrated in plants, but are genetically separable, and that COR is important for Pst DC3000 to overcome both stomatal guard cell- and apoplastic mesophyll cell-based defenses. Of the six mutants defective in bacterium-triggered stomatal closure, three are defective in salicylic acid (SA-induced stomatal closure, but exhibit normal stomatal closure in response to abscisic acid (ABA, and scord7 is compromised in both SA- and ABA-induced stomatal closure. We have cloned SCORD3, which is required for salicylic acid (SA biosynthesis, and SCORD5, which encodes an ATP-binding cassette (ABC protein, AtGCN20/AtABCF3, predicted to be involved in stress-associated protein translation control. Identification of SCORD5 begins to

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo

Energy Technology Data Exchange (ETDEWEB)

Paoletti, Elena [Istituto Protezione Piante, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, I-50019 Sesto Fiorentino (Italy)]. E-mail: e.paoletti@ipp.cnr.it

2005-04-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol{sup -1} O{sub 3}) on stomatal conductance (g{sub s}) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state g{sub s} compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury g{sub s} levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O{sub 3} exposure ('memory effect') and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O{sub 3} exposure. Nevertheless, measurements of steady-state g{sub s} at midday may not account for altered stomatal responses to stressors. - In response to ozone exposure, stomata were slower in closing rather than in opening.

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo

International Nuclear Information System (INIS)

Paoletti, Elena

2005-01-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol -1 O 3 ) on stomatal conductance (g s ) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state g s compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury g s levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O 3 exposure ('memory effect') and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O 3 exposure. Nevertheless, measurements of steady-state g s at midday may not account for altered stomatal responses to stressors. - In response to ozone exposure, stomata were slower in closing rather than in opening

ABA-Induced Stomatal Closure Involves ALMT4, a Phosphorylation-Dependent Vacuolar Anion Channel of Arabidopsis[OPEN

Science.gov (United States)

Baetz, Ulrike; Huck, Nicola V.; Zhang, Jingbo

2017-01-01

Stomatal pores are formed between a pair of guard cells and allow plant uptake of CO2 and water evaporation. Their aperture depends on changes in osmolyte concentration of guard cell vacuoles, specifically of K+ and Mal2−. Efflux of Mal2− from the vacuole is required for stomatal closure; however, it is not clear how the anion is released. Here, we report the identification of ALMT4 (ALUMINUM ACTIVATED MALATE TRANSPORTER4) as an Arabidopsis thaliana ion channel that can mediate Mal2− release from the vacuole and is required for stomatal closure in response to abscisic acid (ABA). Knockout mutants showed impaired stomatal closure in response to the drought stress hormone ABA and increased whole-plant wilting in response to drought and ABA. Electrophysiological data show that ALMT4 can mediate Mal2− efflux and that the channel activity is dependent on a phosphorylatable C-terminal serine. Dephosphomimetic mutants of ALMT4 S382 showed increased channel activity and Mal2− efflux. Reconstituting the active channel in almt4 mutants impaired growth and stomatal opening. Phosphomimetic mutants were electrically inactive and phenocopied the almt4 mutants. Surprisingly, S382 can be phosphorylated by mitogen-activated protein kinases in vitro. In brief, ALMT4 likely mediates Mal2− efflux during ABA-induced stomatal closure and its activity depends on phosphorylation. PMID:28874508

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

Observations of leaf stomatal conductance at the canopy scale: an atmospheric modeling perspective

International Nuclear Information System (INIS)

Avissar, R.

1993-01-01

Plant stomata play a key role in the redistribution of energy received on vegetated land into sensible and latent heat. As a result, they have a considerable impact on the atmospheric planetary boundary layer, the hydrologic cycle, the climate, and the weather. Current parameterizations of the stomatal mechanism in state-of-the-art atmospheric models are based on empirical relations that are established at the leaf scale between stomatal conductance and environmental conditions. In order to evaluate these parameterizations, an experiment was carried out on a potato field in New Jersey during the summer of 1989. Stomatal conductances were measured within a small homogeneous area in the middle of the potato field and under a relatively broad range of atmospheric conditions. A large variability of stomatal conductances was observed. This variability, which was associated with the variability of micro-environmental and physiological conditions that is found even in a homogeneous canopy, cannot be simulated explicitly on the scale of a single agricultural field and,a fortiori, on the scale of atmospheric models. Furthermore, this variability could not be related to the environmental conditions measured at a height of 2 m above the plant canopy simultaneously with the conductances, reinforcing the concept of scale decoupling suggested by Jarvis and McNaughton (1986) and McNaughton and Jarvis (1991). Thus, for atmospheric modeling purposes, a parameterization of stomatal conductance at the canopy scale using external environmental forcing conditions seems more appropriate than a parameterization based on leaf-scale stomatal conductance, as currently adopted in state-of-the-art atmospheric models. The measured variability was characterized by a lognormal probability density function (pdf) that remained relatively stable during the entire measuring period. These observations support conclusions by McNaughton and Jarvis (1991) that, unlike current parameterizations, a

Observations of leaf stomatal conductance at the canopy scale: an atmospheric modeling perspective

International Nuclear Information System (INIS)

Avissar, R.

1993-01-01

Plant stomata play a key role in the redistribution of energy received on vegetated land into sensible and latent heat. As a result, they have a considerable impact on the atmospheric planetary boundary layer, the hydrologic cycle, the climate, and the weather. Current parameterizations of the stomatal mechanism in state-of-the-art atmospheric models are based on empirical relations that are established at the leaf scale between stomatal conductance and environmental conditions. In order to evaluate these parameterizations, an experiment was carried out on a potato field in New Jersey during the summer of 1989. Stomatal conductances were measured within a small homogeneous area in the middle of the potato field and under a relatively broad range of atmospheric conditions. A large variability of stomatal conductances was observed. This variability, which was associated with the variability of micro-environmental and physiological conditions that is found even in a homogeneous canopy, cannot be simulated explicitly on the scale of a single agricultural field and, a fortiori, on the scale of atmospheric models. Furthermore, this variability could not be related to the environmental conditions measured at a height of 2 m above the plant canopy simultaneously with the conductances, reinforcing the concept of scale decoupling suggested by Jarvis and McNaughton (1986) and McNaughton and Jarvis (1991). Thus, for atmospheric modeling purposes, a parameterization of stomatal conductance at the canopy scale using external environmental forcing conditions seems more appropriate than a parameterization based on leaf-scale stomatal conductance, as currently adopted in state-of-the-art atmospheric models. The measured variability was characterized by a lognormal probability density function (pdf) that remained relatively stable during the entire measuring period. These observations support conclusions by McNaughton and Jarvis (1991) that, unlike current parameterizations, a

Simultaneous requirement of carbon dioxide and abscisic acid for stomatal closing in Xanthium strumarium L.

Science.gov (United States)

Raschke, K

1975-01-01

Open stomata of detached leaves of Xanthium strumarium L. closed only when carbon dioxide and abscisic acid (ABA) were presented simultaneously. Three parameters of stomatal closing were determined after additions of ABA to the irrigation water of detached leaves, while the leaves were exposed to various CO2 concentrations ([CO2]s) in the air; a) the delay between addition of ABA and a reduction of stomatal conductance by 5%, b) the velocity of stomatal closing, and c) the new conductance. Changes in all three parameters showed that stomatal responses to ABA were enhanced by CO2; this effect followed saturation kinetics. Half saturation occurred at an estimated [CO2] in the stomatal pore of 200 μl l(-1). With respect to ABA, stomata responded in normal air with half their maximal amplitude at [ABA]s between 10(-6) and 10(-5) M(+-)-ABA. The amounts of ABA taken up by the leaves during the delay increased with a power strumarium.Based on earlier findings and on the results of this investigation it is suggested that stomata close if the cytoplasm of the guard cells contains much malate and H(+). The acid content in turn is determined by the relative rates of production of malic acid (from endogenous as well as exogenous CO2) and its removal (by transport of the anion into the vacuole and exchange of the H(+) for K(+) with the environment of the guard cells). The simultaneous requirement of CO2 and ABA for stomatal closure leads to the inference that ABA inhibits the expulsion of H(+) from guard cells.

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

Oral symptoms and salivary findings in oral lichen planus, oral lichenoid lesions and stomatitis

DEFF Research Database (Denmark)

Larsen, Kristine Roen; Johansen, Jeanne Duus; Reibel, Jesper

2017-01-01

BACKGROUND: To examine if patients with oral lichen planus, oral lichenoid lesions and generalised stomatitis and concomitant contact allergy have more frequent and severe xerostomia, lower unstimulated and chewing-stimulated saliva and citric-acid-stimulated parotid saliva flow rates, and higher...... of xerostomia, clinical examination, sialometry, mucosal biopsy and contact allergy testing. RESULTS: Nineteen patients had oral lichen planus, 19 patients had oral lichenoid lesions and 11 patients had generalised stomatitis. 38.8% had contact allergy. Xerostomia was significantly more common and severe...... in the chewing stimulated saliva samples from patients when compared to healthy controls. The differences were not significant and they were irrespective of the presence of contact allergy. CONCLUSION: Xerostomia is prevalent in patients with oral lichen planus, lichenoid lesions and generalised stomatitis...

Evaluation of Multiple Mechanistic Hypotheses of Leaf Photosynthesis and Stomatal Conductance against Diurnal and Seasonal Data from Two Contrasting Panamanian Tropical Forests

Science.gov (United States)

Serbin, S.; Walker, A. P.; Wu, J.; Ely, K.; Rogers, A.; Wolfe, B.

2017-12-01

Tropical forests play a key role in regulating the global carbon (C), water, and energy cycles and stores, as well as influence climate through the exchanges of mass and energy with the atmosphere. However, projected changes in temperature and precipitation patterns are expected to impact the tropics and the strength of the tropical C sink, likely resulting in significant climate feedbacks. Moreover, the impact of stronger, longer, and more extensive droughts not well understood. Critical for the accurate modeling of the tropical C and water cycle in Earth System Models (ESMs) is the representation of the coupled photosynthetic and stomatal conductance processes and how these processes are impacted by environmental and other drivers. Moreover, the parameterization and representation of these processes is an important consideration for ESM projections. We use a novel model framework, the Multi-Assumption Architecture and Testbed (MAAT), together with the open-source bioinformatics toolbox, the Predictive Ecosystem Analyzer (PEcAn), to explore the impact of the multiple mechanistic hypotheses of coupled photosynthesis and stomatal conductance as well as the additional uncertainty related to model parameterization. Our goal was to better understand how model choice and parameterization influences diurnal and seasonal modeling of leaf-level photosynthesis and stomatal conductance. We focused on the 2016 ENSO period and starting in February, monthly measurements of diurnal photosynthesis and conductance were made on 7-9 dominant species at the two Smithsonian canopy crane sites. This benchmark dataset was used to test different representations of stomatal conductance and photosynthetic parameterizations with the MAAT model, running within PEcAn. The MAAT model allows for the easy selection of competing hypotheses to test different photosynthetic modeling approaches while PEcAn provides the ability to explore the uncertainties introduced through parameterization. We

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

Infection of guinea pigs with vesicular stomatitis New Jersey virus Transmitted by Culicoides sonorensis (Diptera: Ceratopogonidae).

Science.gov (United States)

Pérez De León, Adalberto A; O'Toole, Donal; Tabachnick, Walter J

2006-05-01

Intrathoracically inoculated Culicoides sonorensis Wirth & Jones were capable of transmitting vesicular stomatitis New Jersey virus (family Rhabdoviridae, genus Vesiculovirus, VSNJV) during blood feeding on the abdomen of six guinea pigs. None of the guinea pigs infected in this manner developed clinical signs of vesicular stomatitis despite seroconversion for VSNJV. Guinea pigs infected by intradermal inoculations of VSNJV in the abdomen also failed to develop clinical signs of vesicular stomatitis. Three guinea pigs given intradermal inoculations of VSNJV in the foot pad developed lesions typical of vesicular stomatitis. Transmission by the bite of C. sonorensis may have facilitated guinea pig infection with VSNJV because a single infected C. sonorensis caused seroconversion and all guinea pigs infected by insect bite seroconverted compared with 50% of the guinea pigs infected by intradermal inoculation with a higher titer VSNJV inoculum. The role of C. sonorensis in the transmission of VSNJV is discussed.

Serum cytokine profile and clinicopathological findings in oral lichen planus, oral lichenoid lesions and stomatitis

DEFF Research Database (Denmark)

Larsen, Kristine Røn; Johansen, Jeanne Duus; Reibel, Jesper

2017-01-01

The objective of this study was to examine if clinical and histopathological variables in patients with oral lichen planus (OLP), oral lichenoid lesions (OLL), and generalized stomatitis display different cytokine profiles and if concomitant contact allergy influences this profile. Forty-nine pat......The objective of this study was to examine if clinical and histopathological variables in patients with oral lichen planus (OLP), oral lichenoid lesions (OLL), and generalized stomatitis display different cytokine profiles and if concomitant contact allergy influences this profile. Forty...... analyzed and compared between groups. Nineteen patients had OLP, primarily with ulcerative lesions on the buccal mucosa, 19 patients had OLL, and 11 patients had generalized stomatitis. All patients had oral symptoms, mainly stinging and burning. Nineteen patients and 10 healthy subjects had contact...... higher levels of IL-6 than the healthy subjects. Interferon-γ, IL-12p40, and IL-12p70 were below detection limit. Our findings indicate that OLP, OLL, and generalized stomatitis cannot be discriminated by means of the selected serum cytokines, and that the presence of concomitant contact allergy does...

Evaluation of the stomatal conductance formulation in the EMEP ozone deposition model for Picea abies

Science.gov (United States)

Wieser, G.; Emberson, L. D.

It is widely acknowledged that the possible impacts of ozone on forest trees are more closely related to ozone flux through the stomata than to external ozone exposure. However, the application of the flux approach on a European scale requires the availability of appropriate models, such as the European Monitoring and Evaluation Programme (EMEP) ozone deposition model, for estimating ozone flux and cumulative ozone uptake. Within this model stomatal conductance is the key variable, since it determines the amount of ozone absorbed by the leaves. This paper describes the suitability of the existing EMEP ozone deposition model parameterisation and formulation to represent stomatal behaviour determined from field measurements on adult Norway spruce ( Picea abies (L.) Karst.) trees in the Central European Alps. Parameters affecting maximum stomatal conductance (e.g. seasonal phenology, needle position, needle age, nutrient deficiency and ozone itself) and stomatal response functions to temperature, irradiance, vapour pressure deficit, and soil water content are investigated. Finally, current limitations and possible alterations of the EMEP model will be discussed with respect to spatial scales of available input data for future flux modelling.

Evapotranspiration partitioning, stomatal conductance, and components of the water balance: A special case of a desert ecosystem in China

Science.gov (United States)

Zhao, Wenzhi; Liu, Bing; Chang, Xuexiang; Yang, Qiyue; Yang, Yuting; Liu, Zhiling; Cleverly, James; Eamus, Derek

2016-07-01

Partitioning evapotranspiration (ET) into its components reveals details of the processes that underlie ecosystem hydrologic budgets and their feedback to the water cycle. We measured rates of actual evapotranspiration (ETa), canopy transpiration (Tc), soil evaporation (Eg), canopy-intercepted precipitation (EI), and patterns of stomatal conductance of the desert shrub Calligonum mongolicum in northern China to determine the water balance of this ecosystem. The ETa was 251 ± 8 mm during the growing period, while EI, Tc, and Eg accounted for 3.2%, 63.9%, and 31.3%, respectively, of total water use (256 ± 4 mm) during the growing period. In this unique ecosystem, groundwater was the main water source for plant transpiration and soil evaporation, Tc and exceeded 60% of the total annual water used by desert plants. ET was not sensitive to air temperature in this unique desert ecosystem. Partitioning ET into its components improves our understanding of the mechanisms that underlie adaptation of desert shrubs, especially the role of stomatal regulation of Tc as a determinant of ecosystem water balance.

Actin filaments regulate the adhesion between the plasma membrane and the cell wall of tobacco guard cells.

Science.gov (United States)

Yu, Qin; Ren, Jing-Jing; Kong, Lan-Jing; Wang, Xiu-Ling

2018-01-01

During the opening and closing of stomata, guard cells undergo rapid and reversible changes in their volume and shape, which affects the adhesion of the plasma membrane (PM) to the cell wall (CW). The dynamics of actin filaments in guard cells are involved in stomatal movement by regulating structural changes and intracellular signaling. However, it is unclear whether actin dynamics regulate the adhesion of the PM to the CW. In this study, we investigated the relationship between actin dynamics and PM-CW adhesion by the hyperosmotic-induced plasmolysis of tobacco guard cells. We found that actin filaments in guard cells were depolymerized during mannitol-induced plasmolysis. The inhibition of actin dynamics by treatment with latrunculin B or jasplakinolide and the disruption of the adhesion between the PM and the CW by treatment with RGDS peptide (Arg-Gly-Asp-Ser) enhanced guard cell plasmolysis. However, treatment with latrunculin B alleviated the RGDS peptide-induced plasmolysis and endocytosis. Our results reveal that the actin depolymerization is involved in the regulation of the PW-CW adhesion during hyperosmotic-induced plasmolysis in tobacco guard cells.

Phenotype-gene: 486 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available d in organ named stomatal complex during process named stomatal movement for AT1G20090 Jeon Byeong Wook et a...reased speed in organ named stomatal complex during process named stomatal movement http://metadb.riken.jp/db/SciNetS_ria224i/cria224u1ria224u893i AT1G20090

Overexpression of plasma membrane H+-ATPase in guard cells promotes light-induced stomatal opening and enhances plant growth.

Science.gov (United States)

Wang, Yin; Noguchi, Ko; Ono, Natsuko; Inoue, Shin-ichiro; Terashima, Ichiro; Kinoshita, Toshinori

2014-01-07

Stomatal pores surrounded by a pair of guard cells in the plant epidermis control gas exchange between plants and the atmosphere in response to light, CO2, and the plant hormone abscisic acid. Light-induced stomatal opening is mediated by at least three key components: the blue light receptor phototropin (phot1 and phot2), plasma membrane H(+)-ATPase, and plasma membrane inward-rectifying K(+) channels. Very few attempts have been made to enhance stomatal opening with the goal of increasing photosynthesis and plant growth, even though stomatal resistance is thought to be the major limiting factor for CO2 uptake by plants. Here, we show that transgenic Arabidopsis plants overexpressing H(+)-ATPase using the strong guard cell promoter GC1 showed enhanced light-induced stomatal opening, photosynthesis, and plant growth. The transgenic plants produced larger and increased numbers of rosette leaves, with ∼42-63% greater fresh and dry weights than the wild type in the first 25 d of growth. The dry weights of total flowering stems of 45-d-old transgenic plants, including seeds, siliques, and flowers, were ∼36-41% greater than those of the wild type. In addition, stomata in the transgenic plants closed normally in response to darkness and abscisic acid. In contrast, the overexpression of phototropin or inward-rectifying K(+) channels in guard cells had no effect on these phenotypes. These results demonstrate that stomatal aperture is a limiting factor in photosynthesis and plant growth, and that manipulation of stomatal opening by overexpressing H(+)-ATPase in guard cells is useful for the promotion of plant growth.

Effect of Aggression Regulation on Eating Disorder Pathology: RCT of a Brief Body and Movement Oriented Intervention.

Science.gov (United States)

Boerhout, Cees; Swart, Marte; Van Busschbach, Jooske T; Hoek, Hans W

2016-03-01

The objective of the study is to evaluate the effect of a brief body and movement oriented intervention on aggression regulation and eating disorder pathology for individuals with eating disorders. In a first randomized controlled trial, 40 women were allocated to either the aggression regulation intervention plus supportive contact or a control condition of supportive contact only. The intervention was delivered by a psychomotor therapist. Participants completed questionnaires on anger coping and eating disorder pathology. Independent samples t-tests were performed on the difference between pre-treatment and post-treatment scores. Twenty-nine participants completed questionnaires at pre-intervention and post-intervention. The intervention resulted in a significantly greater improvement of anger coping, as well as of eating disorder pathology. Results indicate that body and movement-oriented aggression regulation may be a viable add-on for treating eating disorders. It tackles a difficult to treat emotion which may have a role in blocking the entire process of treating eating disorders. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Impact of Canopy Coupling on Canopy Average Stomatal Conductance Across Seven Tree Species in Northern Wisconsin

Science.gov (United States)

Ewers, B. E.; Mackay, D. S.; Samanta, S.; Ahl, D. E.; Burrows, S. S.; Gower, S. T.

2001-12-01

Land use changes over the last century in northern Wisconsin have resulted in a heterogeneous landscape composed of the following four main forest types: northern hardwoods, northern conifer, aspen/fir, and forested wetland. Based on sap flux measurements, aspen/fir has twice the canopy transpiration of northern hardwoods. In addition, daily transpiration was only explained by daily average vapor pressure deficit across the cover types. The objective of this study was to determine if canopy average stomatal conductance could be used to explain the species effects on tree transpiration. Our first hypothesis is that across all of the species, stomatal conductance will respond to vapor pressure deficit so as to maintain a minimum leaf water potential to prevent catostrophic cavitiation. The consequence of this hypothesis is that among species and individuals there is a proportionality between high stomatal conductance and the sensitivity of stomatal conductance to vapor pressure deficit. Our second hypothesis is that species that do not follow the proportionality deviate because the canopies are decoupled from the atmosphere. To test our two hypotheses we calculated canopy average stomatal conductance from sap flux measurements using an inversion of the Penman-Monteith equation. We estimated the canopy coupling using a leaf energy budget model that requires leaf transpiration and canopy aerodynamic conductance. We optimized the parameters of the aerodynamic conductance model using a Monte Carlo technique across six parameters. We determined the optimal model for each species by selecting parameter sets that resulted in the proportionality of our first hypothesis. We then tested the optimal energy budget models of each species by comparing leaf temperature and leaf width predicted by the models to measurements of each tree species. In red pine, sugar maple, and trembling aspen trees under high canopy coupling conditions, we found the hypothesized proportionality

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

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...

Stomatal development in barley as a bioassay for cell differentation: its use with X-rays and gibberellic acid

Energy Technology Data Exchange (ETDEWEB)

Zeiger, E; Rafalowsky, J [Chile Univ., Santiago. Departamento de Biologia y Genetica

1976-01-01

A bioassay for cell differentiation during stomatal development in barley (Hordeum vulgare L.) has been defined. It uses cell kinetics analysis to follow the temporal course of cell divisions in the developmental sequence. The rate of displacement of the divisions along the stomatal rows provides a measure of differentiation. Physical factors affecting differentiation may be tested with intact seedlings. The bioassay showed that X-ray irradiation inhibited the divisions leading to stomatal formation. The inhibition kinetics was similar to the one observed in root meristems. Chemical substances are tested by culturing excised shoots in a synthetic medium. Detached leaves responded to sucrose and light with increasing rates of stomatal divisions. Gibberellic acid (GA/sub 3/) was assayed for its effects on the growth of the leaf and the differentiation of stomata. GA/sub 3/ increased the overall length of the leaves without affecting the rates of cell division. The treated cells responded with increased elongation rates and a precocious initiation and completion of cell enlargement. GA/sub 3/ had no specific effect on stomatal differentiation.

A new discrete dynamic model of ABA-induced stomatal closure predicts key feedback loops.

Directory of Open Access Journals (Sweden)

Réka Albert

2017-09-01

Full Text Available Stomata, microscopic pores in leaf surfaces through which water loss and carbon dioxide uptake occur, are closed in response to drought by the phytohormone abscisic acid (ABA. This process is vital for drought tolerance and has been the topic of extensive experimental investigation in the last decades. Although a core signaling chain has been elucidated consisting of ABA binding to receptors, which alleviates negative regulation by protein phosphatases 2C (PP2Cs of the protein kinase OPEN STOMATA 1 (OST1 and ultimately results in activation of anion channels, osmotic water loss, and stomatal closure, over 70 additional components have been identified, yet their relationships with each other and the core components are poorly elucidated. We integrated and processed hundreds of disparate observations regarding ABA signal transduction responses underlying stomatal closure into a network of 84 nodes and 156 edges and, as a result, established those relationships, including identification of a 36-node, strongly connected (feedback-rich component as well as its in- and out-components. The network's domination by a feedback-rich component may reflect a general feature of rapid signaling events. We developed a discrete dynamic model of this network and elucidated the effects of ABA plus knockout or constitutive activity of 79 nodes on both the outcome of the system (closure and the status of all internal nodes. The model, with more than 1024 system states, is far from fully determined by the available data, yet model results agree with existing experiments in 82 cases and disagree in only 17 cases, a validation rate of 75%. Our results reveal nodes that could be engineered to impact stomatal closure in a controlled fashion and also provide over 140 novel predictions for which experimental data are currently lacking. Noting the paucity of wet-bench data regarding combinatorial effects of ABA and internal node activation, we experimentally confirmed

A new discrete dynamic model of ABA-induced stomatal closure predicts key feedback loops.

Science.gov (United States)

Albert, Réka; Acharya, Biswa R; Jeon, Byeong Wook; Zañudo, Jorge G T; Zhu, Mengmeng; Osman, Karim; Assmann, Sarah M

2017-09-01

Stomata, microscopic pores in leaf surfaces through which water loss and carbon dioxide uptake occur, are closed in response to drought by the phytohormone abscisic acid (ABA). This process is vital for drought tolerance and has been the topic of extensive experimental investigation in the last decades. Although a core signaling chain has been elucidated consisting of ABA binding to receptors, which alleviates negative regulation by protein phosphatases 2C (PP2Cs) of the protein kinase OPEN STOMATA 1 (OST1) and ultimately results in activation of anion channels, osmotic water loss, and stomatal closure, over 70 additional components have been identified, yet their relationships with each other and the core components are poorly elucidated. We integrated and processed hundreds of disparate observations regarding ABA signal transduction responses underlying stomatal closure into a network of 84 nodes and 156 edges and, as a result, established those relationships, including identification of a 36-node, strongly connected (feedback-rich) component as well as its in- and out-components. The network's domination by a feedback-rich component may reflect a general feature of rapid signaling events. We developed a discrete dynamic model of this network and elucidated the effects of ABA plus knockout or constitutive activity of 79 nodes on both the outcome of the system (closure) and the status of all internal nodes. The model, with more than 1024 system states, is far from fully determined by the available data, yet model results agree with existing experiments in 82 cases and disagree in only 17 cases, a validation rate of 75%. Our results reveal nodes that could be engineered to impact stomatal closure in a controlled fashion and also provide over 140 novel predictions for which experimental data are currently lacking. Noting the paucity of wet-bench data regarding combinatorial effects of ABA and internal node activation, we experimentally confirmed several predictions

Modelling stomatal ozone flux and deposition to grassland communities across Europe

International Nuclear Information System (INIS)

Ashmore, M.R.; Bueker, P.; Emberson, L.D.; Terry, A.C.; Toet, S.

2007-01-01

Regional scale modelling of both ozone deposition and the risk of ozone impacts is poorly developed for grassland communities. This paper presents new predictions of stomatal ozone flux to grasslands at five different locations in Europe, using a mechanistic model of canopy development for productive grasslands to generate time series of leaf area index and soil water potential as inputs to the stomatal component of the DO 3 SE ozone deposition model. The parameterisation of both models was based on Lolium perenne, a dominant species of productive pasture in Europe. The modelled seasonal time course of stomatal ozone flux to both the whole canopy and to upper leaves showed large differences between climatic zones, which depended on the timing of the start of the growing season, the effect of soil water potential, and the frequency of hay cuts. Values of modelled accumulated flux indices and the AOT40 index showed a five-fold difference between locations, but the locations with the highest flux differed depending on the index used; the period contributing to the accumulation of AOT40 did not always coincide with the modelled period of active ozone canopy uptake. Use of a fixed seasonal profile of leaf area index in the flux model produced very different estimates of annual accumulated total canopy and leaf ozone flux when compared with the flux model linked to a simulation of canopy growth. Regional scale model estimates of both the risks of ozone impacts and of total ozone deposition will be inaccurate unless the effects of climate and management in modifying grass canopy growth are incorporated. - Modelled stomatal flux of ozone to productive grasslands in Europe shows different spatial and temporal variation to AOT40, and is modified by management and soil water status

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.

Ferns are less dependent on passive dilution by cell expansion to coordinate leaf vein and stomatal spacing than angiosperms.

Directory of Open Access Journals (Sweden)

Madeline R Carins Murphy

Full Text Available Producing leaves with closely spaced veins is a key innovation linked to high rates of photosynthesis in angiosperms. A close geometric link between veins and stomata in angiosperms ensures that investment in enhanced venous water transport provides the strongest net carbon return to the plant. This link is underpinned by "passive dilution" via expansion of surrounding cells. However, it is not known whether this 'passive dilution' mechanism is present in plant lineages other than angiosperms and is another key feature of the angiosperms' evolutionary success. Consequently, we sought to determine whether the 'passive dilution' mechanism is; (i exclusive to the angiosperms, (ii a conserved mechanism that evolved in the common ancestor of ferns and angiosperms, or (iii has evolved continuously over time. To do this we first we assessed the plasticity of vein and stomatal density and epidermal cell size in ferns in response to light environment. We then compared the relationships between these traits found among ferns with modelled relationships that assume vein and stomatal density respond passively to epidermal cell expansion, and with those previously observed in angiosperms. Vein density, stomatal density and epidermal cell size were linked in ferns with remarkably similar relationships to those observed in angiosperms, except that fern leaves had fewer veins per stomata. However, plasticity was limited in ferns and stomatal spacing was dependent on active stomatal differentiation as well as passive cell expansion. Thus, ferns (like angiosperms appear to coordinate vein and stomatal density with epidermal cell expansion to some extent to maintain a constant ratio between veins and stomata in the leaf. The different general relationships between vein density and stomatal density in ferns and angiosperms suggests the groups have different optimum balances between the production of vein tissue dedicated to water supply and stomatal tissue for gas

Experience with TL-102M for the treatment of radiation stomatitis

International Nuclear Information System (INIS)

Nishio, Juntaro; Matsuya, Tokuzo; Inoue, Kazuo; Miyazaki, Tadashi; Maeda, Noriaki.

1984-01-01

TL-102M was administered to 14 patients who had radiation stomatitis following radiation therapy for malignant tumors in the oral cavity. Regarding the degree of overall improvement, one of the 14 patients was evaluated as ''extremely improved'', eight as ''improved'', four as ''slightly improved'', and one as ''unchanged''. None of the patients had side effects. Adherent, powdered TL-102M was easy to take for patients. Most of the patients desired to continue to take this drug because of having neither painfulness nor adhesive feeling. The usage of TL-102M could be helpful in promoting the treatment for cancer, thus suggesting that it is useful in treating radiation stomatitis. (Namekawa, K.)

Phenomics allows identification of genomic regions affecting maize stomatal conductance with conditional effects of water deficit and evaporative demand.

Science.gov (United States)

Prado, Santiago Alvarez; Cabrera-Bosquet, Llorenç; Grau, Antonin; Coupel-Ledru, Aude; Millet, Emilie J; Welcker, Claude; Tardieu, François

2018-02-01

Stomatal conductance is central for the trades-off between hydraulics and photosynthesis. We aimed at deciphering its genetic control and that of its responses to evaporative demand and water deficit, a nearly impossible task with gas exchanges measurements. Whole-plant stomatal conductance was estimated via inversion of the Penman-Monteith equation from data of transpiration and plant architecture collected in a phenotyping platform. We have analysed jointly 4 experiments with contrasting environmental conditions imposed to a panel of 254 maize hybrids. Estimated whole-plant stomatal conductance closely correlated with gas-exchange measurements and biomass accumulation rate. Sixteen robust quantitative trait loci (QTLs) were identified by genome wide association studies and co-located with QTLs of transpiration and biomass. Light, vapour pressure deficit, or soil water potential largely accounted for the differences in allelic effects between experiments, thereby providing strong hypotheses for mechanisms of stomatal control and a way to select relevant candidate genes among the 1-19 genes harboured by QTLs. The combination of allelic effects, as affected by environmental conditions, accounted for the variability of stomatal conductance across a range of hybrids and environmental conditions. This approach may therefore contribute to genetic analysis and prediction of stomatal control in diverse environments. © 2017 John Wiley & Sons Ltd.

Open or close the gate – stomata action under the control of phytohormones in drought stress conditions

Directory of Open Access Journals (Sweden)

Agata eDaszkowska-Golec

2013-05-01

Full Text Available Two highly specialized cells, the guard cells that surround the stomatal pore, are able to integrate environmental and endogenous signals in order to control the stomatal aperture and thereby the gas exchange. The uptake of CO2 is associated with a loss of water by leaves. Control of the size of the stomatal aperture optimizes the efficiency of water use through dynamic changes in the turgor of the guard cells. The opening and closing of stomata is regulated by the integration of environmental signals and endogenous hormonal stimuli. The various different factors to which the guard cells respond translates into the complexity of the network of signaling pathways that control stomatal movements. The perception of an abiotic stress triggers the activation of signal transduction cascades that interact with or are activated by phytohormones. Among these, abscisic acid (ABA, is the best-known stress hormone that closes the stomata, although other phytohormones, such as jasmonic acid, brassinosteroids, cytokinins or ethylene are also involved in the stomatal response to stresses. As a part of the drought response, ABA may interact with jasmonic acid and nitric oxide in order to stimulate stomatal closure. In addition, the regulation of gene expression in response to ABA involves genes that are related to ethylene, cytokinins and auxin signaling. In this paper, recent findings on phytohormone crosstalk, changes in signaling pathways including the expression of specific genes and their impact on modulating stress response through the closing or opening of stomata, together with the highlights of gaps that need to be elucidated in the signaling network of stomatal regulation, are reviewed.

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

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......Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of 0.......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...

Differential effects of elevated air humidity on stomatal closing ability of Kalanchoë blossfeldiana between the C

NARCIS (Netherlands)

Fanourakis, Dimitrios; Hyldgaard, Benita; Gebraegziabher, Habtamu; Bouranis, Dimitris; Körner, Oliver; Nielsen, Kai Lønne; Ottosen, Carl-Otto

2017-01-01

High relative air humidity (RH ≥ 85%) impairs stomatal functionality, attenuating plant capacity to cope with abiotic stress. Previous studies were limited to C₃ species, so the RH effect on stomatal physiology of CAM plants remains unexplored. We addressed the topic through

The effect of denture stability, occlusion, oral hygiene and smoking on denture-induced stomatitis

International Nuclear Information System (INIS)

Nimri, Gadeer Mukatash

2008-01-01

This longitudinal clinical investigation was undertaken to find out the effect of denture wearing habit (day versus day and night), denture hygiene and cigarette smoking habit on the frequency of denture induced stomatitis. Comparisons were made between 240 complete denture wearers, half of whom were asked to wear their dentures at the daytime only and the other half to wear the denture day and night. All these participants were male patients with a mean age of 57.6 years who had received maxillary complete acrylic dentures for the first time. Fifty percent of the samples were smokers. A standard method for examination of the mouth and denture construction, insertion and follow up were employed. Putative risk factors (denture wearing habits, denture hygiene and smoking) were investigated. Subjects were recalled 12 months after insertion to examine the quality of the denture and the condition of the maxillary mucosa. No significant correlation was found between deterioration of stability or occlusion and type of habitual use of the dentures (P > 0.05). Fourteen percent of the cases reported with inflamed maxillary mucosa. Deterioration of retention or occlusion separately showed no correlation with the condition of the mucosa. However, associated deterioration of both stability and occlusion proved to be significantly correlated with the occurrence of denture stomatitis (P < 0.05). Denture stomatitis was significantly more frequently with subjects wearing their dentures overnight compared with those who removed them (P < 0.05). A significant correlation was also found between cigarette smoking, poor oral hygiene and the presence of denture induced stomatitis (P < 0.05). Nocturnal denture wearing habit, deficient oral and denture hygiene, and cigarette smoking are all important predisposing factors to denture-induced stomatitis, however, none of these factors was the sole cause of mucosal inflammation. (author)

Quantitative trait loci mapping for stomatal traits in interspecific ...

Indian Academy of Sciences (India)

Dr.YASODHA

seedling raising, field planting and maintenance of the mapping population. ... tereticornis and production of interspecific hybrids displaying hybrid vigour in terms of .... A total of 114, 115 and 129 SSR, ISSR and SRAP markers were generated .... stomatal traits with yield and adaptability would help to improve productivity of ...

The Arabidopsis guard cell outward potassium channel GORK is regulated by CPK33.

Science.gov (United States)

Corratgé-Faillie, Claire; Ronzier, Elsa; Sanchez, Frédéric; Prado, Karine; Kim, Jeong-Hyeon; Lanciano, Sophie; Leonhardt, Nathalie; Lacombe, Benoît; Xiong, Tou Cheu

2017-07-01

A complex signaling network involving voltage-gated potassium channels from the Shaker family contributes to the regulation of stomatal aperture. Several kinases and phosphatases have been shown to be crucial for ABA-dependent regulation of the ion transporters. To date, the Ca 2+ -dependent regulation of Shaker channels by Ca 2+ -dependent protein kinases (CPKs) is still elusive. A functional screen in Xenopus oocytes was launched to identify such CPKs able to regulate the three main guard cell Shaker channels KAT1, KAT2, and GORK. Seven guard cell CPKs were tested and multiple CPK/Shaker couples were identified. Further work on CPK33 indicates that GORK activity is enhanced by CPK33 and unaffected by a nonfunctional CPK33 (CPK33-K102M). Furthermore, Ca 2+ -induced stomatal closure is impaired in two cpk33 mutant plants. © 2017 Federation of European Biochemical Societies.

