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Bibliografias temáticas / Mesophyll

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Literatura científica selecionada sobre o tema "Mesophyll"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 20 de fevereiro de 2023

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Artigos de revistas sobre o assunto "Mesophyll"

1

Sulistiarini, Diah, e Eka Fatmawati Tihurua. "Leaf Anatomy of Three Varians of Arundina graminifolia (D. Don.) Hochr". Jurnal Natur Indonesia 11, n.º 2 (20 de novembro de 2012): 78. http://dx.doi.org/10.31258/jnat.11.2.78-82.

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Three variations of Arundina graminifolia flowers have been recognized, (1) group of big flower with reddish violetlip and purplelish white sepals and petals (2) group of small flower with white lip and white sepals and petals (3)similar to second variation but with purple color on the lip apex. In order to clarify the taxonomy status of thosethree variations, a leaf anatomical study had been carried out. Results of this study showed that there were somedifferences among them in trichome shape and number mesophyll layers. Big flower group of Arundina hastrichome club shape and thick mucous in the apex with mesophyll layer 9-11; for small flower group has white lip,trichome club shape, thick mucous and granulate in the apex, but only 2 mesophyl layers; whereas for other smallflower group with purple lip has trichome cup shape and 10-13 layers of mesophyll. Based on the differences inflower size and their color variation, and combined with leaf anatomical study, we suggested the three variationsof A. graminifolia should be in separated groups.

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2

Liljebjelke, Karen A., e Vincent R. Franceschi. "Differentiation of Mesophyll and Paraveinal Mesophyll in Soybean Leaf". Botanical Gazette 152, n.º 1 (março de 1991): 34–41. http://dx.doi.org/10.1086/337860.

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3

Lersten, Nels R., e Curt L. Brubaker. "Paraveinal mesophyll, and its relationship to vein endings, in Solidago canadensis (Asteraceae)". Canadian Journal of Botany 67, n.º 5 (1 de maio de 1989): 1429–33. http://dx.doi.org/10.1139/b89-190.

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Paraveinal mesophyll is described from leaves of a common goldenrod species, Solidago canadensis L. (tribe Astereae). This is the first report of paraveinal mesophyll from the Asteraceae. It is a uniseriate middle layer consisting of horizontally lobed cells that form a lacy meshwork between veins. It abuts the tightly cylindrical bundle sheath at the level of the xylem in all vascular bundles. Vein endings, however, differ from other vascular bundles in two ways: sieve tube members may extend to the vein tip, end at an intermediate point, or be absent, and lateral bundle sheath cells distal to the terminal sieve tube member swell greatly or protrude horizontally and interdigitate with adjacent paraveinal mesophyll cells. Cells of both paraveinal mesophyll and bundle sheath have fewer and smaller chloroplasts than other mesophyll cells; the chloroplasts mostly lie adjacent to intercellular spaces. During leaf development, the paraveinal mesophyll layer differentiates before other mesophyll layers. Solidago canadensis paraveinal mesophyll resembles the well-studied paraveinal mesophyll of Glycine max, except for differences in its anatomical relationship to minor veins and vein endings.

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4

Kevekordes, K. G., M. E. McCully e M. J. Canny. "The occurrence of an extended bundle sheath system (paraveinal mesophyll) in the legumes". Canadian Journal of Botany 66, n.º 1 (1 de janeiro de 1988): 94–100. http://dx.doi.org/10.1139/b88-014.

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The tissue previously described as paraveinal mesophyll in soybean leaves is shown to have the characters of bundle sheath rather than mesophyll cells and is renamed "extended bundle sheath" (EBS) tissue. Its presence was surveyed by leaf clearing in 66 species of legumes of all three subfamilies. A complete extended bundle sheath system similar to that previously described in soybean was identified in 21 of the species. This system is a paradermally oriented tissue, one cell deep, between the spongy and palisade mesophylls, consisting of extended bundle sheath cells, which join each other across the interveinal space either directly or via bridging cells of somewhat similar shape and size. A newly recognized, attenuated extended bundle sheath system, in which bundle sheath cells extend but do not form a continuum except in very narrow interveinal spaces, is described; it was found in 32 species. Extended bundle sheath tissue was absent from 13 of the species. The presence or form of extended bundle sheath tissue does not follow traditional taxonomic divisions. Extended bundle sheath systems were also found in 3 of 5 nonlegume species.

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5

Kim, InSun, e David G. Fisher. "Structural aspects of the leaves of seven species of Portulaca growing in Hawaii". Canadian Journal of Botany 68, n.º 8 (1 de agosto de 1990): 1803–11. http://dx.doi.org/10.1139/b90-233.

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Seven species of Portulaca growing in Hawaii can be divided into two groups based on the morphology, anatomy, and ultrastructure of their leaves. Portulaca oleracea, P. molokiniensis, P. lutea, forming group A, have spatulate to obovate leaves, paradermal minor veins, and mesophyll cells that completely encircle the minor veins. The chloroplasts in their bundle sheath cells are larger than those in the mesophyll cells and have well-developed grana and reduced peripheral reticulum. Bundle sheath mitochondria are larger and more numerous than those in the mesophyll, and chloroplasts in the mesophyll cells have well-developed grana and peripheral reticulum. Portulaca pilosa, P. villosa, P. sclerocarpa, and P. "ulupalakua," forming group B, have lanceolate to oblong–oblanceolate leaves, peripheral minor veins, and incomplete wreaths of mesophyll cells. The choroplasts in their bundle sheath cells are about the same size as those in the mesophyll and have reduced grana and well-developed peripheral reticulum. The bundle sheath mitochondria are about the same in size and number as those in the mesophyll, and the mesophyll chloroplasts have well-developed grana and reduced peripheral reticulum. Groups A and B may be equivalent, respectively, to types ii and i of R. C. Carolin, S. W. L. Jacobs, and M. Vesk (Aust. J. Bot. 26: 683–698, 1978) and to coronary subtypes B and A of E. V. Voznesenskaya and Y. V. Gamalei (Bot. Zh. Leningrad, 71: 1291–1306, 1986), which constitute groupings of Portulaca species studied by those authors.

