scholarly journals Temperature-dependent changes of membrane potentials in cells of thermonastic tepals of Eranthis hyemalis (L.) Salisb.

2014 ◽  
Vol 63 (3-4) ◽  
pp. 219-227 ◽  
Author(s):  
Zygmunt Hejnowicz ◽  
Kazimierz Trębacz ◽  
Andreas Sievers
Keyword(s):  
External Solution ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Adaxial Side ◽  
Abaxial Side ◽  
Abaxial Epidermis ◽  
Transmembrane Potential Difference ◽  
Tissue Stresses ◽  
Isolated Tissues ◽  
In Cells

The effect of temperature upon the bioelectric potential across the plasma membrane in cells of tepals of <i>Eranthis hyemalis</i> (L.) Salisb. (Winter aconite) is described. Rapid warming of an intact tepal resulted in a transient small increase in the magnitude of transmembrane potential difference followed by a substantial long-lasting depolarization which is considered as an "anomalous" response. Upon rapid cooling the reverse response occurred: a small transient depolarization was followed by a substantial hyperpolarization (also an anomalous response). The anomalous responses were more pronounced in the epidermis on the abaxial side of the tepal than in that on the adaxial side, indicating an electrophysiological dorsiventrality of the tepals. The anomalous responses were much less apparent in cells of isolated tissues than in cells of intact tepals. This difference does not appear to result from wounding or bringing a tissue into direct contact with the external solution because in segments of tepals devoid of the abaxial epidermis only, the PD of the parenchyma behaved in a way similar to that of the intact tepals. It is suggested that the occurrence of the anomalous responses is modulated by the tissue stresses. The functional importance of the responses for thermonastic movements is discussed.

Dualité des corps protéiques du mésophylle adaxial et abaxial des cotylédons de quelques espèces de la tribu des Génistées (Légumineuses)

1987 ◽  
Vol 65 (9) ◽  
pp. 1870-1875 ◽  
Author(s):  
L. Citharel ◽  
J. Citharel
Keyword(s):  
Protein Bodies ◽  
Cytisus Scoparius ◽  
Adaxial Side ◽  
Abaxial Side ◽  
In Cells

The presence of globoids in cotyledon protein bodies is confirmed in several Genistae. In addition, the duality (homogeneous protein bodies in cells on the adaxial side and heterogeneous protein bodies in cells on the abaxial side), previously reported in Cytisus scoparius cotyledons, has now been established in other Cytisus species, as well as in other genera of the Genistae tribe.

Involucral Bracts Anatomy in the Capitulum of Primitive Strains and Modern Genotypes of Sunflower (Helianthus annuus L.)

Helia ◽  
2015 ◽  
Vol 38 (62) ◽  
pp. 141-147
Author(s):  
M. V. Rosetti ◽  
L. F. Hernández
Keyword(s):  
Helianthus Annuus ◽  
Vascular System ◽  
Stomatal Density ◽  
Glandular Trichomes ◽  
Point Of View ◽  
Adaxial Side ◽  
Abaxial Side ◽  
Abaxial Epidermis ◽  
Functional Point ◽  
Secretory Ducts

AbstractThe anatomy of involucral bracts (IB) of the capitulum was studied in two sunflower domesticated primitive genotypes (Helianthus annuus L.), Havasupai and Hopi, HA89B line and DKOP3845 hybrid. Stomata and trichomes were counted on the adaxial and abaxial epidermis. In all cases the IB showed an one-layered adaxial and abaxial epidermis, secretory ducts and parenchymatic cells with abundant chloroplast. The vascular system was similar to that of the foliage leaves; however, their bundles were smaller, with an abaxial surface with higher abundance of glandular and non-glandular trichomes and with the presence of stomatas. IB of Havasupai and Hopi showed higher number of adaxial hypodermic strata than those of HA89B and DKOP3845 (4 vs. 1) and one mesophyllum with inverted polarity with respect to a foliage leaf: the presence of a spongy parenchyma on the adaxial side was observed with a rudimentary palisade parenchyma on the abaxial side. Stomatal density of the IB was significantly higher in Hopi and Havasupai than in HA89B and DKOP3845, with values ranging from 132 to 156 vs. 73 to 110 stomata/mm2 respectively. It is concluded that from the functional point of view, sunflower breeding produced undesired changes in the IB anatomy.