Effect of Aggression Regulation on Eating Disorder Pathology : RCT of a Brief Body and Movement Oriented Intervention

NARCIS (Netherlands)

Boerhout, Cees; Swart, Marte; Van Busschbach, Jooske T.; Hoek, Hans W.

ObjectiveThe objective of the study is to evaluate the effect of a brief body and movement oriented intervention on aggression regulation and eating disorder pathology for individuals with eating disorders. MethodIn a first randomized controlled trial, 40 women were allocated to either the

LMTK1 regulates dendritic formation by regulating movement of Rab11A-positive endosomes.

Science.gov (United States)

Takano, Tetsuya; Urushibara, Tomoki; Yoshioka, Nozomu; Saito, Taro; Fukuda, Mitsunori; Tomomura, Mineko; Hisanaga, Shin-Ichi

2014-06-01

Neurons extend two types of neurites-axons and dendrites-that differ in structure and function. Although it is well understood that the cytoskeleton plays a pivotal role in neurite differentiation and extension, the mechanisms by which membrane components are supplied to growing axons or dendrites is largely unknown. We previously reported that the membrane supply to axons is regulated by lemur kinase 1 (LMTK1) through Rab11A-positive endosomes. Here we investigate the role of LMTK1 in dendrite formation. Down-regulation of LMTK1 increases dendrite growth and branching of cerebral cortical neurons in vitro and in vivo. LMTK1 knockout significantly enhances the prevalence, velocity, and run length of anterograde movement of Rab11A-positive endosomes to levels similar to those expressing constitutively active Rab11A-Q70L. Rab11A-positive endosome dynamics also increases in the cell body and growth cone of LMTK1-deficient neurons. Moreover, a nonphosphorylatable LMTK1 mutant (Ser34Ala, a Cdk5 phosphorylation site) dramatically promotes dendrite growth. Thus LMTK1 negatively controls dendritic formation by regulating Rab11A-positive endosomal trafficking in a Cdk5-dependent manner, indicating the Cdk5-LMTK1-Rab11A pathway as a regulatory mechanism of dendrite development as well as axon outgrowth. © 2014 Takano et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Intraspecific variation in stomatal traits, leaf traits and physiology reflects adaptation along aridity gradients in a South African shrub.

Science.gov (United States)

Carlson, Jane E; Adams, Christopher A; Holsinger, Kent E

2016-01-01

Trait-environment relationships are commonly interpreted as evidence for local adaptation in plants. However, even when selection analyses support this interpretation, the mechanisms underlying differential benefits are often unknown. This study addresses this gap in knowledge using the broadly distributed South African shrub Protea repens. Specifically, the study examines whether broad-scale patterns of trait variation are consistent with spatial differences in selection and ecophysiology in the wild. In a common garden study of plants sourced from 19 populations, associations were measured between five morphological traits and three axes describing source climates. Trait-trait and trait-environment associations were analysed in a multi-response model. Within two focal populations in the wild, selection and path analyses were used to test associations between traits, fecundity and physiological performance. Across 19 populations in a common garden, stomatal density increased with the source population's mean annual temperature and decreased with its average amount of rainfall in midsummer. Concordantly, selection analysis in two natural populations revealed positive selection on stomatal density at the hotter, drier site, while failing to detect selection at the cooler, moister site. Dry-site plants with high stomatal density also had higher stomatal conductances, cooler leaf temperatures and higher light-saturated photosynthetic rates than those with low stomatal density, but no such relationships were present among wet-site plants. Leaf area, stomatal pore index and specific leaf area in the garden also co-varied with climate, but within-population differences were not associated with fitness in either wild population. The parallel patterns of broad-scale variation, differences in selection and differences in trait-ecophysiology relationships suggest a mechanism for adaptive differentiation in stomatal density. Densely packed stomata may improve performance by

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.

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 piroxicam was safe and might be used to decrease the clinical signs of caudal stomatitis in cats. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Suitability of four stomatal conductance models in agro-pastoral ecotone in North China: A case study for potato and oil sunflower.

Science.gov (United States)

Huang, Ming Xia; Wang, Jing; Tang, Jian Zhao; Yu, Qiang; Zhang, Jun; Xue, Qing Yu; Chang, Qing; Tan, Mei Xiu

2016-11-18

The suitability of four popular empirical and semi-empirical stomatal conductance models (Jarvis model, Ball-Berry model, Leuning model and Medlyn model) was evaluated based on para-llel observation data of leaf stomatal conductance, leaf net photosynthetic rate and meteorological factors during the vigorous growing period of potato and oil sunflower at Wuchuan experimental station in agro-pastoral ecotone in North China. It was found that there was a significant linear relationship between leaf stomatal conductance and leaf net photosynthetic rate for potato, whereas the linear relationship appeared weaker for oil sunflower. The results of model evaluation showed that Ball-Berry model performed best in simulating leaf stomatal conductance of potato, followed by Leuning model and Medlyn model, while Jarvis model was the last in the performance rating. The root-mean-square error (RMSE) was 0.0331, 0.0371, 0.0456 and 0.0794 mol·m -2 ·s -1 , the normalized root-mean-square error (NRMSE) was 26.8%, 30.0%, 36.9% and 64.3%, and R-squared (R 2 ) was 0.96, 0.61, 0.91 and 0.88 between simulated and observed leaf stomatal conductance of potato for Ball-Berry model, Leuning model, Medlyn model and Jarvis model, respectively. For leaf stomatal conductance of oil sunflower, Jarvis model performed slightly better than Leuning model, Ball-Berry model and Medlyn model. RMSE was 0.2221, 0.2534, 0.2547 and 0.2758 mol·m -2 ·s -1 , NRMSE was 40.3%, 46.0%, 46.2% and 50.1%, and R 2 was 0.38, 0.22, 0.23 and 0.20 between simulated and observed leaf stomatal conductance of oil sunflower for Jarvis model, Leuning model, Ball-Berry model and Medlyn model, respectively. The path analysis was conducted to identify effects of specific meteorological factors on leaf stomatal conductance. The diurnal variation of leaf stomatal conductance was principally affected by vapour pressure saturation deficit for both potato and oil sunflower. The model evaluation suggested that the stomatal

Inhibition by acrolein of light-induced stomatal opening through inhibition of inward-rectifying potassium channels in Arabidopsis thaliana.

Science.gov (United States)

Islam, Md Moshiul; Ye, Wenxiu; Matsushima, Daiki; Khokon, Md Atiqur Rahman; Munemasa, Shintaro; Nakamura, Yoshimasa; Murata, Yoshiyuki

2015-01-01

Acrolein is a reactive α,β-unsaturated aldehyde derived from lipid peroxides, which are produced in plants under a variety of stress. We investigated effects of acrolein on light-induced stomatal opening using Arabidopsis thaliana. Acrolein inhibited light-induced stomatal opening in a dose-dependent manner. Acrolein at 100 μM inhibited plasma membrane inward-rectifying potassium (Kin) channels in guard cells. Acrolein at 100 μM inhibited Kin channel KAT1 expressed in a heterologous system using Xenopus leaves oocytes. These results suggest that acrolein inhibits light-induced stomatal opening through inhibition of Kin channels in guard cells.

Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency.

Science.gov (United States)

Papanatsiou, Maria; Amtmann, Anna; Blatt, Michael R

2017-04-01

Stomata are microscopic pores formed by specialized cells in the leaf epidermis and permit gaseous exchange between the interior of the leaf and the atmosphere. Stomata in most plants are separated by at least one epidermal pavement cell and, individually, overlay a single substomatal cavity within the leaf. This spacing is thought to enhance stomatal function. Yet, there are several genera naturally exhibiting stomata in clusters and therefore deviating from the one-cell spacing rule with multiple stomata overlaying a single substomatal cavity. We made use of two Begonia species to investigate whether clustering of stomata alters guard cell dynamics and gas exchange under different light and dark treatments. Begonia plebeja, which forms stomatal clusters, exhibited enhanced kinetics of stomatal conductance and CO2 assimilation upon light stimuli that in turn were translated into greater water use efficiency. Our findings emphasize the importance of spacing in stomatal clusters for gaseous exchange and plant performance under environmentally limited conditions. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Oral cryotherapy for the prevention of high-dose melphalan-induced stomatitis in allogeneic hematopoietic stem cell transplant recipients.

Science.gov (United States)

Aisa, Yoshinobu; Mori, Takehiko; Kudo, Masumi; Yashima, Tomoko; Kondo, Sakiko; Yokoyama, Akihiro; Ikeda, Yasuo; Okamoto, Shinichiro

2005-04-01

The purpose of this study was to evaluate the efficacy of oral cryotherapy to prevent high-dose melphalan-induced stomatitis. Eighteen consecutive recipients of allogeneic hematopoietic stem cell transplant conditioned with high-dose melphalan (140 mg/m2) in combination with fludarabine alone or with fludarabine and additional chemotherapy or radiation were enrolled. The severity of stomatitis was graded according to the National Cancer Institute Common Toxicity Criteria. Patients were kept on oral cryotherapy using ice chips and ice-cold water shortly before, during, and for additional 90 min after completion of melphalan administration. Only two of 18 patients (11.1%) developed grade 2 or 3 stomatitis while six of seven patients in the historical control developed it (85.7%; P=0.001). These results suggested that oral cryotherapy could effectively prevent stomatitis caused by high-dose melphalan, and we recommend that it should be incorporated into the conditioning regimen with high-dose melphalan.

A Two-Big-Leaf Model for Canopy Temperature, Photosynthesis, and Stomatal Conductance.

Science.gov (United States)

Dai, Yongjiu; Dickinson, Robert E.; Wang, Ying-Ping

2004-06-01

The energy exchange, evapotranspiration, and carbon exchange by plant canopies depend on leaf stomatal control. The treatment of this control has been required by land components of climate and carbon models. Physiological models can be used to simulate the responses of stomatal conductance to changes in atmospheric and soil environments. Big-leaf models that treat a canopy as a single leaf tend to overestimate fluxes of CO2 and water vapor. Models that differentiate between sunlit and shaded leaves largely overcome these problems.A one-layered, two-big-leaf submodel for photosynthesis, stomatal conductance, leaf temperature, and energy fluxes is presented in this paper. It includes 1) an improved two stream approximation model of radiation transfer of the canopy, with attention to singularities in its solution and with separate integrations of radiation absorption by sunlit and shaded fractions of canopy; 2) a photosynthesis stomatal conductance model for sunlit and shaded leaves separately, and for the simultaneous transfers of CO2 and water vapor into and out of the leaf—leaf physiological properties (i.e., leaf nitrogen concentration, maximum potential electron transport rate, and hence photosynthetic capacity) vary throughout the plant canopy in response to the radiation weight time-mean profile of photosynthetically active radiation (PAR), and the soil water limitation is applied to both maximum rates of leaf carbon uptake by Rubisco and electron transport, and the model scales up from leaf to canopy separately for all sunlit and shaded leaves; 3) a well-built quasi-Newton Raphson method for simultaneous solution of temperatures of the sunlit and shaded leaves.The model was incorporated into the Common Land Model (CLM) and is denoted CLM 2L. It was driven with observational atmospheric forcing from two forest sites [Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) and Boreal Ecosystem Atmosphere Study (BOREAS)] for 2 yr of simulation. The

49 CFR 236.776 - Movement, trailing.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, trailing. 236.776 Section 236.776 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, trailing. The movement of a train over the points of a switch which face in the direction in...

49 CFR 236.774 - Movement, facing.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, facing. 236.774 Section 236.774 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, facing. The movement of a train over the points of a switch which face in a direction opposite to...

A fast method to detect the occurrence of nonhomogeneous distribution of stomatal aperture in heterobaric plant leaves : Experiments with Arbutus unedo L. during the diurnal course.

Science.gov (United States)

Beyschlag, W; Pfanz, H

1990-01-01

Pressure infiltration of water into a leaf via the stomatal pores can be used to quickly determine whether all stomata are open, or as recently described for several mesophytic and xerophytic species, whether there is a non-homogeneous distribution of stomatal opening (stomatal patchiness) on the leaf surface. Information about this phenomenon is important since the commonly used algorithms for calculation of leaf conductance from water vapor exchange measurements imply homogeneously open stomata, which in the occurrence of stomatal patchiness will lead to erroneous results. Infiltration experiments in a growth chamber with leaves of the Mediterranean evergreen shrub Arbutus unedo, carried out under simulated Mediterranean summer day conditions, where the species typically exhibits a strong midday stomatal closure, revealed a temporary occurrence of stomatal patchiness during the phase of stomatal closure in the late morning and during the stomatal reopening in the afternoon. Leaves were, however, found to be fully (i.e. homogeneously) infiltratable in the morning and in the evening. At midday during maximum stomatal closure, leaves were almost non-infiltratable. During the day, the infiltrated amount of water was found to be linearly correlated with porometer measurements of leaf conductance of the same leaves, carried out with the attached leaves immediately before infiltration.

Applicability of common stomatal conductance models in maize under varying soil moisture conditions.

Science.gov (United States)

Wang, Qiuling; He, Qijin; Zhou, Guangsheng

2018-07-01

In the context of climate warming, the varying soil moisture caused by precipitation pattern change will affect the applicability of stomatal conductance models, thereby affecting the simulation accuracy of carbon-nitrogen-water cycles in ecosystems. We studied the applicability of four common stomatal conductance models including Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (USO) models based on summer maize leaf gas exchange data from a soil moisture consecutive decrease manipulation experiment. The results showed that the USO model performed best, followed by the BBL model, BWB model, and the Jarvis model performed worst under varying soil moisture conditions. The effects of soil moisture made a difference in the relative performance among the models. By introducing a water response function, the performance of the Jarvis, BWB, and USO models improved, which decreased the normalized root mean square error (NRMSE) by 15.7%, 16.6% and 3.9%, respectively; however, the performance of the BBL model was negative, which increased the NRMSE by 5.3%. It was observed that the models of Jarvis, BWB, BBL and USO were applicable within different ranges of soil relative water content (i.e., 55%-65%, 56%-67%, 37%-79% and 37%-95%, respectively) based on the 95% confidence limits. Moreover, introducing a water response function, the applicability of the Jarvis and BWB models improved. The USO model performed best with or without introducing the water response function and was applicable under varying soil moisture conditions. Our results provide a basis for selecting appropriate stomatal conductance models under drought conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Study on preventive effects of i.v. administration of flavin adenine dinucleotide (FAD) before irradiation on radiation stomatitis

International Nuclear Information System (INIS)

Nagai, Masao; Houzawa, Jiro; Hakamada, Masaru

1984-01-01

In order to compare the preventive effect on radiation stomatitis, flavin adenine dinucleotide (FAD) or vitamin C was administered intravenously until the blood level reached the maximum at the time of irradiation. Thirtyfive patients with cranial or cervical tumors were allocated into the group with FAD (15), the group with vitamin C (10), and the group with irradiation alone (10). The incidence of stomititis was significantly lower and the number of patients in whom the drug was withdrawn due to stomatitis was extremely smaller in the group with FAD than in the other groups. FAD administered before irradiation was considered very useful in preventing radiation stomatitis. (Namekawa, K.)

Plester sariawan efektif dalam mempercepat penyembuhan stomatitis aftosa rekuren dan ulkus traumatikus

Directory of Open Access Journals (Sweden)

Rahmi Amtha

2017-12-01

Full Text Available Mouth ulcer plaster is effective in accelerating the healing of recurrent aphthous stomatitis and traumatic ulcers. Recurrent aphthous stomatitis (RAS is one of the most commonly occurring oral diseases. The prevalence of oral ulceration worldwide is 4%, with RAS having the largest proportion (25%. Recurrent aphthous stomatitis is oral ulceration which has a self-limiting disease, but the specific medication to reduce pain caused by lesion is still less varied nowadays. This study aimed to examine the differences in the effectiveness between topical application of hyaluronic acid (HA, mouth ulcer plaster (MUP and 0.1% triamcinolone acetonide (TA as a positive control in the healing of RAS and traumatic ulcers (TU. This was a quasi-experimental study by measuring the lesion diameter as well as visual analogue scale (VAS pre- and post-administration of three types of medication. Kruskal-walis test results show that there are differences in effectiveness (p=0.000 of the three types of medication to cure RAS and TU. There are signicant differences in the reduction of RAS and TU lesion diameter (p = 0.015 and VAS (p = 0.038 with the use of HA and MUP on the 4th day. There is no signicant difference in effectiveness (diameter and VAS of MUP and TA medication on the fourth day (p = 0.880 and p = 1.000 respectively. There is no signicant difference among HA, MUP and TA on the healing of the lesions on the seventh day (p>0.05. It can be concluded that the effectiveness of MUP is similar to that of topical medications containing corticosteroids in the healing of RAS and traumatic ulcers. ABSTRAK Stomatitis aftosa rekuren (SAR merupakan salah satu penyakit mulut yang paling umum terjadi. Prevalensi ulserasi mulut di seluruh dunia adalah 4%, dengan SAR menempati urutan terbesar yaitu 25%. Stomatitis aftosa rekuren merupakan ulserasi mulut yang memiliki self-limiting disease, namun sediaan obat yang spesifik untuk mengurangi rasa sakit yang

Chlorella induces stomatal closure via NADPH oxidase-dependent ROS production and its effects on instantaneous water use efficiency in Vicia faba.

Directory of Open Access Journals (Sweden)

Yan Li

Full Text Available Reactive oxygen species (ROS have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs. Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2 scavenger, catalase (CAT, significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI, and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM, suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi in Vicia faba via a reduction in leaf transpiration rate (E without a parallel reduction in net photosynthetic rate (Pn assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels.

Phenotype-gene: 61 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available iency during process named stomatal movement in environment of light regimen for AT3G53720 Padmanaban Senthi...24u17337534i decreased efficiency during process named stomatal movement in envir

Stomatal responses to CO2 during a diel Crassulacean acid metabolism cycle in Kalanchoe daigremontiana and Kalanchoe pinnata.

Science.gov (United States)

von Caemmerer, Susanne; Griffiths, Howard

2009-05-01

To investigate the diurnal variation of stomatal sensitivity to CO2, stomatal response to a 30 min pulse of low CO2 was measured four times during a 24 h time-course in two Crassulacean acid metabolism (CAM) species Kalanchoe daigremontiana and Kalanchoe pinnata, which vary in the degree of succulence, and hence, expression and commitment to CAM. In both species, stomata opened in response to a reduction in pCO2 in the dark and in the latter half of the light period, and thus in CAM species, chloroplast photosynthesis is not required for the stomatal response to low pCO2. Stomata did not respond to a decreased pCO2 in K. daigremontiana in the light when stomata were closed, even when the supply of internal CO2 was experimentally reduced. We conclude that stomatal closure during phase III is not solely mediated by high internal pCO2, and suggest that in CAM species the diurnal variability in the responsiveness of stomata to pCO2 could be explained by hypothesizing the existence of a single CO2 sensor which interacts with other signalling pathways. When not perturbed by low pCO2, CO2 assimilation rate and stomatal conductance were correlated both in the light and in the dark in both species.

RNAi-mediated downregulation of poplar plasma membrane intrinsic proteins (PIPs) changes plasma membrane proteome composition and affects leaf physiology.

Science.gov (United States)

Bi, Zhen; Merl-Pham, Juliane; Uehlein, Norbert; Zimmer, Ina; Mühlhans, Stefanie; Aichler, Michaela; Walch, Axel Karl; Kaldenhoff, Ralf; Palme, Klaus; Schnitzler, Jörg-Peter; Block, Katja

2015-10-14

Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement. Copyright © 2015. Published by Elsevier B.V.

Changes in the physiological activity of soybean (Glycine max L. Merr. under the influence of exogenous growth regulators

Directory of Open Access Journals (Sweden)

Anna Nowak

2015-07-01

Full Text Available In a two-year pot experiment (2008–2009 conducted at the Vegetation Hall, West Pomeranian University of Technology in Szczecin, we investigated the influence of exogenous growth regulators, i.e. indole-3-butyric acid (IBA and 6-benzylaminopurine (BAP and their mixture, on the activity of gas exchange and selected physiological features of soybeans (Glycine max L. Merr.. The experimental factors included the following Polish soybean cultivars: ‘Aldana’, ‘Progres’ and ‘Jutro’. During plant growth, CO2 assimilation (A, transpiration rate (E, stomatal conductance (gs, and substomatal CO2 concentration (ci were determined. Two soybean cultivars, i.e. ‘Jutro’ and ‘Progres’, showed a significant increase in the intensity of assimilation and transpiration after using all kinds of growth regulators as compared with the control plants. It was found that the ‘Jutro’ cultivar, after using a mixture of growth regulators (IBA + BAP, was characterized by the significantly highest CO2 assimilation (A and transpiration (E as well as the highest stomatal conductance (gs. The ‘Aldana’ cultivar, on the other hand, responded by a significant reduction in the transpiration rate, stomatal conductance and subsomatal CO2 concentration. The spraying of the plants with exogenous growth regulators had a significant influence on the increase in the number of stomata and stomatal pore length, mostly on the lower epidermis of the lamina. It was also found that plants from the ‘Jutro’ and ‘Aldana’ cultivars sprayed with IBA and IBA + BAP were characterized by the highest yield, as compared with the control plants. In the case of the ‘Jutro’ cultivar, after using the growth regulators, a positive correlation was observed between the assimilation and transpiration rates and the length of stomata, which in consequence produced increased yields.

Differences in the response sensitivity of stomatal index to atmospheric CO2 among four genera of Cupressaceae conifers.

Science.gov (United States)

Haworth, Matthew; Heath, James; McElwain, Jennifer C

2010-03-01

The inverse relationship between stomatal density (SD: number of stomata per mm(2) leaf area) and atmospheric concentration of CO2 ([CO2]) permits the use of plants as proxies of palaeo-atmospheric CO2. Many stomatal reconstructions of palaeo-[CO2] are based upon multiple fossil species. However, it is unclear how plants respond to [CO2] across genus, family or ecotype in terms of SD or stomatal index (SI: ratio of stomata to epidermal cells). This study analysed the stomatal numbers of conifers from the ancient family Cupressaceae, in order to examine the nature of the SI-[CO2] relationship, and potential implications for stomatal reconstructions of palaeo-[CO2]. Methods Stomatal frequency measurements were taken from historical herbarium specimens of Athrotaxis cupressoides, Tetraclinis articulata and four Callitris species, and live A. cupressoides grown under CO2-enrichment (370, 470, 570 and 670 p.p.m. CO2). T. articulata, C. columnaris and C. rhomboidea displayed significant reductions in SI with rising [CO2]; by contrast, A. cupressoides, C. preissii and C. oblonga show no response in SI. However, A. cupressoides does reduce SI to increases in [CO2] above current ambient (approx. 380 p.p.m. CO2). This dataset suggests that a shared consistent SI-[CO2] relationship is not apparent across the genus Callitris. Conclusions The present findings suggest that it is not possible to generalize how conifer species respond to fluctuations in [CO2] based upon taxonomic relatedness or habitat. This apparent lack of a consistent response, in conjunction with high variability in SI, indicates that reconstructions of absolute palaeo-[CO2] based at the genus level, or upon multiple species for discrete intervals of time are not as reliable as those based on a single or multiple temporally overlapping species.

Relationship between ammonia stomatal compensation point and nitrogen metabolism in arable crops: Current status of knowledge and potential modelling approaches

International Nuclear Information System (INIS)

Massad, Raia Silvia; Loubet, Benjamin; Tuzet, Andree; Cellier, Pierre

2008-01-01

The ammonia stomatal compensation point of plants is determined by leaf temperature, ammonium concentration ([NH 4 + ] apo ) and pH of the apoplastic solution. The later two depend on the adjacent cells metabolism and on leaf inputs and outputs through the xylem and phloem. Until now only empirical models have been designed to model the ammonia stomatal compensation point, except the model of Riedo et al. (2002. Coupling soil-plant-atmosphere exchange of ammonia with ecosystem functioning in grasslands. Ecological Modelling 158, 83-110), which represents the exchanges between the plant's nitrogen pools. The first step to model the ammonia stomatal compensation point is to adequately model [NH 4 + ] apo . This [NH 4 + ] apo has been studied experimentally, but there are currently no process-based quantitative models describing its relation to plant metabolism and environmental conditions. This study summarizes the processes involved in determining the ammonia stomatal compensation point at the leaf scale and qualitatively evaluates the ability of existing whole plant N and C models to include a model for [NH 4 + ] apo . - A model for ammonia stomatal compensation point at the leaf level scale was developed

Effect of Light Quality on Stomatal Opening in Leaves of Xanthium strumarium L.

Science.gov (United States)

Sharkey, T D; Raschke, K

1981-11-01

Flux response curves were determined at 16 wavelengths of light for the conductance for water vapor of the lower epidermis of detached leaves of Xanthium strumarium L. An action spectrum of stomatal opening resulted in which blue light (wavelengths between 430 and 460 nanometers) was nearly ten times more effective than red light (wavelengths between 630 and 680 nanometers) in producing a conductance of 15 centimoles per square meter per second. Stomata responded only slightly to green light. An action spectrum of stomatal responses to red light corresponded to that of CO(2) assimilation; the inhibitors of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-s-triazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, eliminated the response to red light. This indicates that light absorption by chlorophyll is the cause of stomatal sensitivity to red light. Determination of flux response curves on leaves in the normal position (upper epidermis facing the light) or in the inverted position (lower epidermis facing the light) led to the conclusion that the photoreceptors for blue as well as for red light are located on or near the surfaces of the leaves; presumably they are in the guard cells themselves.

JST Thesaurus Headwords and Synonyms: vesicular stomatitis virus [MeCab user dictionary for science technology term[Archive

Lifescience Database Archive (English)

Full Text Available MeCab user dictionary for science technology term vesicular stomatitis virus 名詞 一般 ...* * * * 水疱性口内炎ウイルス スイホウセイコウナイエンウイルス スイホーセイコーナイエンウイルス Thesaurus2015 200906056003651861 C LS07 UNKNOWN_2 vesicular stomatitis virus

An ancestral stomatal patterning module revealed in the non-vascular land plant Physcomitrella patens

Science.gov (United States)

Chater, Caspar C.; Kamisugi, Yasuko

2016-01-01

The patterning of stomata plays a vital role in plant development and has emerged as a paradigm for the role of peptide signals in the spatial control of cellular differentiation. Research in Arabidopsis has identified a series of epidermal patterning factors (EPFs), which interact with an array of membrane-localised receptors and associated proteins (encoded by ERECTA and TMM genes) to control stomatal density and distribution. However, although it is well-established that stomata arose very early in the evolution of land plants, until now it has been unclear whether the established angiosperm stomatal patterning system represented by the EPF/TMM/ERECTA module reflects a conserved, universal mechanism in the plant kingdom. Here, we use molecular genetics to show that the moss Physcomitrella patens has conserved homologues of angiosperm EPF, TMM and at least one ERECTA gene that function together to permit the correct patterning of stomata and that, moreover, elements of the module retain function when transferred to Arabidopsis. Our data characterise the stomatal patterning system in an evolutionarily distinct branch of plants and support the hypothesis that the EPF/TMM/ERECTA module represents an ancient patterning system. PMID:27407102

Relationship between ammonia stomatal compensation point and nitrogen metabolism in arable crops: Current status of knowledge and potential modelling approaches

Energy Technology Data Exchange (ETDEWEB)

Massad, Raia Silvia [Institut National de la Recherche Agronomique (INRA), Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France)], E-mail: massad@grignon.inra.fr; Loubet, Benjamin; Tuzet, Andree; Cellier, Pierre [Institut National de la Recherche Agronomique (INRA), Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France)

2008-08-15

The ammonia stomatal compensation point of plants is determined by leaf temperature, ammonium concentration ([NH{sub 4}{sup +}]{sub apo}) and pH of the apoplastic solution. The later two depend on the adjacent cells metabolism and on leaf inputs and outputs through the xylem and phloem. Until now only empirical models have been designed to model the ammonia stomatal compensation point, except the model of Riedo et al. (2002. Coupling soil-plant-atmosphere exchange of ammonia with ecosystem functioning in grasslands. Ecological Modelling 158, 83-110), which represents the exchanges between the plant's nitrogen pools. The first step to model the ammonia stomatal compensation point is to adequately model [NH{sub 4}{sup +}]{sub apo}. This [NH{sub 4}{sup +}]{sub apo} has been studied experimentally, but there are currently no process-based quantitative models describing its relation to plant metabolism and environmental conditions. This study summarizes the processes involved in determining the ammonia stomatal compensation point at the leaf scale and qualitatively evaluates the ability of existing whole plant N and C models to include a model for [NH{sub 4}{sup +}]{sub apo}. - A model for ammonia stomatal compensation point at the leaf level scale was developed.

Tree density and permafrost thaw depth influence water limitations on stomatal conductance in Siberian Arctic boreal forests

Science.gov (United States)

Kropp, H.; Loranty, M. M.; Natali, S.; Kholodov, A. L.; Alexander, H. D.; Zimov, N.

2017-12-01

Boreal forests may experience increased water stress under global climate change as rising air temperatures increase evaporative demand and decrease soil moisture. Increases in plant water stress can decrease stomatal conductance, and ultimately, decrease primary productivity. A large portion of boreal forests are located in Siberia, and are dominated by deciduous needleleaf trees, Larix spp. We investigated the variability and drivers of canopy stomatal conductance in upland Larix stands with different stand density that arose from differing fire severity. Our measurements focus on an open canopy stand with low tree density and deep permafrost thaw depth, and a closed canopy stand with high tree density and shallow permafrost thaw depth. We measured canopy stomatal conductance, soil moisture, and micrometeorological variables. Our results demonstrate that canopy stomatal conductance was significantly lower in the closed canopy stand with a significantly higher sensitivity to increases in atmospheric evaporative demand. Canopy stomatal conductance in both stands was tightly coupled to precipitation that occurred over the previous week; however, the closed canopy stand showed a significantly greater sensitivity to increases in precipitation compared to the open canopy stand. Differences in access to deep versus shallow soil moisture and the physical characteristics of the soil profile likely contribute to differences in sensitivity to precipitation between the two stands. Our results indicate that Larix primary productivity may be highly sensitive to changes in evaporative demand and soil moisture that can result of global climate change. However, the effect of increasing air temperatures and changes in precipitation will differ significantly depending on stand density, thaw depth, and the hydraulic characteristics of the soil profile.

Natural variation in stomatal response to closing stimuli among Arabidopsis thaliana accessions after exposure to lowe VPD as a tool to recognize the mechanism of disturbed stomatal functioning

NARCIS (Netherlands)

Ali Niaei Fard, S.; Meeteren, van U.

2014-01-01

Stomatal responses to closing stimuli are disturbed after long-term exposure of plants to low vapour pressure deficit (VPD). The mechanism behind this disturbance is not fully understood. Genetic variation between naturally occurring ecotypes can be helpful to elucidate the mechanism controlling

Influence of stomatic aperture on photosynthetic activity of bean-seedlings leaves

International Nuclear Information System (INIS)

Suarez Moya, J.; Fernandez Gonzalez, J.

1984-01-01

The present paper contains the data of photosynthetic activity and stomatic aperture of bean-seedlings Ieaves, and the relations obtained with both results. It has been observed that the product of photosynthetic activity by the resistance; to transpiration measured by a promoter ia a constant, between some limits. (Author) 45 refs

Redundancy of stomatal control for the circadian photosynthetic rhythm in Kalanchoë daigremontiana Hamet et Perrier.

Science.gov (United States)

Wyka, T P; Duarte, H M; Lüttge, U E

2005-03-01

In continuous light, the Crassulacean acid metabolism plant Kalanchoe daigremontiana Hamet et Perrier has a circadian rhythm of gas exchange with peaks occurring during the subjective night. The rhythm of gas exchange is coupled to a weak, reverse phased rhythm of quantum yield of photosystem II (Phi (PSII)). To test if the rhythm of Phi (PSII) persists in the absence of stomatal control, leaves were coated with a thin layer of translucent silicone grease which prevented CO2 and H2O exchange. In spite of this treatment, the rhythm of Phi (PSII) occurred with close to normal phase timing and with a much larger amplitude than in uncoated leaves. The mechanism underlying the Phi (PSII) rhythm in coated leaves can be explained by a circadian activity of phosphoenolpyruvate carboxylase (PEPC). At peaks of PEPC activity, the small amount of CO2 contained in the coated leaf could have become depleted, preventing the carboxylase activity of Rubisco and causing decreases in electron transport rates (observed as deep troughs of Phi (PSII) at 23-h in LL and at ca. 24-h intervals afterwards). Peaks of Phi (PSII) would be caused by a downregulation of PEPC leading to improved supply of CO2 to Rubisco. Substrate limitation of photochemistry at 23 h (trough of Phi (PSII)) was also suggested by the weak response of ETR in coated leaves to stepwise light enhancement. These results show that photosynthetic rhythmicity in K. daigremontiana is independent of stomatal regulation and may originate in the mesophyll.

Effect of Light Quality on Stomatal Opening in Leaves of Xanthium strumarium L. 1

Science.gov (United States)

Sharkey, Thomas D.; Raschke, Klaus

1981-01-01

Flux response curves were determined at 16 wavelengths of light for the conductance for water vapor of the lower epidermis of detached leaves of Xanthium strumarium L. An action spectrum of stomatal opening resulted in which blue light (wavelengths between 430 and 460 nanometers) was nearly ten times more effective than red light (wavelengths between 630 and 680 nanometers) in producing a conductance of 15 centimoles per square meter per second. Stomata responded only slightly to green light. An action spectrum of stomatal responses to red light corresponded to that of CO2 assimilation; the inhibitors of photosynthetic electron transport, cyanazine (2-chloro-4[1-cyano-1-methylethylamino]-6-ethylamino-s-triazine) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, eliminated the response to red light. This indicates that light absorption by chlorophyll is the cause of stomatal sensitivity to red light. Determination of flux response curves on leaves in the normal position (upper epidermis facing the light) or in the inverted position (lower epidermis facing the light) led to the conclusion that the photoreceptors for blue as well as for red light are located on or near the surfaces of the leaves; presumably they are in the guard cells themselves. PMID:16662069

Identifying the tundra-forest border in the stomate record: an analysis of lake surface samples from the Yellowknife area, Northwest Territories, Canada

Energy Technology Data Exchange (ETDEWEB)

Hansen, B.C.S. [Minnesota Univ., Minneapolis, MN (United States). Limnological Research Center; MacDonald, G.M. [California Univ., Los Angeles, CA (United States). Dept. of Botanical Sciences; Moser, K.A. [McMaster Univ., Hamilton, ON (Canada)

1996-05-01

The relationship between conifer stomata and existing vegetation across tundra, forest-tundra, and closed zones in the Yellowknife area of the Northwest Territories was studied. Conifer stomata were identified in surface samples from lakes in the treeline zone, but were absent in samples from tundra lakes. Stomate analysis was recorded and the results were presented in a concentration diagram plotting stomate concentrations according to vegetation zone. Conifer stomate analysis was not able to resolve differences between forest-tundra and closed forest. Nevertheless, it was suggested that stomate analysis will become an important technique supplementing pollen analysis for reconstructing past tree-line changes since the presence of stomata in lakes make it possible to separate the tundra from forest-tundra and closed forest. The limited dispersal of conifer stomata permitted a better resolution of tree-line boundaries than did pollen. 13 refs., 3 figs.

Investigation of the effect of the rebamipide mouthwash on the crisis of the stomatitis induced by the cancer chemotherapy and/or radiotherapy

International Nuclear Information System (INIS)

Kawata, Keishi; Hanawa, Takehisa; Hanawa, Kazumi

2001-01-01

Stomatitis is well-known as one of the undesirable side effects induced by high and/or multiple dosing of cytotoxic drugs such as 5-fluorouracil (5-FU). Stomatitis causes pain in the oral cavity, impaired swallowing or loss of appetite, and finally, lowering of the quality of life (QOL) of patients. In this study, we attempted to apply a new mouthwash containing rebamipide (REB) which is known as the anti-activated oxygen agent. Rebamipide mouthwash (REB-M) showed the effectiveness to the crisis of the stomatitis during the cancer chemotherapy and/or radiotherapy. (author)

Nitric Oxide (NO) Measurements in Stomatal Guard Cells.