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6

Pshennikova, L. M. "The implication of leaf anatomical structure for the selective breeding of lilacs". Vavilov Journal of Genetics and Breeding 25, n.º 5 (10 de setembro de 2021): 534–42. http://dx.doi.org/10.18699/vj21.060.

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The cultivars of the common lilac (Syringa vulgaris) grown in the south of the Russian Far East are not always winter-hardy and are often damaged by fungal diseases due to a very humid climate. A promising trend in the selective breeding of lilacs in Russia is the creation of new breeding material based on the gene pool of the broadleaf lilac (S. oblata) and its hybrids in order to introduce valuable adaptive traits into cultivars. The present work aimed to identify the traits of leaf anatomy in species and cultivars of Syringa resistant and susceptible to Pseudocercospora lilacis, the causative agent of brown leaf spot disease. The study was carried out on the living collection of the Botanical Garden-Institute, Far Eastern Branch, Russian Academy of Sciences (Vladivostok). The leaf anatomical structure of two Syringa species showing different degrees of resistance to P. lilacis in the monsoon climate of the Far East (resistant S. oblata and weakly resistant S. vulgaris, and also their hybrid cultivars) has been analyzed. The differences between species, subspecies, and cultivars are quantitative: they differ in the number of spongy mesophyll layers, the cell height in the first layer of palisade mesophyll, the cell height in the upper and lower epidermises, and the thickness of both mesophylls. The interspecific hybrids resistant or weakly resistant to P. lilacis (brown leaf spot disease) mainly retain the leaf anatomy structure of the maternal plant. One of the traits determining the resistance of hybrid lilac cultivars is an increased number of spongy mesophyll layers in the leaf blade. The study of leaf anatomy has shown that the four-layered spongy mesophyll leaf parenchyma correlates with the resistance of lilacs from the subsection Euvulgaris to P. lilacis. In S. oblata, this trait is inherited down the maternal line. To establish lilac cultivars resistant to fungal diseases, it is advisable to cross the two species (S. oblata and S. vulgaris) or their cultivars using one of S. oblata subspecies as a maternal plant.

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7

Théroux-Rancourt, Guillaume, Adam B. Roddy, J. Mason Earles, Matthew E. Gilbert, Maciej A. Zwieniecki, C. Kevin Boyce, Danny Tholen, Andrew J. McElrone, Kevin A. Simonin e Craig R. Brodersen. "Maximum CO 2 diffusion inside leaves is limited by the scaling of cell size and genome size". Proceedings of the Royal Society B: Biological Sciences 288, n.º 1945 (24 de fevereiro de 2021): 20203145. http://dx.doi.org/10.1098/rspb.2020.3145.

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Maintaining high rates of photosynthesis in leaves requires efficient movement of CO 2 from the atmosphere to the mesophyll cells inside the leaf where CO 2 is converted into sugar. CO 2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to characterize because of their inherently three-dimensional organization. Yet faster CO 2 diffusion inside the leaf was probably critical in elevating rates of photosynthesis that occurred among angiosperm lineages. Here we characterize the three-dimensional surface area of the leaf mesophyll across vascular plants. We show that genome size determines the sizes and packing densities of cells in all leaf tissues and that smaller cells enable more mesophyll surface area to be packed into the leaf volume, facilitating higher CO 2 diffusion. Measurements and modelling revealed that the spongy mesophyll layer better facilitates gaseous phase diffusion while the palisade mesophyll layer better facilitates liquid-phase diffusion. Our results demonstrate that genome downsizing among the angiosperms was critical to restructuring the entire pathway of CO 2 diffusion into and through the leaf, maintaining high rates of CO 2 supply to the leaf mesophyll despite declining atmospheric CO 2 levels during the Cretaceous.

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8

Gibadulina, I. I., M. V. Larionov e N. N. Maslennikova. "Anatomical and Morphological Features of the Leaves of Tilia Cordata Mill. As an Indicator of the Adaptive Capabilities of the Species to the Conditions of the Urban Environment". IOP Conference Series: Earth and Environmental Science 988, n.º 3 (1 de fevereiro de 2022): 032082. http://dx.doi.org/10.1088/1755-1315/988/3/032082.

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Abstract Study of the anatomical and morphological features of the photosynthetic apparatus of Tilia cordata Mill. showed that the volume of leaf mesophyll cells in an urbanized environment is higher than in natural plantings. The cells of the palisade mesophyll of the leaf have a greater variability of this indicator during the growing season as compared to the cells of the spongy mesophyll. Positive correlations of the indicator of the volume of cells of the palisade mesophyll with the indicator of the air pollution index, the content of phenol, formaldehyde, benzo(a)pyrene and negative correlations with the content of nitrogen dioxide were noted. The indicator of the volume of cells of the leaf spongy mesophyll positively correlates only with the indicator of the atmospheric pollution index and the content of formaldehyde.

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9

Zvereva, G. K. "The structure of the mesophyll and assimilative apparatus of the chloridoid grasses leaves". Проблемы ботаники южной сибири и монголии 19, n.º 2 (8 de outubro de 2020): 202–6. http://dx.doi.org/10.14258/pbssm.2020103.