Surface and Internalized Escherichia coli O157:H7 on Field-Grown Spinach and Lettuce Treated with Spray-Contaminated Irrigation Water

2010 ◽  
Vol 73 (6) ◽  
pp. 1023-1029 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
CATHY C. WEBB ◽  
JUAN CARLOS DIAZ-PEREZ ◽  
SHARAD C. PHATAK ◽  
JOHN J. SILVOY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Irrigation Water ◽  
Enrichment Culture ◽  
Field Studies ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Contaminated Irrigation Water

Numerous field studies have revealed that irrigation water can contaminate the surface of plants; however, the occurrence of pathogen internalization is unclear. This study was conducted to determine the sites of Escherichia coli O157:H7 contamination and its survival when the bacteria were applied through spray irrigation water to either field-grown spinach or lettuce. To differentiate internalized and surface populations, leaves were treated with a surface disinfectant wash before the tissue was ground for analysis of E. coli O157:H7 by direct plate count or enrichment culture. Irrigation water containing E. coli O157:H7 at 102, 104, or 106 CFU/ml was applied to spinach 48 and 69 days after transplantation of seedlings into fields. E. coli O157:H7 was initially detected after application on the surface of plants dosed at 104 CFU/ml (4 of 20 samples) and both on the surface (17 of 20 samples) and internally (5 of 20 samples) of plants dosed at 106 CFU/ml. Seven days postspraying, all spinach leaves tested negative for surface or internal contamination. In a subsequent study, irrigation water containing E. coli O157:H7 at 108 CFU/ml was sprayed onto either the abaxial (lower) or adaxial (upper) side of leaves of field-grown lettuce under sunny or shaded conditions. E. coli O157:H7 was detectable on the leaf surface 27 days postspraying, but survival was higher on leaves sprayed on the abaxial side than on leaves sprayed on the adaxial side. Internalization of E. coli O157:H7 into lettuce leaves also occurred with greater persistence in leaves sprayed on the abaxial side (up to 14 days) than in leaves sprayed on the adaxial side (2 days).

The effect of temperature-dependent thermal parameters in thermal models of subduction zones

2021 ◽  
Author(s):  
Iris van Zelst ◽  
Timothy J. Craig ◽  
Cedric Thieulot
Keyword(s):  
Subduction Zones ◽  
Thermal Parameters ◽  
Dislocation Creep ◽  
Seismogenic Zone ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Thermal Models ◽  
Intermediate Depth ◽  
Dehydration Reactions ◽  
Model Setup

&lt;p&gt;The thermal structure of subduction zones plays an important role in the seismicity that occurs there with e.g., the downdip limit of the seismogenic zone associated with particular isotherms (350 &amp;#176;C - 450 &amp;#176;C) and intermediate-depth seismicity linked to dehydration reactions that occur at specific temperatures and pressures. Therefore, accurate thermal models of subduction zones that include the complexities found in laboratory studies are necessary. One of the often-ignored effects in models is the temperature-dependence of the thermal parameters such as the thermal conductivity, heat capacity, and density.&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;Here, we build upon the model setup presented by Van Keken et al., 2008 by including temperature-dependent thermal parameters to an otherwise clearly constrained, simple model setup of a subducting plate. We consider a fixed kinematic slab dipping at 45&amp;#176; and a stationary overriding plate with a dynamic mantle wedge. Such a simple setup allows us to isolate the effect of temperature-dependent thermal parameters. We add a more complex plate cooling model for the oceanic plate for consistency with the thermal parameters.&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;We test the effect of temperature-dependent thermal parameters on models with different rheologies, such as an isoviscous wedge, diffusion and dislocation creep. We find that slab temperatures can change by up to 65 &amp;#176;C which affects the location of isotherm depths. The downdip limit of the seismogenic zone defined by e.g., the 350 &amp;#176;C isotherm shifts by approximately 4 km, thereby increasing the maximum possible rupture area of the seismogenic zone. Similarly, the 600 &amp;#176;C isotherm is shifted approximately 30 km deeper, affecting the depth at which dehydration reactions and hence intermediate-depth seismicity occurs. Our results therefore show that temperature-dependent thermal parameters in thermal models of subduction zones cannot be ignored when studying subduction-related seismicity.&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt;

Lack of Internalization of Escherichia coli O157:H7 in Lettuce (Lactuca sativa L.) after Leaf Surface and Soil Inoculation

2009 ◽  
Vol 72 (10) ◽  
pp. 2028-2037 ◽  
Author(s):  
GUODONG ZHANG ◽  
LI MA ◽  
LARRY R. BEUCHAT ◽  
MARILYN C. ERICKSON ◽  
VANESSA H. PHELAN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Escherichia Coli O157 ◽  
Adaxial Side ◽  
Abaxial Side ◽  
E Coli ◽  
Lactuca Sativa L ◽  
Leaf Surfaces ◽  
Leaves And Roots ◽  
Leaf Lettuce