Science.gov (United States)

Agurla, Srinivas; Gayatri, Gunja; Raghavendra, Agepati S

2016-01-01

The quantitative measurement of nitric oxide (NO) in plant cells acquired great importance, in view of the multifaceted function and involvement of NO as a signal in various plant processes. Monitoring of NO in guard cells is quite simple because of the large size of guard cells and ease of observing the detached epidermis under microscope. Stomatal guard cells therefore provide an excellent model system to study the components of signal transduction. The levels and functions of NO in relation to stomatal closure can be monitored, with the help of an inverted fluorescence or confocal microscope. We can measure the NO in guard cells by using flouroprobes like 4,5-diamino fluorescein diacetate (DAF-2DA). This fluorescent dye, DAF-2DA, is cell permeable and after entry into the cell, the diacetate group is removed by the cellular esterases. The resulting DAF-2 form is membrane impermeable and reacts with NO to generate the highly fluorescent triazole (DAF-2T), with excitation and emission wavelengths of 488 and 530 nm, respectively. If time-course measurements are needed, the epidermis can be adhered to a cover-glass or glass slide and left in a small petri dishes. Fluorescence can then be monitored at required time intervals; with a precaution that excitation is done minimally, only when a fluorescent image is acquired. The present method description is for the epidermis of Arabidopsis thaliana and Pisum sativum and should work with most of the other dicotyledonous plants.

Carbonic anhydrases are upstream regulators of CO2-controlled stomatal movements in guard cells

KAUST Repository

Hu, Honghong; Boisson-Dernier, Auré lien; Israelsson-Nordströ m, Maria; Bö hmer, Maik; Xue, Shaowu; Ries, Amber; Godoski, Jan; Kuhn, Josef M.; Schroeder, Julian I.

2009-01-01

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

Altered dopaminergic regulation of the dorsal striatum is able to induce tic-like movements in juvenile rats

Science.gov (United States)

Rizzo, Francesca; Boeckers, Tobias; Schulze, Ulrike

2018-01-01

Motor tics are sudden, repetitive, involuntary movements representing the hallmark behaviors of the neurodevelopmental disease Tourette’s syndrome (TS). The primary cause of TS remains unclear. The initial observation that dopaminergic antagonists alleviate tics led to the development of a dopaminergic theory of TS etiology which is supported by post mortem and in vivo studies indicating that non-physiological activation of the striatum could generate tics. The striatum controls movement execution through the balanced activity of dopamine receptor D1 and D2-expressing medium spiny neurons of the direct and indirect pathway, respectively. Different neurotransmitters can activate or repress striatal activity and among them, dopamine plays a major role. In this study we introduced a chronic dopaminergic alteration in juvenile rats, in order to modify the delicate balance between direct and indirect pathway. This manipulation was done in the dorsal striatum, that had been associated with tic-like movements generation in animal models. The results were movements resembling tics, which were categorized and scored according to a newly developed rating scale and were reduced by clonidine and riluzole treatment. Finally, post mortem analyses revealed altered RNA expression of dopaminergic receptors D1 and D2, suggesting an imbalanced dopaminergic regulation of medium spiny neuron activity as being causally related to the observed phenotype. PMID:29698507

Stomatal and pavement cell density linked to leaf internal CO2 concentration

Czech Academy of Sciences Publication Activity Database

Šantrůček, Jiří; Vráblová, M.; Šimková, Marie; Hronková, Marie; Drtinová, M.; Květoň, J.; Vrábl, D.; Kubásek, J.; Macková, J.; Wiesnerová, Dana; Neuwithová, J.; Schreiber, L.

2014-01-01

Roč. 114, č. 2 (2014), s. 191-202 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GAP501/12/1261 Institutional support: RVO:60077344 Keywords : Stomatal density * Stomata development * Pavement cells Subject RIV: CE - Biochemistry Impact factor: 3.654, year: 2014

Estimating Latest Cretaceous and Tertiary Atmospheric PCO2 from Stomatal Indices

Science.gov (United States)

Royer, D. L.; Wing, S. L.; Beerling, D. J.

2001-05-01

Most modern C3 seed plants show an inverse relationship between PCO2 and stomatal index (SI), where SI is the proportion of epidermal cells that are stomatal packages. This plant-atmosphere response therefore provides a reliable approach for estimating paleo-CO2 levels. Since stomatal responses to CO2 are generally species-specific, one is limited in paleo-reconstructions to species that exist both in the fossil record and living today. Fossils morphologically similar to living Ginkgo biloba and Metasequoia glyptostroboides extend back to the early and late Cretaceous, respectively, indicating that the fossil and living forms are very closely related. Measurements of SI made on fossil Ginkgo and Metasequoia were calibrated with historical collections of G. biloba and M. glyptostroboides leaves from sites that developed during the anthropogenically-driven CO2 increases of the past 145 years (288-369 ppmv) and with saplings of G. biloba and M. glyptostroboides grown in CO2 controlled growth chambers (350-800 ppmv). Both nonlinear regressions are highly significant (Ginkgo: n = 40, r2 = 0.91; Metasequoia: n = 18; r2 = 0.85). Results from a sequence of 23 latest Cretaceous to early Eocene-aged Ginkgo-bearing sites indicate that CO2 remained between 300 and 450 ppmv with the exception of one high estimate ( ~800 ppmv) near the Paleocene/Eocene boundary, and results from 4 middle Miocene-aged Ginkgo- and Metasequoia-bearing sites indicate that CO2 was between 320 and 400 ppmv. If correct, the CO2 values estimated here are too low to explain via the CO2 greenhouse effect alone the higher global mean temperatures (e.g., 3-4 ° C for the early Eocene) inferred from models and geological data for these two intervals.

7 CFR 301.92 - Restrictions on interstate movement.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Restrictions on interstate movement. 301.92 Section... Restrictions on interstate movement. (a) No person may move interstate from any quarantined area any regulated... plant that was found infected with Phytophthora ramorum, unless such movement is in accordance with part...

Recalibrating the Ginkgo Stomatal Index Proxy for Past CO2 with Herbarium Specimens

Science.gov (United States)

Conde, G. D.; Retallack, G.

2015-12-01

The stomatal index of plant cuticles is inversely related to atmospheric CO2 concentrations, as calibrated from greenhouse experiments and herbarium specimens. Such calibration data for Ginkgo biloba are available for the ongoing rise in atmospheric CO2 and for high levels of CO2 anticipated in the future, but lacking for low CO2 levels of preindustrial and glacial ages. The oldest modern specimen that we have been able to obtain consists of leaf fragments collected in 1829 and provided by Arne Anderberg from the Swedish Natural History Museum. The specimen was labeled "Argentina", but also "Hortus Botanicus Augustinus", a garden founded in 1638 in Amsterdam, Netherlands. Ginkgo has a very thin cuticle that is difficult to prepare, but images very similar to cuticular preparation can be obtained by backscatter SEM imagery. We also obtained secondary SEM images of the same areas and counted 13 images with 6,184 cells from five leaf fragments. Our analyses yield a stomatal index of 10.9 ± 0.9 % for an atmospheric CO2 of 286 ppm, as determined by ice core data from Ciais and Sabine for IPCC-2013. This value is lower than from previous calibration curves for this level of CO2 and changes their curvature. With additional late nineteenth, twentieth and twenty-first century leaves, we can improve both the precision and lower limits of the transfer function for atmospheric CO2 from Ginkgo stomatal index last revised in 2009.

Internal coordination between hydraulics and stomatal control in leaves.

Science.gov (United States)

Brodribb, Tim J; Jordan, Gregory J

2008-11-01

The stomatal response to changing leaf-atmospheric vapour pressure gradient (D(l)) is a crucial yet enigmatic process that defines the daily course of leaf gas exchange. Changes in the hydration of epidermal cells are thought to drive this response, mediated by the transpiration rate and hydraulic conductance of the leaf. Here, we examine whether species-specific variation in the sensitivity of leaves to perturbation of D(l) is related to the efficiency of water transport in the leaf (leaf hydraulic conductivity, K(leaf)). We found good correlation between maximum liquid (K(leaf)) and gas phase conductances (g(max)) in leaves, but there was no direct correlation between normalized D(l) sensitivity and K(leaf). The impact of K(leaf) on D(l) sensitivity in our diverse sample of eight species was important only after accounting for the strong relationship between K(leaf) and g(max). Thus, the ratio of g(max)/K(leaf) was strongly correlated with stomatal sensitivity to D(l). This ratio is an index of the degree of hydraulic buffering of the stomata against changes in D(l), and species with high g(max) relative to K(leaf) were the most sensitive to D(l) perturbation. Despite the potentially high adaptive significance of this phenomenon, we found no significant phylogenetic or ecological trend in our species.

Modern pollen and stomate deposition in lake surface sediments from across the treeline on the Kola Peninsula, Russia.

Science.gov (United States)

Gervais, B R.; MacDonald, G M.

2001-04-01

We sampled and analyzed surface sediments from 31 lakes along a latitudinal transect crossing the coniferous treeline on the Kola Peninsula, Russia. The major vegetation zones along the transect were tundra, birch-forest tundra, pine-forest tundra, and forest. The results indicate that the major vegetation types in our study area have distinct pollen spectra. Sum-of-squares cluster analysis and principal components analysis (PCA) groupings of pollen sites correspond to the major vegetation zones. PCA ordination of taxa indicates that the first axis separates taxa typical of the forest zone (Pinus, Picea) from taxa typical of tundra and forest-tundra zones (Polypodiaceae, Ericaceae, and Betula). The current position of the coniferous treeline, defined in our region by Pinus sylvestris, occurs roughly where Pinus pollen values reach 35% or greater. Arboreal pollen (AP)/non-arboreal pollen (NAP) ratios were calculated for each site and plotted against geographic distance along the transect. AP/NAP ratios of 7 or greater are found within pine-forest tundra and forest vegetation zones. Pinus stomates (dispersed stomatal guard cells) are absent from sites north of the coniferous treeline and all but two samples from the forested sites contain stomates. Stomate concentrations among the samples are highly variable and range from 10 to 458 per ml and positively correlate with the changing Pinus pollen values.

Acquired changes in stomatal characteristics in response to ozone during plant growth and leaf development of bush beans (Phaseolus vulgaris L.) indicate phenotypic plasticity

International Nuclear Information System (INIS)

Elagoez, Vahram; Han, Susan S.; Manning, William J.

2006-01-01

Bush bean (Phaseolus vulgaris L.) lines 'S156' (O 3 -sensitive)/'R123' (O 3 -tolerant) and cultivars 'BBL 290' (O 3 -sensitive)/'BBL 274' (O 3 -tolerant) were used to study the effects of O 3 on stomatal conductance (g s ), density, and aperture size on leaf and pod surfaces with the objective of establishing links between the degree of plant sensitivity to O 3 and plasticity of stomatal properties in response to O 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 3 sensitivity and g s : while 'S156' had higher g s rates than 'R123' earlier in development, similar differences between 'BBL 290' and 'BBL 274' were observed at later stages. G s rates on the abaxial leaf surfaces of 'S156' and 'BBL 290', accompanied by low leaf temperatures, were significantly higher than their O 3 -tolerant counterparts. Exposure to O 3 in CSTRs had greater and more consistent impacts on both stomatal densities and aperture sizes of O 3 -sensitive cultivars. Stomatal densities were highest on the abaxial leaf surfaces of 'S156' and 'BBL 290' at higher O 3 concentrations (60 ppb), but the largest aperture sizes were recorded on the adaxial leaf surfaces at moderate O 3 concentrations (30 ppb). Exposure to O 3 eliminated aperture size differences on the adaxial leaf surfaces between sensitive and tolerant cultivars. Regardless of sensitivity to O 3 and treatment regimes, the smallest aperture sizes and highest stomatal densities were found on the abaxial leaf surface. Our studies showed that O 3 has the potential to affect stomatal plasticity and confirmed the presence of different control mechanisms for stomatal development on each leaf surface. This appeared to be more evident in O 3 -sensitive cultivars. - O 3 has the potential to affect stomatal development and the presence of different control mechanisms on each leaf surface is confirmed

Updated stomatal flux and flux-effect models for wheat for quantifying effects of ozone on grain yield, grain mass and protein yield.

Science.gov (United States)

Grünhage, Ludger; Pleijel, Håkan; Mills, Gina; Bender, Jürgen; Danielsson, Helena; Lehmann, Yvonne; Castell, Jean-Francois; Bethenod, Olivier

2012-06-01

Field measurements and open-top chamber experiments using nine current European winter wheat cultivars provided a data set that was used to revise and improve the parameterisation of a stomatal conductance model for wheat, including a revised value for maximum stomatal conductance and new functions for phenology and soil moisture. For the calculation of stomatal conductance for ozone a diffusivity ratio between O(3) and H(2)O in air of 0.663 was applied, based on a critical review of the literature. By applying the improved parameterisation for stomatal conductance, new flux-effect relationships for grain yield, grain mass and protein yield were developed for use in ozone risk assessments including effects on food security. An example of application of the flux model at the local scale in Germany shows that negative effects of ozone on wheat grain yield were likely each year and on protein yield in most years since the mid 1980s. Copyright © 2012 Elsevier Ltd. All rights reserved.

Resource use and efficiency, and stomatal responses to environmental drivers of oak and pine species in an Atlantic Coastal Plain forest

Directory of Open Access Journals (Sweden)

Heidi J Renninger

2015-05-01

Full Text Available Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource uptake and efficiency. Therefore, we compared resource use in terms of transpiration rates and leaf nitrogen content and resource-use efficiency including water-use efficiency (WUE via gas exchange and leaf carbon isotopes and photosynthetic nitrogen-use efficiency (PNUE between oaks (Quercus alba, Q. prinus, Q. velutina and pines (Pinus rigida, P. echinata. We also determined environmental drivers (vapor pressure deficit (VPD, soil moisture, solar radiation of canopy stomatal conductance (GS estimated via sap flow and stomatal sensitivity to light and soil moisture. Net assimilation rates were similar between genera, but oak leaves used about 10% more water and pine foliage contained about 20% more N per unit leaf area. Therefore, oaks exhibited greater PNUE while pines had higher WUE based on gas exchange, although WUE from carbon isotopes was not significantly different. For the environmental drivers of GS, oaks had about 10% lower stomatal sensitivity to VPD normalized by reference stomatal conductance compared with pines. Pines exhibited a significant positive relationship between shallow soil moisture and GS, but only GS in Q. velutina was positively related to soil moisture. In contrast, stomatal sensitivity to VPD was significantly related to solar radiation in all oak species but only pines at one site. Therefore, oaks rely more heavily on groundwater resources but have lower WUE, while pines have larger leaf areas and nitrogen acquisition but lower PNUE demonstrating a trade-off between using water and nitrogen efficiently in a resource-limited ecosystem.

Resource use and efficiency, and stomatal responses to environmental drivers of oak and pine species in an Atlantic Coastal Plain forest.

Science.gov (United States)

Renninger, Heidi J; Carlo, Nicholas J; Clark, Kenneth L; Schäfer, Karina V R

2015-01-01

Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource uptake and efficiency. Therefore, we compared resource use in terms of transpiration rates and leaf nitrogen content and resource-use efficiency including water-use efficiency (WUE) via gas exchange and leaf carbon isotopes and photosynthetic nitrogen-use efficiency (PNUE) between oaks (Quercus alba, Q. prinus, Q. velutina) and pines (Pinus rigida, P. echinata). We also determined environmental drivers [vapor pressure deficit (VPD), soil moisture, solar radiation] of canopy stomatal conductance (GS) estimated via sap flow and stomatal sensitivity to light and soil moisture. Net assimilation rates were similar between genera, but oak leaves used about 10% more water and pine foliage contained about 20% more N per unit leaf area. Therefore, oaks exhibited greater PNUE while pines had higher WUE based on gas exchange, although WUE from carbon isotopes was not significantly different. For the environmental drivers of GS, oaks had about 10% lower stomatal sensitivity to VPD normalized by reference stomatal conductance compared with pines. Pines exhibited a significant positive relationship between shallow soil moisture and GS, but only GS in Q. velutina was positively related to soil moisture. In contrast, stomatal sensitivity to VPD was significantly related to solar radiation in all oak species but only pines at one site. Therefore, oaks rely more heavily on groundwater resources but have lower WUE, while pines have larger leaf areas and nitrogen acquisition but lower PNUE demonstrating a trade-off between using water and nitrogen efficiently in a resource-limited ecosystem.

What determines the complex kinetics of stomatal conductance under blueless PAR in Festuca arundinacea? Subsequent effects on leaf transpiration.

Science.gov (United States)

Barillot, Romain; Frak, Ela; Combes, Didier; Durand, Jean-Louis; Escobar-Gutiérrez, Abraham J

2010-06-01

Light quality and, in particular, its content of blue light is involved in plant functioning and morphogenesis. Blue light variation frequently occurs within a stand as shaded zones are characterized by a simultaneous decrease of PAR and blue light levels which both affect plant functioning, for example, gas exchange. However, little is known about the effects of low blue light itself on gas exchange. The aims of the present study were (i) to characterize stomatal behaviour in Festuca arundinacea leaves through leaf gas exchange measurements in response to a sudden reduction in blue light, and (ii) to test the putative role of Ci on blue light gas exchange responses. An infrared gas analyser (IRGA) was used with light transmission filters to study stomatal conductance (gs), transpiration (Tr), assimilation (A), and intercellular concentration of CO(2) (Ci) responses to blueless PAR (1.80 mumol m(-2) s(-1)). The results were compared with those obtained under a neutral filter supplying a similar photosynthetic efficiency to the blueless PAR filter. It was shown that the reduction of blue light triggered a drastic and instantaneous decrease of gs by 43.2% and of Tr by 40.0%, but a gradual stomatal reopening began 20 min after the start of the low blue light treatment, thus leading to new steady-states. This new stomatal equilibrium was supposed to be related to Ci. The results were confirmed in more developed plants although they exhibited delayed and less marked responses. It is concluded that stomatal responses to blue light could play a key role in photomorphogenetic mechanisms through their effect on transpiration.

Contribution of competition for light to within-species variability in stomatal conductance

Science.gov (United States)

Loranty, Michael M.; Mackay, D. Scott; Ewers, Brent E.; Traver, Elizabeth; Kruger, Eric L.

2010-05-01

Sap flux (JS) measurements were collected across two stands dominated by either trembling aspen or sugar maple in northern Wisconsin. Observed canopy transpiration (EC-obs) values derived from JS were used to parameterize the Terrestrial Regional Ecosystem Exchange Simulator ecosystem model. Modeled values of stomatal conductance (GS) were used to determine reference stomatal conductance (GSref), a proxy for GS that removes the effects of temporal responses to vapor pressure deficit (D) on spatial patterns of GS. Values of GSref were compared to observations of soil moisture, several physiological variables, and a competition index (CI) derived from a stand inventory, to determine the underlying cause of observed variability. Considerable variability in GSref between individual trees was found, with values ranging from 20 to 200 mmol m-2 s-1 and 20 to 100 mmol m-2 s-1 at the aspen and maple stands, respectively. Model-derived values of GSref and a sensitivity to D parameter (m) showed good agreement with a known empirical relationship for both stands. At both sites, GSref did not vary with topographic position, as indicated by surface soil moisture. No relationships were observed between GSref and tree height (HT), and a weak correlation with sapwood area (AS) was only significant for aspen. Significant nonlinear inverse relationships between GSref and CI were observed at both stands. Simulations with uniform reductions in incident photosynthetically active radiation (Q0) resulted in better agreement between observed and simulated EC. Our results suggest a link between photosynthesis and plant hydraulics whereby individual trees subject to photosynthetic limitation as a result of competitive shading exhibit a dynamic stomatal response resulting in a more conservative strategy for managing hydrologic resources.

7 CFR 301.85-9 - Movement of live golden nematodes.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

7 CFR 301.48-6 - Movement of live Japanese beetles.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of live Japanese beetles. 301.48-6 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Japanese Beetle Quarantine and Regulations § 301.48-6 Movement of live Japanese beetles. Regulations requiring a permit for and otherwise...

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

Phenotype-gene: 494 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available 494 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u3ria224u1491i inpaired stomatal movement... http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u12773379i inpaired stomatal movement in presence

Modeling daily gas exchange of a Douglas-fir forest : comparison of three stomatal conductance models with and without a soil water stress function

NARCIS (Netherlands)

Wijk, van M.T.; Dekker, S.C.; Bouten, W.; Bosveld, F.C.; Kohsiek, W.; Kramer, K.; Mohren, G.M.J.

2000-01-01

Modeling stomatal conductance is a key element in predicting tree growth and water use at the stand scale. We compared three commonly used models of stomatal conductance, the Jarvis-Loustau, Ball-Berry and Leuning models, for their suitability for incorporating soil water stress into their

Photosynthesis down-regulation precedes carbohydrate accumulation under sink limitation in Citrus.

Science.gov (United States)

Nebauer, Sergio G; Renau-Morata, Begoña; Guardiola, José Luis; Molina, Rosa-Victoria

2011-02-01

Photosynthesis down-regulation due to an imbalance between sources and sinks in Citrus leaves could be mediated by excessive accumulation of carbohydrates. However, there is limited understanding of the physiological role of soluble and insoluble carbohydrates in photosynthesis regulation and the elements triggering the down-regulation process. In this work, the role of non-structural carbohydrates in the regulation of photosynthesis under a broad spectrum of source-sink relationships has been investigated in the Salustiana sweet orange. Soluble sugar and starch accumulation in leaves, induced by girdling experiments, did not induce down-regulation of the photosynthetic rate in the presence of sinks (fruits). The leaf-to-fruit ratio did not modulate photosynthesis but allocation of photoassimilates to the fruits. The lack of strong sink activity led to a decrease in the photosynthetic rate and starch accumulation in leaves. However, photosynthesis down-regulation due to an excess of total soluble sugars or starch was discarded because photosynthesis and stomatal conductance reduction occurred prior to any significant accumulation of these carbohydrates. Gas exchange and fluorescence parameters suggested biochemical limitations to photosynthesis. In addition, the expression of carbon metabolism-related genes was altered within 24 h when strong sinks were removed. Sucrose synthesis and export genes were inhibited, whereas the expression of ADP-glucose pyrophosphorylase was increased to cope with the excess of assimilates. In conclusion, changes in starch and soluble sugar turnover, but not sugar content per se, could provide the signal for photosynthesis regulation. In these conditions, non-stomatal limitations strongly inhibited the photosynthetic rate prior to any significant increase in carbohydrate levels.

Global CO2 rise leads to reduced maximum stomatal conductance in Florida vegetation

NARCIS (Netherlands)

Lammertsma, E.I.; de Boer, H.J.; Dekker, S.C.; Dilcher, D.L.; Lotter, A.F.; Wagner-Cremer, F.

2011-01-01

A principle response of C3 plants to increasing concentrations of atmospheric CO2 (CO2) is to reduce transpirational water loss by decreasing stomatal conductance (gs) and simultaneously increase assimilation rates. Via this adaptation, vegetation has the ability to alter hydrology and climate.

Species climate range influences hydraulic and stomatal traits in Eucalyptus species.

Science.gov (United States)

Bourne, Aimee E; Creek, Danielle; Peters, Jennifer M R; Ellsworth, David S; Choat, Brendan

2017-07-01

Plant hydraulic traits influence the capacity of species to grow and survive in water-limited environments, but their comparative study at a common site has been limited. The primary aim of this study was to determine whether selective pressures on species originating in drought-prone environments constrain hydraulic traits among related species grown under common conditions. Leaf tissue water relations, xylem anatomy, stomatal behaviour and vulnerability to drought-induced embolism were measured on six Eucalyptus species growing in a common garden to determine whether these traits were related to current species climate range and to understand linkages between the traits. Hydraulically weighted xylem vessel diameter, leaf turgor loss point, the water potential at stomatal closure and vulnerability to drought-induced embolism were significantly ( P Eucalyptus trees has important implications for the limits of species responses to changing environmental conditions and thus for species survival and distribution into the future, and yields new information for physiological models. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Diurnal regulation of photosynthesis in Jatropha curcas under drought during summer in a semi-arid region

International Nuclear Information System (INIS)

Tominaga, Jun; Inafuku, Sayuri; Coetzee, Tidimalo; Kawamitsu, Yoshinobu

2014-01-01

The diurnal photosynthetic responses to drought in Jatropha curcas have not been well assessed under field conditions in harsh semi-arid habitats. To illustrate this, diurnal changes in chlorophyll fluorescence and gas exchange rates were measured in field-grown Jatropha with or without a short (13 days) water recovery treatment under drought conditions during hot summer in a semi-arid. Sensitive stomatal closure coordinated with a drying atmosphere strictly limited a net CO 2 assimilation rate with a predominant morning peak, eventually turning negative during the day. Even though the risk of excess excitation energy which potentially causes photodamage increased with the extremely low capacity for CO 2 fixation, Jatropha preserved the integrity of PSII. Quantitative analysis of quenching partitioning revealed that regulated thermal energy dissipation accounted a large fraction of both instantaneous and daily absorbed energy by up to 80 and 72%, respectively, under the drought condition. Water recovery treatment more than doubled daily CO 2 uptake via mitigating diurnal stomatal closure. The regulated thermal dissipation flexibly adjusted PSII quantum efficiency to capacity of CO 2 fixation. In addition, downregulation of PSII quantum efficiency via sustained regulated thermal dissipation was observed and thought to be an additional photoprotective function. It is clear that Jatropha strongly rely upon the regulated thermal dissipation under drought condition, which must be critically important for this strict water conserving species, especially under a climate with high solar radiation loads as is seen in semi-arid regions. - Highlights: • Diurnal gas exchange and the fate of absorbed energy were assessed in Jatropha. • The dynamic stomatal closure was the predominant restriction under water stress. • The PSII integrity was preserved even under severe water stress. • The regulated thermal dissipation accounted by up to 72% of daily absorbed energy. �

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

Simulation of stomatal conductance for Aleppo pine to estimate its ozone uptake

Energy Technology Data Exchange (ETDEWEB)

Elvira, Susana [Ecotoxicology of Air Pollution, CIEMAT, Avda. Complutense 22 (ed. 70), 28040 Madrid (Spain); Alonso, Rocio [Ecotoxicology of Air Pollution, CIEMAT, Avda. Complutense 22 (ed. 70), 28040 Madrid (Spain); Gimeno, Benjamin S. [Ecotoxicology of Air Pollution, CIEMAT, Avda. Complutense 22 (ed. 70), 28040 Madrid (Spain)]. E-mail: benjamin.gimeno@ciemat.es

2007-04-15

The data from a previous experiment carried out in open-top chambers to assess the effects of ozone (O{sub 3}) exposure on growth and physiology of Aleppo pine (Pinus halepensis Mill.) were re-assessed to test the performance of the EMEP O{sub 3} stomatal conductance model used to estimate tree O{sub 3} uptake at a European scale. Aleppo pine seedlings were exposed during three consecutive years to three different O{sub 3} treatments: charcoal filtered air, non-filtered air and non-filtered air supplemented with 40 nl l{sup -1}. The results of the model using the default parameterisation already published for Mediterranean conifers showed a poor performance when compared to measured data. Therefore, modifications of g {sub max}, f {sub min}, and new f {sub VPD}, f {sub temp} and f {sub phen} functions were developed according to the observed data. This re-parameterisation resulted in a significant improvement of the performance of the model when compared to its original version. - Current EMEP stomatal uptake module needs to be re-parameterised for Mediterranean tree species.

Simulation of stomatal conductance for Aleppo pine to estimate its ozone uptake

International Nuclear Information System (INIS)

Elvira, Susana; Alonso, Rocio; Gimeno, Benjamin S.

2007-01-01

The data from a previous experiment carried out in open-top chambers to assess the effects of ozone (O 3 ) exposure on growth and physiology of Aleppo pine (Pinus halepensis Mill.) were re-assessed to test the performance of the EMEP O 3 stomatal conductance model used to estimate tree O 3 uptake at a European scale. Aleppo pine seedlings were exposed during three consecutive years to three different O 3 treatments: charcoal filtered air, non-filtered air and non-filtered air supplemented with 40 nl l -1 . The results of the model using the default parameterisation already published for Mediterranean conifers showed a poor performance when compared to measured data. Therefore, modifications of g max , f min , and new f VPD , f temp and f phen functions were developed according to the observed data. This re-parameterisation resulted in a significant improvement of the performance of the model when compared to its original version. - Current EMEP stomatal uptake module needs to be re-parameterised for Mediterranean tree species

Stomatal vs. genome size in angiosperms: the somatic tail wagging the genomic dog?

NARCIS (Netherlands)

Hodgson, J.G.; Sharafi, M.; Jalili, A.; Diaz, S.; Montserrat-Marti, G.; Palmer, C.; Cerabolini, B.; Pierce, S.; Hamzehee, B.; Asri, Y.; Jamzad, Z.; Wilson, P.; Zarrinkamar, F.; Raven, J.; Band, S.R.; Basconcelo, S.; Bogard, A.; Carter, G.; Charles, M.; Castro-Diez, P.; Cornelissen, J.H.C.; Funes, G.; Jones, M.; Khoshnevis, M.; Perez-Harguindeguy, N.; Perez-Rontome, M.C.; Shirvany, F.A.; Vendramini, F.; Yazdani, S.; Abbas-Azimi, R.; Boustani, S.; Dehghan, M.; Hynd, F.A.; Kowsary, E.; Kazemi-Saeed, F.; Siavash, B.; Villar-Salvador, P.; Cragie, R.; Naqinezhad, A.; Romo-Diez, A.; De Torres Espuny, L.; Simmons, E.

2010-01-01

Background and Aims 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

A new mechanism for the regulation of stomatal aperture size in intact leaves: accumulation of mesophyll-derived sucrose in the guard-cell wall of Vicia faba

International Nuclear Information System (INIS)

Lu, P.; Outlaw, W.H. Jr.; Smith, B.G.; Freed, G.A.

1997-01-01

At various times after pulse-labeling broad bean (Vicia faba L.) leaflets with 14CO2, whole-leaf pieces and rinsed epidermal peels were harvested and subsequently processed for histochemical analysis. Cells dissected from whole leaf retained apoplastic contents, whereas those from rinsed peels contained only symplastic contents. Sucrose (Suc)-specific radioactivity peaked (111 GBq mol-1) in palisade cells at 20 min. In contrast, the 14C content and Suc-specific radioactivity were very low in guard cells for 20 min, implying little CO2 incorporation; both then peaked at 40 min. The guard-cell apoplast had a high maximum Suc-specific radioactivity (204 GBq mol-1) and a high Suc influx rate (0.05 pmol stoma-1 min-1). These and other comparisons implied the presence of (a) multiple Suc pools in mesophyll cells, (b) a localized mesophyll-apoplast region that exchanges with phloem and stomata, and (c) mesophyll-derived Suc in guard-cell walls sufficient to diminish stomatal opening by approximately 3 micrometers. Factors expected to enhance Suc accumulation in guard-cell walls are (a) high transpiration rate, which closes stomata, and (b) high apoplastic Suc concentration, which is elevated when mesophyll Suc efflux exceeds translocation. Therefore, multiple physiological factors are integrated in the attenuation of stomatal aperture size by this previously unrecognized mechanism

Compromised Photosynthetic Electron Flow And H2O2 Generation Correlate with Genotype-Specific Stomatal Dysfunctions During Resistance Against Powdery Mildew In Oats.

Directory of Open Access Journals (Sweden)

Javier Sánchez-Martín

2016-11-01

Full Text Available Stomatal dysfunction known as locking has been linked to the elicitation of a hypersensitive response (HR following attack of fungal pathogens in cereals. We here assess how spatial and temporal patterns of different resistance mechanisms, such as HR and penetration resistance influence stomatal and photosynthetic parameters in oat (Avena sativa and the possible involvement of hydrogen peroxide (H2O2 in the dysfunctions observed. Four oat cultivars with differential resistance responses (i.e. penetration resistance, early and late HR to powdery mildew (Blumeria graminis f. sp. avenae, Bga were used. Results demonstrated that stomatal dysfunctions were genotype but not response-type dependent since genotypes with similar resistance responses when assessed histologically showed very different locking patterns. Maximum quantum yield (Fv/Fm of photosystem II were compromised in most Bga–oat interactions and photoinhibition increased. However, the extent of the photosynthetic alterations was not directly related to the extent of HR. H2O2 generation is triggered during the execution of resistance responses and can influence stomatal function. Artificially increasing H2O2 by exposing plants to increased light intensity further reduced Fv/Fm ratios and augmented the patterns of stomatal dysfunctions previously observed. The latter results suggest that the observed dysfunctions and hence a cost of resistance may be linked with oxidative stress occurring during defence induced photosynthetic disruption.

Plasticity in stomatal size and density of potato leaves under different irrigation and phosphorus regimes.

Science.gov (United States)

Sun, Yanqi; Yan, Fei; Cui, Xiaoyong; Liu, Fulai

2014-09-01

The morphological features of stomata including their size and density could be modulated by environmental cues; however, the underlying mechanisms remain largely elusive. Here, the effect of different irrigation and phosphorus (P) regimes on stomatal size (SS) and stomatal density (SD) of potato leaves was investigated. The plants were grown in split-root pots under two P fertilization rates (viz., 0 and 100mgkg(-1) soil, denoted as P0 and P1, respectively) and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation regimes. Results showed that SS and SD were unresponsive to P but significantly affected by the irrigation treatment. FI plants had the largest SS, followed by DI, and PRD the smallest; and the reverse was the case for SD. Compared to FI and DI, PRD plants had significantly lower values of specific leaf area (SLA) and leaf carbon isotope discrimination (Δ(13)C) under P0. Midday leaf water potential (Ψleaf) and stomatal conductance (gs) was similar for DI and PRD, which was significantly lower than that of FI. Leaf contents of C, N, K, Ca and Mg were higher in PRD than in DI plants, particularly under P0. When analyzed across the three irrigation regimes, it was found that the P1 plants had significantly higher leaf contents of P and Mg, but significantly lower leaf K content compared to the P0 plants. Linear correlation analyses revealed that SS was positively correlated with Ψleaf and Δ(13)C; whereas SD was negatively correlated with Ψleaf, Δ(13)C and SLA, and positively correlated with leaf C, N and Ca contents. And gs was positively correlated with SS but negatively correlated with SD. Collectively, under low P level, the smaller and denser stomata in PRD plants may bring about a more efficient stomatal control over gas exchange, hereby potentially enhance water-use efficiency as exemplified by the lowered leaf Δ(13)C under fluctuating soil moisture conditions. Copyright © 2014 Elsevier GmbH. All rights reserved.

Antimicrobial photodynamic therapy for infectious stomatitis in snakes: Clinical views and microbiological findings.

Science.gov (United States)

Grego, Kathleen Fernandes; Carvalho, Marcelo Pires Nogueira de; Cunha, Marcos Paulo Vieira; Knöbl, Terezinha; Pogliani, Fabio Celidonio; Catão-Dias, José Luiz; Sant'Anna, Sávio Stefanini; Ribeiro, Martha Simões; Sellera, Fábio Parra

2017-12-01

Antimicrobial photodynamic therapy (APDT) has been broadly investigated as an alternative to treat localized infections, without leading to the selection of resistant microorganisms. Infectious stomatitis is a multifactorial disease frequently reported in captive snakes characterized by infection of the oral mucosa and surrounding tissues. In this study, we investigated methylene blue (MB)-mediated APDT to treat infectious stomatitis in snakes and verified the resistance phenotype and genotype before and after APDT. Three Boid snakes presented petechiae, edema and caseous material in their oral cavities. MB (0.01%) was applied on the lesions and after 5min they were irradiated using a red laser (λ=660nm), fluence of 280J/cm 2 , 8J and 80s per point, 100mW, spot size 0.028cm 2 and fluence rate of 3.5W/cm 2 . APDT was repeated once a week during 3 months. Samples of the lesions were collected to identify bacteria and antibiotic resistance profiles. To analyze the clonality of bacterial isolates before and after APDT, isolates were subjected to ERIC PCR analysis. Snakes presented clinical improvement such as reduction of inflammatory signs and caseous material. Pseudomonas aeruginosa and Escherichia coli were present in all snakes; Klebsiella pneumoniae and Morganella morganii were also identified in some animals. We also observed that the oral microbiota was completely replaced following APDT. However, K. pneumoniae isolates before and after APDT were a single clone with 100% of genetic similarity that lost resistance phenotype for seven antibiotics of four classes. These results show that APDT can be used to treat infectious stomatitis in snakes. Copyright © 2017 Elsevier B.V. All rights reserved.

Utilization of Dexaltin ointment to radiation stomatitis in patients with cancer of the oral cavity

International Nuclear Information System (INIS)

Ohhashi, Yasushi; Abe, Masaki; Ueda, Noboru

1981-01-01

Dexaltin ointment (sodium polyactylic acid, containing 0.1% dexamethasone) was used to the patients with stomatitis induced by radiotherapy. Fifteen patients with cancer of the oral cavity, aged from 44 to 77, were exposed to 60 Co γ-rays or electron beams, with the irradiation dose of 2400 to 9000 rad. About 60 g of the ointment was pasted for mean period of 6.6 weeks after meals, before sleep, and whenever the patients wanted. Therapeutic effect was observed in every case and in 87% of the case the pain at meals was decreased. The ointment adhered mostly for 1 - 2 hrs and in some cases, more than 3 hrs. No adverse reaction was observed. Therefore it was suggested that Dexaltin was a promising ointment to the radiation stomatitis. (Nakanishi, T.)