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The structure of the mesophyll and assimilative apparatus of leaf blades and leaf sheaths was studied atchloridoid grasses Aeluropus intermedius, Cleistogenes squarrosa, Crypsis aculeata and Tripogon chinensis, growing indifferent habitats of Siberia. All plant species are characterized by the manifestation of C4-coronary syndrome. Spatialforms of mesophyll cells radially arranged around Kranz cells and intercostal zone cells were considered. It is shown, thatleaf mesophyll at xerophytes Cleistogenes squarrosa and Tripogon chinensis is composed of cellular cells. At the grasses of saline habitats Aeluropus intermedius and Crypsis aculeata, a simplification of the shape of mesophyll cells is observed, primarily in the intercostal zone and to a greater extent, in leaf sheaths. According to the density of chloroplasts inthe leaf mesophyll, chloridoid С4-grasses approach to mesophytic and xeromesophytic С3-grasses.

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10

Fujita, Takashi, Ko Noguchi, Hiroshi Ozaki e Ichiro Terashima. "Confirmation of mesophyll signals controlling stomatal responses by a newly devised transplanting method". Functional Plant Biology 46, n.º 5 (2019): 467. http://dx.doi.org/10.1071/fp18250.

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There are opposing views on whether the responses of stomata to environmental stimuli are all autonomous reactions of stomatal guard cells or whether mesophyll is involved in these responses. Transplanting isolated epidermis onto mesophyll is a potent methodology for examining the roles of mesophyll-derived signals in stomatal responses. Here we report on development of a new transplanting method. Leaf segments of Commelina communis L. were pretreated in the light or dark at 10, 39 or 70Pa ambient CO2 for 1h. Then the abaxial epidermises were removed and the epidermal strips prepared from the other leaves kept in the dark at 39Pa CO2, were transplanted onto the mesophyll. After illumination of the transplants for 1h at 39Pa CO2, stomatal apertures were measured. We also examined the molecular sizes of the mesophyll signals by inserting the dialysis membrane permeable to molecules smaller than 100–500Da or 500–1000Da between the epidermis and mesophyll. Mesophyll pretreatments in the light at low CO2 partial pressures accelerated stomatal opening in the transplanted epidermal strips, whereas pretreatments at 70Pa CO2 suppressed stomatal opening. Insertion of these dialysis membranes did not suppress stomatal opening significantly at 10Pa CO2 in the light, whereas insertion of the 100–500Da membrane decelerated stomatal closure at high CO2. It is probable that the mesophyll signals inducing stomatal opening at low CO2 in the light would permeate both membranes, and that those inducing stomatal closure at high CO2 would not permeate the 100–500Da membrane. Possible signal compounds are discussed.

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Mais fontes

Teses / dissertações sobre o assunto "Mesophyll"

1

Sheard, J. P. "Glucose uptake by pea mesophyll protoplasts". Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235210.

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2

Lee, Joonsang. "Influence of the mesophyll on stomatal opening". Thesis, University of Aberdeen, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314415.

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This study shows that stomata in the isolated epidermis do not behave like those in the intact leaf and that the mesophyll plays an important role in the mechanism of stomatal opening over short periods. The results suggested that the opening of stomata in isolated epidermis was inferior to that in the intact leaf and was influenced by the concentration of KCl in the medium rather than by light. Stomatal opening in isolated epidermis of Commelina was not only insensitive to light but also unaffected by CO₂ in the medium containing 100 mol m^-3 KCl. The absence of an effect of light and CO₂ on the stomata in isolated epidermis and the evidence that they possessed the potential of those in the intact leaf to open wide, suggested that the mesophyll could be important in influencing stomatal opening in the intact leaf. The solution in which the mesophyll cells were incubated was separated by centrifugation. The medium from cells previously incubated in the light caused the stomata in the isolated epidermis to open but that from cells kept in the dark had no effect. Thus the stimulatory influence of the mesophyll cells in bringing about stomatal opening could be separated from the cells into solution. For ease of description it is tentatively suggested that the putative factor which promotes stomatal opening indicated by the results be called stomatin. Stomatin will be produced when the chloroplasts in the mesophyll are exposed to white light.

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3

Newell, Jane Marie. "Vacuole development in evacuolated oat mesophyll protoplasts". Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295919.

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4

Hörtensteiner, Stefan. "Re-formation of vacuoles in evacuolated tobacco mesophyll protoplasts /". [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10426.

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5

Stoll, Marion. "Aktivierende T-DNA-Mutagenese in Nicotiana-tabacum-Mesophyll-Protoplasten". [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96491638X.

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6

Shrestha, Arjina. "Variability in mesophyll conductance to CO2 in grain legumes". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17559.

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Mesophyll conductance (gm) limits the diffusion of CO2 from sub-stomatal cavities to the carboxylation site and is a significant limitation to photosynthesis. However, there is a lack of complete understanding of gm variability and its regulation under different environmental conditions, and relevant studies in grain legumes are scarce. My research projects aimed to characterize genetic variability in gm, to quantify the response of gm to short- and long-term environmental changes and to assess the relationship of gm with leaf water-use efficiency (WUE) in grain legumes. gm and leaf hydraulic conductance (Kleaf) were examined simultaneously under growth conditions to see if they show coordinated response. gm varied significantly among genotypes for most of the legumes studied, but the genotypes did not vary in cell wall and plasma membrane conductance (measured from the oxygen isotope method). gm responded to growth or measurement environments, increasing rapidly with increasing light intensity but decreasing under blue light. However, genotypes differed in their interactive response to water stress, light intensity and light quality. Rapid response of gm to changes in light intensity was affected by N source (N2-fixing or inorganic-N fed). Short-term temperature response of gm varied between species. Chloroplast membrane conductance varied among species and genotypes and with growth environment. Environmentally driven leaf anatomical traits were not the major factors determining gm, but genotypes differed in the degree to which leaf anatomy influenced gm. Our results did not show coordination between gm and Kleaf. gm was strongly associated with photosynthetic rate but not with stomatal conductance. The results of this project provide useful information for crop genetic improvement through gm in legumes under climate change scenarios. Increasing gm in legumes will increase photosynthetic rate and possibly WUE, when there is no increase in stomatal conductance.