Survival and internalization characteristics of Escherichia coli O157:H7 in iceberg, romaine, and leaf lettuce after inoculation of leaf surfaces and soil were determined. A five-strain mixture of E. coli O157:H7 in water and cow manure extract was used as an inoculum for abaxial and adaxial sides of leaves at populations of 6 to 7 log and 4 log CFU per plant. The five strains were individually inoculated into soil at populations of 3 and 6 log CFU/g. Soil, leaves, and roots were analyzed for the presence and population of E. coli O157:H7. Ten (4.7%) of 212 samples of leaves inoculated on the adaxial side were positive for E. coli O157:H7, whereas 38 (17.9%) of 212 samples inoculated on the abaxial side were positive. E. coli O157:H7 survived for at least 25 days on leaf surfaces, with survival greater on the abaxial side of the leaves than on the adaxial side. All 212 rhizosphere samples and 424 surface-sanitized leaf and root samples from plants with inoculated leaves were negative for E. coli O157:H7, regardless of plant age at the time of inoculation or the location on the leaf receiving the inoculum. The pathogen survived in soil for at least 60 days. Five hundred ninety-eight (99.7%) of 600 surface-sanitized leaf and root samples from plants grown in inoculated soil were negative for E. coli O157:H7. Internalization of E. coli O157:H7 in lettuce leaves and roots did not occur, regardless of the type of lettuce, age of plants, or strain of E. coli O157:H7.

scholarly journals Leaf Morphoanatomy of Diploon Cronquist (Sapotaceae Juss.)

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Renata Gabriela Vila Nova de Lima ◽  
Liliane Ferreira Lima ◽  
Angélica Cândida Ferreira ◽  
Josiane Silva Araújo ◽  
Carmen Silvia Zickel
Keyword(s):  
Vascular System ◽  
Morphological Characteristics ◽  
Higher Order ◽  
External Morphology ◽  
Stalk Cell ◽  
Palisade Parenchyma ◽  
Abaxial Side ◽  
Abaxial Epidermis ◽  
Venation Pattern ◽  
Cell Layers

Abstract: Diploon is a monospecific genus represented by Diploon cuspidatum, an arboreal species that has morphological characteristics distinct from those of other Sapotaceae species. In this study, Diploon cuspidatum leaves were characterized morphoanatomically in order to reveal additional diagnostic characters of their external morphology of the genus. The Diploon petiole presents shape and arrangement of the vascular system flat-convex, occasionally with one or two accessory bundles, many laticifers, and many prismatic crystals. The midrib is biconvex with a U-shaped cuticle on the abaxial side, and laticifers are associated with the vascular tissues. Mesophyll is dorsiventral, palisade parenchyma has two cell layers, T- and Y-shaped malpighiaceous trichomes are on the abaxial epidermis with a small stalk cell and long arm. The venation pattern is brochidodromous. Intersecondary veins run parallel to the secondary veins, and quaternary veins branch freely. Higher order veins are not present. Morphoanatomical analysis revealed important characteristics that reveal a set of structures common to Sapotaceae, in addition to characters that are important for the recognition and identification of D. cuspidatum.

The Effect of Temperature Dependent Yield Strength on Upper Bounds for Creep Ratcheting

2006 ◽  
Author(s):  
Timothy E. McGreevy ◽  
Frederick A. Leckie ◽  
Peter Carter ◽  
Douglas L. Marriott
Keyword(s):  
Yield Strength ◽  
Upper Bounds ◽  
Effect Of Temperature ◽  
Strain Accumulation ◽  
Core Concept ◽  
Temperature Dependent ◽  
Inelastic Analysis ◽  
Asme Code ◽  
Inelastic Design ◽  
Very High

The Bree model and the elastic core concept have been used as the foundation for the simplified inelastic design analysis methods in the ASME Code for the design of components at elevated temperature for nearly three decades. The methodology provides upper bounds for creep strain accumulation and a physical basis for ascertaining if a structure under primary and secondary loading will behave elastically, plastically, shakedown, or ratchet. Comparisons of the method with inelastic analysis results have demonstrated its conservatism in stainless steel at temperatures representative of those in LMBR applications. The upper bounds on creep accumulation are revisited for very high temperatures representative of VHTR applications, where the yield strength of the material is strongly dependent upon temperature. The effect of the variation in yield strength on the evolution of the core stress is illustrated, and is shown to extend the shakedown regions, and affects the location of the boundaries between shakedown, ratcheting, and plasticity.

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