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

Czech Academy of Sciences Publication Activity Database

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

2013-01-01

Roč. 67, MAR (2013), s. 242-251 ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : Ozone fluxes * Stomatal conductance models * GPP * Mediterranean forest Subject RIV: EH - Ecology, Behaviour Impact factor: 3.062, year: 2013

78 FR 8987 - Interstate Movement of Sharwil Avocados From Hawaii

Science.gov (United States)

2013-02-07

.... APHIS-2012-0008] RIN 0579-AD70 Interstate Movement of Sharwil Avocados From Hawaii AGENCY: Animal and... Hawaii quarantine regulations to allow the interstate movement of untreated Sharwil avocados from Hawaii into the continental United States. As a condition of movement, Sharwil avocados from Hawaii would have...

48 CFR 247.370 - DD Form 1384, Transportation Control and Movement Document.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false DD Form 1384, Transportation Control and Movement Document. 247.370 Section 247.370 Federal Acquisition Regulations System... Transportation in Supply Contracts 247.370 DD Form 1384, Transportation Control and Movement Document. The...

Self-Active Relaxation Therapy (SART) and Self-Regulation: A Comprehensive Review and Comparison of the Japanese Body Movement Approach

Science.gov (United States)

Kabir, Russell S.; Haramaki, Yutaka; Ki, Hyeyoung; Ohno, Hiroyuki

2018-01-01

Relaxation programs are known for their versatility, cost-effectiveness, and ability to help people obtain skills to regulate their mental states and promote and maintain health. Self-Active Relaxation Therapy (SART) is a body-oriented approach to psychological rehabilitation that grew out of the suite of movement tasks developed in the Japanese psychotherapy known as Dohsa-hou, or the body movement method. The program for SART is designed to stretch, twist, and release areas of the upper, lower, and whole body through a set of movements which are guided by the practitioner and performed “self-actively” by the client to empower them to learn to recognize points of tension in the body and act on their own to achieve a relaxed state. Numerous studies have showed that SART is associated with reduced negative mood states and enhanced body awareness. A short version of SART has been investigated as a psychological support salon activity for the elderly, mothers raising children, special needs students, and children adapting to school. The full program has also been applied in clinical settings to address or supplement treatments for psychological and developmental conditions, and longitudinally employed in community contexts to assist residents facing long-term disaster recovery circumstances in Japan. This paper reviews the research and applications of SART as a bodymind approach by critically examining evidence and research gaps for future studies, comparing it with techniques established in the literature, and positing a self-regulatory framework for SART as a tool to become aware of bodily states, regulate mood, and manage stress through the deliberate practice of relaxation. PMID:29472851

Leaf temperature and stomatal influences on sap velocity diurnal hysteresis in the Amazon rainforest

Science.gov (United States)

Jardine, K.; Gimenez, B.; Negron Juarez, R. I.; Koven, C.; Powell, T.; Higuchi, N.; Chambers, J.; Varadharajan, C.

2016-12-01

In order to improve our ability to predict terrestrial evapotranspiration fluxes, an understanding of the interactions between plant physiology and environmental conditions is necessary, but remains poorly characterized, especially in tropical ecosystems. In this study we show a tight positive correlation between sap velocity (at 1 m of height) and leaf surface temperature (LST, 20-30 m of height) in canopy dominant trees in two primary rainforest sites in the Amazon basin (Santarém and Manaus, Brazil). As leaf temperatures varied throughout the day, sap velocity responded with little delay (<15 min). Positive sap velocity was often observed at night, but also closely followed night time LSTs. When plotted versus LST, sap velocity showed an exponential increase before reaching a reflection point and a plateau and is characterized as a sigmoidal curve, in all observed trees. Moreover, a clear diurnal hysteresis in sap velocity was evident with morning periods showing higher temperature sensitivities than afternoon and night periods. Diurnal leaf observations showed a morning peak in stomatal conductance ( 10:00-10:30), but a mid-day to afternoon peak in transpiration and leaf temperature (12:00-14:00). Our observations suggest the sap velocity-LST hysteresis pattern arises due to the temporal offset between stomatal conductance and vapor pressure deficits (VPD) and demonstrates the dominating effect of VPD over stomatal conductance in maintaining high transpiration/sap flow rates under elevated temperatures. Our results have important implications for modeling tropical forest transpiration and suggests the possibility of predicting evapotranspiration fluxes at the ecosystem to regional scales based on remote sensed vegetation temperature.

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...

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.

Serum cytokine profile and clinicopathological findings in oral lichen planus, oral lichenoid lesions and stomatitis

Science.gov (United States)

Johansen, Jeanne Duus; Reibel, Jesper; Zachariae, Claus; Pedersen, Anne Marie Lynge

2017-01-01

Abstract The objective of this study was to examine if clinical and histopathological variables in patients with oral lichen planus (OLP), oral lichenoid lesions (OLL), and generalized stomatitis display different cytokine profiles and if concomitant contact allergy influences this profile. Forty‐nine patients and 29 healthy age‐ and gender‐matched subjects were included. Demographic and clinical data immunohistochemical findings in mucosal specimens, results of contact allergy testing, and serum levels of tumor necrosis factor‐α, interferon‐γ, interleukin (IL)‐6, IL‐10, IL‐12p40, and IL‐12p70 were analyzed and compared between groups. Nineteen patients had OLP, primarily with ulcerative lesions on the buccal mucosa, 19 patients had OLL, and 11 patients had generalized stomatitis. All patients had oral symptoms, mainly stinging and burning. Nineteen patients and 10 healthy subjects had contact allergies, primarily to fragrance ingredients. Patient groups did not differ with regard to oral symptoms, clinical pattern of the lesions, or contact allergy. Serum cytokine levels did not differ between the different patient groups and were not related to histopathological findings. The patients had higher levels of IL‐6 than the healthy subjects. Interferon‐γ, IL‐12p40, and IL‐12p70 were below detection limit. Our findings indicate that OLP, OLL, and generalized stomatitis cannot be discriminated by means of the selected serum cytokines, and that the presence of concomitant contact allergy does not influence the cytokine expression. PMID:29744205

Detecting the differences in responses of stomatal conductance to moisture stresses between deciduous shrubs and Artemisia subshrubs.

Science.gov (United States)

Gao, Qiong; Yu, Mei; Zhou, Chan

2013-01-01

Shrubs and subshrubs can tolerate wider ranges of moisture stresses in both soil and air than other plant life forms, and thus represent greater nonlinearity and uncertainty in ecosystem physiology. The objectives of this paper are to model shrub/subshrub stomatal conductance by synthesizing the field leaf gas exchanges data of 24 species in China, in order to detect the differences between deciduous shrubs and Artemisia subshrubs in their responses of stomatal conductance to changes in the moisture stresses. We revised a model of stomatal conductance by incorporating the tradeoff between xylem hydraulic efficiency and cavitation loss risk. We then fit the model at the three hierarchical levels: global (pooling all data as a single group), three functional groups (deciduous non-legume shrubs, deciduous legume shrubs, and subshrubs in Artemisia genus), and individual observations (species × sites). Bayesian inference with Markov Chain Monte Carlo method was applied to obtain the model parameters at the three levels. We found that the model at the level of functional groups is a significant improvement over that at the global level, indicating the significant differences in the stomatal behavior among the three functional groups. The differences in tolerance and sensitivities to changes in moisture stresses are the most evident between the shrubs and the subshrubs: The two shrub groups can tolerate much higher soil water stress than the subshrubs. The analysis at the observation level is also a significant improvement over that at the functional group level, indicating great variations within each group. Our analysis offered a clue for the equivocal issue of shrub encroachment into grasslands: While the invasion by the shrubs may be irreversible, the dominance of subshrubs, due to their lower resistance and tolerance to moisture stresses, may be put down by appropriate grassland management.

7 CFR 330.212 - Movement of plant pests by baggage.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of plant pests by baggage. 330.212 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.212 Movement of plant pests by baggage...

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

International Nuclear Information System (INIS)

Braun, Sabine; Schindler, Christian; Leuzinger, Sebastian

2010-01-01

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 DO 3 SE model. - A method was developed to derive stomatal functions and ozone uptake calculation from sap flow.

Maximum leaf conductance driven by CO2 effects on stomatal size and density over geologic time.

Science.gov (United States)

Franks, Peter J; Beerling, David J

2009-06-23

Stomatal pores are microscopic structures on the epidermis of leaves formed by 2 specialized guard cells that control the exchange of water vapor and CO(2) between plants and the atmosphere. Stomatal size (S) and density (D) determine maximum leaf diffusive (stomatal) conductance of CO(2) (g(c(max))) to sites of assimilation. Although large variations in D observed in the fossil record have been correlated with atmospheric CO(2), the crucial significance of similarly large variations in S has been overlooked. Here, we use physical diffusion theory to explain why large changes in S necessarily accompanied the changes in D and atmospheric CO(2) over the last 400 million years. In particular, we show that high densities of small stomata are the only way to attain the highest g(cmax) values required to counter CO(2)"starvation" at low atmospheric CO(2) concentrations. This explains cycles of increasing D and decreasing S evident in the fossil history of stomata under the CO(2) impoverished atmospheres of the Permo-Carboniferous and Cenozoic glaciations. The pattern was reversed under rising atmospheric CO(2) regimes. Selection for small S was crucial for attaining high g(cmax) under falling atmospheric CO(2) and, therefore, may represent a mechanism linking CO(2) and the increasing gas-exchange capacity of land plants over geologic time.

5 CFR 362.206 - Movement between departments or agencies.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Movement between departments or agencies. 362.206 Section 362.206 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PRESIDENTIAL MANAGEMENT FELLOWS PROGRAM Program Administration § 362.206 Movement between...

Cytosolic nucleotides block and regulate the Arabidopsis vacuolar anion channel AtALMT9.

Science.gov (United States)

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-09-12

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al(3+) to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Cytosolic Nucleotides Block and Regulate the Arabidopsis Vacuolar Anion Channel AtALMT9*

Science.gov (United States)

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-01-01

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al3+ to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. PMID:25028514

Brief oral cryotherapy for the prevention of high-dose melphalan-induced stomatitis in allogeneic hematopoietic stem cell transplant recipients.

Science.gov (United States)

Mori, Takehiko; Yamazaki, Rie; Aisa, Yoshinobu; Nakazato, Tomonori; Kudo, Masumi; Yashima, Tomoko; Kondo, Sakiko; Ikeda, Yasuo; Okamoto, Shinichiro

2006-04-01

We previously reported the efficacy of oral cryotherapy for the prevention of high-dose melphalan-induced stomatitis. The purpose of this study was to evaluate whether the further shortening of the duration of oral cryotherapy could minimize its side effects while sparing its efficacy. Seventeen consecutive recipients of allogeneic hematopoieic stem cell transplant conditioned with high-dose melphalan in combination with fludarabine alone or with fludarabine and additional radiation were enrolled in the study. The severity of stomatitis was graded according to the National Cancer Institute-Common Toxicity Criteria. Patients were kept on oral cryotherapy shortly before, during, and for additional 30 min after the completion of melphalan administration (60-min oral cryotherapy). Patients who were also enrolled in our previous study received the same type of oral cryotherapy but for additional 90 min after the completion of melphalan administration (120-min oral cryotherapy), and they served as controls. Only 2 (11.8%) of 17 patients receiving 60-min oral cryotherapy and 2 (11.1%) of 18 patients receiving 120-min oral cryotherapy developed grade 2 or 3 stomatitis, respectively. The difference between groups was not statistically significant (P = 0.677). The incidence of unpleasant symptoms such as chills and nausea during oral cryotherapy decreased significantly with 60-min oral cryotherapy, as compared with that associated with 120-min oral cryotherapy (P cryotherapy is as effective as 120-min oral cryotherapy at preventing high-dose melphalan-induced stomatitis, and shorter treatment might have contributed to relieve patient discomfort during oral cryotherapy.

Quantitative Estimation of Yeast on Maxillary Denture in Patients with Denture Stomatitis and the Effect of Chlorhexidine Gluconate in Reduction of Yeast

Directory of Open Access Journals (Sweden)

Jaykumar R Gade

2011-01-01

Full Text Available Denture stomatitis is a condition associated with wearing of a denture. The predisposing factor leading to denture stomatitis could be poor oral hygiene, ill-fitting denture and relief areas. Around 30 patients with denture stomatitis were advised to rinse with chlorhexidine gluconate mouthwash for 14 days and were directed to immerse the upper denture in the chlorhexidine solution for 8 hours. The samples were collected by scraping maxillary denture in saline at three intervals, prior to, at the end of 24 hours and after 14 days of treatment, then were inoculated and quantitative estimation of the yeast growth on Sabouraud′s dextrose agar plate was done. It was observed that after a period of 14 days, there was a reduction in the growth of yeast and also improvement in the clinical picture of the oral mucosa

From social movement to food industry

DEFF Research Database (Denmark)

Kristensen, Niels Heine; Nielsen, Thorkild

1998-01-01

The paper report the organic movements impact on international institutions (EU, USDA, WTO and Codex Alimentarius). It focuses on the Danish experiences with 10 years of regulation on the organic sector...

From social movement to food industry

DEFF Research Database (Denmark)

Kristensen, Niels Heine; Nielsen, Thorkild

1998-01-01

The paper report the organic movements impact on international institutions (EU, USDA, WTO and Codex Alimentarius). It focuses on the Danish experiences with 10 years of regulation on the organic sector....

Recurrent aphthous stomatitis (RAS and exfoliative cheilitis in elderly psoriasis sufferer

Directory of Open Access Journals (Sweden)

Siti Hardiyanti Nurhasanah

2016-04-01

Full Text Available Recurrent Aphthous Stomatitis (RAS is a disorder in the oral cavity, with a characterized symptom as ulceration, recurrent and very painfull. The etiology is idiopathic, with multifactorial predisposition. Exfoliative cheilitis is a persistent lesion on the lip, with a characterized cracking and desquamative, with crustae and inflammation. An elderly male (72 yrs suffered with ulcer on his oral cavity, cracking lips and pain on both of his cheeks, skin, since 5 years ago. The pain is recurrent. On the clinical examination, there were some desquamation, both on the skin and vermilion border, whether on the inner lips (labial fold mucosa, there were ulcers with diameter about 1 cm. The laboratory test was within normal limits, except the LED was 40 mm/hour (n:<15. The diagnosis was Recurrent Aphthous Stomatitis (RAS for the ulcer and Exfoliative cheilitis for the cracking lips. The treatment he received was a gargle liquid, topical corticosteroid and supplement. The skin’s disorder was revered to the skin and genital disease department, for further management. As a dental general practioner, had to be very careful and familiar for every changes that may be occur both in the outer or inner oral cavity. Other disorder that need refferal, had to be done with team work, to the colleague from the right connection.

An equilibrium-point model for fast, single-joint movement: I. Emergence of strategy-dependent EMG patterns.

Science.gov (United States)

Latash, M L; Gottlieb, G L

1991-09-01

We describe a model for the regulation of fast, single-joint movements, based on the equilibrium-point hypothesis. Limb movement follows constant rate shifts of independently regulated neuromuscular variables. The independently regulated variables are tentatively identified as thresholds of a length sensitive reflex for each of the participating muscles. We use the model to predict EMG patterns associated with changes in the conditions of movement execution, specifically, changes in movement times, velocities, amplitudes, and moments of limb inertia. The approach provides a theoretical neural framework for the dual-strategy hypothesis, which considers certain movements to be results of one of two basic, speed-sensitive or speed-insensitive strategies. This model is advanced as an alternative to pattern-imposing models based on explicit regulation of timing and amplitudes of signals that are explicitly manifest in the EMG patterns.

Sleep and behavior during vesicular stomatitis virus induced encephalitis in BALB/cJ and C57BL/6J mice

Science.gov (United States)

Machida, Mayumi; Ambrozewicz, Marta A.; Breving, Kimberly; Wellman, Laurie L.; Yang, Linghui; Ciavarra, Richard P.; Sanford, Larry D.

2013-01-01

Intranasal application of vesicular stomatitis virus (VSV) produces a well-characterized model of viral encephalitis in mice. Within one day post-infection (PI), VSV travels to the olfactory bulb and, over the course of 7 days, it infects regions and tracts extending into the brainstem followed by clearance and recovery in most mice by PI day 14 (PI 14). Infectious diseases are commonly accompanied by excessive sleepiness; thus, sleep is considered a component of the acute phase response to infection. In this project, we studied the relationship between sleep and VSV infection using C57BL/6 (B6) and BALB/c mice. Mice were implanted with transmitters for recording EEG, activity and temperature by telemetry. After uninterrupted baseline recordings were collected for 2 days, each animal was infected intranasally with a single low dose of VSV (5 × 104 PFU). Sleep was recorded for 15 consecutive days and analyzed on PI 0, 1, 3, 5, 7, 10, and 14. Compared to baseline, amounts of non-rapid eye movement sleep (NREM) were increased in B6 mice during the dark period of PI 1–5, whereas rapid eye movement sleep (REM) was significantly reduced during the light periods of PI 0–14. In contrast, BALB/c mice showed significantly fewer changes in NREM and REM. These data demonstrate sleep architecture is differentially altered in these mouse strains and suggests that, in B6 mice, VSV can alter sleep before virus progresses into brain regions that control sleep. PMID:24055862

78 FR 34635 - Notice of Request for Extension of Approval of an Information Collection; Interstate Movement of...

Science.gov (United States)

2013-06-10

... Collection; Interstate Movement of Certain Land Tortoises AGENCY: Animal and Plant Health Inspection Service... with regulations for the interstate movement of certain land tortoises. DATES: We will consider all... regulations for the interstate movement of certain land tortoises, contact Dr. Christa Speekmann, Import...

Stomatal Closure and SA-, JA/ET-Signaling Pathways Are Essential for Bacillus amyloliquefaciens FZB42 to Restrict Leaf Disease Caused by Phytophthora nicotianae in Nicotiana benthamiana

Directory of Open Access Journals (Sweden)

Liming Wu

2018-04-01

Full Text Available Bacillus amyloliquefaciens FZB42 is a plant growth-promoting rhizobacterium that induces resistance to a broad spectrum of pathogens. This study analyzed the mechanism by which FZB42 restricts leaf disease caused by Phytophthora nicotianae in Nicotiana benthamiana. The oomycete foliar pathogen P. nicotianae is able to reopen stomata which had been closed by the plant innate immune response to initiate penetration and infection. Here, we showed that root colonization by B. amyloliquefaciens FZB42 restricted pathogen-mediated stomatal reopening in N. benthamiana. Abscisic acid (ABA and salicylic acid (SA-regulated pathways mediated FZB42-induced stomatal closure after pathogen infection. Moreover, the defense-related genes PR-1a, LOX, and ERF1, involved in the SA and jasmonic acid (JA/ethylene (ET signaling pathways, respectively, were overexpressed, and levels of the hormones SA, JA, and ET increased in the leaves of B. amyloliquefaciens FZB42-treated wild type plants. Disruption of one of these three pathways in N. benthamiana plants increased susceptibility to the pathogen. These suggest that SA- and JA/ET-dependent signaling pathways were important in plant defenses against the pathogen. Our data thus explain a biocontrol mechanism of soil rhizobacteria in a plant.

Vesicular Stomatitis Virus Infection Promotes Immune Evasion by Preventing NKG2D-Ligand Surface Expression

DEFF Research Database (Denmark)

Jensen, Helle; Andresen, Lars; Nielsen, Jens

2011-01-01

Vesicular stomatitis virus (VSV) has recently gained attention for its oncolytic ability in cancer treatment. Initially, we hypothesized that VSV infection could increase immune recognition of cancer cells through induction of the immune stimulatory NKG2D-ligands. Here we show that VSV infection ...

Lack of photosynthetic or stomatal regulation after 9 years of elevated [CO2] and 4 years of soil warming in two conifer species at the alpine treeline.

Science.gov (United States)

Streit, Kathrin; Siegwolf, Rolf T W; Hagedorn, Frank; Schaub, Marcus; Buchmann, Nina

2014-02-01

Alpine treelines are temperature-limited vegetation boundaries. Understanding the effects of elevated [CO2 ] and warming on CO2 and H2 O gas exchange may help predict responses of treelines to global change. We measured needle gas exchange of Larix decidua Mill. and Pinus mugo ssp. uncinata DC trees after 9 years of free air CO2 enrichment (575 µmol mol(-1) ) and 4 years of soil warming (+4 °C) and analysed δ(13) C and δ(18) O values of needles and tree rings. Tree needles under elevated [CO2 ] showed neither nitrogen limitation nor end-product inhibition, and no down-regulation of maximal photosynthetic rate (Amax ) was found. Both tree species showed increased net photosynthetic rates (An ) under elevated [CO2 ] (L. decidua: +39%; P. mugo: +35%). Stomatal conductance (gH2O ) was insensitive to changes in [CO2 ], thus transpiration rates remained unchanged and intrinsic water-use efficiency (iWUE) increased due to higher An . Soil warming affected neither An nor gH2O . Unresponsiveness of gH2O to [CO2 ] and warming was confirmed by δ(18) O needle and tree ring values. Consequently, under sufficient water supply, elevated [CO2 ] induced sustained enhancement in An and lead to increased C inputs into this ecosystem, while soil warming hardly affected gas exchange of L. decidua and P. mugo at the alpine treeline. © 2013 John Wiley & Sons Ltd.

49 CFR 177.823 - Movement of motor vehicles in emergency situations.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Movement of motor vehicles in emergency situations... CARRIAGE BY PUBLIC HIGHWAY General Information and Regulations § 177.823 Movement of motor vehicles in... government; (2) The carrier has permission from the Department; or (3) Movement of the transport vehicle is...

Deliberate ROS production and auxin synergistically trigger the asymmetrical division generating the subsidiary cells in Zea mays stomatal complexes.

Science.gov (United States)

Livanos, Pantelis; Galatis, Basil; Apostolakos, Panagiotis

2016-07-01

Subsidiary cell generation in Poaceae is an outstanding example of local intercellular stimulation. An inductive stimulus emanates from the guard cell mother cells (GMCs) towards their laterally adjacent subsidiary cell mother cells (SMCs) and triggers the asymmetrical division of the latter. Indole-3-acetic acid (IAA) immunolocalization in Zea mays protoderm confirmed that the GMCs function as local sources of auxin and revealed that auxin is polarly accumulated between GMCs and SMCs in a timely-dependent manner. Besides, staining techniques showed that reactive oxygen species (ROS) exhibit a closely similar, also time-dependent, pattern of appearance suggesting ROS implication in subsidiary cell formation. This phenomenon was further investigated by using the specific NADPH-oxidase inhibitor diphenylene iodonium, the ROS scavenger N-acetyl-cysteine, menadione which leads to ROS overproduction, and H2O2. Treatments with diphenylene iodonium, N-acetyl-cysteine, and menadione specifically blocked SMC polarization and asymmetrical division. In contrast, H2O2 promoted the establishment of SMC polarity and subsequently subsidiary cell formation in "younger" protodermal areas. Surprisingly, H2O2 favored the asymmetrical division of the intervening cells of the stomatal rows leading to the creation of extra apical subsidiary cells. Moreover, H2O2 altered IAA localization, whereas synthetic auxin analogue 1-napthaleneacetic acid enhanced ROS accumulation. Combined treatments with ROS modulators along with 1-napthaleneacetic acid or 2,3,5-triiodobenzoic acid, an auxin efflux inhibitor, confirmed the crosstalk between ROS and auxin functioning during subsidiary cell generation. Collectively, our results demonstrate that ROS are critical partners of auxin during development of Z. mays stomatal complexes. The interplay between auxin and ROS seems to be spatially and temporarily regulated.

Evolution of the bHLH genes involved in stomatal development: implications for the expansion of developmental complexity of stomata in land plants.

Directory of Open Access Journals (Sweden)

Jin-Hua Ran

Full Text Available Stomata play significant roles in plant evolution. A trio of closely related basic Helix-Loop-Helix (bHLH subgroup Ia genes, SPCH, MUTE and FAMA, mediate sequential steps of stomatal development, and their functions may be conserved in land plants. However, the evolutionary history of the putative SPCH/MUTE/FAMA genes is still greatly controversial, especially the phylogenetic positions of the bHLH Ia members from basal land plants. To better understand the evolutionary pattern and functional diversity of the bHLH genes involved in stomatal development, we made a comprehensive evolutionary analysis of the homologous genes from 54 species representing the major lineages of green plants. The phylogenetic analysis indicated: (1 All bHLH Ia genes from the two basal land plants Physcomitrella and Selaginella were closely related to the FAMA genes of seed plants; and (2 the gymnosperm 'SPCH' genes were sister to a clade comprising the angiosperm SPCH and MUTE genes, while the FAMA genes of gymnosperms and angiosperms had a sister relationship. The revealed phylogenetic relationships are also supported by the distribution of gene structures and previous functional studies. Therefore, we deduce that the function of FAMA might be ancestral in the bHLH Ia subgroup. In addition, the gymnosperm "SPCH" genes may represent an ancestral state and have a dual function of SPCH and MUTE, two genes that could have originated from a duplication event in the common ancestor of angiosperms. Moreover, in angiosperms, SPCHs have experienced more duplications and harbor more copies than MUTEs and FAMAs, which, together with variation of the stomatal development in the entry division, implies that SPCH might have contributed greatly to the diversity of stomatal development. Based on the above, we proposed a model for the correlation between the evolution of stomatal development and the genes involved in this developmental process in land plants.

Transmission of vesicular stomatitis New Jersey virus to cattle by the biting midge Culicoides sonorensis (Diptera: Ceratopogonidae).

Science.gov (United States)

Perez de Leon, Adalberto A; Tabachnick, Walter J

2006-03-01

Laboratory-reared Culicoides sonorensis Wirth & Jones were infected with vesicular stomatitis virus serotype New Jersey (family Rhabdoviridae, genus Vesiculovirus, VSNJV) through intrathoracic inoculation. After 10-d incubation at 25 degrees C, these insects were allowed to blood feed on four steers. Two other steers were exposed to VSNJV through intralingual inoculation with 10(8) tissue culture infective dose50 VSNJV. All six steers became seropositive for VSNJV. The results demonstrate the ability of C. sonorensis to transmit VSNJV to livestock. Only the animals intralingually inoculated with VSNJV showed clinical signs in the form of vesicles at the site of inoculation. Uninfected C. sonorensis allowed to feed on the exposed animals did not become infected with VSNJV. Animals infected by C. sonorensis showed a slower antibody response compared with intralingually inoculated animals. This is probably because of different amounts of virus received via insect transmission and syringe inoculation. A significant difference was found in the serum acute-phase protein alpha-1-acid glycoprotein in animals that received VSNJV through C. sonorensis transmission. These animals had previously been exposed to insect attack in the field compared with intralingually inoculated animals and C. sonorensis-infected animals that had been protected from insect attack. The failure to observe clinical signs of vesicular stomatitis through transmission of VSNJV by C. sonorensis may explain widespread subclinical infections during vesicular stomatitis epidemics.

Plasticity in stomatal size and density of potato leaves under different irrigation and phosphorus regimes

DEFF Research Database (Denmark)

Sun, Yanqi; Yan, Fei; Cui, Xiaoyong

2014-01-01

The morphological features of stomata including their size and density could be modulated by environmental cues; however, the underlying mechanisms remain largely elusive. Here, the effect of different irrigation and phosphorus (P) regimes on stomatal size (SS) and stomatal density (SD) of potato...... potentially enhance water-use efficiency as exemplified by the lowered leaf δ13C under fluctuating soil moisture conditions....... leaves was investigated. The plants were grown in split-root pots under two P fertilization rates (viz., 0 and 100mgkg-1 soil, denoted as P0 and P1, respectively) and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation regimes. Results showed that SS and SD were...... unresponsive to P but significantly affected by the irrigation treatment. FI plants had the largest SS, followed by DI, and PRD the smallest; and the reverse was the case for SD. Compared to FI and DI, PRD plants had significantly lower values of specific leaf area (SLA) and leaf carbon isotope discrimination...

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

International Nuclear Information System (INIS)

Alonso, R.; Bermejo, V.; Sanz, J.; Valls, B.; Elvira, S.; Gimeno, B.S.

2007-01-01

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 3 sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g 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 3 critical levels for semi-natural Mediterranean species. - The stomatal conductance model incorporated within the EMEP DO 3 SE deposition module needs to be re-parameterised for Mediterranean semi-natural vegetation

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

Increasing water use efficiency along the C3 to C4 evolutionary pathway: a stomatal optimization perspective.

Science.gov (United States)

Way, Danielle A; Katul, Gabriel G; Manzoni, Stefano; Vico, Giulia

2014-07-01

C4 photosynthesis evolved independently numerous times, probably in response to declining atmospheric CO2 concentrations, but also to high temperatures and aridity, which enhance water losses through transpiration. Here, the environmental factors controlling stomatal behaviour of leaf-level carbon and water exchange were examined across the evolutionary continuum from C3 to C4 photosynthesis at current (400 μmol mol(-1)) and low (280 μmol mol(-1)) atmospheric CO2 conditions. To this aim, a stomatal optimization model was further developed to describe the evolutionary continuum from C3 to C4 species within a unified framework. Data on C3, three categories of C3-C4 intermediates, and C4 Flaveria species were used to parameterize the stomatal model, including parameters for the marginal water use efficiency and the efficiency of the CO2-concentrating mechanism (or C4 pump); these two parameters are interpreted as traits reflecting the stomatal and photosynthetic adjustments during the C3 to C4 transformation. Neither the marginal water use efficiency nor the C4 pump strength changed significantly from C3 to early C3-C4 intermediate stages, but both traits significantly increased between early C3-C4 intermediates and the C4-like intermediates with an operational C4 cycle. At low CO2, net photosynthetic rates showed continuous increases from a C3 state, across the intermediates and towards C4 photosynthesis, but only C4-like intermediates and C4 species (with an operational C4 cycle) had higher water use efficiencies than C3 Flaveria. The results demonstrate that both the marginal water use efficiency and the C4 pump strength increase in C4 Flaveria to improve their photosynthesis and water use efficiency compared with C3 species. These findings emphasize that the advantage of the early intermediate stages is predominantly carbon based, not water related. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Estimating variation in stomatal frequency at intra-individual, intra-site, and inter-taxonomic levels in populations of the Leonardoxa africana (Fabaceae) complex over environmental gradients in Cameroon

Science.gov (United States)

Finsinger, Walter; Dos Santos, Thibaut; McKey, Doyle

2013-07-01

Variation of stomatal frequency (stomatal density and stomatal index) includes genetically-based, potentially-adaptive variation, and variation due to phenotypic plasticity, the degree of which may be fundamental to the ability to maintain high water-use efficiency and thus to deal with environmental change. We analysed stomatal frequency and morphology (pore length, pore width) in leaves from several individuals from nine populations of four sub-species of the Leonardoxa africana complex. The dataset represents a hierarchical sampling wherein factors are nested within each level (leaves in individuals, individuals in sites, etc.), allowing estimation of the contribution of different levels to overall variation, using variance-component analysis. SI showed significant variation among sites ("site" is largely confounded with "sub-species"), being highest in the sub-species localized in the highest-elevation site. However, most of the observed variance was accounted for at intra-site and intra-individual levels. This variance could reflect great phenotypic plasticity, presumably in response to highly local variation in micro-environmental conditions.

Photodynamic antimicrobial therapy in the treatment of denture stomatitis

International Nuclear Information System (INIS)

Senna, Andre Machado de

2012-01-01

Denture stomatitis (DS), also called chronic atrophic candidiasis, is the most common oral fungal infection in denture wearers. It has a multifactorial etiology, but the presence of Candida spp. biofilm on the denture is considered the most important factor for the establishment of the DS. This study aimed to evaluate the treatment of DS through the use of photodynamic antimicrobial therapy (PAT), mediated by methylene blue. For this purpose, preclinical studies and clinical trials were performed. Simulators prototypes dentures were made of methyl methacrylate polymer to serve as a basis for biofilm growth of the following species of Candida: C. albicans, C. glabrata, C. dubliniensis, C. krusei, C. tropicalis, C. parapsilosis and C. guilliermondii. Methylene blue solution at a concentration of 450 μg/mL was used as a photosensitizer. The prototypes and biofilms were irradiated with a laser of wavelength of 660 nm, potency of 100 mW, for 80 seconds. For the clinical study, subjects were divided into two groups. The first group received conventional treatment based on the use of antifungal Miconazole. The second group received the treatment by PAT. The preclinical results showed that all species of the genus Candida were susceptible to PAT, with a reduction in colonies that ranged from 2.48 to 3.93 log 10 . Clinical outcomes were evaluated for the reduction of colonies of Candida spp. located in the mucosa and in the prosthesis and relative to the improvement of the clinical aspect of the affected mucosa. Both the conventional therapy and PAT were effective in treating DS. There was no significant statistical difference between PAT and conventional treatment for any of the factors evaluated. Thus, it was concluded that PAT is effective in the treatment of denture stomatitis. (author)

Results of the Study of Helminths-Carrying as a Comorbidity in Children with Herpetic Stomatitis

Directory of Open Access Journals (Sweden)

E.S. Suerkulov

2016-09-01

Full Text Available The paper analyzes the helminths-carrying in children with herpetic stomatitis according to the data of the department of maxillofacial surgery of the National center of mother and child welfare, and determines the relationship of oral diseases with disorders of various parts of the gastrointestinal tract.

Stomatal conductance, canopy temperature, and leaf area index estimation using remote sensing and OBIA techniques

Science.gov (United States)

S. Panda; D.M. Amatya; G. Hoogenboom

2014-01-01

Remotely sensed images including LANDSAT, SPOT, NAIP orthoimagery, and LiDAR and relevant processing tools can be used to predict plant stomatal conductance (gs), leaf area index (LAI), and canopy temperature, vegetation density, albedo, and soil moisture using vegetation indices like normalized difference vegetation index (NDVI) or soil adjusted...

Modelling of stomatal conductance and ozone deposition flux of Norway Spruce using deposition model

Czech Academy of Sciences Publication Activity Database

Zapletal, M.; Chroust, P.; Večeřa, Zbyněk; Mikuška, Pavel; Cudlín, Pavel; Urban, Otmar; Pokorný, Radek; Czerný, Radek; Janouš, Dalibor; Taufarová, Klára

2009-01-01

Roč. 12, 2-3 (2009), s. 75-81 ISSN 1335-339X R&D Projects: GA MŽP SP/1B7/189/07 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z40310501 Keywords : ozone concentration * ozone deposition * stomatal conductance * deposition velocity * resistance model * tropo-spheric ozone Subject RIV: DG - Athmosphere Sciences, Meteorology

Stomatal behavior in fruits and leaves of the purple passion fruit (Passiflora edulis Sims and fruits and cladodes of the yellow pitaya [Hylocereus megalanthus (K. Schum. ex Vaupel Ralf Bauer

Directory of Open Access Journals (Sweden)

Camilo Sánchez

2013-04-01

Full Text Available Plants as C3 and CAM react photosynthetically different but both can grow in the same agroecological zone in the tropics. Therefore we studied the behavior of stomatal opening in fruits and leaves of the purple passion fruit and fruits and cladodes of the yellow pitaya was studied under natural growing conditions in Granada and Fusagasuga, Cundinamarca (Colombia. Imprints were made on the surface of leaves, fruits and cladodes using cosmetic enamel impressions. Three cycles were carried out, each cycle took 72 hours, obtaining three different samples every 3 hours; then the impressions were observed by microscope and the opened and closed stomata were counted in each species. In each sampling, data of solar radiation, temperature and relative humidity (RH were measured. The purple passion fruit had the typical behavior of a C3 plant in the leaves as well as the fruits, and a positive correlation between the stomatal aperture and radiation and temperature was found, along with a negative correlation between stomatal aperture and RH. The pitaya showed the typical behavior of a CAM plant with a negative correlation between the stomatal opening and radiation and temperature, as well as a positive correlation between stomatal opening and RH. Radiation, temperature and RH affected the stomatal opening in the fruits and cladodes. Stomatal densities differed greatly between the species and plant organs. In the purple passion fruit, 106.53 stomata per mm² leaf surface were found, but only 12.64 stomata per mm² fruit surface; whereas in the pitaya, 11.28 and 1.43 stomata per mm² were found on the cladodes and fruits, respectively

Phenotype-gene: 580 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available 580 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u3ria224u1577i non-functional stomatal movement...db/SciNetS_ria224i/cria224u4ria224u16990135i non-functional stomatal movement http://metadb.riken.jp/db/SciNetS_ria224i/cria224u1ria224u956i AT1G52400

Transpiration and stomatal conductance in a young secondary tropical montane forest: contrasts between native trees and invasive understorey shrubs.