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7

Vosloh, Daniel. "Subcellular compartmentation of primary carbon metabolism in mesophyll cells of Arabidopsis thaliana". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5553/.

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Metabolismus in Pflanzenzellen ist stark kompartimentiert. Viele Stoffwechselwege haben Reaktionen in mehr als einem Kompartiment. Zum Beispiel wird während der Photosynthese in pflanzlichen Mesophyllzellen Kohlenstoff in Form von Stärke in den Chloroplasten synthetisiert, während es im Zytosol in Form von Sacharose gebildet und in der Vakuole gespeichert wird. Diese Reaktionen sind strikt reguliert um ein Gleichgewicht der Kohlenstoffpools der verschiedenen Kompartimente aufrecht zu erhalten und die Energieversorgung aller Teile der Zelle für anabolische Reaktionen sicher zu stellen. Ich wende eine Methode an, bei der die Zellen unter nicht-wässrigen Bedingungen fraktioniert werden und daher der metabolische Status der während der Ernte herrschte über den ganzen Zeitraum der Auftrennung beibehalten wird. Durch die Kombination von nichtwässriger Fraktionierung und verschiedener Massenspektrometrietechniken (Flüssigchromotagraphie- und Gaschromotagraphie basierende Massenspekrometrie) ist es möglich die intrazelluläre Verteilung der meisten Intermediate des photosynthetischen Kohlenstoffstoffwechsels und der Produkte der nachgelagerten metabolischen Reaktionen zu bestimmen. Das Wissen über die in vivo Konzentrationen dieser Metabolite wurde genutzt um die Änderung der freien Gibbs Energie in vivo zu bestimmen. Mit Hilfe dessen kann bestimmt werden, welche Reaktion sich in einem Gleichgewichtszustand befinden und welche davon entfernt sind. Die Konzentration der Enzyme und der Km Werte wurden mit den Konzentrationen der Metabolite in vivo verglichen, um festzustellen, welche Enzyme substratlimitiert sind und somit sensitiv gegenüber Änderungen der Substratkonzentration sind. Verschiedene Intermediate des Calvin-Benson Zyklus sind gleichzeitig Substrate für andere Stoffwechselwege, als da wären Dihyroxyaceton-phosphat (DHAP, Saccharosesynthese), Fructose 6-phosphat (Fru6P, Stärkesynthese), Erythrose 4-phosphat (E4P, Shikimat Stoffwechselweg) und Ribose 5-phosphat (R5P, Nukleotidbiosynthese). Die Enzyme, die diese Intermediate verstoffwechseln, liegen an den Abzweigungspunkten zu diesen Stoffwechselwegen. Diese sind Trisose phosphat isomerase (DHAP), Transketolase (E4P), Sedoheptulose-1,7 biphosphat aldolase (E4P) und Ribose-5-phosphat isomerase (R5P), welche nicht mit ihren Substraten gesättigt sind, da die jeweilige Substratkonzentration geringer als der zugehörige Km Wert ist. Für metabolische Kontrolle bedeutet dies, dass diese Schritte am sensitivsten gegenüber Änderungen der Substratkonzentrationen sind. Im Gegensatz dazu sind die regulierten irreversiblen Schritte von Fructose-1,6.biphosphatase und Sedoheptulose-1,7-biphosphatase relativ insensitiv gegenüber Änderungen der Substratkonzentration. Für den Stoffwechselweg der Saccharosesynthese konnte gezeigt werden, dass die zytosolische Aldolase eine geringer Bindeseitenkonzentration als Substratkonzentration (DHAP) aufweist, und dass die Konzentration von Saccharose-6-phosphat geringer als der Km Wert des synthetisierenden Enzyms Saccharose-phosphatase ist. Sowohl die Saccharose-phosphat-synthase, also auch die Saccharose-phosphatase sind in vivo weit von einem Gleichgewichtszustand entfernt. In Wildtyp Arabidopsis thaliana Columbia-0 Blättern wurde der gesamte Pool von ADPGlc im Chloroplasten gefunden. Das Enzyme ADPGlc pyrophosphorylase ist im Chloroplasten lokalisiert und synthetisiert ADPGlc aus ATP und Glc1P. Dieses Verteilungsmuster spricht eindeutig gegen die Hypothese von Pozueta-Romero und Kollegen, dass ADPGlc im Zytosol durch ADP vermittelte Spaltung von Saccharose durch die Saccharose Synthase erzeugt wird. Basierend auf dieser Beobachtung und anderen veröffentlichten Ergebnissen wurde geschlußfolgert, dass der generell akzeptierte Stoffwechselweg der Stärkesynthese durch ADPGlc Produktion via ADPGlc pyrophosphorylase in den Chloroplasten korrekt ist, und die Hypothese des alternativen Stoffwechselweges unhaltbar ist. Innerhalb des Stoffwechselweges der Saccharosesynthsese wurde festgestellt, dass die Konzentration von ADPGlc geringer als der Km Wert des Stärkesynthase ist, was darauf hindeutet, dass das Enzym substratlimitiert ist. Eine generelle Beobachtung ist, dass viele Enzmye des Calvin-Benson Zyklus ähnliche Bindeseitenkonzentrationen wie Metabolitkonzentrationen aufweisen, wohingegen in den Synthesewegen von Saccharose und Stärke die Bindeseitenkonzentrationen der Enzyme viel geringer als die Metabolitkonzentrationen sind.
Metabolism in plant cells is highly compartmented, with many pathways involving reactions in more than one compartment. For example, during photosynthesis in leaf mesophyll cells, primary carbon fixation and starch synthesis take place in the chloroplast, whereas sucrose is synthesized in the cytosol and stored in the vacuole. These reactions are tightly regulated to keep a fine balance between the carbon pools of the different compartments and to fulfil the energy needs of the organelles. I applied a technique which fractionates the cells under non-aqueous conditions, whereby the metabolic state is frozen at the time of harvest and held in stasis throughout the fractionation procedure. With the combination of non-aqueous fractionation and mass spectrometry based metabolite measurements (LC-MS/MS, GC-MS) it was possible to investigate the intracellular distributions of the intermediates of photosynthetic carbon metabolism and its products in subsequent metabolic reactions. With the knowledge about the in vivo concentrations of these metabolites under steady state photosynthesis conditions it was possible to calculate the mass action ratio and change in Gibbs free energy in vivo for each reaction in the pathway, to determine which reactions are near equilibrium and which are far removed from equilibrium. The Km value and concentration of each enzyme were compared with the concentrations of its substrates in vivo to assess which reactions are substrate limited and so sensitive to changes in substrate concentration. Several intermediates of the Calvin-Benson cycle are substrates for other pathways, including dihydroxyacetone-phosphate (DHAP,sucrose synthesis), fructose 6-phosphate (Fru6P, starch synthesis), erythrose 4-phosphate (E4P,shikimate pathway) and ribose 5-phosphate (R5P, nucleotide synthesis). Several of the enzymes that metabolise these intermediates, and so lie at branch points in the pathway, are triose-phosphate isomerase (DHAP), transketolase (E4P, Fru6P), sedoheptulose-1,7-bisphosphate aldolase (E4P) and ribose-5-phosphate isomerase (R5P) are not saturated with their respective substrate as the metabolite concentration is lower than the respective Km value. In terms of metabolic control these are the steps that are most sensitive to changes in substrate availability, while the regulated irreversible reactions of fructose-1,6-bisphosphatase and sedoheptulose-1,7-bisphosphatase are relatively insensitive to changes in the concentrations of their substrates. In the pathway of sucrose synthesis it was shown that the concentration of the catalytic binding site of the cytosolic aldolase is lower than the substrate concentration of DHAP, and that the concentration of Suc6P is lower than the Km of sucrose-phosphatase for this substrate. Both the sucrose-phosphate synthase and sucrose-phosphatase reactions are far removed from equilibrium in vivo. In wild type A. thaliana Columbia-0 leaves, all of the ADPGlc was found to be localised in the chloroplasts. ADPglucose pyrophosphorylase is localised to the chloroplast and synthesises ADPGlc from ATP and Glc1P. This distribution argues strongly against the hypothesis proposed by Pozueta-Romero and colleagues that ADPGlc for starch synthesis is produced in the cytosol via ADP-mediated cleavage of sucrose by sucrose synthase. Based on this observation and other published data it was concluded that the generally accepted pathway of starch synthesis from ADPGlc produced by ADPglucose pyrophosphorylase in the chloroplasts is correct, and that the alternative pathway is untenable. Within the pathway of starch synthesis the concentration of ADPGlc was found to be well below the Km value of starch synthase for ADPGlc, indicating that the enzyme is substrate limited. A general finding in the comparison of the Calvin-Benson cycle with the synthesis pathways of sucrose and starch is that many enzymes in the Calvin Benson cycle have active binding site concentrations that are close to the metabolite concentrations, while for nearly all enzymes in the synthesis pathways the active binding site concentrations are much lower than the metabolite concentrations.

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8

Freiesleben, Konstanze. "Biosynthese der Luteolin-Glucuronide im Roggenprimärblatt-Mesophyll: Charakterisierung der Glucuronosyltransferasen". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971655162.

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9

Lin, Quan. "Differentiation of tracheary elements from mesophyll cells of Zinnia elegens L". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358693.

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10

Gillham, Malcolm C. "Biosysmetric studies on some mesophyll-feeding leafhoppers associated with trees and shrubs". Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375963.

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Mais fontes

Livros sobre o assunto "Mesophyll"

1

Morrison, Paul. Paul Morrison: Mésophylle = mesophyll. Grenoble: Magasin, 2003.

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2

Sheard, Jonathan P. Glucose uptake by pea mesophyll protoplasts. Norwich: University of East Anglia, 1988.

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McCutcheon, Steve L. Amino acid transport: The special case of a H/L-glutamate cotransport system in Asparagus sprengeri mesophyll cells. St. Catharines [Ont.]: Dept. of Biological Sciences, Brock University, 1987.

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4

Liljebjelke, Karen Anne. Paraveinal mesophyll differentiation and patterns of DNA and RNA synthesis during soybean leaf ontogeny. 1988.

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5

Mawson, Bruce Thomas. Thermal acclimation of photosynthesis in mesophyll and guard cell chloroplasts of the Arctic plant, "Saxifraga cernua". 1986.

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6

Krakat, Niclas. Molekularbiologische Erfassung Der Bakteriellen Diversitat in Mesophil Und Thermophil Betriebenen Biogasfermentern Mit Korrelation Zu Verfahrenstechnischen Prozessgrossen. Logos Verlag Berlin, 2012.