Science.gov (United States)

Ghimire, Chandra Prasad; Bruijnzeel, L Adrian; Lubczynski, Maciek W; Zwartendijk, Bob W; Odongo, Vincent Omondi; Ravelona, Maafaka; van Meerveld, H J Ilja

2018-04-21

It has been suggested that vigorous secondary tropical forests can have very high transpiration rates, but sap flow and stomatal conductance dynamics of trees and shrubs in these forests are understudied. In an effort to address this knowledge gap, sap flow (thermal dissipation method, 12 trees) and stomatal conductance (porometry, six trees) were measured for young (5-7 years) Psiadia altissima (DC.) Drake trees, a widely occurring species dominating young regrowth following abandonment of swidden agriculture in upland eastern Madagascar. In addition, stomatal conductance (gs) was determined for three individuals of two locally common invasive shrubs (Lantana camara L. and Rubus moluccanus L.) during three periods with contrasting soil moisture conditions. Values of gs for the three investigated species were significantly higher and more sensitive to climatic conditions during the wet period compared with the dry period. Further, gs of the understorey shrubs was much more sensitive to soil moisture content than that of the trees. Tree transpiration rates (Ec) were relatively stable during the dry season and were only affected somewhat by soil water content at the end of the dry season, suggesting the trees had continued access to soil water despite drying out of the topsoil. The Ec exhibited a plateau-shaped relation with vapour pressure deficit (VPD), which was attributed to stomatal closure at high VPD. Vapour pressure deficit was the major driver of variation in Ec, during both the wet and the dry season. Overall water use of the trees was modest, possibly reflecting low site fertility after three swidden cultivation cycles. The observed contrast in gs response to soil water and climatic conditions for the trees and shrubs underscores the need to take root distributions into account when modelling transpiration from regenerating tropical forests.

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. © 2013 John Wiley & Sons Ltd.

In situ temperature relationships of biochemical and stomatal controls of photosynthesis in four lowland tropical tree species.

Science.gov (United States)

Slot, Martijn; Winter, Klaus

2017-12-01

Net photosynthetic carbon uptake of Panamanian lowland tropical forest species is typically optimal at 30-32 °C. The processes responsible for the decrease in photosynthesis at higher temperatures are not fully understood for tropical trees. We determined temperature responses of maximum rates of RuBP-carboxylation (V CMax ) and RuBP-regeneration (J Max ), stomatal conductance (G s ), and respiration in the light (R Light ) in situ for 4 lowland tropical tree species in Panama. G s had the lowest temperature optimum (T Opt ), similar to that of net photosynthesis, and photosynthesis became increasingly limited by stomatal conductance as temperature increased. J Max peaked at 34-37 °C and V CMax ~2 °C above that, except in the late-successional species Calophyllum longifolium, in which both peaked at ~33 °C. R Light significantly increased with increasing temperature, but simulations with a photosynthesis model indicated that this had only a small effect on net photosynthesis. We found no evidence for Rubisco-activase limitation of photosynthesis. T Opt of V CMax and J Max fell within the observed in situ leaf temperature range, but our study nonetheless suggests that net photosynthesis of tropical trees is more strongly influenced by the indirect effects of high temperature-for example, through elevated vapour pressure deficit and resulting decreases in stomatal conductance-than by direct temperature effects on photosynthetic biochemistry and respiration. © 2017 John Wiley & Sons Ltd.

Rice Stomatal Closure Requires Guard Cell Plasma Membrane ATP-Binding Cassette Transporter RCN1/OsABCG5.

Science.gov (United States)

Matsuda, Shuichi; Takano, Sho; Sato, Moeko; Furukawa, Kaoru; Nagasawa, Hidetaka; Yoshikawa, Shoko; Kasuga, Jun; Tokuji, Yoshihiko; Yazaki, Kazufumi; Nakazono, Mikio; Takamure, Itsuro; Kato, Kiyoaki

2016-03-07

Water stress is one of the major environmental stresses that affect agricultural production worldwide. Water loss from plants occurs primarily through stomatal pores. Here, we report that an Oryza sativa half-size ATP-binding cassette (ABC) subfamily G protein, RCN1/OsABCG5, is involved in stomatal closure mediated by phytohormone abscisic acid (ABA) accumulation in guard cells. We found that the GFP-RCN1/OsABCG5-fusion protein was localized at the plasma membrane in guard cells. The percentage of guard cell pairs containing both ABA and GFP-RCN1/OsABCG5 increased after exogenous ABA treatment, whereas they were co-localized in guard cell pairs regardless of whether exogenous ABA was applied. ABA application resulted in a smaller increase in the percentage of guard cell pairs containing ABA in rcn1 mutant (A684P) and RCN1-RNAi than in wild-type plants. Furthermore, polyethylene glycol (drought stress)-inducible ABA accumulation in guard cells did not occur in rcn1 mutants. Stomata closure mediated by exogenous ABA application was strongly reduced in rcn1 mutants. Finally, rcn1 mutant plants had more rapid water loss from detached leaves than the wild-type plants. These results indicate that in response to drought stress, RCN1/OsABCG5 is involved in accumulation of ABA in guard cells, which is indispensable for stomatal closure. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

5 CFR 630.1014 - Movement between voluntary leave bank programs.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Movement between voluntary leave bank programs. 630.1014 Section 630.1014 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1014 Movement between voluntary leave bank...

Transpiration directly regulates the emissions of water-soluble short-chained OVOCs.

Science.gov (United States)

Rissanen, K; Hölttä, T; Bäck, J

2018-04-20

Most plant-based emissions of volatile organic compounds (VOCs) are considered mainly temperature dependent. However, certain oxygenated VOCs (OVOCs) have high water solubility; thus, also stomatal conductance could regulate their emissions from shoots. Due to their water solubility and sources in stem and roots, it has also been suggested that their emissions could be affected by transport in xylem sap. Yet, further understanding on the role of transport has been lacking until present. We used shoot-scale long-term dynamic flux data from Scots pines (Pinus sylvestris) to analyse the effects of transpiration and transport in xylem sap flow on emissions of three water soluble OVOC: methanol, acetone and acetaldehyde. We found a direct effect of transpiration on the shoot emissions of the three OVOCs. The emissions were best explained by a regression model that combined linear transpiration and exponential temperature effects. In addition, a structural equation model indicated that stomatal conductance affects emissions mainly indirectly, by regulating transpiration. A part of temperature's effect is also indirect. The tight coupling of shoot emissions to transpiration clearly evidences that these OVOCs are transported in xylem sap from their sources in roots and stem to leaves and to ambient air. This article is protected by copyright. All rights reserved.

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...

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

. Experimental data was compared to simulated results from the new enhanced Daisy model which include modelling 2D soil water flow, abscisic acid (ABA) signalling and its effect on stomatal conductance and hence on transpiration and assimilation, and finally crop yield. The results demonstrated that the enhanced...

Conditional expression of the vesicular stomatitis virus glycoprotein gene in Escherichia coli.

OpenAIRE

Rose, J K; Shafferman, A

1981-01-01

Bacterial plasmids that directed expression of the vesicular stomatitis virus glycoprotein (G-protein) gene under control of the tryptophan operon regulatory region were constructed. A plasmid directing the synthesis of a G-protein-like protein (containing the NH2-terminal segment of seven amino acids encoded by the trpE gene fused to the complete G-protein sequence lacking only its NH2-terminal methionine) could be transformed into trpR+ (repressed) but not into trpR- (derepressed) cells. Th...

Growth performance and stomatal behavior in relation to ecotypic adaptations in cynodon dactylon (L.) pers

International Nuclear Information System (INIS)

Tufail, A.; Ahmad, F.; Hameed, M.; Ahmad, R.

2017-01-01

Evolution has great ecological significance in terms of plant morphological and stomatal characteristics that must have been genetically fixed during the long evolutionary period. Impact of environmental conditions on growth and stomatal features of twelve ecotypes of Cynodon dactylon that were collected from ecologically different habitats in the Punjab, Pakistan were evaluated. The collected ecotypes Derawar Fort-saline desert (DF-SD), Muzaffar garh-River bank (M-RB), Khabbeki Lake-hyper saline (KL-HS), Ucchali Lake-hyper saline (UL-HS), Kalar Kahar Lake-saline (KKL-S), Treemu-saline wetland (T-SW), Sahianwala-saline wetland (S-SW), Sahianwala-hyper saline (S-HS), Pakka Anna-hyper saline (PA-HS), Pakka Anna-reclaimed field (PA-RF), Botanic Garden-non saline (BG-NS) and Gatwala-saline semiarid (G-SSA) were grown in controlled environments at University of Agriculture, Faisalabad till their acclimatization to evaluate genetically fixed characteristics. After 6-month growth in soil, the plants were transferred to half-strength Hoagland's nutrient medium. There was a huge variation in all morphological characteristics recorded during the investigation, which were due to environmental heterogeniety to which these ecotypes were originally adapted. An exclusive feature of the DF-SD ecotypes is the long and numerous roots, and tillering capacity that surpassed all other ecotypes. Leaves per plant were also exceptionally high that may improve the photosymthetic efficiency of the plant. It showed a good potential of overall growth and biomass production. The robust growth was also recorded in the KKL-S ecotypes, and this can be related to the complete dominance of these two ecotypes in their respective habitats. Small stomata were recorded in the three ecotypes (DF-SD, KL-HS and PA-HS), which are of great ecological significance. Stomatal shape, however, is different in different ecotypes, but its contribution towards stress tolerance is still to be investigated. (author)

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

Seawater spray injury to Quercus acutissima leaves: crystal deposition, stomatal clogging, and chloroplast degeneration.

Science.gov (United States)

Kim, Ki Woo; Koo, Kyosang; Kim, Pan-Gi

2011-05-01

Effects of seawater spray on leaf structure were investigated in Quercus acutissima by electron microscopy and X-ray microanalysis. Two-year-old seedlings of Q. acutissima were sprayed with seawater and kept in a greenhouse maintained at 25°C. The most recognizable symptoms of seawater-sprayed seedlings included leaf necrosis, crystal deposition, stomatal clogging, and chloroplast degeneration. Field emission scanning electron microscopy revealed that the leaf surface was covered with additional layers of remnants of seawater spray. Composed of sodium and chloride, cube-shaped crystals (halite) were prevalently found on trichomes and epidermis, and formed aggregates. Meanwhile, wedge-shaped crystals were deposited on epidermis and consisted of calcium and sulfur. As a result of stomatal clogging by crystal deposition on the abaxial surface, it was conceivable that plant respiration became severely hampered. Transmission electron microscopy showed degenerated cytoplasm of seawater-sprayed leaves. It was common to observe severe plasmolysis and disrupted chloroplasts with a reduced number of thylakoids in grana. These results indicate that foliar applications of seawater were sufficient to induce necrosis of Q. acutissima seedlings as an abiotic disturbance factor. Copyright © 2010 Wiley-Liss, Inc.

Black fly involvement in the epidemic transmission of vesicular stomatitis New Jersey virus (Rhabdoviridae: Vesiculovirus).

Science.gov (United States)

Mead, Daniel G; Howerth, Elizabeth W; Murphy, Molly D; Gray, Elmer W; Noblet, Raymond; Stallknecht, David E

2004-01-01

The transmission routes of Vesicular stomatitis New Jersey virus (VSNJV), a causative agent of vesicular stomatitis, an Office International des Epizooties List-A disease, are not completely understood. Epidemiological and entomological studies conducted during the sporadic epidemics in the western United States have identified potential virus transmission routes involving insect vectors and animal-to-animal contact. In the present study we experimentally tested the previously proposed transmission routes which were primarily based on field observations. Results obtained provide strong evidence for the following: (1) hematophagous insects acquire VSNJV by unconventional routes while blood feeding on livestock, (2) clinical course of VSNJV infection in livestock following transmission by an infected insect is related to insect bite site, (3) infection of livestock via insect bite can result in multiple transmission possibilities, including animal-to-animal contact. Taken together, these data significantly add to our understanding of the transmission routes of a causative agent of one of the oldest known infectious diseases of livestock, for which the details have remained largely unknown despite decades of research.

Activation of Nrf2 Signaling Augments Vesicular Stomatitis Virus Oncolysis via Autophagy-Driven Suppression of Antiviral Immunity.

Science.gov (United States)

Olagnier, David; Lababidi, Rassin R; Hadj, Samar Bel; Sze, Alexandre; Liu, Yiliu; Naidu, Sharadha Dayalan; Ferrari, Matteo; Jiang, Yuan; Chiang, Cindy; Beljanski, Vladimir; Goulet, Marie-Line; Knatko, Elena V; Dinkova-Kostova, Albena T; Hiscott, John; Lin, Rongtuan

2017-08-02

Oncolytic viruses (OVs) offer a promising therapeutic approach to treat multiple types of cancer. In this study, we show that the manipulation of the antioxidant network via transcription factor Nrf2 augments vesicular stomatitis virus Δ51 (VSVΔ51) replication and sensitizes cancer cells to viral oncolysis. Activation of Nrf2 signaling by the antioxidant compound sulforaphane (SFN) leads to enhanced VSVΔ51 spread in OV-resistant cancer cells and improves the therapeutic outcome in different murine syngeneic and xenograft tumor models. Chemoresistant A549 lung cancer cells that display constitutive dominant hyperactivation of Nrf2 signaling are particularly vulnerable to VSVΔ51 oncolysis. Mechanistically, enhanced Nrf2 signaling stimulated viral replication in cancer cells and disrupted the type I IFN response via increased autophagy. This study reveals a previously unappreciated role for Nrf2 in the regulation of autophagy and the innate antiviral response that complements the therapeutic potential of VSV-directed oncolysis against multiple types of OV-resistant or chemoresistant cancer. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

Science.gov (United States)

Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

2016-05-01

Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

Evidence That Drought-Induced Stomatal Closure Is Not an Important Constraint on White Spruce Performance Near the Arctic Treeline in Alaska

Science.gov (United States)

Sullivan, P.; Brownlee, A.; Ellison, S.; Sveinbjornsson, B.

2014-12-01

Tree cores collected from trees growing at high latitudes have long been used to reconstruct past climates, because of close positive correlations between temperature and tree growth. However, in recent decades and at many sites, these relationships have deteriorated and have even become negative in some instances. The observation of declining tree growth in response to rising temperature has prompted many investigators to suggest that high latitude trees may be increasingly exhibiting drought-induced stomatal closure. In the Brooks Range of northern Alaska, the observation of low and declining growth of white spruce is more prevalent in the central and eastern parts of the range, where precipitation is lower, providing superficial support for the drought stress hypothesis. In this study, we investigated the occurrence of white spruce drought-induced stomatal closure in four watersheds along a west to east gradient near the Arctic treeline in the Brooks Range. We obtained a historical perspective on tree growth and water relations by collecting increment cores for analysis of ring widths and carbon isotopes in tree-ring alpha-cellulose. Meanwhile, we made detailed assessments of contemporary water relations at the scales of the whole canopy and the needle. All of our data indicate that drought-induced stomatal closure is probably not responsible for low and declining growth in the central and eastern Brooks Range. Carbon isotope discrimination has generally increased over the past century and our calculations indicate that needle inter-cellular CO2 concentration is much greater now than it was in the early 1900's. Measurements of needle gas exchange are consistent with the tree core record, in the sense that instances of low photosynthesis at our sites are not coincident with similarly low stomatal conductance and low inter-cellular CO2 concentration. Finally, hourly measurements of xylem sap flow indicate that trees at our study sites are able to maintain near

7 CFR 800.83 - Sampling provisions by kind of movement.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Sampling provisions by kind of movement. 800.83... REGULATIONS Inspection Methods and Procedures § 800.83 Sampling provisions by kind of movement. (a) Export cargo movements—(1) Bulk grain. Except as may be approved by the Administrator on a shipment-by-shipment...

1995 epizootic of vesicular stomatitis (New Jersey serotype) in the western United States: an entomologic perspective.

Science.gov (United States)

Schmidtmann, E T; Tabachnick, W J; Hunt, G J; Thompson, L H; Hurd, H S

1999-01-01

Entomologic and epizootic data are reviewed concerning the potential for transmission of vesicular stomatitis (VS) virus by insects, including field data from case-positive premises in New Mexico and Colorado during the 1995 outbreak of the New Jersey serotype (VSNJ). As with previous outbreaks of VSNJ in the western United States, the 1995 epizootic illustrated that risk of exposure is seasonal, increasing during warm weather and decreasing with onset of cool weather; virus activity spread from south to north along river valleys of the southwestern and Rocky Mountain states; clinical disease was detected most commonly in horses, but also occurred in cattle and 1 llama; and most infections were subclinical. Overall, 367 case-positive premises were identified during the 1995 outbreak, with foci of virus activity along the Rio Grande River south of Albuquerque, NM, in southwestern Colorado, and along the Colorado River near Grand Junction, CO. The establishment of a 16-km (10-mile) radius zone of restricted animal movement around confirmed positive premises, along with imposition of state and international embargoes, created economic hardship for livestock owners and producers. The importance of defining the role of blood-feeding insects as biological vectors of VSNJ virus relative to risk factors that promote high levels of insect transmission, such as the presence of livestock along western river valleys, blood feeding activity, and frequent transport of animals for recreational purposes, is emphasized as a basis for developing effective disease management.

Free movement of products in Europe in 1993

International Nuclear Information System (INIS)

Andreini, P.

1993-01-01

This article illustrates the procedures that will govern the free movement of products in Europe, beginning 1 January, 1993, for the industries regulated by Community directives and for those not yet regulated. It also describes the duties of the public administrations and reports on progress in the development of technical standards and the harmonization of certification and testing

Autism: The Micro-Movement Perspective

Directory of Open Access Journals (Sweden)

Elizabeth B Torres

2013-07-01

Full Text Available The current assessment of behaviors in the inventories to diagnose autism spectrum disorders (ASD focus on observation and discrete categorizations. Behaviors require movements, yet measurements of physical movements are seldom included. Their inclusion however, could provide an objective characterization of behavior to help unveil interactions between the peripheral and the central nervous systems. Such interactions are critical for the development and maintenance of spontaneous autonomy, self-regulation and voluntary control. At present, current approaches cannot deal with the heterogeneous, dynamic and stochastic nature of development. Accordingly, they leave no avenues for real-time or longitudinal assessments of change in a coping system continuously adapting and developing compensatory mechanisms. We offer a new unifying statistical framework to reveal re-afferent kinesthetic features of the individual with ASD. The new methodology is based on the non-stationary stochastic patterns of minute fluctuations (micro-movements inherent to our natural actions. Such patterns of behavioral variability provide re-entrant sensory feedback contributing to the autonomous regulation and coordination of the motor output. From an early age, this feedback supports centrally driven volitional control and fluid, flexible transitions between intentional and spontaneous behaviors. We show that in ASD there is a disruption in the maturation of this form of proprioception. Despite this disturbance, each individual has unique adaptive compensatory capabilities that we can unveil and exploit to evoke faster and more accurate decisions. Measuring the kinesthetic re-afference in tandem with stimuli variations we can detect changes in their micro-movements indicative of a more predictive and reliable kinesthetic percept. Our methods address the heterogeneity of ASD with a personalized approach grounded in the inherent sensory-motor abilities that the individual has

PFAPA (Periodic fever, aphtous stomatitis, pharingitis, cervical adenitis) or Marshall’s syndrome in children

OpenAIRE

N N Kuzmina; G R Movsisyan

2005-01-01

PFAPA (periodic fever, aphtous stomatitis, pharingitis, cervical adenitis) or Marshall’s syndrome is one of the rare periodic fever conditions appearing in children. Its cause is unknown. This syndrome may continue for several years. During interictal period the child is quite well, grows and develops normally. The disease should be differentiated from Behcet’s disease, cyclic neutropenia, familial Mediterranean fever, familial Ireland fever, hyperimmunoglobulinemia D syndrome, systemic juven...

Enhanced Gene Transfer with Fusogenic Liposomes Containing Vesicular Stomatitis Virus G Glycoprotein

Science.gov (United States)

Abe, Akihiro; Miyanohara, Atsushi; Friedmann, Theodore

1998-01-01

Exposure of Lipofectin-DNA complexes to the partially purified G glycoprotein of the vesicular stomatitis virus envelope (VSV-G) results in loss of serum-mediated inhibition and in enhanced efficiency of gene transfer. Sucrose density gradient sedimentation analysis indicated that the VSV-G associates physically with the DNA-lipid complex to produce a VSV-G liposome. The ability to incorporate surrogate viral or cellular envelope components such as VSV-G into liposomes may allow more-efficient and possibly targeted gene delivery by lipofection, both in vitro and in vivo. PMID:9621082

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

International Nuclear Information System (INIS)

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

2008-01-01

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. - Both biochemical and biophysical processes may regulate EDU action

7 CFR 1427.16 - Movement and protection of warehouse-stored cotton.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Movement and protection of warehouse-stored cotton. 1427.16 Section 1427.16 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY... Cotton Loan and Loan Deficiency Payments § 1427.16 Movement and protection of warehouse-stored cotton. (a...

Dynamics of spatial heterogeneity of stomatal closure in Tradescantia virginiana altered by growth at high relative air humidity

NARCIS (Netherlands)

Rezaei Nejad, A.; Harbinson, J.; Meeteren, van U.

2006-01-01

The spatial heterogeneity of stomatal closure in response to rapid desiccation of excised well-watered Tradescantia virginiana leaves grown at moderate (55%) or high (90%) relative air humidity (RH) was studied using a chlorophyll fluorescence imaging system under non-photorespiratory conditions.

Prevention of everolimus-related stomatitis in women with hormone receptor-positive, HER2-negative metastatic breast cancer using dexamethasone mouthwash (SWISH): a single-arm, phase 2 trial.

Science.gov (United States)

Rugo, Hope S; Seneviratne, Lasika; Beck, J Thaddeus; Glaspy, John A; Peguero, Julio A; Pluard, Timothy J; Dhillon, Navneet; Hwang, Leon Christopher; Nangia, Chaitali; Mayer, Ingrid A; Meiller, Timothy F; Chambers, Mark S; Sweetman, Robert W; Sabo, J Randy; Litton, Jennifer K

2017-05-01

Stomatitis is a class effect associated with the inhibition of mTOR and is associated with everolimus therapy for breast cancer. Topical steroids might reduce stomatitis incidence and severity, and the need for dose reductions and interruptions of everolimus. Anecdotal use of topical steroid oral prophylaxis has been reported in patients with breast cancer. We aimed to assess dexamethasone-based mouthwash for prevention of stomatitis in patients with breast cancer. This US-based, multicentre, single-arm, phase 2 prevention study enrolled women aged 18 years and older with postmenopausal status who had histologically or cytologically confirmed metastatic hormone receptor-positive, HER2-negative breast cancer. Beginning on day 1 of cycle 1, patients received everolimus 10 mg plus exemestane 25 mg daily, with 10 mL of alcohol-free dexamethasone 0·5 mg per 5 mL oral solution (swish for 2 min and spit, four times daily for 8 weeks). After 8 weeks, dexamethasone mouthwash could be continued for up to eight additional weeks at the discretion of the clinician and patient. The primary endpoint was incidence of grade 2 or worse stomatitis by 8 weeks assessed in the full analysis set (patients who received at least one dose of everolimus and exemestane and at least one confirmed dose of dexamethasone mouthwash) versus historical controls from the BOLERO-2 trial (everolimus and exemestane treatment in patients with hormone receptor-positive advanced breast cancer who were not given dexamethasone mouthwash for prevention of stomatitis). This trial is registered at ClinicalTrials.gov, number NCT02069093. Between May 28, 2014, and Oct 8, 2015, we enrolled 92 women; 85 were evaluable for efficacy. By 8 weeks, the incidence of grade 2 or worse stomatitis was two (2%) of 85 patients (95% CI 0·29-8·24), versus 159 (33%) of 482 patients (95% CI 28·8-37·4) for the duration of the BOLERO-2 study. Overall, 83 (90%) of 92 patients had at least one adverse event. The most frequently

49 CFR 236.330 - Locking dog of switch-and-lock movement.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Locking dog of switch-and-lock movement. 236.330 Section 236.330 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Rules and Instructions § 236.330 Locking dog of switch-and-lock movement. Locking dog of switch-and-lock...

Leaf stomatal traits variation within and among black poplar native populations in Serbia

OpenAIRE

Cortan, Dijana; Vilotic, Dragica; Sijacic-Nikolic, Mirjana; Miljkovic, Danijela

2017-01-01

Populus nigra as a keystone riparian pioneer tree species is one of the rarest and most endangered species in Europe due to the loss of its natural habitats. Genetic diversity existence is a key factor in survival of one species, and stomata as genetically controlled trait could be used for differentiation studies. With the aim of proving stomatal phenotypic variation of the four native populations of Populus nigra located on the banks of three biggest river valleys (Dunabe, Tisa and Sava) in...

Grapevine acclimation to water deficit: the adjustment of stomatal and hydraulic conductance differs from petiole embolism vulnerability.

Science.gov (United States)

Hochberg, Uri; Bonel, Andrea Giulia; David-Schwartz, Rakefet; Degu, Asfaw; Fait, Aaron; Cochard, Hervé; Peterlunger, Enrico; Herrera, Jose Carlos

2017-06-01

Drought-acclimated vines maintained higher gas exchange compared to irrigated controls under water deficit; this effect is associated with modified leaf turgor but not with improved petiole vulnerability to cavitation. A key feature for the prosperity of plants under changing environments is the plasticity of their hydraulic system. In the present research we studied the hydraulic regulation in grapevines (Vitis vinifera L.) that were first acclimated for 39 days to well-watered (WW), sustained water deficit (SD), or transient-cycles of dehydration-rehydration-water deficit (TD) conditions, and then subjected to varying degrees of drought. Vine development under SD led to the smallest leaves and petioles, but the TD vines had the smallest mean xylem vessel and calculated specific conductivity (k ts ). Unexpectedly, both the water deficit acclimation treatments resulted in vines more vulnerable to cavitation in comparison to WW, possibly as a result of developmental differences or cavitation fatigue. When exposed to drought, the SD vines maintained the highest stomatal (g s ) and leaf conductance (k leaf ) under low stem water potential (Ψ s ), despite their high xylem vulnerability and in agreement with their lower turgor loss point (Ψ TLP ). These findings suggest that the down-regulation of k leaf and g s is not associated with embolism, and the ability of drought-acclimated vines to maintain hydraulic conductance and gas exchange under stressed conditions is more likely associated with the leaf turgor and membrane permeability.

Sap flux density and stomatal conductance of European beech and common oak trees in pure and mixed stands during the summer drought of 2003

Science.gov (United States)

Jonard, F.; André, F.; Ponette, Q.; Vincke, C.; Jonard, M.

2011-10-01

SummarySap flux density of European beech and common oak trees was determined from sap flow measurements in pure and mixed stands during the summer drought of 2003. Eight trees per species and per stand were equipped with sap flow sensors. Soil water content was monitored in each stand at different depths by using time-domain reflectometry (TDR). Leaf area index and vertical root distribution were also investigated during the growing season. From sap flux density ( SFD) data, mean stomatal conductance of individual trees ( G s) was calculated by inverting the Penman-Monteith equation. Linear mixed models were developed to analyse the effects of species and stand type (pure vs. mixed) on SFD and G s and on their sensitivity to environmental variables (vapour pressure deficit ( D), incoming solar radiation ( R G), and relative extractable water ( REW)). For reference environmental conditions, we did not find any tree species or stand type effects on SFD. The sensitivity of SFD to D was higher for oak than for beech in the pure stands ( P sapwood-to-leaf area ratio compared to oak. The sensitivity of G s to REW was higher for beech than for oak and was ascribed to a higher vulnerability of beech to air embolism and to a more sensitive stomatal regulation. The sensitivity of beech G s to REW was lower in the mixed than in the pure stand, which could be explained by a better sharing of the resources in the mixture, by facilitation processes (hydraulic lift), and by a rainfall partitioning in favour of beech.

Quantification of ozone exposure- and stomatal uptake-yield response relationships for soybean in Northeast China.

Science.gov (United States)

Zhang, Weiwei; Feng, Zhaozhong; Wang, Xiaoke; Liu, Xiaobing; Hu, Enzhu

2017-12-01

High ground-level O 3 is a new threat to agricultural production in Northeast China with the increasing ambient O 3 concentration. Little is known about its impacts on soybean production in this key agricultural region. Accumulated O 3 exposure-response and stomatal O 3 flux-response relationships were developed during two continuous growing seasons to evaluate O 3 -induced yield reduction of four typical soybean cultivars in Northeast China. Results showed that critical levels of AOT40 (accumulated hourly O 3 concentrations over a threshold of 40nmol·mol -1 ), SUM06 (sum of all hourly average O 3 concentrations over 0.06μmol·mol -1 ) and W126 (sum of O 3 concentrations weighted by a sigmoidal function) in relation to 5% reduction in relative seed yield were 4.2, 7.6 and 6.8μmol·mol -1 ·h, respectively. The effect of O 3 on plants was influenced by leaf position in canopy. An improved Jarvis stomatal conductance model including leaf (node) position fitted well with field measurements. The best linear relationship between stomatal O 3 flux and relative soybean yield was obtained when phytotoxic ozone dose was integrated over a threshold of 9.6nmol·m -2 ·s -1 (POD 9.6 ) to represent the detoxification capacity of soybean. POD 9.6 and the commonly used POD 6 in relation to 5% reduction in relative seed yield of soybean were 0.9mmol·m -2 and 1.8mmol·m -2 , respectively. O 3 concentrations above ~38nmol·mol -1 contributed to POD 9.6 and caused seed yield loss in soybean. Current annual yield loss of soybean at ambient O 3 was estimated to range between 23.4% and 30.2%. The O 3 dose-response relationships and corresponding thresholds obtained here will benefit regional O 3 risk assessment on soybean production in Northeast China. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Mechano-chemical signaling maintains the rapid movement of Dictyostelium cells

International Nuclear Information System (INIS)

Lombardi, M.L.; Knecht, D.A.; Lee, J.

2008-01-01

The survival of Dictyostelium cells depends on their ability to efficiently chemotax, either towards food or to form multicellular aggregates. Although the involvement of Ca 2+ signaling during chemotaxis is well known, it is not clear how this regulates cell movement. Previously, fish epithelial keratocytes have been shown to display transient increases in intracellular calcium ([Ca 2+ ] i ) that are mediated by stretch-activated calcium channels (SACs), which play a role in retraction of the cell body [J. Lee, A. Ishihara, G. Oxford, B. Johnson, and K. Jacobson, Regulation of cell movement is mediated by stretch-activated calcium channels. Nature, 1999. 400(6742): p. 382-6.]. To investigate the involvement of SACs in Dictyostelium movement we performed high resolution calcium imaging in wild-type (NC4A2) Dictyostelium cells to detect changes in [Ca 2+ ] i . We observed small, brief, Ca 2+ transients in randomly moving wild-type cells that were dependent on both intracellular and extracellular sources of calcium. Treatment of cells with the SAC blocker gadolinium (Gd 3+ ) inhibited transients and decreased cell speed, consistent with the involvement of SACs in regulating Dictyostelium motility. Additional support for SAC activity was given by the increase in frequency of Ca 2+ transients when Dictyostelium cells were moving on a more adhesive substratum or when they were mechanically stretched. We conclude that mechano-chemical signaling via SACs plays a major role in maintaining the rapid movement of Dictyostelium cells

7 CFR 330.211 - Labeling of plant pests for movement under permits.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Labeling of plant pests for movement under permits... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.211 Labeling of...

Islamic Puritanism Movements in Indonesia as Transnational Movements

Directory of Open Access Journals (Sweden)

Benny Baskara

2017-04-01

Full Text Available Islamic puritanism movements are the movements compelling to return to the teachings of Quran and Sunnah, as the pure teachings of Islam and abandon even abolish other teachings outside the teachings of Quran and Sunnah. The movements of Islamic puritanism can be considered as transnational movements because they spread their teachings and ideologies, create organizations, networks, and provide financial supports across nations. This paper describes Islamic puritanism movements in Indonesia and their transnational connections. Some Islamic puritanism movements in Indonesia can be considered as part of Islamic transnational movements, in which most of the movements are centered in the Middle East. In Indonesia, Islamic puritanism movements firstly appeared in the beginning of the nineteenth century, called Padri movement in West Sumatra. It was then continued to the emergence of Islamic organizations in the twentieth century. Recently, Islamic puritanism movements in Indonesia mostly take form as Salafism-Wahabism movements.

Stomatal density and metabolic determinants mediate salt stress adaptation and water use efficiency in basil (Ocimum basilicum L.).

Science.gov (United States)

Barbieri, Giancarlo; Vallone, Simona; Orsini, Francesco; Paradiso, Roberta; De Pascale, Stefania; Negre-Zakharov, Florence; Maggio, Albino

2012-11-15

Increasing salinity tolerance and water-use efficiency in crop plants are two major challenges that agriculture must face in the next decades. Many physiological mechanisms and molecular components mediating crop response to environmental stresses have been identified. However, the functional inter-links between stress adaptation responses have not been completely understood. Using two basil cultivars (Napoletano and Genovese) with contrasting ability to respond to salt stress, here we demonstrate that reduced stomatal density, high ascorbate level and polyphenol oxidase (PPO) activity coordinately contribute to improve basil adaptation and water use efficiency (WUE) in saline environment. The constitutively reduced stomatal density was associated with a "delayed" accumulation of stress molecules (and growth inhibiting signals) such as abscisic acid (ABA) and proline, in the more tolerant Genovese. Leaf volatile profiling also revealed cultivar-specific patterns, which may suggest a role for the volatile phenylpropanoid eugenol and monoterpenes in conferring stress tolerance via antioxidant and signalling functions. Copyright © 2012 Elsevier GmbH. All rights reserved.

Current Diagnosis and Treatment Models of Periodic Fever, Aphthous Stomatitis, Pharyngitis and Cervical Lymphadenitis Syndrome

Directory of Open Access Journals (Sweden)

Ayşenur Paç Kısaarslan

2017-06-01

Full Text Available Periodic fever, aphthous stomatitis, pharyngitis, and cervical lymphadenitis (PFAPA syndrome is the most frequent cause of periodic fever in childhood. The pathogenesis of PFAPA is still unknown. Differantial diagnosis must be made with cyclic neutropenia and other autoinflammatory diseases. Because PFAPA is self limiting and benign, there is no certain treatment model. Treatment options must be specific to the patient, with a strong family and doctor relationship.

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

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.

Down-Regulation of p53 by Double-Stranded RNA Modulates the Antiviral Response

OpenAIRE

Marques, Joao T.; Rebouillat, Dominique; Ramana, Chilakamarti V.; Murakami, Junko; Hill, Jason E.; Gudkov, Andrei; Silverman, Robert H.; Stark, George R.; Williams, Bryan R. G.

2005-01-01

p53 has been well characterized as a tumor suppressor gene, but its role in antiviral defense remains unclear. A recent report has demonstrated that p53 can be induced by interferons and is activated after vesicular stomatitis virus (VSV) infection. We observed that different nononcogenic viruses, including encephalomyocarditis virus (EMCV) and human parainfluenza virus type 3 (HPIV3), induced down-regulation of p53 in infected cells. Double-stranded RNA (dsRNA) and a mutant vaccinia virus la...

Do facial movements express emotions or communicate motives?

Science.gov (United States)

Parkinson, Brian

2005-01-01

This article addresses the debate between emotion-expression and motive-communication approaches to facial movements, focusing on Ekman's (1972) and Fridlund's (1994) contrasting models and their historical antecedents. Available evidence suggests that the presence of others either reduces or increases facial responses, depending on the quality and strength of the emotional manipulation and on the nature of the relationship between interactants. Although both display rules and social motives provide viable explanations of audience "inhibition" effects, some audience facilitation effects are less easily accommodated within an emotion-expression perspective. In particular, emotion is not a sufficient condition for a corresponding "expression," even discounting explicit regulation, and, apparently, "spontaneous" facial movements may be facilitated by the presence of others. Further, there is no direct evidence that any particular facial movement provides an unambiguous expression of a specific emotion. However, information communicated by facial movements is not necessarily extrinsic to emotion. Facial movements not only transmit emotion-relevant information but also contribute to ongoing processes of emotional action in accordance with pragmatic theories.

Analysis of the RNA species isolated from defective particles of vesicular stomatitis virus.

Science.gov (United States)

Adler, R; Banerjee, A K

1976-10-01

Serial high multiplicity passage of a cloned stock of vesicular stomatitis virus was found to generate defective interfering particles containing three size classes of RNA, with sedimentaiton coefficients of 31 S, 23 S and 19 S. The 31 S and 23 S RNA species were found to be complementary to both the 12 to 18 S and 31 S size classes of VSV mRNAs. The 19 S class of RNA was found to be partially base-paired. All three RNA species were found to contain ppAp at their 5' termini.

First case report of vesicular stomatitis in the State of Paraíba, Brazil

Directory of Open Access Journals (Sweden)

Inácio José Clementino

2014-10-01

Full Text Available The present report describes the first case of vesicular stomatitis in the State of Paraíba, Brazil. Records from the Official Veterinary Services of the State of Paraíba were analyzed while responding to a suspected case of vesicular disease at a property (property I in the municipality of Pombal in which the cattle showed clinical signs and lesions of vesicular disease. Surveillance in the surrounding area revealed similar lesions in cattle at two other properties (II and III. Based on these events, the suspicion was considered well founded, and samples were collected for evaluation at the National Agricultural Laboratory of the State of Pará. The property was interdicted, and those located within a 3 km radius (perifocal from the focus were inspected. At property I, 42.86% (6/14 of the cattle showed vesicular disease lesions characterized by intense sialorrhea, ruptured oral vesicles, epithelial detachment of the tongue and muzzle, and vesicular lesions in the udder and interdigital space. Similar lesions were detected in cattle at properties II and III, affecting 80.95% (34/42 and 11.54% (3/26 of the animals, respectively. Tissue samples collected from the three properties were positive for the vesicular stomatitis virus (Indiana 3 subtype. The properties were monitored for 21 days after the last infected animal was cured, and afterwards, the three properties were released.