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7

Lugilde Yáñez, Juan, Ignacio Bárbara e Viviana Peña. Algas coralinas (Corallinophycidae, Rhodophyta) de Galicia y norte de Portugal. 2022^a ed. Servizo de Publicacións da UDC, 2022. http://dx.doi.org/10.17979/spudc.000004.

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Se muestra la diversidad de algas rojas coralinas del noroeste ibérico, mediante la integración de información de especies previamente conocidas con nuevos datos de trabajo experimental. La revisión bibliográfica y de material de herbario se combinó con la exploración del intermareal y submareal de 74 localidades en 6 provincias de Galicia y el norte de Portugal. Se seleccionaron 1300 especímenes, entre 2016 y 2020, que se procesaron mediante microscopía óptica, microscopía electrónica de barrido y análisis moleculares. Se han catalogado 46 especies de los órdenes Corallinales y Hapalidiales, que son descritas e ilustradas, aportando datos sobre morfología, reproducción, hábitat y distribución, así como una clave de identificación. Se aporta una introducción morfo-anatómica con los principales caracteres diagnóstico seleccionados para algas coralinas, además de información sobre la reproducción y hábitat de las especies en el área de estudio. Algunos géneros se han estudiado en detalle, como Jania y Phymatolithon, y se describen variaciones morfológicas para Jania longifurca, J. rubens, Phymatolithon lamii y P. lenormandii. Estudios moleculares permitieron detectar diversidad críptica en los géneros Lithophyllum, Lithothamnion, Phymatolithon y Mesophyllum. Finalmente, se plantean dudas sobre la existencia de seis especies en el noroeste ibérico (Boreolithon van-heurckii, Hydrolithon farinosum, Lithophyllum vickersiae, Leptophytum bisporum, Lithothamnion sonderi, Titanoderma cystoseirae).

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Capítulos de livros sobre o assunto "Mesophyll"

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Meyer, Y. "Mitotic Cycle of Mesophyll Protoplasts". In Proceedings in Life Sciences, 143–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-70144-3_17.

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Meyer, Yves, Yvette Chartier, Jean Grosset, Isabelle Marty, Christophe Brugidou, Paulo Marinho e Renata Rivera. "Gene Expression in Mesophyll Protoplasts". In Morphogenesis in Plants, 221–36. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1265-7_12.

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Meyer, Y., Y. Chartier e J. Grosset. "Why do Mesophyll Protoplasts Dedifferentiate?" In Progress in Plant Protoplast Research, 133–34. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2788-9_47.

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Sugiyama, Munetaka, e Hiroo Fukuda. "Zinnia mesophyll culture system to study xylogenesis". In Plant Tissue Culture Manual, 91–105. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0303-9_5.

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Wallin, A. "Isolation and Culture of Apple Mesophyll Protoplasts". In Progress in Plant Protoplast Research, 103–4. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2788-9_35.

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Jover, R., M. C. Brisa e J. Segura. "Factors Influencing Digitalis Obscura Mesophyll Protoplast Development". In Progress in Plant Protoplast Research, 111–12. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2788-9_39.

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Sugiyama, Munetaka, e Hiroo Fukuda. "Zinnia mesophyll culture system to study xylogenesis". In Plant Tissue Culture Manual, 1017–31. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0103-2_55.

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Genty, Bernard, Sylvie Meyer, Clément Piel, Franz Badeck e Rodolphe Liozon. "CO2 Diffusion Inside Leaf Mesophyll of Ligneous Plants". In Photosynthesis: Mechanisms and Effects, 3961–66. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_919.

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Uemoto, Kyohei, Takashi Araki e Motomu Endo. "Isolation of Arabidopsis Palisade and Spongy Mesophyll Cells". In Methods in Molecular Biology, 141–48. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8657-6_9.

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Nyman, Marie, e Anita Wallin. "Plant Regeneration from Strawberry (Fragaria Ananassa) Mesophyll Protoplasts". In Progress in Plant Protoplast Research, 101–2. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2788-9_34.

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Trabalhos de conferências sobre o assunto "Mesophyll"

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Zvereva, G. K. "The structure of the needles mesophyll in species of the Pinaceae family with flat leaves". In Problems of studying the vegetation cover of Siberia. TSU Press, 2020. http://dx.doi.org/10.17223/978-5-94621-927-3-2020-13.

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The spatial organization of mesophyll and three-dimensional forms of assimilative cells are considered on the example of 7 species of the Pinaceae family with flattened leaves: Abies cephalonica, A. concolor, A. sibirica, Larix sibirica, Picea omorica, Pseudotsuga menziesii and Tsida canadensis. It was shown that three types of mesophyll cells are distinguished in the flattened needles: palisade, spongy and median. Median cells are appreciable both with well-defined and weak differentiation of assimilative tissue; they can have simple and complex cellular forms.

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Zhang, Gaina. "Plant regeneration from mesophyll protoplasts of Radix Gentianae Macrophyllae". In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5966163.

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Korpiun, P., e B. Büchner. "Frequency dependence of the photothermal signal on mesophyll cell sizes of leaves". In PHOTOACOUSTIC AND PHOTOTHERMAL PHENOMENA. ASCE, 1999. http://dx.doi.org/10.1063/1.58146.

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Su, Poyu, Ting-Ying Lee e Szu-Yu Chen. "4D Two-photon Fluorescence Hyperspectral Image of Mesophyll Cells inside Intact Leaves". In Frontiers in Optics. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/fio.2015.jtu4a.85.

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Gataullina, M. O., A. E. Gribanova, D. N. Fedorin e A. T. Eprintsev. "Features of the functioning of malate dehydrogenase in corn mesophyll under different lighting conditions". In IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-115.

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Maleva, M. G., O. S. Sinenko, I. S. Kiseleva, D. Latowski e K. Strzałka. "REACTION OF PHOTOSYNTHETIC APPARATUS TO TEMPERATURE STRESS IN BARLEY MESOPHYLL CELLS OF DIFFERENT AGE". In The All-Russian Scientific Conference with International Participation and Schools of Young Scientists "Mechanisms of resistance of plants and microorganisms to unfavorable environmental". SIPPB SB RAS, 2018. http://dx.doi.org/10.31255/978-5-94797-319-8-496-500.

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Kim, Hyejeong, Kiwoong Kim e Sang Joon Lee. "Compact and Thermosensitive Micropump Inspired by Plant Leaf". In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69148.

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Liquid transportation without employing a bulky power source, often observed in nature, has been an essential prerequisite for smart applications of microfluidic devices. In this report, a leaf-inspired micropump (LIM) which is composed of thermo-responsive stomata inspired membrane (SIM) and mesophyll-inspired agarose cryogel (MAC) is proposed. The LIM provides a durable flow rate of 30 μl/ḣcm2 for more than 30 h at room temperature without external mechanical power source. By adapting a thermo-responsive polymer, the LIM can smartly adjust the delivery rate of a therapeutic liquid in response to temperature changes. In addition, as the LIM is compact, portable, and easily integrated into any liquid, it might be utilized as an essential component in advanced hand-held drug delivery devices.

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Cheryatova, Yu S. "Features of the anatomy of the leaves of Laurocerasus officinalis M. Roem." In Растениеводство и луговодство. Тимирязевская сельскохозяйственная академия, 2020. http://dx.doi.org/10.26897/978-5-9675-1762-4-2020-80.

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The article presents the results of microscopic analysis of the leaves of L. officinalis. The main anatomical and diagnostic features that can be used in identifying and evaluating the authenticity of medicinal plant raw materials are established. Analysis of the anatomical structure showed that the leaves of L. officinalis are dorsoventral; the leaf plastic is hypostomatic, and the stomatal apparatus is anomocytic. The main vein of the leaf blade and petiole is represented by a bicollateral conducting bundle. Idioblasts represented by round- shaped essential oil cells were first identified in the columnar and spongy mesophyll of the leaf and petiole. Single diamond-shaped crystals and calcium oxalate druses were also found in the leaves. The information obtained can serve as a basis for the development of the section "Microscopy" in the draft regulatory documentation.

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Valeriu Iancu, Valeriu, Laura Adriana Bucur, Verginica Schröder e Manuela Rossemary Apetroaei. "PRELIMINARY STUDIES RELATED TO MICROSCOPY AND THE SEDEM EXPERT SYSTEM PROFILE ON FREEZED-DRIED EXTRACT OF LYTHRI HERBA". In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b1/v3/16.

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"The floral tips of the plant species Lythrum salicaria L. represent a rich source of total polyphenols, among which with the largest share we mention tannins, and this is why this plant material has a standardized monograph in the European Pharmacopoeia 10.0th edition. According to the literature accessed so far, the plant material has antioxidant, anti-inflammatory, hemostatic, antibacterial and antifungal properties, along with modulatory action on carbohydrate metabolism. Powder microscopic examination is an important step in establishing the identity of the plant species used, highlighting elements specific to the aerial part such as spiral vessels of the stem, fragments of the spongy mesophyll with calcium oxalate clusters cells and anomocytic stomata. The application of the SeDeM method on dried plant extracts represents an innovative trend in pharmaceutical technology and contributes to the collection of data in a structured and standardized form. In this paper, the functions and applications of the SeDeM expert system are illustrated upon the freeze-dried extract of Lythri herba for the purpose of easier identification and standardization. Future applications may include obtaining chewable gums or tablets by direct compression."

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Röckmann, Thomas, Getachew Adnew, Thijs Pons, Gerbrand Koren e Wouter Peters. "Exploring the use of ¹⁷O-excess in CO₂ for estimating mesophyll conductance of C₃ and C₄ plants". In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.12010.

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Relatórios de organizações sobre o assunto "Mesophyll"

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Lu, P., W. H. Jr Outlaw, B. G. Smith e G. A. Freed. 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. Office of Scientific and Technical Information (OSTI), dezembro de 1996. http://dx.doi.org/10.2172/629405.

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Hochman, Ayala, Thomas Nash III e Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, janeiro de 2011. http://dx.doi.org/10.32747/2011.7697115.bard.

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Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.

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Bray, Elizabeth, Zvi Lerner e Alexander Poljakoff-Mayber. The Role of Phytohormones in the Response of Plants to Salinity Stress. United States Department of Agriculture, setembro de 1994. http://dx.doi.org/10.32747/1994.7613007.bard.