Leaf movement, photosynthesis and resource use efficiency responses to multiple environmental stress in Glycine max (soybean)

International Nuclear Information System (INIS)

Rosa, L.M.G.

1993-01-01

Increases in the concentration of greenhouse gases in the atmosphere, may cause a significant increase in temperature, with implications for general wind patterns and precipitation. Reductions in stratospheric ozone will result in increased levels of UV-B reaching earth's surface. During their lifetime plants must deal with a variety of co-occurring environmental stresses. Accordingly, studies into plant responses to multiple environmental factors is important to our understanding of limits to their growth, productivity, and distribution. Heliotropic leaf movements are a generalized plant response to environmental stresses, and the pattern of these movements can be altered by resource availability (e.g., water, and nitrogen). Previous greenhouse and field studies have demonstrated damaging effects of UV-B radiation in crop species, including soybean. Documented in this paper are Leaf movement and gas exchange responses of four soybean cultivars with different sensitivity to UV-B radiation to enhanced levels of UV-B, and modifications of these responses caused by water stress and nitrogen fertilization. UV-B radiation had no effect on the patterns of leaf orientation in soybean; however, a ranking of the cultivars based on midday leaf angles was the same as the ranking of these cultivars based on their sensitivity to UV-B radiation. Water and nitrogen altered the leaf movement patterns of soybeans. Gas exchange parameters in all four cultivars responded in a similar fashion to changes in leaf water potential. Reductions in water availability resulted in lower discrimination. Nitrogen fertilization in cv Forrest, also resulted in lower discrimination, especially under low water regimes, indicating a higher water use efficiency for fertilized plants. UV-B radiation resulted in lower discrimination in the UV-B sensitive CNS cultivar, indicating a stronger stomatal limitation to photosynthesis under increased UV-B levels

5 CFR 630.1015 - Movement between voluntary leave bank and leave transfer programs.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Movement between voluntary leave bank and leave transfer programs. 630.1015 Section 630.1015 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1015 Movement...

49 CFR 220.49 - Radio communication used in shoving, backing or pushing movements.

Science.gov (United States)

2010-10-01

... pushing movements. 220.49 Section 220.49 Transportation Other Regulations Relating to Transportation... Wireless Communication Procedures § 220.49 Radio communication used in shoving, backing or pushing movements. When radio communication is used in connection with the shoving, backing or pushing of a train...

Haematological parameters and recurrent aphthous stomatitis

International Nuclear Information System (INIS)

Khan, N. F.; Saeed, M.; Chaudhary, S.

2013-01-01

Objective: To find out the relationship between recurrent aphthous stomatitis (RAS) with deficiencies of haemoglobin, haematocrit, serum vitamin B12, serum Ferritin and red blood cells (RBC) Folate level. Study Design: An analytical cross-sectional study. Place and Duration of Study: Department of Oral Health Sciences, Shaikh Zayed Federal Postgraduate Medical Complex, Lahore, from February to July 2008. Methodology: Sixty consecutive subjects with active RAS were taken as the aphthous group; 60 age and gender matched subjects without RAS were as the Non-Aphthous group. Five milliliter blood was taken from both groups to evaluate the levels of serum B12, and RBC Folate through radio immuno assay and serum ferritin with enzyme linked immuno-sorbent assay tests. Complete blood count was carried out to determine the level of haemoglobin and haematocrit in both groups. Proportion of subjects with lower values was compared using 2 text of proportions with significance at p < 0.05. Results: Serum Ferritin (p = 0.001), haematocrit (p < 0.001), RBC Folate (p < 0.001) and serum B12 (p < 0.001) were significantly lower in the RAS group. Combined deficiency state (haemoglobin, serum Ferritin, haematocrit, RBC Folate and serum B12) was identified in 13% (n = 8) RAS patients. Conclusion: Frequency of haematinic deficiencies was high in RAS patients. Serum B12 and RBC Folate were significantly low in aphthous group. (author)

Quality of life in patients with recurrent aphthous stomatitis treated with a mucoadhesive patch containing citrus essential oil

Directory of Open Access Journals (Sweden)

Kürklü-Gürleyen E

2016-05-01

Full Text Available Esma Kürklü-Gürleyen,1 Merve Öğüt-Erişen,1 Onur Çakır,1 Ömer Uysal,2 Gülsüm Ak1 1Department of Oral Surgery, Faculty of Dentistry, Istanbul University, 2Department of Biostatistics and Medical Informatics, Faculty of Medicine, BezmiÂlem Vakif University, Istanbul, Turkey Purpose: To assess 1 patient satisfaction of a mucoadhesive biopatch with citrus essential oil and 2 the change in pain severity and the oral health-related quality of life in patients with recurrent aphthous stomatitis. Patients and methods: Thirty-seven patients with recurrent aphthous stomatitis participated in the study. Baseline records of personal data, ulcer assessment, visual analog scale, and Oral Health Impact Profile-14 were documented. A mucoadhesive patch was applied over the ulcer. Patients were recommended more applications if pain continued. On the fifth day, a post-therapy assessment was made. Results: The mean visual analog scale scores at baseline and posttreatment were significantly different (7.3±2.11 and 4.9±2.6, respectively; P=0.001. The mean duration of pain reduced after patch application. The mean total Oral Health Impact Profile-14 scores before and after treatment showed a statistically significant difference (P=0.001. In total, 78.4% of patients reported a considerable improvement in oral functions after treatment (P=0.008. Conclusion: The mucoadhesive biopatch containing citrus essential oil resulted in satisfying pain alleviation and restoration of oral functions with a significant improvement in the oral health-related quality of life. Keywords: recurrent aphthous stomatitis, pain, quality of life, essential oil, biopatch, local therapy 

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.

GeoVisual Analytics for the Exploration of Complex Movement Patterns on Arterial Roads

DEFF Research Database (Denmark)

Kveladze, Irma; Agerholm, Niels

2018-01-01

Visualization of complex spatio-temporal traffic movements on the road network is a challenging task since it requires simultaneous representation of vehicle measurement characteristics and traffic network regulation rules. Previously proposed visual representations addressed issues related....... Arterial roads are important for the mobility and connectivity of modern society, but they also have traffic regulations that are not always followed by the vulnerable road users. In order to understand complex movement behaviors between vehicle drivers and pedestrians on the arterial roads, a Geo......Visual Analytics approach was developed in dialog with traffic experts. The exploratory interactive tools have assisted experts to extract unknown information about movement patterns from large traffic data at different levels of details. The results of the analysis revealed detailed patterns of speed variations...

Diagnosis and management of recurrent herpetiform stomatitis and Behçet syndrome like recurrent aphthous stomatitis herpetiform type

Directory of Open Access Journals (Sweden)

Endah Ayu Tri Wulandari

2008-11-01

Full Text Available Recurrent Aphthous Stomatitis (RAS is a common inflammatory condition of the oral mucosa. The aetiology of RAS remains unclear, yet there are several predisposing factors which could be involved in the onset of the lesion. The herpetiform type of RAS appeared to be similar to recurrent oral Herpes Simplex infection and also could be part of Behçet Syndrome. This case report discussed a patient suffering from a herpetiform type of RAS with its clinical appearance resembling recurrent oral Herpes Simplex infection and Behçet syndrome. Initial treatment was undertaken based on the empirical treatment, yet the respond was not satisfactory. Then, laboratory tests were undertaken, including complete blood count, the total population of T lymphocyte, B lymphocyte, T helper, T suppressor, NK cells, T helper/T suppressor ratio, C3, C4, IgG, IgA, and IgM. These tests showed that there were immune and hematinic deficiency condition. Nevertheless, the clinical appearance, laboratory findings and consultation did not support the diagnosis of recurrent oral Herpes Simplex infection and Behçet Syndrome, thus, enhancing the definite diagnosis of the herpetiform type of RAS with immune and hematinic deficiency as the underlying condition. Based on the definite diagnosis, treatment plan was then revised to target the underlying condition.

Radioimmunological determination of plasma cortisol following application of a stomatic paste containing prednisolone (DontisolonR)

International Nuclear Information System (INIS)

Stehn, H.

1985-01-01

A radioimmunological method was used to determine the cortisol plasma levels of 69 patients, treated with a stomatic paste containing prednisolone. Significant changes in plasma cortisol were only established in connection with a dose regimen of 3 times 1.25 mg daily. In isolated cases, however, there were major decreases in response to exposure to prednisolone. Therefore, the anamnestic data of any one patient being prescribed corticoids must be examined with care. (TRV) [de

The influence of climate change on stomatal ozone flux to a mountain Norway spruce forest

Czech Academy of Sciences Publication Activity Database

Zapletal, M.; Pretel, J.; Chroust, P.; Cudlín, Pavel; Edwards-Jonášová, Magda; Urban, Otmar; Pokorný, Radek; Czerný, Radek; Hůnová, I.

2012-01-01

Roč. 169, OCT 2012 (2012), s. 267-273 ISSN 0269-7491 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk OC10022; GA MŠk(CZ) LM2010007 Institutional research plan: CEZ:AV0Z60870520 Keywords : Stomatal ozone flux * AOT40 * Phytotoxic Ozone Dose * Norway spruce * Net ecosystem production * Ozone * Climate change Subject RIV: EH - Ecology, Behaviour Impact factor: 3.730, year: 2012

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (pfapa) syndrome in children.

Science.gov (United States)

Semianchuk, Vira B

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome refers to a group of primary immunodeficiencies, namely autoinflammatory diseases. Most pediatricians and otolaryngologists do not suspect PFAPA syndrome when treating recurrent pharyngitis (according to Ukrainian classification - tonsillitis) and stomatitis. Therefore, patients with a given syndrome receive unnecessary treatment (antibiotic therapy or antiviral drugs) and the diagnosis is made late. The aim of the research was to provide pediatricians, family physicians and otolaryngologists with information on the importance of early diagnosis of PFAPA syndrome. The analysis of the prevalence and diagnosis of PFAPA syndrome in Ukraine and worldwide has been made as well as a late diagnosis of PFAPA syndrome in a child living in Ivano-Frankivsk, Ukraine has been described (case report). The Сase report 7-year-old boy, who grows and develops normally. The symptoms of pharyngitis including high body temperature (>40 º С), sore throat and white spots on the tonsils appeared for the first time at the age of two years. The boy received antibacterial drugs about 10 times a year. During a four-year period of recurrent episodes of the disease antimicrobial susceptibility testing to determine susceptibility of the oropharyngeal flora to the antibiotics were continuously performed, different blood tests for herpes viruses, Epstein-Barr virus infection and cytomegalovirus in particular were made using the enzyme immunoassay (EIA) and polymerase chain reaction (PCR) in addition to long-term treatment. An example of late diagnosing PFAPA syndrome (four years after the onset of first symptoms) resulting in regular examinations, medical manoeuvres, outpatient and inpatient treatment, use of antibiotic therapy including intravenous injections on a monthly basis has been studied.

Stomatal closure of Pelargonium × hortorum in response to soil water deficit is associated with decreased leaf water potential only under rapid soil drying.

Science.gov (United States)

Boyle, Richard K A; McAinsh, Martin; Dodd, Ian C

2016-01-01

Soil water deficits applied at different rates and for different durations can decrease both stomatal conductance (gs ) and leaf water potential (Ψleaf ). Understanding the physiological mechanisms regulating these responses is important in sustainable irrigation scheduling. Glasshouse-grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at various fractions of plant evapotranspiration (100, 75 and 50% ET) for 20 days or irrigation was withheld for 4 days. Xylem sap was collected and gs and Ψleaf were measured on days 15 and 20, and on days 16-19 for the respective treatments. Xylem sap pH and NO3 (-) and Ca(2+) concentrations did not differ between irrigation treatments. Xylem abscisic acid (ABA) concentrations ([ABA]xyl ) increased within 24 h of irrigation being withheld whilst gs and Ψleaf decreased. Supplying irrigation at a fraction of daily ET produced a similar relationship between [ABA]xyl and gs , but did not change Ψleaf . Treatment differences occurred independently of whether Ψleaf was measured in whole leaves with a pressure chamber, or in the lamina with a thermocouple psychrometer. Plants that were irrigated daily showed lower [ABA]xyl than plants from which irrigation was withheld, even at comparable soil moisture content. This implies that regular re-watering attenuates ABA signaling due to maintenance of soil moisture in the upper soil levels. Crucially, detached leaves supplied with synthetic ABA showed a similar relationship between [ABA]xyl and gs as intact plants, suggesting that stomatal closure of P. hortorum in response to soil water deficit is primarily an ABA-induced response, independent of changes in Ψleaf . © 2015 Scandinavian Plant Physiology Society.

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.

The paradox of uranium development: A Polanyian analysis of social movements surrounding the Pinon Ridge Uranium Mill

Science.gov (United States)

Malin, Stephanie A.

Renewal of nuclear energy development has been proposed as one viable solution for reducing greenhouse gas emissions and impacts of climate change. This discussion became concrete as the first uranium mill proposed since the end of the Cold War, the Pinon Ridge Uranium Mill, received state permits in January 2011 to process uranium in southwest Colorado's Paradox Valley. Though environmental contamination from previous uranium activity caused one local community to be bulldozed to the ground, local support for renewed uranium activity emerges among local residents in communities like Nucla, Naturita, and Bedrock, Colorado. Regionally, however, a coalition of organized, oppositionbased grassroots groups fights the decision to permit the mill. Combined, these events allow social scientists a natural laboratory through which to view social repercussions of nuclear energy development. In this dissertation, I use a Polanyian theoretical framework to analyze social, political-economic, and environmental contexts of social movements surrounding PR Mill. My overarching research problem is: How might Polanyian double movement theory be applied to and made empirically testable within the social and environmental context of uranium development? I intended this analysis to inform energy policy debates regarding renewable energy. In Chapter 1, I found various forms of social dislocation lead to two divergent social movement outcomes. Economic social dislocation led to strong mill support among most local residents, according to archival, in-depth interview, and survey data. On the other hand, residents in regional communities experienced two other types of social dislocation -- another kind of economic dislocation, related to concern over boom-bust economies, and environmental health dislocations related to uranium exposure, creating conditions for a regional movement in opposition to PR Mill. In Chapter 2, I focus on regulations and find that two divergent social movements

Role of norepinephrine in the regulation of rapid eye movement sleep

Indian Academy of Sciences (India)

Sleep and wakefulness are instinctive behaviours that are present across the animal species. Rapid eye movement (REM) sleep is a unique biological phenomenon expressed during sleep. It evolved about 300 million years ago and is noticed in the more evolved animal species. Although it has been objectively identified ...

Trends in stomatal density and 13C/12C ratios of Pinus flexilis needles during last glacial-interglacial cycle

International Nuclear Information System (INIS)

Van de Water, P.K.; Leavitt, S.W.; Betancourt, J.L.

1994-01-01

Measurements of stomatal density and delta 13C of limber pine (Pinus flexilis) needles (leaves) preserved in pack rat middens from the Great Basin reveal shifts in plant physiology and leaf morphology during the last 30,000 years. Sites were selected so as to offset glacia to Holocene climatic differences and thus to isolate the effects of changing atmospheric CO2 levels. Stomatal density decreased approximately 17 percent and delta 13C decreased approximately 1.5 per ml during deglaciation from 15,000 to 12,000 years ago, concomitant with a 30 percent increase in atmospheric CO2. Water-use efficiency increased approximately 15 percent during deglaciation, if temperature and humidity were held constant and the proxy values for CO2 and delta 13C of past atmospheres are accurate. The delta 13C variations may help constrain hypotheses about the redistribution of carbon between the atmosphere and biosphere during the last glacial-interglacial cycle

Leptotene/zygotene chromosome movement via the SUN/KASH protein bridge in Caenorhabditis elegans.

Science.gov (United States)

Baudrimont, Antoine; Penkner, Alexandra; Woglar, Alexander; Machacek, Thomas; Wegrostek, Christina; Gloggnitzer, Jiradet; Fridkin, Alexandra; Klein, Franz; Gruenbaum, Yosef; Pasierbek, Pawel; Jantsch, Verena

2010-11-24

The Caenorhabditis elegans inner nuclear envelope protein matefin/SUN-1 plays a conserved, pivotal role in the process of genome haploidization. CHK-2-dependent phosphorylation of SUN-1 regulates homologous chromosome pairing and interhomolog recombination in Caenorhabditis elegans. Using time-lapse microscopy, we characterized the movement of matefin/SUN-1::GFP aggregates (the equivalent of chromosomal attachment plaques) and showed that the dynamics of matefin/SUN-1 aggregates remained unchanged throughout leptonene/zygotene, despite the progression of pairing. Movement of SUN-1 aggregates correlated with chromatin polarization. We also analyzed the requirements for the formation of movement-competent matefin/SUN-1 aggregates in the context of chromosome structure and found that chromosome axes were required to produce wild-type numbers of attachment plaques. Abrogation of synapsis led to a deceleration of SUN-1 aggregate movement. Analysis of matefin/SUN-1 in a double-strand break deficient mutant revealed that repair intermediates influenced matefin/SUN-1 aggregate dynamics. Investigation of movement in meiotic regulator mutants substantiated that proper orchestration of the meiotic program and effective repair of DNA double-strand breaks were necessary for the wild-type behavior of matefin/SUN-1 aggregates.

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

75 FR 31747 - Notice of Request for Extension of Approval of an Information Collection; Interstate Movement of...

Science.gov (United States)

2010-06-04

...] Notice of Request for Extension of Approval of an Information Collection; Interstate Movement of Certain... interstate movement of certain land tortoises. DATES: We will consider all comments that we receive on or... FURTHER INFORMATION CONTACT: For information on regulations for the interstate movement of certain land...

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

Science.gov (United States)

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

2010-01-01

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...

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...

Stomatal conductance, mesophyll conductance, and trans piration efficiency in relation to leaf anatomy in rice and wheat genotypes under drought

NARCIS (Netherlands)

Ouyang, Wenjing; Struik, Paul C.; Yin, Xinyou; Yang, Jianchang

2017-01-01

Increasing leaf transpiration efficiency (TE) may provide leads for growing rice like dryland cereals such as wheat (Triticum aestivum). To explore avenues for improving TE in rice, variations in stomatal conductance (g s) and mesophyll conductance (g m) and their anatomical determinants were

Zona Hambat Ekstrak Daun Sirih Merah Terhadap Staphylococcus Aureus Dan Candida Albicans Diisolasi Dari Denture Stomatitis

OpenAIRE

Veronika, lara

2017-01-01

Zona Hambat Ekstrak Daun Sirih Merah terhadap Staphylococcus aureus dan Candida albicans diisolasi dari denture stomatitis xi + 43 halaman Ekstrak daun sirih merah merupakan salah satu obat tradisional yang saat ini banyak digunakan masyarakat Indonesia. Ekstrak daun sirih merah ini dapat menghambat pertumbuhan bakteri dan jamur disebabkan karena adanya senyawa alkaloid, flavonoid, polifenol, tanin dan minyak atsiri. Salah satu bakteri dan jamur yang dapat dihambat oleh ekstrak daun sir...

The Arabidopsis Cysteine-Rich Receptor-Like Kinase CRK36 Regulates Immunity through Interaction with the Cytoplasmic Kinase BIK1

Directory of Open Access Journals (Sweden)

Dong Sook Lee

2017-10-01

Full Text Available Receptor-like kinases are important signaling components that regulate a variety of cellular processes. In this study, an Arabidopsis cDNA microarray analysis led to the identification of the cysteine-rich receptor-like kinase CRK36 responsive to the necrotrophic fungal pathogen, Alternaria brassicicola. To determine the function of CRK36 in plant immunity, T-DNA-insertion knockdown (crk36 and overexpressing (CRK36OE plants were prepared. CRK36OE plants exhibited increased hypersensitive cell death and ROS burst in response to avirulent pathogens. Treatment with a typical pathogen-associated molecular pattern, flg22, markedly induced pattern-triggered immune responses, notably stomatal defense, in CRK36OE plants. The immune responses were weakened in crk36 plants. Protein-protein interaction assays revealed the in vivo association of CRK36, FLS2, and BIK1. CRK36 enhanced flg22-triggered BIK1 phosphorylation, which showed defects with Cys mutations in the DUF26 motifs of CRK36. Disruption of BIK1 and RbohD/RbohF genes further impaired CRK36-mediated stomatal defense. We propose that CRK36, together with BIK1 and NADPH oxidases, may form a positive activation loop that enhances ROS burst and leads to the promotion of stomatal immunity.

The inappropriate occurrence of rapid eye movement sleep in narcolepsy is not due to a defect in homeostatic regulation of rapid eye movement sleep.

Science.gov (United States)

Roman, Alexis; Meftah, Soraya; Arthaud, Sébastien; Luppi, Pierre-Hervé; Peyron, Christelle

2018-06-01

Narcolepsy type 1 is a disabling disorder with four primary symptoms: excessive-daytime-sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. The later three symptoms together with a short rapid eye movement (REM) sleep latency have suggested impairment in REM sleep homeostatic regulation with an enhanced propensity for (i.e. tendency to enter) REM sleep. To test this hypothesis, we challenged REM sleep homeostatic regulation in a recognized model of narcolepsy, the orexin knock-out (Orex-KO) mice and their wild-type (WT) littermates. We first performed 48 hr of REM sleep deprivation using the classic small-platforms-over-water method. We found that narcoleptic mice are similarly REM sleep deprived to WT mice. Although they had shorter sleep latency, Orex-KO mice recovered similarly to WT during the following 10 hr of recovery. Interestingly, Orex-KO mice also had cataplexy episodes immediately after REM sleep deprivation, anticipating REM sleep rebound, at a time of day when cataplexy does not occur in baseline condition. We then evaluated REM sleep propensity using our new automated method of deprivation that performs a specific and efficient REM sleep deprivation. We showed that REM sleep propensity is similar during light phase in Orex-KO and WT mice. However, during the dark phase, REM sleep propensity was not suppressed in Orex-KO mice when hypocretin/orexin neuropeptides are normally released. Altogether our data suggest that in addition to the well-known wake-promoting role of hypocretin/orexin, these neuropeptides would also suppress REM sleep. Therefore, hypocretin/orexin deficiency would facilitate the occurrence of REM sleep at any time of day in an opportunistic manner as seen in human narcolepsy.

76 FR 34033 - Notice of Request for Extension of Approval of an Information Collection; Interstate Movement of...

Science.gov (United States)

2011-06-10

...] Notice of Request for Extension of Approval of an Information Collection; Interstate Movement of Sheep... movement of sheep and goats to control the spread of scrapie. DATES: We will consider all comments that we... . FOR FURTHER INFORMATION CONTACT: For information on regulations for the interstate movement of sheep...

Testing a hydraulic trait based model of stomatal control: results from a controlled drought experiment on aspen (Populus tremuloides, Michx.) and ponderosa pine (Pinus ponderosa, Douglas)

Science.gov (United States)

Love, D. M.; Venturas, M.; Sperry, J.; Wang, Y.; Anderegg, W.

2017-12-01

Modeling approaches for tree stomatal control often rely on empirical fitting to provide accurate estimates of whole tree transpiration (E) and assimilation (A), which are limited in their predictive power by the data envelope used to calibrate model parameters. Optimization based models hold promise as a means to predict stomatal behavior under novel climate conditions. We designed an experiment to test a hydraulic trait based optimization model, which predicts stomatal conductance from a gain/risk approach. Optimal stomatal conductance is expected to maximize the potential carbon gain by photosynthesis, and minimize the risk to hydraulic transport imposed by cavitation. The modeled risk to the hydraulic network is assessed from cavitation vulnerability curves, a commonly measured physiological trait in woody plant species. Over a growing season garden grown plots of aspen (Populus tremuloides, Michx.) and ponderosa pine (Pinus ponderosa, Douglas) were subjected to three distinct drought treatments (moderate, severe, severe with rehydration) relative to a control plot to test model predictions. Model outputs of predicted E, A, and xylem pressure can be directly compared to both continuous data (whole tree sapflux, soil moisture) and point measurements (leaf level E, A, xylem pressure). The model also predicts levels of whole tree hydraulic impairment expected to increase mortality risk. This threshold is used to estimate survivorship in the drought treatment plots. The model can be run at two scales, either entirely from climate (meteorological inputs, irrigation) or using the physiological measurements as a starting point. These data will be used to study model performance and utility, and aid in developing the model for larger scale applications.

7 CFR 330.206 - Permits for plant pest movement associated with National Defense projects.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Permits for plant pest movement associated with... (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.206...

The annual variation in stomatal ammonia compensation point of rye grass (Lolium perenne L.) leaves in an intensively managed grassland

NARCIS (Netherlands)

Hove, van L.W.A.; Heeres, P.; Bossen, M.E.

2002-01-01

The stomatal ammonia compensation point for ammonia (NH3) of an intensively managed pasture of rye grass (Lolium perenne L.) was followed from mid January till November 2000. Leaf samples were taken every week. Simultaneously, the ambient NH3 concentration was measured. Meteorological data

The lipidomes of vesicular stomatitis virus, semliki forest virus, and the host plasma membrane analyzed by quantitative shotgun mass spectrometry

DEFF Research Database (Denmark)

Kalvodova, Lucie; Sampaio, Julio L; Cordo, Sandra

2009-01-01

kidney cells can be infected by two different viruses, namely, vesicular stomatitis virus and Semliki Forest virus, from the Rhabdoviridae and Togaviridae families, respectively. We purified the host plasma membrane and the two different viruses after exit from the host cells and analyzed the lipid...

Stomatal and pavement cell density linked to leaf internal CO2 concentration.

Science.gov (United States)

Santrůček, Jiří; Vráblová, Martina; Simková, Marie; Hronková, Marie; Drtinová, Martina; Květoň, Jiří; Vrábl, Daniel; Kubásek, Jiří; Macková, Jana; Wiesnerová, Dana; Neuwithová, Jitka; Schreiber, Lukas

2014-08-01

Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. (13)C abundance (δ(13)C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci-SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Tactile information processing in primate hand somatosensory cortex (S1) during passive arm movement.

Science.gov (United States)

Song, Weiguo; Francis, Joseph Thachil

2013-11-01

Motor output mostly depends on sensory input, which also can be affected by action. To further our understanding of how tactile information is processed in the primary somatosensory cortex (S1) in dynamic environments, we recorded neural responses to tactile stimulation of the hand in three awake monkeys under arm/hand passive movement and rest. We found that neurons generally responded to tactile stimulation under both conditions and were modulated by movement: with a higher baseline firing rate, a suppressed peak rate, and a smaller dynamic range during passive movement than during rest, while the area under the response curve was stable across these two states. By using an information theory-based method, the mutual information between tactile stimulation and neural responses was quantified with rate and spatial coding models under the two conditions. The two potential encoding models showed different contributions depending on behavioral contexts. Tactile information encoded with rate coding from individual units was lower than spatial coding of unit pairs, especially during movement; however, spatial coding had redundant information between unit pairs. Passive movement regulated the mutual information, and such regulation might play different roles depending on the encoding strategies used. The underlying mechanisms of our observation most likely come from a bottom-up strategy, where neurons in S1 were regulated through the activation of the peripheral tactile/proprioceptive receptors and the interactions between these different types of information.

Longevity of guard cell chloroplasts in falling leaves: implication for stomatal function and cellular aging.

Science.gov (United States)

Zeiger, E; Schwartz, A

1982-11-12

Guard cell chloroplasts in senescing leaves from 12 species of perennial trees and three species of annual plants survived considerably longer than their mesophyll counterparts. In Ginkgo biloba, stomata from yellow leaves opened during the day and closed at night; guard cell chloroplasts from these leaves showed fluorescence transients associated with electron transport and photophosphorylation. These findings indicate that guard cell chloroplasts are highly conserved throughout the life-span of the leaf and that leaves retain stomatal control during senescence.

Characteristics of rapid eye movement sleep behavior disorder in narcolepsy

DEFF Research Database (Denmark)

Jennum, Poul Jørgen; Frandsen, Rune Asger Vestergaard; Knudsen, Stine

2013-01-01

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by dream-enacting behavior and impaired motor inhibition during REM sleep (REM sleep without atonia, RSWA). RBD is commonly associated with Parkinsonian disorders, but is also reported in narcolepsy. Most patients...... of hypocretin deficiency. Thus, hypocretin deficiency is linked to the two major disturbances of REM sleep motor regulation in narcolepsy: RBD and cataplexy. Moreover, it is likely that hypocretin deficiency independently predicts periodic limb movements in REM and NREM sleep, probably via involvement...... of the dopaminergic system. This supports the hypothesis that an impaired hypocretin system causes general instability of motor regulation during wakefulness, REM and NREM sleep in human narcolepsy. We propose that hypocretin neurons are centrally involved in motor tone control during wakefulness and sleep in humans...

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

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 low...

Atmospheric CO2 Alters Resistance of Arabidopsis to Pseudomonas syringae by Affecting Abscisic Acid Accumulation and Stomatal Responsiveness to Coronatine

NARCIS (Netherlands)

Zhou, Y.; Vroegop-Vos, I.; Schuurink, R.C.; Pieterse, C.M.J.; Van Wees, S.C.M.

Atmospheric CO2 influences plant growth and stomatal aperture. Effects of high or low CO2 levels on plant disease resistance are less well understood. Here, resistance of Arabidopsis thaliana against the foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) was investigated at three different

Movement: How the Brain Communicates with the World.

Science.gov (United States)

Schwartz, Andrew B

2016-03-10

Voluntary movement is a result of signals transmitted through a communication channel that links the internal world in our minds to the physical world around us. Intention can be considered the desire to effect change on our environment, and this is contained in the signals from the brain, passed through the nervous system to converge on muscles that generate displacements and forces on our surroundings. The resulting changes in the world act to generate sensations that feed back to the nervous system, closing the control loop. This Perspective discusses the experimental and theoretical underpinnings of current models of movement generation and the way they are modulated by external information. Movement systems embody intentionality and prediction, two factors that are propelling a revolution in engineering. Development of movement models that include the complexities of the external world may allow a better understanding of the neuronal populations regulating these processes, as well as the development of solutions for autonomous vehicles and robots, and neural prostheses for those who are motor impaired. Copyright © 2016 Elsevier Inc. All rights reserved.

A movement ecology paradigm for unifying organismal movement research.

Science.gov (United States)

Nathan, Ran; Getz, Wayne M; Revilla, Eloy; Holyoak, Marcel; Kadmon, Ronen; Saltz, David; Smouse, Peter E

2008-12-09

Movement of individual organisms is fundamental to life, quilting our planet in a rich tapestry of phenomena with diverse implications for ecosystems and humans. Movement research is both plentiful and insightful, and recent methodological advances facilitate obtaining a detailed view of individual movement. Yet, we lack a general unifying paradigm, derived from first principles, which can place movement studies within a common context and advance the development of a mature scientific discipline. This introductory article to the Movement Ecology Special Feature proposes a paradigm that integrates conceptual, theoretical, methodological, and empirical frameworks for studying movement of all organisms, from microbes to trees to elephants. We introduce a conceptual framework depicting the interplay among four basic mechanistic components of organismal movement: the internal state (why move?), motion (how to move?), and navigation (when and where to move?) capacities of the individual and the external factors affecting movement. We demonstrate how the proposed framework aids the study of various taxa and movement types; promotes the formulation of hypotheses about movement; and complements existing biomechanical, cognitive, random, and optimality paradigms of movement. The proposed framework integrates eclectic research on movement into a structured paradigm and aims at providing a basis for hypothesis generation and a vehicle facilitating the understanding of the causes, mechanisms, and spatiotemporal patterns of movement and their role in various ecological and evolutionary processes. "Now we must consider in general the common reason for moving with any movement whatever." (Aristotle, De Motu Animalium, 4th century B.C.).

Growth, leaf and stomatal traits of crabwood (Carapa guianensis Aubl. in central Amazonia

Directory of Open Access Journals (Sweden)

Miguel Angelo Branco Camargo

2012-02-01

Full Text Available Crabwood (Carapa guianensis Aubl. is a fast growing tree species with many uses among Amazonian local communities. The main objective of this study was to assess the effect of seasonal rainfall pattern on growth rates, and seasonal and diurnal changes in leaf gas exchange and leaf water potential (ΨL in crabwood. To assess the effect of rainfall seasonality on growth and physiological leaf traits an experiment was conducted in Manaus, AM (03º 05' 30" S, 59º 59' 35" S. In this experiment, six 6-m tall plants were used to assess photosynthetic traits and ΨL. In a second experiment the effect of growth irradiance on stomatal density (S D, size (S S and leaf thickness was assessed in 0.8-m tall saplings. Stomatal conductance (g s and light-saturated photosynthesis (Amax were higher in the wet season, and between 09:00 and 15:00 h. However, no effect of rainfall seasonality was found on ΨL and potential photosynthesis (CO2-saturated. ΨL declined from -0.3 MPa early in the morning to -0.75 MPa after midday. It increased in the afternoon but did not reach full recovery at sunset. Growth rates of crabwood were high, and similar in both seasons (2 mm month-1. Leaf thickness and S D were 19% and 47% higher in sun than in shade plants, whereas the opposite was true for S S. We conclude that ΨL greatly affects carbon assimilation of crabwood by reducing g s at noon, although this effect is not reflected on growth rates indicating that other factors offset the effect of g s on Amax.

7 CFR 330.302 - Domestic movements of earth (including soil), stone, etc.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Domestic movements of earth (including soil), stone, etc. 330.302 Section 330.302 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY...

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.

How should leaf area, sapwood area and stomatal conductance vary with tree height to maximize growth?

Science.gov (United States)

Buckley, Thomas N; Roberts, David W

2006-02-01

Conventional wisdom holds that the ratio of leaf area to sapwood area (L/S) should decline during height (H) growth to maintain hydraulic homeostasis and prevent stomatal conductance (g(s)) from declining. We contend that L/S should increase with H based on a numerical simulation, a mathematical analysis and a conceptual argument: (1) numerical simulation--a tree growth model, DESPOT (Deducing Emergent Structure and Physiology Of Trees), in which carbon (C) allocation is regulated to maximize C gain, predicts L/S should increase during most of H growth; (2) mathematical analysis--the formal criterion for optimal C allocation, applied to a simplified analytical model of whole tree carbon-water balance, predicts L/S should increase with H if leaf-level gas exchange parameters including g(s) are conserved; and (3) conceptual argument--photosynthesis is limited by several substitutable resources (chiefly nitrogen (N), water and light) and H growth increases the C cost of water transport but not necessarily of N and light capture, so if the goal is to maximize C gain or growth, allocation should shift in favor of increasing photosynthetic capacity and irradiance, rather than sustaining g(s). Although many data are consistent with the prediction that L/S should decline with H, many others are not, and we discuss possible reasons for these discrepancies.

The diversity of (13)C isotope discrimination in a Quercus robur full-sib family is associated with differences in intrinsic water use efficiency, transpiration efficiency, and stomatal conductance.

Science.gov (United States)

Roussel, Magali; Dreyer, Erwin; Montpied, Pierre; Le-Provost, Grégoire; Guehl, Jean-Marc; Brendel, Oliver

2009-01-01

(13)C discrimination in organic matter with respect to atmospheric CO(2) (Delta(13)C) is under tight genetic control in many plant species, including the pedunculate oak (Quercus robur L.) full-sib progeny used in this study. Delta(13)C is expected to reflect intrinsic water use efficiency, but this assumption requires confirmation due to potential interferences with mesophyll conductance to CO(2), or post-photosynthetic discrimination. In order to dissect the observed Delta(13)C variability in this progeny, six genotypes that have previously been found to display extreme phenotypic values of Delta(13)C [either very high ('high Delta') or low ('low Delta') phenotype] were selected, and transpiration efficiency (TE; accumulated biomass/transpired water), net CO(2) assimilation rate (A), stomatal conductance for water vapour (g(s)), and intrinsic water use efficiency (W(i)=A/g(s)) were compared with Delta(13)C in bulk leaf matter, wood, and cellulose in wood. As expected, 'high Delta' displayed higher values of Delta(13)C not only in bulk leaf matter, but also in wood and cellulose. This confirmed the stability of the genotypic differences in Delta(13)C recorded earlier. 'High Delta' also displayed lower TE, lower W(i), and higher g(s). A small difference was detected in photosynthetic capacity but none in mesophyll conductance to CO(2). 'High Delta' and 'low Delta' displayed very similar leaf anatomy, except for higher stomatal density in 'high Delta'. Finally, diurnal courses of leaf gas exchange revealed a higher g(s) in 'high Delta' in the morning than in the afternoon when the difference decreased. The gene ERECTA, involved in the control of water use efficiency, leaf differentiation, and stomatal density, displayed higher expression levels in 'low Delta'. In this progeny, the variability of Delta(13)C correlated closely with that of W(i) and TE. Genetic differences of Delta(13)C and W(i) can be ascribed to differences in stomatal conductance and stomatal

Independence of Movement Preparation and Movement Initiation.

Science.gov (United States)

Haith, Adrian M; Pakpoor, Jina; Krakauer, John W

2016-03-09

Initiating a movement in response to a visual stimulus takes significantly longer than might be expected on the basis of neural transmission delays, but it is unclear why. In a visually guided reaching task, we forced human participants to move at lower-than-normal reaction times to test whether normal reaction times are strictly necessary for accurate movement. We found that participants were, in fact, capable of moving accurately ∼80 ms earlier than their reaction times would suggest. Reaction times thus include a seemingly unnecessary delay that accounts for approximately one-third of their duration. Close examination of participants' behavior in conventional reaction-time conditions revealed that they generated occasional, spontaneous errors in trials in which their reaction time was unusually short. The pattern of these errors could be well accounted for by a simple model in which the timing of movement initiation is independent of the timing of movement preparation. This independence provides an explanation for why reaction times are usually so sluggish: delaying the mean time of movement initiation relative to preparation reduces the risk that a movement will be initiated before it has been appropriately prepared. Our results suggest that preparation and initiation of movement are mechanistically independent and may have a distinct neural basis. The results also demonstrate that, even in strongly stimulus-driven tasks, presentation of a stimulus does not directly trigger a movement. Rather, the stimulus appears to trigger an internal decision whether to make a movement, reflecting a volitional rather than reactive mode of control. Copyright © 2016 the authors 0270-6474/16/363007-10$15.00/0.

Computational movement analysis

CERN Document Server

Laube, Patrick

2014-01-01

This SpringerBrief discusses the characteristics of spatiotemporal movement data, including uncertainty and scale. It investigates three core aspects of Computational Movement Analysis: Conceptual modeling of movement and movement spaces, spatiotemporal analysis methods aiming at a better understanding of movement processes (with a focus on data mining for movement patterns), and using decentralized spatial computing methods in movement analysis. The author presents Computational Movement Analysis as an interdisciplinary umbrella for analyzing movement processes with methods from a range of fi

TCR Down-Regulation Controls Virus-Specific CD8+ T Cell Responses

DEFF Research Database (Denmark)

Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil

2008-01-01

The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the antiapoptotic...... molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in virus...

Abscisic Acid Content, Transpiration, and Stomatal Conductance As Related to Leaf Age in Plants of Xanthium strumarium L.

Science.gov (United States)

Raschke, K; Zeevaart, J A

1976-08-01

Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L. the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (+/-)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells.The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight.

Two transcription products of the vesicular stomatitis virus genome may control L-cell protein synthesis

International Nuclear Information System (INIS)

Dunigan, D.D.; Lucas-Lenard, J.M.

1983-01-01

When mouse L-cells are infected with vesicular stomatitis virus, there is a decrease in the rate of protein synthesis ranging from 20 to 85% of that in mock-infected cells. Vesicular stomatitis virus, irradiated with increasing doses of UV light, eventually loses this capacity to inhibit protein synthesis. The UV inactivation curve was biphasic, suggesting that transcription of two regions of the viral genome is necessary for the virus to become inactivated in this capacity. The first transcription produced corresponded to about 373 nucleotides, and the second corresponded to about 42 nucleotides. Inhibition of transcription of the larger product by irradiating the virus with low doses of UV light left a residual inhibition of protein synthesis consisting of approximately 60 to 65% of the total inhibition. This residual inhibition could be obviated by irradiating the virus with a UV dose of greater than 20,000 ergs/mm 2 and was thus considered to represent the effect of the smaller transcription product. In the R1 mutant of another author, the inhibition of transcription of the larger product sufficed to restore protein synthesis to the mock-infected level, suggesting that the smaller transcription product is nonfunctional with respect to protein synthesis inhibition. Extracts from cells infected with virus irradiated with low doses of UV light showed a protein synthesis capacity quite similar to that of their in vivo counterparts, indicating that these extracts closely reflect the in vivo effects of virus infection

Low doses of glyphosate enhance growth, CO2 assimilation, stomatal conductance and transpiration in sugarcane and eucalyptus.

Science.gov (United States)

Nascentes, Renan F; Carbonari, Caio A; Simões, Plinio S; Brunelli, Marcela C; Velini, Edivaldo D; Duke, Stephen O

2018-05-01

Sublethal doses of herbicides can enhance plant growth and stimulate other process, an effect known as hormesis. The magnitude of hormesis is dependent on the plant species, the herbicide and its dose, plant development stage and environmental parameters. Glyphosate hormesis is well established, but relatively little is known of the mechanism of this phenomenon. The objective of this study was to determine if low doses of glyphosate that cause growth stimulation in sugarcane and eucalyptus concomitantly stimulate CO 2 assimilation. Shoot dry weight in both species increased at both 40 and 60 days after application of 6.2 to 20.2 g a.e. ha -1 glyphosate. The level of enhanced shoot dry weight was 11 to 37%, depending on the time after treatment and the species. Concomitantly, CO 2 assimilation, stomatal conductance and transpiration were increased by glyphosate doses similar to those that caused growth increases. Glyphosate applied at low doses increased the dry weight of sugarcane and eucalyptus plants in all experiments. This hormetic effect was related to low dose effects on CO 2 assimilation rate, stomatal conductance and transpiration rate, indicating that low glyphosate doses enhance photosynthesis of plants. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Epizootic vesicular stomatitis in Colorado, 1982: epidemiologic and entomologic studies.

Science.gov (United States)

Walton, T E; Webb, P A; Kramer, W L; Smith, G C; Davis, T; Holbrook, F R; Moore, C G; Schiefer, T J; Jones, R H; Janney, G C

1987-01-01

An epizootic of vesicular stomatitis (VS) caused by the New Jersey serotype of VS virus affected livestock and humans in 14 western states in 1982-1983. Epidemiological observations were made on at least 10% of the cattle in 4 dairy herds that were located in the vicinity of Grand Junction, Colorado. High rates of neutralizing antibody to the New Jersey serotype were seen in all cattle regardless of whether livestock in the dairy had clinical VS or a decrease in mild production. Antibody titers remained high in these cattle for as long as 2 years after the epizootic. No virus isolations were made from 32 humans with clinical signs compatible with viral disease. Entomological information was obtained during the epizootic from 23 premises in northwestern Colorado. Insect collections yielded 4 isolates from Culicoides spp. midges, 2 from C. variipennis, and 1 each from C. stellifer and C. (Selfia) spp. This is the first report of VS virus isolations from field-collected Culicoides.

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.

78 FR 40651 - Regulated Navigation Area; Special Buzzards Bay Vessel Regulation, Buzzards Bay, MA

Science.gov (United States)

2013-07-08

... Carrier Program RNA Regulated Navigation Area RA Technical Risk Assessment VMRS Vessel Movement Reporting... avoid the fragmentation of regulatory regimes as a vessel transits across State [[Page 40652

Rapid eye movement sleep behaviour disorder in patients with narcolepsy is associated with hypocretin-1 deficiency

DEFF Research Database (Denmark)

Knudsen, Stine; Gammeltoft, Steen; Jennum, Poul J

2010-01-01

Rapid eye movement sleep behaviour disorder is characterized by dream-enacting behaviour and impaired motor inhibition during rapid eye movement sleep. Rapid eye movement sleep behaviour disorder is commonly associated with neurodegenerative disorders, but also reported in narcolepsy with cataplexy....... Most narcolepsy with cataplexy patients lack the sleep-wake, and rapid eye movement sleep, motor-regulating hypocretin neurons in the lateral hypothalamus. In contrast, rapid eye movement sleep behaviour disorder and hypocretin deficiency are rare in narcolepsy without cataplexy. We hypothesized...... that rapid eye movement sleep behaviour disorder coexists with cataplexy in narcolepsy due to hypocretin deficiency. In our study, rapid eye movement sleep behaviour disorder was diagnosed by the International Classification of Sleep Disorders (2nd edition) criteria in 63 narcolepsy patients with or without...

The Free Movement of Capital and Foreign Direct Investment

DEFF Research Database (Denmark)

Hindelang, Steffen

2009-01-01

The scope of protection offered to foreign investors by EU law has become a matter of intense political debate. Neo-protectionist policies are on the rise within EU Member States, who are struggling to acclimatise to increasing inward direct investment from developing countries. Strict regulations...... are being implemented to control the flow of this investment, undermining the principle of free movement of capital. Are such policies permitted under EU law? What impact does EU law have on foreign direct investment? This book addresses these questions through a coherent doctrinal reconstruction of the EC...... Treaty provisions on free movement of capital in a third country context. Opening with a timely restatement of the central features of the EU law of free movement of capital, the book then asks the central question: What rights does a private market participant, engaged in cross-border direct investment...

Movement of Abscisic Acid into the Apoplast in Response to Water Stress in Xanthium strumarium L.

Science.gov (United States)

Cornish, K; Zeevaart, J A

1985-07-01

The effect of water stress on the redistribution of abcisic acid (ABA) in mature leaves of Xanthium strumarium L. was investigated using a pressure dehydration technique. In both turgid and stressed leaves, the ABA in the xylem exudate, the ;apoplastic' ABA, increased before ;bulk leaf' stress-induced ABA accumulation began. In the initially turgid leaves, the ABA level remained constant in both the apoplast and the leaf as a whole until wilting symptoms appeared. Following turgor loss, sufficient quantities of ABA moved into the apoplast to stimulate stomatal closure. Thus, the initial increase of apoplastic ABA may be relevant to the rapid stomatal closure seen in stressed leaves before their bulk leaf ABA levels rise.Following recovery from water stress, elevated levels of ABA remained in the apoplast after the bulk leaf contents had returned to their prestress values. This apoplastic ABA may retard stomatal reopening during the initial recovery period.

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...

An exploration of sensory and movement differences from the perspective of individuals with autism

Directory of Open Access Journals (Sweden)

Jodi eRobledo

2012-11-01

Full Text Available Parents, teachers, and people who themselves experience sensory and movement differences have consistently reported disturbances of sensation and movement associated with autism. Our review of the literature has revealed both historical and recent references to and research about sensory and movement difference characteristics and symptoms for individuals with autism. What is notably infrequent in this literature, however, is research that highlights the perspective of the individual with autism. If we wish to truly understand the experience of sensory and movement differences for individuals with autism, we must explore their experiences and perspectives. This study presents a qualitative analysis of more than 40 hours in-depth inquiry into the lives of five individuals with the autism label. Data were sorted into six categories: perception, action, posture, emotion, communication, and cognition. The insights into sensory and movement differences and autism offered by these individuals was illuminating. We found that the data strongly supported the presence of disruption of organization and regulation of sensory and movement differences in the lived experience of these participants with autism. The present data suggests that in autism this disruption of organization and regulation is amplified in terms of quantity, quality, intensity, and may affect everyday life. These data contribute to a more expansive view of autism that incorporates the possibility that autism is a disorder that affects motor planning, behavior, communication, the sensory motor system, and the dynamic interaction of all of these.

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...

Characterization of Vesicular Stomatitis Virus Recombinants That Express and Incorporate High Levels of Hepatitis C Virus Glycoproteins

OpenAIRE

Buonocore, Linda; Blight, Keril J.; Rice, Charles M.; Rose, John K.

2002-01-01

We generated recombinant vesicular stomatitis viruses (VSV) expressing genes encoding hybrid proteins consisting of the extracellular domains of hepatitis C virus (HCV) glycoproteins fused at different positions to the transmembrane and cytoplasmic domains of the VSV G glycoprotein (E1G and E2G). We show that these chimeric proteins are transported to the cell surface and incorporated into VSV virions efficiently. We also generated VSV recombinants in which the gene encoding the VSV G protein...

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

Social-movement analysis of the American antinuclear movement

International Nuclear Information System (INIS)

Ladd, A.E.

1981-01-01

Utilizing data from a survey of participants at the May 6, 1979 antinuclear rally in Washington, DC (N = 420), this dissertation explored some of the major structural and ideological characteristics of the American Antinuclear Movement. By organizing the data around three of the key analytical concepts in the study of social movements - mobilization, recruitment, and ideology - the author was able to derive from the demonstration sample a descriptive and illustrative analysis of those individuals, organizations, and processes involved in the national antinuclear crusade. Given that few researchers have actively studied the antinuclear movement beyond the scope of local or regional protests, this work constitutes the only empirical study to date examining a cross section of the movement's participants from a sociological perspective. It is also one of the few attempts to use a national demonstration as a social laboratory for the study of a social movement in general. In terms of the mobilization variables examined in the study, it was found that organizational networks, past movement activism, and individual resources were important factors in the May 6 mobilization effort. While less than one-half of the demonstrators were part of the antinuclear organizational network per se, most of them had been active in the major protest movements of the 1960's and 1970's. The demonstrators were relatively high in socio-economic resources and had occupational or educational schedules conducive to creating the necessary discretionary time for movement participation

A prospective pilot study on the effect of sucralfate mouth-swishing in reducing stomatitis during radiotherapy of the oral cavity

International Nuclear Information System (INIS)

Pfeiffer, P.; Hansen, O.; Madsen, E.L.; May, O.

1990-01-01

Radiotherapy in sufficient dose involving the oral cavity always causes stomatitis, the severity of which is dependent on primary diagnosis, age, oral status and whether concomitant chemotherapy is given or not. The aim of the present pilot study was to assess whether mouth-swishing with sucralfate suspension might reduce oral radiation mucositis without disturbing side effects. (orig./MG)

A prospective pilot study on the effect of sucralfate mouth-swishing in reducing stomatitis during radiotherapy of the oral cavity

Energy Technology Data Exchange (ETDEWEB)

Pfeiffer, P.; Hansen, O.; Madsen, E.L.; May, O. (Odense Univ. (Denmark). Dept. of Oncology)

1990-01-01

Radiotherapy in sufficient dose involving the oral cavity always causes stomatitis, the severity of which is dependent on primary diagnosis, age, oral status and whether concomitant chemotherapy is given or not. The aim of the present pilot study was to assess whether mouth-swishing with sucralfate suspension might reduce oral radiation mucositis without disturbing side effects. (orig./MG).

PAK4 crystal structures suggest unusual kinase conformational movements.

Science.gov (United States)

Zhang, Eric Y; Ha, Byung Hak; Boggon, Titus J

2018-02-01

In order for protein kinases to exchange nucleotide they must open and close their catalytic cleft. These motions are associated with rotations of the N-lobe, predominantly around the 'hinge region'. We conducted an analysis of 28 crystal structures of the serine-threonine kinase, p21-activated kinase 4 (PAK4), including three newly determined structures in complex with staurosporine, FRAX486, and fasudil (HA-1077). We find an unusual motion between the N-lobe and C-lobe of PAK4 that manifests as a partial unwinding of helix αC. Principal component analysis of the crystal structures rationalizes these movements into three major states, and analysis of the kinase hydrophobic spines indicates concerted movements that create an accessible back pocket cavity. The conformational changes that we observe for PAK4 differ from previous descriptions of kinase motions, and although we observe these differences in crystal structures there is the possibility that the movements observed may suggest a diversity of kinase conformational changes associated with regulation. Protein kinases are key signaling proteins, and are important drug targets, therefore understanding their regulation is important for both basic research and clinical points of view. In this study, we observe unusual conformational 'hinging' for protein kinases. Hinging, the opening and closing of the kinase sub-domains to allow nucleotide binding and release, is critical for proper kinase regulation and for targeted drug discovery. We determine new crystal structures of PAK4, an important Rho-effector kinase, and conduct analyses of these and previously determined structures. We find that PAK4 crystal structures can be classified into specific conformational groups, and that these groups are associated with previously unobserved hinging motions and an unusual conformation for the kinase hydrophobic core. Our findings therefore indicate that there may be a diversity of kinase hinging motions, and that these may

Abscisic Acid Content, Transpiration, and Stomatal Conductance As Related to Leaf Age in Plants of Xanthium strumarium L. 1

Science.gov (United States)

Raschke, Klaus; Zeevaart, Jan A. D.

1976-01-01

Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L. the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the older leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (±)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells. The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight. PMID:16659640

Bowel Movement

Science.gov (United States)

A bowel movement is the last stop in the movement of food through your digestive tract. Your stool passes out of ... what you eat and drink. Sometimes a bowel movement isn't normal. Diarrhea happens when stool passes ...

Goal-selection and movement-related conflict during bimanual reaching movements.

Science.gov (United States)

Diedrichsen, Jörn; Grafton, Scott; Albert, Neil; Hazeltine, Eliot; Ivry, Richard B

2006-12-01

Conflict during bimanual movements can arise during the selection of movement goals or during movement planning and execution. We demonstrate a behavioral and neural dissociation of these 2 types of conflict. During functional magnetic resonance imaging scanning, participants performed bimanual reaching movements with symmetric (congruent) or orthogonal (incongruent) trajectories. The required movements were indicated either spatially, by illuminating the targets, or symbolically, using centrally presented letters. The processing of symbolic cues led to increased activation in a left hemisphere network including the intraparietal sulcus, premotor cortex, and inferior frontal gyrus. Reaction time cost for incongruent movements was substantially larger for symbolic than for spatial cues, indicating that the cost was primarily associated with the selection and assignment of movement goals, demands that are minimized when goals are directly specified by spatial cues. This goal-selection conflict increased activity in the pre-supplementary motor area and cingulate motor areas. Both cueing conditions led to larger activation for incongruent movements in the convexity of the superior parietal cortex, bilaterally, making this region a likely neural site for conflict that arises during the planning and execution of bimanual movements. These results suggest distinct neural loci for 2 forms of constraint on our ability to perform bimanual reaching movements.

Rapid eye movement sleep behaviour disorder in patients with narcolepsy is associated with hypocretin-1 deficiency

DEFF Research Database (Denmark)

Knudsen, Stine; Gammeltoft, Steen; Jennum, Poul J

2010-01-01

variables were analysed in relation to cataplexy and hypocretin deficiency with uni- and multivariate logistic/linear regression models, controlling for possible rapid eye movement sleep behaviour disorder biasing factors (age, gender, disease duration, previous anti-cataplexy medication). Only hypocretin......Rapid eye movement sleep behaviour disorder is characterized by dream-enacting behaviour and impaired motor inhibition during rapid eye movement sleep. Rapid eye movement sleep behaviour disorder is commonly associated with neurodegenerative disorders, but also reported in narcolepsy with cataplexy....... Most narcolepsy with cataplexy patients lack the sleep-wake, and rapid eye movement sleep, motor-regulating hypocretin neurons in the lateral hypothalamus. In contrast, rapid eye movement sleep behaviour disorder and hypocretin deficiency are rare in narcolepsy without cataplexy. We hypothesized...

Market, Regulation, Market, Regulation

DEFF Research Database (Denmark)

Frankel, Christian; Galland, Jean-Pierre

2015-01-01

barriers to trade in Europe, realized the free movement of products by organizing progressively several orders of markets and regulation. Based on historical and institutional documents, on technical publications, and on interviews, this article relates how the European Commission and the Member States had......This paper focuses on the European Regulatory system which was settled both for opening the Single Market for products and ensuring the consumers' safety. It claims that the New Approach and Standardization, and the Global Approach to conformity assessment, which suppressed the last technical...... alternatively recourse to markets and to regulations, at the three main levels of the New Approach Directives implementation. The article focuses also more specifically on the Medical Devices sector, not only because this New Approach sector has long been controversial in Europe, and has recently been concerned...

Constraint-induced movement therapy promotes motor function recovery and downregulates phosphorylated extracellular regulated protein kinase expression in ischemic brain tissue of rats

Directory of Open Access Journals (Sweden)

Bei Zhang

2015-01-01

Full Text Available Motor function impairment is a common outcome of stroke. Constraint-induced movement therapy (CIMT involving intensive use of the impaired limb while restraining the unaffected limb is widely used to overcome the effects of ′learned non-use′ and improve limb function after stroke. However, the underlying mechanism of CIMT remains unclear. In the present study, rats were randomly divided into a middle cerebral artery occlusion (model group, a CIMT + model (CIMT group, or a sham group. Restriction of the affected limb by plaster cast was performed in the CIMT and sham groups. Compared with the model group, CIMT significantly improved the forelimb functional performance in rats. By western blot assay, the expression of phosphorylated extracellular regulated protein kinase in the bilateral cortex and hippocampi of cerebral ischemic rats in the CIMT group was significantly lower than that in the model group, and was similar to sham group levels. These data suggest that functional recovery after CIMT may be related to decreased expression of phosphorylated extracellular regulated protein kinase in the bilateral cortex and hippocampi.

State Response to Contemporary Urban Movements in Turkey : A Critical Overview of State Entrepreneurialism and Authoritarian Interventions

NARCIS (Netherlands)

Eraydin, A.; Tasa-Kok, T.

2013-01-01

This paper grapples with the state's response to contemporary urban movements. In light of recent debates on the changing nature of urban movements, it presents an overview of the responses of states in different modes of regulation, ranging from a Keynesian regime to sequential stages of

Alterations in Rubisco activity and in stomatal behavior induce a daily rhythm in photosynthesis of aerial leaves in the amphibious-plant Nuphar lutea.

Science.gov (United States)

Snir, Ainit; Gurevitz, Michael; Marcus, Yehouda

2006-12-01

Nuphar lutea is an amphibious plant with submerged and aerial foliage, which raises the question how do both leaf types perform photosynthetically in two different environments. We found that the aerial leaves function like terrestrial sun-leaves in that their photosynthetic capability was high and saturated under high irradiance (ca. 1,500 mumol photons m(-2) s(-1)). We show that stomatal opening and Rubisco activity in these leaves co-limited photosynthesis at saturating irradiance fluctuating in a daily rhythm. In the morning, sunlight stimulated stomatal opening, Rubisco synthesis, and the neutralization of a night-accumulated Rubisco inhibitor. Consequently, the light-saturated quantum efficiency and rate of photosynthesis increased 10-fold by midday. During the afternoon, gradual closure of the stomata and a decrease in Rubisco content reduced the light-saturated photosynthetic rate. However, at limited irradiance, stomatal behavior and Rubisco content had only a marginal effect on the photosynthetic rate, which did not change during the day. In contrast to the aerial leaves, the photosynthesis rate of the submerged leaves, adapted to a shaded environment, was saturated under lower irradiance. The light-saturated quantum efficiency of these leaves was much lower and did not change during the day. Due to their low photosynthetic affinity for CO(2) (35 muM) and inability to utilize other inorganic carbon species, their photosynthetic rate at air-equilibrated water was CO(2)-limited. These results reveal differences in the photosynthetic performance of the two types of Nuphar leaves and unravel how photosynthetic daily rhythm in the aerial leaves is controlled.

Oxidative stress and myeloperoxidase levels in saliva of patients with recurrent aphthous stomatitis.

Science.gov (United States)

Cağlayan, F; Miloglu, O; Altun, O; Erel, O; Yilmaz, A B

2008-11-01

Recurrent aphthous stomatitis (RAS) is the most common oral ulcerative condition affecting 5-25% of the general population. The aim of this study was to evaluate the oxidative stress parameters in saliva of patients with RAS and to investigate the relationship among these parameters in either group. The study involved 50 patients with RAS of whom 24 were male and 26 were female, and 25 healthy controls of whom 13 were male and 12 were female. There was no statistically significant difference in the salivary total antioxidant capacity, total oxidant status, oxidative stress index levels, and myeloperoxidase activity between patients with RAS and those in the control group. The results show that reactive oxygen species may not play a role in the etiology of RAS.

Slope movements

International Nuclear Information System (INIS)

Wagner, P.

2009-01-01

On this poster some reasons of slope movements on the territory of the Slovak Republic are presented. Slope movements induced deterioration of land and forests, endangering of towns villages, and communications as well as hydro-engineering structures. Methods of preventing and stabilisation of slope movements are presented.

7 CFR 330.207 - Permits for movement of organisms issued by other agencies.

Science.gov (United States)

2010-01-01

... pests, any further conditions of movement to carry out the purposes of the Plant Protection Act which...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS...

Tuberous Roots Yield, Transpiration Rate, Stomatal Conductance and Water Use Efficiency of Divergent Cassava Clones as Influenced by Climate and Growth Stage

International Nuclear Information System (INIS)

Githunguri, C.M; Chewa, J.A; Ekanayake, I.J

1999-01-01

Cassava roots provide a cheap source of dietary energy to millions of people in the tropics. Variations in yield, stomatal conductance, transpiration rate and water use efficiency occur due to various factors. This makes selection of clones with wide ecological adaptation and high yield difficult. The influence of crop age and agroecozones (AEZ) in Nigeria on above parametres were studied. The tested AEZs were Sudan savanna (Minjibir), Southern Guinea savanna (Mokwa) and forest-savanna transition (Ibadan) AEZ. The environment plays a significant role in determining root yield with plant age playing a bigger role at the early stages. Results suggest root development was restricted by low moisture stress. Cassava ought to be harvested at eight months after planting (MAP) rather than at 12 MAP in order to obtain maximum yields. Yields at Mokwa were significantly higher than both Minjibir and Ibadan suggesting that cassava is not a crop for either forest or semi arid zones. During both seasons Minjbir had the highest stomatal conductance trend while Ibadan had the lowest. Stomatal conductance at Minjibir becomes critical at 12 MAP. The highest transpiration rate was recorded at Minijibir at 4 and 12 MAP. The lowest transpiration rate ws observed at Ibadan. The lowest transpiration rate was also observed during drought. There was a close positive close relationship between tuberous roots yield and transpiration. The lowest and highest water use efficiency (WUE) was recorded at 4 and 8 MAP during rains. The lowest and the highest WUE was recorded at Ibadan and Mokwa respectively. The two seasons trends were similar. Clone TMS 50395 had the highest WUE. Tere was close positive relationship between WUE and tuberous roots yield

Protest movements

International Nuclear Information System (INIS)

Rucht, D.

1989-01-01

The author describes the development of protest movements in postwar Germay and outlines two essential overlapping 'flow cycles'. The first of these was characterised by the restaurative postwar years. It culminated and ended in the students' revolt. This revolt is at the same time the start of a second cycle of protest which encompasses all subsequent individual movement and is initated by an economic, political and sociocultural procrastination of modernisation. This cycle culminates in the late 70s and early 80s and clearly lost momentum over the last few years. The follwoing phases and themes are described profoundly: against restauration and armament in the 1950; the revolutionary impatience of the students' movement, politisation of everyday life by the womens' movement and citizens' action groups, antinuclear- and ecological movement, differentiation and stabilisation of the movement in the 70s and 80s; break-up and continuity in the German protest behaviour. The paper contains a detailed chronicle of protest activities since 1945. (orig.) [de

Resource use and efficiency, and stomatal responses to environmental drivers of oak and pine species in an Atlantic Coastal Plain forest

Science.gov (United States)

Heidi J. Renninger; Nicholas J. Carlo; Kenneth L. Clark; Karina V.R. Schäfer

2015-01-01

Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource...

Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

Directory of Open Access Journals (Sweden)

Giuseppe Sorrentino

Full Text Available The rate of photosynthesis (A of plants exposed to water deficit is a function of stomatal (gs and mesophyll (gm conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci. Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis.

Participation, Democracy and Freedom Centered on Solidarity Economy . The Effectiveness of Labor Standard in Ibero-America , from the Social Movements and Social Movements Theories

Directory of Open Access Journals (Sweden)

Everaldo Gaspar Lopes de Andrade

2016-06-01

Full Text Available The theme effectiveness of labor standard in space even though it appears from those that make up the foundations of the Labour Law or his General Theory, classical scholars do not give them due attention. Still, when he refers, but included in that dimension of importance, they do to portray which standard to apply to the hired worker to provide services outside the country; or those who were transferred provisionally or permanently, and ultimately to resolve conflicts involving specific professional categories. This study aims to give an analytical and categorical treatment to the effectiveness of labor standards in space, to the extent that out as a theme linked to the philosophical discourse of modernity, the universal / legitimation of free / paid employment and receipt of this in advance by calling organizations and international cooperation, as well as the regulations dictated by the European Union and Mercosur. The study aims to establish a different narrative: put face to face the normative regulation / enforcement and universal absolute arising from modern legal-labor system and social movements of libertarian roots that will be triggered by the new labor internationalism. Aims to unravel the apparent harmony between capital and labor and demonstrate the intrinsic and inherent class antagonism. Social movements and theories of social movements form the basis of this theoretical-dogmatic reconfiguration, in order to privilege the Solidarity Economy in Iberoamerica.

BORC Functions Upstream of Kinesins 1 and 3 to Coordinate Regional Movement of Lysosomes along Different Microtubule Tracks.

Science.gov (United States)

Guardia, Carlos M; Farías, Ginny G; Jia, Rui; Pu, Jing; Bonifacino, Juan S

2016-11-15

The multiple functions of lysosomes are critically dependent on their ability to undergo bidirectional movement along microtubules between the center and the periphery of the cell. Centrifugal and centripetal movement of lysosomes is mediated by kinesin and dynein motors, respectively. We recently described a multi-subunit complex named BORC that recruits the small GTPase Arl8 to lysosomes to promote their kinesin-dependent movement toward the cell periphery. Here, we show that BORC and Arl8 function upstream of two structurally distinct kinesin types: kinesin-1 (KIF5B) and kinesin-3 (KIF1Bβ and KIF1A). Remarkably, KIF5B preferentially moves lysosomes on perinuclear tracks enriched in acetylated α-tubulin, whereas KIF1Bβ and KIF1A drive lysosome movement on more rectilinear, peripheral tracks enriched in tyrosinated α-tubulin. These findings establish BORC as a master regulator of lysosome positioning through coupling to different kinesins and microtubule tracks. Common regulation by BORC enables coordinate control of lysosome movement in different regions of the cell. Published by Elsevier Inc.

Deriving Animal Movement Behaviors Using Movement Parameters Extracted from Location Data

Directory of Open Access Journals (Sweden)

Maryam Teimouri

2018-02-01

Full Text Available We present a methodology for distinguishing between three types of animal movement behavior (foraging, resting, and walking based on high-frequency tracking data. For each animal we quantify an individual movement path. A movement path is a temporal sequence consisting of the steps through space taken by an animal. By selecting a set of appropriate movement parameters, we develop a method to assess movement behavioral states, reflected by changes in the movement parameters. The two fundamental tasks of our study are segmentation and clustering. By segmentation, we mean the partitioning of the trajectory into segments, which are homogeneous in terms of their movement parameters. By clustering, we mean grouping similar segments together according to their estimated movement parameters. The proposed method is evaluated using field observations (done by humans of movement behavior. We found that on average, our method agreed with the observational data (ground truth at a level of 80.75% ± 5.9% (SE.

Bottle gourd rootstock-grafting promotes photosynthesis by regulating the stomata and non-stomata performances in leaves of watermelon seedlings under NaCl stress.

Science.gov (United States)

Yang, Yanjuan; Yu, Li; Wang, Liping; Guo, Shirong

2015-08-15

Previously, we found that the amelioration of photosynthetic capacity by bottle gourd (Lagenaria siceraria Standl.) rootstock in watermelon seedlings (Citrullus lanatus [Thunb.] Mansf.) with salt treatment might be closely related to the enzymes in Calvin cycle such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (Yang et al., 2012). We confirmed this and showed more details in this study that improved photosynthesis of watermelon plants by bottle gourd rootstock was associated with the decreased stomata resistance and the increased photochemical activity and photosynthetic metabolism with or without 100mM NaCl stress for 3 days. The analysis of gas exchange parameters showed that self-grafted plants suffered serious non-stomatal limitation to photosynthesis under salt stress while rootstock-grafted plants were mainly affected by stomata limitation in stress conditions. Further, results showed that NaCl stress markedly reduced the chlorophyll content, damaged the structure of photosynthetic apparatus, and inhibited photochemical activity and CO2 assimilation in self-grafted plants. In contrast, rootstock-grafting increased the chlorophyll content, especially chlorophyll b, and minimized the harmful effects on photosystem II (PSII) reaction center and the thylakoids structure induced by NaCl stress. Furthermore, rootstock-grafting enhanced the content and activity of Rubisco and thus elevated carbon fixation in the leaves of watermelon scions under salt stress. The gene expressions of enzymes related to ribulose-1,5-bisphosphate (RuBP) regeneration were also up-regulated by rootstock and this probably guaranteed the sufficient supply of RuBP for the operation of Calvin cycle in watermelon scions under salt stress. Thus, bottle gourd rootstock promoted photosynthesis by the activation of stomatal and non-stomatal abilities, especially the regulation of a variety of photosynthetic enzymes, including Rubisco in grafted watermelon plants under NaCl stress

Striking a balance: does nitrate uptake and metabolism regulate both NO generation and scavenging?

DEFF Research Database (Denmark)

Mur, Luis A J; Hebelstrup, Kim; Gupta, Kapuganti J

2013-01-01

Nitric oxide (NO) influences many aspects of plant development and responses to stress.The concentration of NO can play an important role in influencing its action (for example, in stomatal regulation; Wilson et al., 2009) so that the mechanisms through which NO content is modulated must...... be an important facet of NO research. Whilst NO generation mechanisms are clearly important, NO removal is of equal relevance, especially as plants will be continually exposed to NOx (NO + NO2) gases derived from soil microbial activity (Mur et al., 2013). Establishing and regulating a poise between NO generation......, NO fumigation from external sources and NO scavenging, which also needs to be flexible enough to change in response to a variety of physiological cues, is an under-considered aspect of plant NO biology...

Movement - uncontrolled or slow

Science.gov (United States)

Dystonia; Involuntary slow and twisting movements; Choreoathetosis; Leg and arm movements - uncontrollable; Arm and leg movements - uncontrollable; Slow involuntary movements of large muscle groups; Athetoid movements

Differences between water permeability of astomatous and stomatous cuticular membranes: effects of air humidity in two species of contrasting drought-resistance strategy

Czech Academy of Sciences Publication Activity Database

Karbulková, J.; Schreiber, L.; Macek, Petr; Šantrůček, Jiří

2008-01-01

Roč. 59, č. 14 (2008), s. 3987-3995 ISSN 0022-0957 R&D Projects: GA AV ČR(CZ) IAA601410505 Institutional research plan: CEZ:AV0Z50510513; CEZ:AV0Z60050516 Keywords : Hedera helix * stomatal conductance * Zamioculcas zamiifolia Subject RIV: EF - Botanics Impact factor: 4.001, year: 2008

7 CFR 301.86-2 - Regulated articles.

Science.gov (United States)

2010-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Pale Cyst Nematode § 301.86-2 Regulated articles. The following are regulated articles: (a) Pale cyst nematodes.2 2 Permit and other requirements for the interstate movement of pale cyst nematodes are contained in part 330 of this chapter. (b) The...

Movement of Abscisic Acid into the Apoplast in Response to Water Stress in Xanthium strumarium L. 1

Science.gov (United States)

Cornish, Katrina; Zeevaart, Jan A. D.

1985-01-01

The effect of water stress on the redistribution of abcisic acid (ABA) in mature leaves of Xanthium strumarium L. was investigated using a pressure dehydration technique. In both turgid and stressed leaves, the ABA in the xylem exudate, the `apoplastic' ABA, increased before `bulk leaf' stress-induced ABA accumulation began. In the initially turgid leaves, the ABA level remained constant in both the apoplast and the leaf as a whole until wilting symptoms appeared. Following turgor loss, sufficient quantities of ABA moved into the apoplast to stimulate stomatal closure. Thus, the initial increase of apoplastic ABA may be relevant to the rapid stomatal closure seen in stressed leaves before their bulk leaf ABA levels rise. Following recovery from water stress, elevated levels of ABA remained in the apoplast after the bulk leaf contents had returned to their prestress values. This apoplastic ABA may retard stomatal reopening during the initial recovery period. PMID:16664294

Prechilling of Xanthium strumarium L. Reduces Net Photosynthesis and, Independently, Stomatal Conductance, While Sensitizing the Stomata to CO(2).

Science.gov (United States)

Drake, B; Raschke, K

1974-06-01

Greenhouse-grown plants of Xanthium strumarium L. were exposed in a growth cabinet to 10 C during days and 5 C during nights for periods of up to 120 hours. Subsequently, CO(2) exchange, transpiration, and leaf temperature were measured on attached leaves and in leaf sections at 25 or 30 C, 19 C dew point of the air, 61 milliwatts per square centimeter irradiance, and CO(2) concentrations between 0 and 1000 microliters per liter ambient air. Net photosynthesis and stomatal conductance decreased and dark respiration increased with increasing duration of prechilling. The reduction in net photosynthesis was not a consequence of decreased stomatal conductance because the intercellular CO(2) concentration in prechilled leaves was equal to or greater than that in greenhouse-grown controls. The intercellular CO(2) concentration at which one-half maximum net photosynthesis occurred remained the same in prechilled leaves and controls (175 to 190 microliters per liter). Stomata of the control plants responded to changes in the CO(2) concentration of the air only slightly. Prechilling for 24 hours or more sensitized stomata to CO(2); they responded to changes in CO(2) concentration in the range from 100 to 1000 microliters per liter.

Prechilling of Xanthium strumarium L. Reduces Net Photosynthesis and, Independently, Stomatal Conductance, While Sensitizing the Stomata to CO21

Science.gov (United States)

Drake, B.; Raschke, K.