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Salinity is an increasing problem in many irrigated areas of crop production and is a significant factor in reducing crop productivity. Developmental, physiological, and molecular responses to salinity were studied in order to improve our understanding of these responses. Improvements in our understanding of plant responses to salinity are necessary in order to develop crops with improved salt tolerance. Previously, in Israel, it was shown that Sorghum biccolor can adapt to an otherwise lethal concentration of NaCl. These experiments were refined and it was shown that there is a specific window of development in which this adaption can occur. Past the window of development, Sorghum plants can not be adapted. In addition, the ability to adapt is not present in all genotypes of Sorghum. Cultivars that adapt have an increased coefficient of variation for many of the physiological parameters measured during the mid-phase of adaptation. Therefore, it is possible that the adaptation process does not occur identically in the entire population. A novel gene was identified, isolated and characterized from Sorghum that is induced in roots in response to salinity. This gene is expressed in roots in response to salt treatments, but it is not salt-induced in leaves. In leaves, the gene is expressed without a salt treatment. The gene encodes a proline-rich protein with a novel proline repeat, PEPK, repeated more than 50 times. An antibody produced to the PEPK repeat was used to show that the PEPK protein is present in the endodermal cell wall of the root during salt treatments. In the leaves, the protein is also found predominantly in the cell wall and is present mainly in the mesophyll cells. It is proposed that this protein is involved in the maintenance of solute concentration.

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Philosoph-Hadas, Sonia, Richard Crain, Shimon Meir, Nehemia Aharoni e Susan Lurie. Calcium-Mediated Signal Transduction during Leaf Senescence. United States Department of Agriculture, novembro de 1995. http://dx.doi.org/10.32747/1995.7604925.bard.

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We have examined the possibility that modulation of [Ca2+]cyt may represent a signal which induces senescence processes in leaves, through triggering of lipid hydrolysis leading to the cascade of detriorative events. Characterization of the signal transduction components operating during leaf senescence was gained by studying various Ca2+-dependent activities of parsley and chrysanthemum leaves, in relation to several senescence functions, and in response to senescence-modulating hormones (ethylene,ABA, BA and IAA). Some innovative findings regarding the control of senescence processes by [Ca2+]cyt were established: Several Ca2+-or CaM-related compounds were shown to modulate [Ca2+]cyt and action, thereby affecting whole leaf senescence. The involvement of [Ca2+]cyt in mediating the effects of senescence-modulating hormones has been demonstrated. Loss of energized Ca2+-transport capability of PM was found to an early event in leaf senescence, which occurs before changes in senescence parameters are observed, and while other PM ATPase enzymes still retain about 50% of their activities. A general pattern of increased phosphorylation of PM proteins with advanced senescence, which could be modified by plant hormones applied in vivo (BA) or in vitro (ABA), sa found. Taken together, all this indirect evidence indicate that [Ca2+]cyt is elevated due to the senescence-induced decrease in the ability to extrude Ca2+, which results particularly from reduced PM Ca2++-transport capability rather than increased operation of Ca2+ channels or elevated Ins(1,4,5)P3 levels. The direct proof for such a senescence-related elevation in [Ca2+]cyt was provided for the first time by the Ca2+ imaging measures with fura-2, showing a rise in [Ca2+]cyt of mesophyll cells upon senescence induction, which preceeded changes in typical senescence characteristics. This research provides strong evidence for regarding the rise in [Ca2+]cyt as a primary event in induction of the senescence syndrome in detached leaves. The findings have also broad implications for postharvest handling of leafy crops and ornamentals, and open new avenues for employing Ca2+-related inhibitors to delay leaf senescence.

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Shahak, Yosepha, e Donald R. Ort. Physiological Bases for Impaired Photosynthetic Performance of Chilling-Sensitive Fruit Trees. United States Department of Agriculture, maio de 2001. http://dx.doi.org/10.32747/2001.7575278.bard.

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Chilling-sensitivity is an important agricultural problem in both the U.S. and Israel. Most research attention has focused so far on herbaceous crop plants, even though the problem is also acute in the fruit tree industry. Under BARD funding we made substantial progress in identifying the mechanisms involved in the disruption of photosynthesis following a chill in mango. Our investigation with fruit trees has been substantially accelerated by drawing on our knowledge and experience with herbaceous crops. The four original research objectives, focused or discovering the underlying mechanisms of chill-induced inhibition of photosynthesis in fruit trees, and the main achievements are listed below. [1] Separating stomatal from non-stomatal components of chilling on photosynthesis in fruit trees. We found evidence that the dark chill-induced inhibition of photosynthesis in mango was E combination of both stomatal and mesophyll components. [2] Differentiating photo damage from light-induced photo protection of photosystem II (PSII). Dark chilling exacerbate high light photoinhibition, as a result of primary inhibition in the carbor reduction cycle. Nevertheless, in Israeli orchards we observed chronic photoinhibition of PSII photochemistry in the winter. This photo damage was reversible over a few days if sunlight was attenuated with filters or night temperature rose. Practical implications of this finding deserve further investment. Additional achievement was the development of a new biophysical tool to study macro-structural changes of LHCII particles in intact, attached leaves. [3] Determine the role of oxidative stress in the dark-chilling-induced inhibition, with emphasis on oxygen radical scavenging, lipid peroxidation and redox-controlled carbon-cycle enzymes. We found an increase in lipid peroxidation following a dark chill, and partial protective effects or an antioxidant. However, the photoinhibition observed in mango orchards in Israel during the winter did not appear to be a general oxidative stress. [4] Investigate whether chilling interferes with the diurnal and circadian rhythm of gene expression of key photosynthetic proteins as has been shown for chilling-sensitive crop plants. The results indicated that most of the circadian rhythm in photosynthesis was due to reduced lea: internal CO2 concentrations during the subjective night, as a result of rhythmic stomatal closure Chilling-induced interference with circadian timing in mango, does not play the central role in chilling inhibition of photosynthesis that has previously been demonstrated in certain chilling sensitive herbaceous plants. Practical implications of the research achievements are feasible, but require few more years of research.

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Pell, Eva J., Sarah M. Assmann, Amnon Schwartz e Hava Steinberger. Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis. United States Department of Agriculture, dezembro de 2000. http://dx.doi.org/10.32747/2000.7573082.bard.

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Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.

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