1974-01-01

Greenhouse-grown plants of Xanthium strumarium L. were exposed in a growth cabinet to 10 C during days and 5 C during nights for periods of up to 120 hours. Subsequently, CO2 exchange, transpiration, and leaf temperature were measured on attached leaves and in leaf sections at 25 or 30 C, 19 C dew point of the air, 61 milliwatts per square centimeter irradiance, and CO2 concentrations between 0 and 1000 microliters per liter ambient air. Net photosynthesis and stomatal conductance decreased and dark respiration increased with increasing duration of prechilling. The reduction in net photosynthesis was not a consequence of decreased stomatal conductance because the intercellular CO2 concentration in prechilled leaves was equal to or greater than that in greenhouse-grown controls. The intercellular CO2 concentration at which one-half maximum net photosynthesis occurred remained the same in prechilled leaves and controls (175 to 190 microliters per liter). Stomata of the control plants responded to changes in the CO2 concentration of the air only slightly. Prechilling for 24 hours or more sensitized stomata to CO2; they responded to changes in CO2 concentration in the range from 100 to 1000 microliters per liter. PMID:16658795

Effects of diffuse light on radiation use efficiency depend on the response of stomatal conductance to dynamic light intensity

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Tao eLi

2016-02-01

Full Text Available The stimulating effect of diffuse light on radiation use efficiency (RUE of crops is often explained by the more homogeneous spatial light distribution, while rarely considering differences in temporal light distribution at leaf level. This study investigated whether diffuse light effects on crop RUE can be explained by dynamic responses of leaf photosynthesis to temporal changes of photosynthetic photon flux density (PPFD.Two Anthurium andreanum cultivars (‘Pink Champion’ and ‘Royal Champion’ were grown in two glasshouses covered by clear (control and diffuse glass, with similar light transmission. On clear days, diffusing the light resulted in less temporal fluctuations of PPFD. Stomatal conductance (gs varied strongly in response to transient PPFD in ‘Royal Champion’, whereas it remained relatively constant in ‘Pink Champion’. Instantaneous net leaf photosynthesis (Pn in both cultivars approached steady state Pn in diffuse light treatment. In control treatment this only occurred in ‘Pink Champion’. These cultivar differences were reflected by a higher RUE (8% in ‘Royal Champion’ in diffuse light treatment compared with control, whereas no effect on RUE was observed in ‘Pink Champion’. We conclude that the stimulating effect of diffuse light on RUE depends on the stomatal response to temporal PPFD fluctuations, which response is cultivar dependent.

Stomatal conductance, mesophyll conductance, and transpiration efficiency in relation to leaf anatomy in rice and wheat genotypes under drought.

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Ouyang, Wenjing; Struik, Paul C; Yin, Xinyou; Yang, Jianchang

2017-11-02

Increasing leaf transpiration efficiency (TE) may provide leads for growing rice like dryland cereals such as wheat (Triticum aestivum). To explore avenues for improving TE in rice, variations in stomatal conductance (gs) and mesophyll conductance (gm) and their anatomical determinants were evaluated in two cultivars from each of lowland, aerobic, and upland groups of Oryza sativa, one cultivar of O. glaberrima, and two cultivars of T. aestivum, under three water regimes. The TE of upland rice, O. glaberrima, and wheat was more responsive to the gm/gs ratio than that of lowland and aerobic rice. Overall, the explanatory power of the particular anatomical trait varied among species. Low stomatal density mostly explained the low gs in drought-tolerant rice, whereas rice genotypes with smaller stomata generally responded more strongly to drought. Compared with rice, wheat had a higher gm, which was associated with thicker mesophyll tissue, mesophyll and chloroplasts more exposed to intercellular spaces, and thinner cell walls. Upland rice, O. glaberrima, and wheat cultivars minimized the decrease in gm under drought by maintaining high ratios of chloroplasts to exposed mesophyll cell walls. Rice TE could be improved by increasing the gm/gs ratio via modifying anatomical traits. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Structural and biomechanical basis of mitochondrial movement in eukaryotic cells

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Wu M

2013-10-01

Full Text Available Min Wu,1 Aruna Kalyanasundaram,2 Jie Zhu1 1Laboratory of Biomechanics and Engineering, Institute of Biophysics, College of Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China; 2College of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA Abstract: Mitochondria serve as energy-producing organelles in eukaryotic cells. In addition to providing the energy supply for cells, the mitochondria are also involved in other processes, such as proliferation, differentiation, information transfer, and apoptosis, and play an important role in regulation of cell growth and the cell cycle. In order to achieve these functions, the mitochondria need to move to the corresponding location. Therefore, mitochondrial movement has a crucial role in normal physiologic activity, and any mitochondrial movement disorder will cause irreparable damage to the organism. For example, recent studies have shown that abnormal movement of the mitochondria is likely to be the reason for Charcot–Marie–Tooth disease, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and schizophrenia. So, in the cell, especially in the particular polarized cell, the appropriate distribution of mitochondria is crucial to the function and survival of the cell. Mitochondrial movement is mainly associated with the cytoskeleton and related proteins. However, those components play different roles according to cell type. In this paper, we summarize the structural basis of mitochondrial movement, including microtubules, actin filaments, motor proteins, and adaptin, and review studies of the biomechanical mechanisms of mitochondrial movement in different types of cells. Keywords: mitochondrial movement, microtubules, actin filaments, motor proteins, adaptin

Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes.

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Limousin, Jean-Marc; Bickford, Christopher P; Dickman, Lee T; Pangle, Robert E; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Osuna, Jessica L; Pockman, William T; McDowell, Nate G

2013-10-01

Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA. © 2013 John Wiley & Sons Ltd.

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

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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.

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.

Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals.

Science.gov (United States)

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

2014-01-01

A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMG) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both "discrete-rhythmic movements" such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the

Sensitivity analysis of a parameterization of the stomatal component of the DO3SE model for Quercus ilex to estimate ozone fluxes

International Nuclear Information System (INIS)

Alonso, Rocio; Elvira, Susana; Sanz, Maria J.; Gerosa, Giacomo; Emberson, Lisa D.; Bermejo, Victoria; Gimeno, Benjamin S.

2008-01-01

A sensitivity analysis of a proposed parameterization of the stomatal conductance (g s ) module of the European ozone deposition model (DO 3 SE) for Quercus ilex was performed. The performance of the model was tested against measured g s in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f phen and f SWP were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites. - No redundancy between phenological and water-related modifying functions was found when estimating stomatal behavior of Holm oak

Diurnal photosynthesis and stomatal resistance in field-grown soybeans

International Nuclear Information System (INIS)

Miller, J.E.; Muller, R.N.; Seegers, P.

1976-01-01

The process of photosynthesis in green plants is the major determinant of crop yield. Although the effects of air pollutants, such as sulfur dioxide, on photosynthesis has been studied, many unsolved questions remain. This is especially true with regard to reduction of photosynthetic rate under conditions of chronic exposure causing little or no visible injury. It was the purpose of these studies to develop techniques suitable for measuring photosynthetic rates of field-grown plants without dramatically altering the microenvironment of the plants. Gross photosynthetic rates of soybeans (Glycine max. cv. Wayne) in the field were measured by exposing a small section of representative leaves for 30 seconds to 14 CO 2 in a normal atmospheric mixture by a technique similar to that of Incoll and Wright. A 1-cm 2 section of the area exposed to 14 CO 2 is punched from the leaf and processed for liquid scintillation counting. Since the treatment period is of such short duration, there is little photorespiratory loss of 14 CO 2 , and thus, the amount of 14 C fixed in the leaf can be related to the gross photosynthetic rate. Other parameters measured during the course of these experiments were stomatal resistance, light intensity, leaf water potential, and air temperature

Co-ordination of physiological and morphological responses of stomata to elevated [CO2] in vascular plants.

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Haworth, Matthew; Elliott-Kingston, Caroline; McElwain, Jennifer C

2013-01-01

Plant stomata display a wide range of short-term behavioural and long-term morphological responses to atmospheric carbon dioxide concentration ([CO(2)]). The diversity of responses suggests that plants may have different strategies for controlling gas exchange, yet it is not known whether these strategies are co-ordinated in some way. Here, we test the hypothesis that there is co-ordination of physiological (via aperture change) and morphological (via stomatal density change) control of gas exchange by plants. We examined the response of stomatal conductance (G(s)) to instantaneous changes in external [CO(2)] (C(a)) in an evolutionary cross-section of vascular plants grown in atmospheres of elevated [CO(2)] (1,500 ppm) and sub-ambient [O(2)] (13.0 %) compared to control conditions (380 ppm CO(2), 20.9 % O(2)). We found that active control of stomatal aperture to [CO(2)] above current ambient levels was not restricted to angiosperms, occurring in the gymnosperms Lepidozamia peroffskyana and Nageia nagi. The angiosperm species analysed appeared to possess a greater respiratory demand for stomatal movement than gymnosperm species displaying active stomatal control. Those species with little or no control of stomatal aperture (termed passive) to C(a) were more likely to exhibit a reduction in stomatal density than species with active stomatal control when grown in atmospheres of elevated [CO(2)]. The relationship between the degree of stomatal aperture control to C(a) above ambient and the extent of any reduction in stomatal density may suggest the co-ordination of physiological and morphological responses of stomata to [CO(2)] in the optimisation of water use efficiency. This trade-off between stomatal control strategies may have developed due to selective pressures exerted by the costs associated with passive and active stomatal control.

Examining Age-Related Movement Representations for Sequential (Fine-Motor) Finger Movements

Science.gov (United States)

Gabbard, Carl; Cacola, Priscila; Bobbio, Tatiana

2011-01-01

Theory suggests that imagined and executed movement planning relies on internal models for action. Using a chronometry paradigm to compare the movement duration of imagined and executed movements, we tested children aged 7-11 years and adults on their ability to perform sequential finger movements. Underscoring this tactic was our desire to gain a…

A Somatic Movement Approach to Fostering Emotional Resiliency through Laban Movement Analysis

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Rachelle P. Tsachor

2017-09-01

Full Text Available Although movement has long been recognized as expressing emotion and as an agent of change for emotional state, there was a dearth of scientific evidence specifying which aspects of movement influence specific emotions. The recent identification of clusters of Laban movement components which elicit and enhance the basic emotions of anger, fear, sadness and happiness indicates which types of movements can affect these emotions (Shafir et al., 2016, but not how best to apply this knowledge. This perspective paper lays out a conceptual groundwork for how to effectively use these new findings to support emotional resiliency through voluntary choice of one's posture and movements. We suggest that three theoretical principles from Laban Movement Analysis (LMA can guide the gradual change in movement components in one's daily movements to somatically support shift in affective state: (A Introduce new movement components in developmental order; (B Use LMA affinities-among-components to guide the expansion of expressive movement range and (C Sequence change among components based on Laban's Space Harmony theory to support the gradual integration of that new range. The methods postulated in this article have potential to foster resiliency and provide resources for self-efficacy by expanding our capacity to adapt emotionally to challenges through modulating our movement responses.

Functional Movement Disorder

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... Publications Patient Organizations International Parkinson and Movement Disorder Society National Institute of Mental Health (NIMH) See all related organizations Publications Order NINDS Publications Definition Psychogenic movement is an unwanted muscle movement such ...

Movement monitoring device

International Nuclear Information System (INIS)

Ichikawa, Takashi; Yoneda, Yasuaki; Hanatsumi, Masaharu.

1997-01-01

The present invention provides a device suitable to accurate recognition for the moving state of reactor core fuels as an object to be monitored in a nuclear power plant. Namely, the device of the present invention prepares each of scheduled paths for the movement of the object to be monitored and executed moving paths along with the movement based on the information of the movement obtained from scheduled information for the movement of the reactor core fuels as a object to be monitored and the actual movement of the object to be monitored. The results of the preparation are outputted. As an output mode, (1) the results of preparation for each of the paths for movement and the results of the monitoring obtained by monitoring the state of the object to be monitored are jointed and outputted, (2) images showing each of the paths for the movement are formed, and the formed images are displayed on a screen, and (3) each of the moving paths is prepared as an image, and the image is displayed together with the image of the regions before and after the movement of the object to be monitored. In addition, obtained images of each of the paths for the movement and the monitored images obtained by monitoring the state of the object to be monitored are joined and displayed. (I.S.)

What is the role of genetic testing in movement disorders practice?

Science.gov (United States)

Schneider, Susanne A; Klein, Christine

2011-08-01

Genetic testing holds many promises in movement disorders, but also pitfalls that require careful consideration for meaningful results. These include the primary indication for testing in the first place, concerns regarding the implications of symptomatic, presymptomatic, and susceptibility testing, the mutation frequency in the gene of interest, the general lack of neuroprotective treatment options for neurodegenerative movement disorders, the prognosis of the condition diagnosed, and patient confidentiality concerns. Furthermore, new technical achievements and the available technical expertise, feasibility of specific gene testing, and its coverage through a health insurance carrier should be considered. Guidelines for testing have been established by some disease societies to advise clinicians and in parallel legal regulations are being adjusted at a national and international level. We review these and other critical points and recent developments regarding genetic testing in the field of movement disorders.

Regulation of water, salinity, and cold stress responses by salicylic acid

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Kenji eMiura

2014-01-01

Full Text Available Salicylic acid (SA is a naturally occurring phenolic compound. SA plays an important role in the regulation of plant growth, development, ripening, and defense responses. The role of SA in the plant-pathogen relationship has been extensively investigated. In addition to defense responses, SA plays an important role in the response to abiotic stresses, including drought, low temperature, and salinity stresses. It has been suggested that SA has great agronomic potential to improve the stress tolerance of agriculturally important crops. However, the utility of SA is dependent on the concentration of the applied SA, the mode of application, and the state of the plants (e.g., developmental stage and acclimation. Generally, low concentrations of applied SA alleviate the sensitivity to abiotic stresses, and high concentrations of applied induce high levels of oxidative stress, leading to a decreased tolerance to abiotic stresses. In this chapter, the effects of SA on the water stress responses and regulation of stomatal closure are reviewed.

Repeatedly pairing vagus nerve stimulation with a movement reorganizes primary motor cortex.

Science.gov (United States)

Porter, Benjamin A; Khodaparast, Navid; Fayyaz, Tabbassum; Cheung, Ryan J; Ahmed, Syed S; Vrana, William A; Rennaker, Robert L; Kilgard, Michael P

2012-10-01

Although sensory and motor systems support different functions, both systems exhibit experience-dependent cortical plasticity under similar conditions. If mechanisms regulating cortical plasticity are common to sensory and motor cortices, then methods generating plasticity in sensory cortex should be effective in motor cortex. Repeatedly pairing a tone with a brief period of vagus nerve stimulation (VNS) increases the proportion of primary auditory cortex responding to the paired tone (Engineer ND, Riley JR, Seale JD, Vrana WA, Shetake J, Sudanagunta SP, Borland MS, Kilgard MP. 2011. Reversing pathological neural activity using targeted plasticity. Nature. 470:101-104). In this study, we predicted that repeatedly pairing VNS with a specific movement would result in an increased representation of that movement in primary motor cortex. To test this hypothesis, we paired VNS with movements of the distal or proximal forelimb in 2 groups of rats. After 5 days of VNS movement pairing, intracranial microstimulation was used to quantify the organization of primary motor cortex. Larger cortical areas were associated with movements paired with VNS. Rats receiving identical motor training without VNS pairing did not exhibit motor cortex map plasticity. These results suggest that pairing VNS with specific events may act as a general method for increasing cortical representations of those events. VNS movement pairing could provide a new approach for treating disorders associated with abnormal movement representations.

Pharmacological factors in the saliva of blood-feeding insects. Implications for vesicular stomatitis epidemiology.

Science.gov (United States)

Tabachnick, W J

2000-01-01

Vesicular stomatitis (VS) epizootics in the Western United States have caused substantial economic losses to U.S. livestock industries in 1995, 1997, and 1998. The role of arthropods in transmitting VS to U.S. livestock is unclear. In particular, the impact of arthropod salivary gland factors in VS infections in livestock needs study. Pharmacological effects of arthropod salivary gland factors on animals are reviewed. The potential effects of arthropod saliva on the transmission and spread of VS virus to livestock in the Western U.S. is presented with emphasis on the biting midge, Culicoides sonorensis. Information is discussed with attention to vector potential of C. sonorensis, and its use as a model for evaluating insect salivary gland pharmacology on livestock response to VS.

A Comparison of Independent Event-Related Desynchronization Responses in Motor-Related Brain Areas to Movement Execution, Movement Imagery, and Movement Observation.

Science.gov (United States)

Duann, Jeng-Ren; Chiou, Jin-Chern

2016-01-01

Electroencephalographic (EEG) event-related desynchronization (ERD) induced by movement imagery or by observing biological movements performed by someone else has recently been used extensively for brain-computer interface-based applications, such as applications used in stroke rehabilitation training and motor skill learning. However, the ERD responses induced by the movement imagery and observation might not be as reliable as the ERD responses induced by movement execution. Given that studies on the reliability of the EEG ERD responses induced by these activities are still lacking, here we conducted an EEG experiment with movement imagery, movement observation, and movement execution, performed multiple times each in a pseudorandomized order in the same experimental runs. Then, independent component analysis (ICA) was applied to the EEG data to find the common motor-related EEG source activity shared by the three motor tasks. Finally, conditional EEG ERD responses associated with the three movement conditions were computed and compared. Among the three motor conditions, the EEG ERD responses induced by motor execution revealed the alpha power suppression with highest strengths and longest durations. The ERD responses of the movement imagery and movement observation only partially resembled the ERD pattern of the movement execution condition, with slightly better detectability for the ERD responses associated with the movement imagery and faster ERD responses for movement observation. This may indicate different levels of involvement in the same motor-related brain circuits during different movement conditions. In addition, because the resulting conditional EEG ERD responses from the ICA preprocessing came with minimal contamination from the non-related and/or artifactual noisy components, this result can play a role of the reference for devising a brain-computer interface using the EEG ERD features of movement imagery or observation.

Normal Morning Melanin-Concentrating Hormone Levels and No Association with Rapid Eye Movement or Non-Rapid Eye Movement Sleep Parameters in Narcolepsy Type 1 and Type 2

DEFF Research Database (Denmark)

Schrölkamp, Maren; Jennum, Poul J; Gammeltoft, Steen

2017-01-01

in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep regulation. Hypocretin neurons reciprocally interact with MCH neurons. We hypothesized that altered MCH secretion contributes to the symptoms and sleep abnormalities of narcolepsy and that this is reflected in morning cerebrospinal fluid...... MCH levels. CONCLUSIONS: Our study shows that MCH levels in CSF collected in the morning are normal in narcolepsy and not associated with the clinical symptoms, REM sleep abnormalities, nor number of muscle movements during REM or NREM sleep of the patients. We conclude that morning lumbar CSF MCH......STUDY OBJECTIVES: Other than hypocretin-1 (HCRT-1) deficiency in narcolepsy type 1 (NT1), the neurochemical imbalance of NT1 and narcolepsy type 2 (NT2) with normal HCRT-1 levels is largely unknown. The neuropeptide melanin-concentrating hormone (MCH) is mainly secreted during sleep and is involved...

Movement and Space

DEFF Research Database (Denmark)

Riisgaard Hansen, Thomas; Eriksson, Eva; Lykke-Olesen, Andreas

2005-01-01

In this paper we explore the space in which movement based interaction takes place. We have in several projects explored how fixed and mobile cameras can be used in movement based interaction and will shortly describe these projects. Based on our experience with working with movement......-based interaction we will briefly introduce and discuss how learning, mapping and multi-user interaction are important when designing movement based interaction....

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.

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.

Seasonal trends of light-saturated net photosynthesis and stomatal conductance of loblolly pine trees grown in contrasting environments of nutrition, water and carbon dioxide

Science.gov (United States)

Ramesh Murthy; Stanley J. Zarnoch; P.M. Dougherty

1997-01-01

Repeated measures analysis was used to evaluate the effect of long-term CO2 enhancement on seasonal trends of light-saturated rates of net photosynthesis (Asat) and stomatal conductance to water vapour (gsat) of 9-year-old loblolly pine (Pinus taeda L.; trees grown in a 2x2...

Movement - uncoordinated

Science.gov (United States)

... Loss of coordination; Coordination impairment; Ataxia; Clumsiness; Uncoordinated movement ... Smooth graceful movement requires a balance between different muscle groups. A part of the brain called the cerebellum manages this balance.

Body Awareness and Movement for Students with Multiple Disabilities Including Visual Impairments

Science.gov (United States)

DePountis, Vicki; Cady, Deborah; Hallak, Tracy

2013-01-01

This conference presentation examines concept development for congenitally blind students. It presents current research on best-practice for teaching this population. Examples of strategies to reinforce understanding of body concepts, spatial awareness, and positional language, while promoting mirroring, self regulation, and purposeful movement to…

Oxidative stress protection and stomatal patterning as components of salinity tolerance mechanism in quinoa (Chenopodium quinoa).

Science.gov (United States)

Shabala, Lana; Mackay, Alex; Tian, Yu; Jacobsen, Sven-Erik; Zhou, Daowei; Shabala, Sergey

2012-09-01

Two components of salinity stress are a reduction in water availability to plants and the formation of reactive oxygen species. In this work, we have used quinoa (Chenopodium quinoa), a dicotyledonous C3 halophyte species displaying optimal growth at approximately 150 mM NaCl, to study mechanisms by which halophytes cope with the afore-mentioned components of salt stress. The relative contribution of organic and inorganic osmolytes in leaves of different physiological ages (e.g. positions on the stem) was quantified and linked with the osmoprotective function of organic osmolytes. We show that the extent of the oxidative stress (UV-B irradiation) damage to photosynthetic machinery in young leaves is much less when compared with old leaves, and attribute this difference to the difference in the size of the organic osmolyte pool (1.5-fold difference under control conditions; sixfold difference in plants grown at 400 mM NaCl). Consistent with this, salt-grown plants showed higher Fv/Fm values compared with control plants after UV-B exposure. Exogenous application of physiologically relevant concentrations of glycine betaine substantially mitigated oxidative stress damage to PSII, in a dose-dependent manner. We also show that salt-grown plants showed a significant (approximately 30%) reduction in stomatal density observed in all leaves. It is concluded that accumulation of organic osmolytes plays a dual role providing, in addition to osmotic adjustment, protection of photosynthetic machinery against oxidative stress in developing leaves. It is also suggested that salinity-induced reduction in stomatal density represents a fundamental mechanism by which plants optimize water use efficiency under saline conditions. Copyright © Physiologia Plantarum 2012.

New stomatal flux-based critical levels for ozone effects on vegetation

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Mills, Gina; Pleijel, Håkan; Braun, Sabine; Büker, Patrick; Bermejo, Victoria; Calvo, Esperanza; Danielsson, Helena; Emberson, Lisa; Fernández, Ignacio González; Grünhage, Ludger; Harmens, Harry; Hayes, Felicity; Karlsson, Per-Erik; Simpson, David

2011-09-01

The critical levels for ozone effects on vegetation have been reviewed and revised by the LRTAP Convention. Eight new or revised critical levels based on the accumulated stomatal flux of ozone (POD Y, the Phytotoxic Ozone Dose above a threshold flux of Y nmol m -2 PLA s -1, where PLA is the projected leaf area) have been agreed. For each receptor, data were combined from experiments conducted under naturally fluctuating environmental conditions in 2-4 countries, resulting in linear dose-response relationships with response variables specific to each receptor ( r2 = 0.49-0.87, p Norway spruce. For (semi-)natural vegetation, the critical level for effects on productive and high conservation value perennial grasslands was based on effects on important component species of the genus Trifolium (clover species). These critical levels can be used to assess protection against the damaging effects of ozone on food security, important ecosystem services provided by forest trees (roundwood production, C sequestration, soil stability and flood prevention) and the vitality of pasture.

Sleep-related movement disorders.

Science.gov (United States)

Merlino, Giovanni; Gigli, Gian Luigi

2012-06-01

Several movement disorders may occur during nocturnal rest disrupting sleep. A part of these complaints is characterized by relatively simple, non-purposeful and usually stereotyped movements. The last version of the International Classification of Sleep Disorders includes these clinical conditions (i.e. restless legs syndrome, periodic limb movement disorder, sleep-related leg cramps, sleep-related bruxism and sleep-related rhythmic movement disorder) under the category entitled sleep-related movement disorders. Moreover, apparently physiological movements (e.g. alternating leg muscle activation and excessive hypnic fragmentary myoclonus) can show a high frequency and severity impairing sleep quality. Clinical and, in specific cases, neurophysiological assessments are required to detect the presence of nocturnal movement complaints. Patients reporting poor sleep due to these abnormal movements should undergo non-pharmacological or pharmacological treatments.

Plant Physiology: Redefining the Enigma of Metabolism in Stomatal Movement.

Science.gov (United States)

Blatt, Michael R

2016-02-08

Stomata open at the leaf epidermis, driven by solute accumulation in the surrounding guard cells. Transmembrane ion transport has long been recognised to contribute to this process. A new study makes it clear that guard cells also metabolise starch to accelerate opening. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recent crustal movements

Science.gov (United States)

Maelzer, H.

Calculation of temporal height changes for the determination of recent vertical crustal movements in northern, western, and southern Germany is described. Precise geodetic measurements and their analysis for the determination of recent crustal movements in north-eastern Iceland, western Venezuela, and central Peru are described. Determination of recent vertical crustal movements by leveling and gravity data; geodetic modeling of deformations and recent crustal movements; geodetic modeling of plate motions; and instrumental developments in geodetic measuring are discussed.

Evaluation of head movement periodicity and irregularity during locomotion of Caenorhabditis elegans

Directory of Open Access Journals (Sweden)

Ryuzo eShingai

2013-03-01

Full Text Available Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx or 50% (the mid-body point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.

Sensitivity analysis of a parameterization of the stomatal component of the DO{sub 3}SE model for Quercus ilex to estimate ozone fluxes

Energy Technology Data Exchange (ETDEWEB)

Alonso, Rocio [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: rocio.alonso@ciemat.es; Elvira, Susana [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: susana.elvira@ciemat.es; Sanz, Maria J. [Fundacion CEAM, Charles Darwin 14, 46980 Paterna, Valencia (Spain)], E-mail: mjose@ceam.es; Gerosa, Giacomo [Department of Mathematics and Physics, Universita Cattolica del Sacro Cuore, via Musei 41, 25121 Brescia (Italy)], E-mail: giacomo.gerosa@unicatt.it; Emberson, Lisa D. [Stockholm Environment Institute, University of York, York YO 10 5DD (United Kingdom)], E-mail: lde1@york.ac.uk; Bermejo, Victoria [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: victoria.bermejo@ciemat.es; Gimeno, Benjamin S. [Ecotoxicology of Air Pollution, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)], E-mail: benjamin.gimeno@ciemat.es

2008-10-15

A sensitivity analysis of a proposed parameterization of the stomatal conductance (g{sub s}) module of the European ozone deposition model (DO{sub 3}SE) for Quercus ilex was performed. The performance of the model was tested against measured g{sub s} in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f{sub phen} and f{sub SWP} were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites. - No redundancy between phenological and water-related modifying functions was found when estimating stomatal behavior of Holm oak.

Spatio-temporal diversification of the cell wall matrix materials in the developing stomatal complexes of Zea mays.

Science.gov (United States)

Giannoutsou, E; Apostolakos, P; Galatis, B

2016-11-01

The matrix cell wall materials, in developing Zea mays stomatal complexes are asymmetrically distributed, a phenomenon appearing related to the local cell wall expansion and deformation, the establishment of cell polarity, and determination of the cell division plane. In cells of developing Zea mays stomatal complexes, definite cell wall regions expand determinately and become locally deformed. This differential cell wall behavior is obvious in the guard cell mother cells (GMCs) and the subsidiary cell mother cells (SMCs) that locally protrude towards the adjacent GMCs. The latter, emitting a morphogenetic stimulus, induce polarization/asymmetrical division in SMCs. Examination of immunolabeled specimens revealed that homogalacturonans (HGAs) with a high degree of de-esterification (2F4- and JIM5-HGA epitopes) and arabinogalactan proteins are selectively distributed in the extending and deformed cell wall regions, while their margins are enriched with rhamnogalacturonans (RGAs) containing highly branched arabinans (LM6-RGA epitope). In SMCs, the local cell wall matrix differentiation constitutes the first structural event, indicating the establishment of cell polarity. Moreover, in the premitotic GMCs and SMCs, non-esterified HGAs (2F4-HGA epitope) are preferentially localized in the cell wall areas outlining the cytoplasm where the preprophase band is formed. In these areas, the forthcoming cell plate fuses with the parent cell walls. These data suggest that the described heterogeneity in matrix cell wall materials is probably involved in: (a) local cell wall expansion and deformation, (b) the transduction of the inductive GMC stimulus, and (c) the determination of the division plane in GMCs and SMCs.

Complex regional pain syndrome related movement disorders : studies on pathophysiology and therapy.

NARCIS (Netherlands)

Munts, Alexander Gerard

2011-01-01

Complex regional pain syndrome (CRPS) may occur after trauma, usually to one limb, and is characterised by pain and disturbed blood flow, temperature regulation and motor control. Knowledge on CRPS and its movement disorders is scarce. Dysfunction in small nerve fiber processing was found in CRPS

Centriole movements in mammalian epithelial cells during cytokinesis

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Tanke Hans J

2010-05-01

Full Text Available Abstract Background In cytokinesis, when the cleavage furrow has been formed, the two centrioles in each daughter cell separate. It has been suggested that the centrioles facilitate and regulate cytokinesis to some extent. It has been postulated that termination of cytokinesis (abscission depends on the migration of a centriole to the intercellular bridge and then back to the cell center. To investigate the involvement of centrioles in cytokinesis, we monitored the movements of centrioles in three mammalian epithelial cell lines, HeLa, MCF 10A, and the p53-deficient mouse mammary tumor cell line KP-7.7, by time-lapse imaging. Centrin1-EGFP and α-Tubulin-mCherry were co-expressed in the cells to visualize respectively the centrioles and microtubules. Results Here we report that separated centrioles that migrate from the cell pole are very mobile during cytokinesis and their movements can be characterized as 1 along the nuclear envelope, 2 irregular, and 3 along microtubules forming the spindle axis. Centriole movement towards the intercellular bridge was only seen occasionally and was highly cell-line dependent. Conclusions These findings show that centrioles are highly mobile during cytokinesis and suggest that the repositioning of a centriole to the intercellular bridge is not essential for controlling abscission. We suggest that centriole movements are microtubule dependent and that abscission is more dependent on other mechanisms than positioning of centrioles.

The oral microbiota of patients with recurrent aphthous stomatitis

Directory of Open Access Journals (Sweden)

Maria Bankvall

2014-10-01

Full Text Available Background: Specific pathogenic bacteria have been implicated in recurrent aphthous stomatitis (RAS, a chronic inflammatory condition characterised by ulcerations in the oral mucosa. However, the aetiology behind this condition still remains unclear. Objective: The buccal microbiota of patients with RAS was compared to that of control subjects to investigate its potential role for this condition. Design: Buccal swabs were obtained from non-ulcerative areas of 60 patients, of whom 42 patients had lesions at the time of sampling, and 60 healthy age- and gender-matched controls. Bacterial DNA was extracted and analysed by Terminal-Restriction Fragment Length Polymorphism, using enzymatic digestion of the polymerase chain reaction-amplified 16S rRNA gene, yielding a series of peaks, each representing a bacterial taxon. Results: Two peaks, 60 and 489, were more prevalent in patients with RAS than controls. Conversely, peaks 58 and 490 were less common in patients than controls. When the patients were divided into subgroups, we found that the observed differences in peak-pattern were related to the presence of lesions during sampling. Conclusions: The microbiota of the non-inflamed buccal mucosa differed between patients and controls. The differences were most pronounced in patients who presented with lesions during sampling, suggesting that a disturbance in the normal buccal microbiota triggers the presence of lesions or that presence of lesions alters the microbiota.

Degeneration of rapid eye movement sleep circuitry underlies rapid eye movement sleep behavior disorder.

Science.gov (United States)

McKenna, Dillon; Peever, John

2017-05-01

During healthy rapid eye movement sleep, skeletal muscles are actively forced into a state of motor paralysis. However, in rapid eye movement sleep behavior disorder-a relatively common neurological disorder-this natural process is lost. A lack of motor paralysis (atonia) in rapid eye movement sleep behavior disorder allows individuals to actively move, which at times can be excessive and violent. At first glance this may sound harmless, but it is not because rapid eye movement sleep behavior disorder patients frequently injure themselves or the person they sleep with. It is hypothesized that the degeneration or dysfunction of the brain stem circuits that control rapid eye movement sleep paralysis is an underlying cause of rapid eye movement sleep behavior disorder. The link between brain stem degeneration and rapid eye movement sleep behavior disorder stems from the fact that rapid eye movement sleep behavior disorder precedes, in the majority (∼80%) of cases, the development of synucleinopathies such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, which are known to initially cause degeneration in the caudal brain stem structures where rapid eye movement sleep circuits are located. Furthermore, basic science and clinical evidence demonstrate that lesions within the rapid eye movement sleep circuits can induce rapid eye movement sleep-specific motor deficits that are virtually identical to those observed in rapid eye movement sleep behavior disorder. This review examines the evidence that rapid eye movement sleep behavior disorder is caused by synucleinopathic neurodegeneration of the core brain stem circuits that control healthy rapid eye movement sleep and concludes that rapid eye movement sleep behavior disorder is not a separate clinical entity from synucleinopathies but, rather, it is the earliest symptom of these disorders. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and

7 CFR 301.91 - Quarantine and regulations; restrictions on interstate movement of regulated articles. 1

Science.gov (United States)

2010-01-01

..., and 434 of the Plant Protection Act (7 U.S.C. 7714, 7731, and 7754). (a) Quarantines and regulations... Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC...

Sensation of Movement

DEFF Research Database (Denmark)

Sensation of Movement will discuss the role of sensation in the control of action, bodily self-recognition, and sense of agency. Sensing movement is dependent on a range of information received by the brain, from signalling in the peripheral sensory organs to the establishment of higher order goals....... This volume will question whether one type of information is more relevant for the ability to sense and control movements, and demonstrate the importance of integrating neuroscientific knowledge with philosophical perspectives, in order to arrive at new insights into how sensation of movement can be studied...

[Professor GAO Yuchun's experience on "sequential acupuncture leads to smooth movement of qi"].

Science.gov (United States)

Wang, Yanjun; Xing, Xiao; Cui, Linhua

2016-01-01

Professor GAO Yuchun is considered as the key successor of GAO's academic school of acupuncture and moxibustion in Yanzhao region. Professor GAO's clinical experience of, "sequential acupuncture" is introduced in details in this article. In Professor GAO's opinions, appropriate acupuncture sequence is the key to satisfactory clinical effects during treatment. Based on different acupoints, sequential acupuncture can achieve the aim of qi following needles and needles leading qi; based on different symptoms, sequential acupuncture can regulate qi movement; based on different body positions, sequential acupuncture can harmonize qi-blood and reinforcing deficiency and reducing excess. In all, according to the differences of disease condition and constitution, based on the accurate acupoint selection and appropriate manipulation, it is essential to capture the nature of diseases and make the order of acupuncture, which can achieve the aim of regulating qi movement and reinforcing deficiency and reducing excess.

Advertising and the Consumerism Movement in Europe: The Case of West Germany and Switzerland

OpenAIRE

Saeed Samiee; John K Ryans

1982-01-01

In recent years, European countries have faced an ever increasing levels of activities by consumerists. Much of this activity is aimed at regulating and controlling advertising. This article examines the views of advertising industry and corporate advertising executives toward this movement in two neighboring European countries: West Germany and Switzerland. Results show that even though these countries have different levels of advertising regulation, the executives in both countries hold gen...

Analysis on regulation strategies for extending service life of hydropower turbines

Science.gov (United States)

Yang, W.; Norrlund, P.; Yang, J.

2016-11-01

Since a few years, there has been a tendency that hydropower turbines experience fatigue to a greater extent, due to increasingly more regulation movements of governor actuators. The aim of this paper is to extend the service life of hydropower turbines, by reasonably decreasing the guide vane (GV) movements with appropriate regulation strategies, e.g. settings of PI (proportional-integral) governor parameters and controller filters. The accumulated distance and number of GV movements are the two main indicators of this study. The core method is to simulate the long-term GV opening of Francis turbines with MATLAB/Simulink, based on a sequence of one-month measurements of the Nordic grid frequency. Basic theoretical formulas are also discussed and compared to the simulation results, showing reasonable correspondence. Firstly, a model of a turbine governor is discussed and verified, based on on-site measurements of a Swedish hydropower plant. Then, the influence of governor parameters is discussed. Effects of different settings of controller filters (e.g. dead zone, floating dead zone and linear filter) are also examined. Moreover, a change in GV movement might affect the quality of the frequency control. This is also monitored via frequency deviation characteristics, determined by elementary simulations of the Nordic power system. The results show how the regulation settings affect the GV movements and frequency quality, supplying suggestions for optimizing the hydropower turbine operation for decreasing the wear and tear.

Interactions of macrophages with probiotic bacteria lead to increased antiviral response against vesicular stomatitis virus